WO2005005571A1

WO2005005571A1 - Colour changing media for light emitting display devices

Info

Publication number: WO2005005571A1
Application number: PCT/EP2004/051294
Authority: WO
Inventors: Hiroshi Yamamoto; Norihisa Dan
Original assignee: Ciba Specialty Chemicals Holding Inc.
Priority date: 2003-07-09
Filing date: 2004-06-30
Publication date: 2005-01-20
Also published as: TW200502357A

Abstract

The present invention relates to electroluminescent elements comprising an organic or inorganic electroluminescent material part which emits a blue light and at least one fluorescent material part which absorbs said blue light and emits a fluorescence in a visible light range from bluish green to red light said fluorescent material part exists outside of the electroluminescent material part and comprises a diketopyrrolopyrrole compound.

Description

COLOUR CHANGING MEDIA FOR LIGHT EMITTING DISPLAY DEVICES

Organic electroluminescent devices, also known as organic light emitting diode ("OLED") devices, have been known for approximately two decades. All OL-EDs work on the same general principles. One or more layers of semi-conducting organic material are sandwiched between two electrodes, an anode and a cathode. An electric current is applied to the device, causing electrons to move into the organic material(s) from the cathode and positive charges, typically referred to as holes, to move into the organic material(s) from the anode. The positive and negative charges recombine in the electroluminescent medium (i. e., the emitter layer) and produce photons. The wavelength of the photons, and consequently the color of the emitted light, depends on the electronic properties of the organic materials in which the photons are generated.

Therefore, the color of light emitted from an OLED device may be controlled by the selection of the organic materials in the emitter layer. Specifically, the precise color of emitted light can be controlled by the selection of host materials and dopants in the emitter layer. In addition, color filters and color changing media may be used to alter the color of light emitted from the emitter layer of an OLED.

An OLED display may be monochromatic, that is, each pixel comprising the display emits light of the same color. Alternatively, various pixels of an OLED display may emit different colors. A full-color OLED display is formed from an array of pixels comprising a red, a green and a blue sub-pixel. The sub-pixels in any particular pixel can be activated in various combinations to generate an entire spectrum of colors.

A second approach for making full-color OLED displays employs OLEDs that emit white light combined with color filters that are precisely aligned over each OLED. Certain wavelengths of light are filtered out by the filters, with the result that the various color filters generate red, green and blue light for the sub-pixels. The use of color filters can be inefficient, however, because the filters inevitably absorb some light. A third approach for making full-color OLED displays is to use a monochromatic OLED array with color changing materials (instead of color filters) aligned on top of the pixels. Color changing materials work by absorbing light of shorter wavelength (e. g., blue light) and then emitting light of longer wavelength by fluorescence or phosphorescence

(photoluminescence) (e. g., red or green light). The use of color changing materials is known in the art (see e. g., US-B-5, 126,214 (Idemitsu Kosan Co., Ltd.) and US-B-5,294,870 (Eastman Kodak Co.)).

All pixels emit the same color and the filter media can be patterned and aligned with each OLED to form the different color sub-pixels. When the relevant layers have high quantum efficiency of photoluminescence and internal losses are minimized, the third approach provides higher efficiency.

Nevertheless, the use of color changing materials also has drawbacks. Most materials used as color changing materials have broad emission photoluminescence spectra that require the use of optical filters for spectral correction, i. e., to insure that each sub-pixel emits red, green or blue light in a narrow wavelength range. The use of optical filters in addition to the color changing materials may introduce additional loss of intensity of emitted light.

There is clearly a need for a color changing materials for high-resolution, full-color OLED display devices.

Accordingly the present invention relates to an electroluminescent element comprising an organic or inorganic electroluminescent material part which emits a blue light and at least one fluorescent material part which absorbs said blue light and emits a fluorescence in a visible light range from bluish green to red light said fluorescent material part exists outside of the electroluminescent material part and comprises a diketopyrrolopyrrole compound.

The diketopyrrolopyrrole compounds are characterized by a high absorption coefficient and a high fluorescence quantum yield.

The diketopyrrolopyrrole is generally a compound of formula

wherein

R¹ and R² are independently of each other an organic group, and

Ar¹ and Ar² are independently of each other an aryl group or an heteroaryl group, which can be substituted.

R¹ and R²may be the same or different and are preferably selected from a C C₂₅alkyl group, which can be substituted by fluorine, chlorine or bromine, an allyl group, which can be substituted one to three times with CrC₄alkyl, a cycloalkyl group, or a cycloalkyl group, which can be condensed one or two times by phenyl which can be substituted one to three times with Cι-C₄-alkyl, halogen, nitro or cyano, an alkenyl group, a cycloalkenyl group, an alkynyl group, a haloalkyl group, a haloalkenyl group, a haloalkynyl group, a group Y-R³², a silyl group, a siloxanyl group, -X²-X³, A² or -CR⁷³R⁷⁴-(CH₂)_m-A², wherein R⁷³ and R⁷⁴ independently from each other stand for hydrogen or d-C₄alkyl, or phenyl which can be substituted one to three times with Cι-C alkyl, Y, R³², X² and X³ are as defined below, and

A² stands for aryl or heteroaryl, in particular phenyl or 1- or 2-naphthyl which can be substituted one to three times with CrC₈alkyl and/or C-ι-C₈alkoxy, and m stands for 0, 1 , 2, 3 or 4.

Ar¹ and Ar²can be different, but preferably have the same meaning.

If Ar¹ and Ar² are an aryl group, they are preferably a group of formula

, wherein R⁵⁵, R⁵⁶, and R⁵⁷ independently from each other stands for hydrogen, Cι-C₂₅-alkyl, C₁-C₂₅- alkoxy, -CR⁶ R⁶²-(CH₂)_m-A¹ _J cyano, halogen, -OR⁵⁹, -S(O)_pR⁶⁰, -X¹-X²-X³, or phenyl, which can be substituted one to three times with C C₈alkyl or CrC₈alkoxy, wherein

A¹ stands for aryl or heteroaryl, in particular phenyl or 1 - or 2-naphthyl, which can be substituted one to three times with C C₈alkyl and/or CrC₈alkoxy,

R⁶⁸ stands for C₂-C₂o-heteroaryl, or C₆-C₂₄-aryl,

R⁵⁹ stands for Cι-C₂₅-alkyl, C₅-Cι₂-cycloalkyl, -CR⁶ R⁶²-(CH₂)_m-Ph, C₆-C₂ -aryl, or a saturated or unsaturated heterocyclic radical comprising five to seven ring atoms, wherein the ring consists of carbon atoms and one to three hetero atoms selected from the group consisting of nitrogen, oxygen and sulfur,

R⁶⁰ stands for Cι-C₂₅-alkyl, C₅-Cι₂-cycloalkyl, -CR⁶¹R⁶²-(CH₂)_m-Ph,

R⁶¹ and R⁶² independently from each other stand for hydrogen, fluorine, chlorine, bromine, cyano or C C₄alkyl, which can be substituted by fluorine, chlorine or bromine, or phenyl which can be substituted one to three times with d-C alkyl, p stands for 0, 1, 2 or 3, m and n stands for 0, 1, 2, 3 or 4, or

Ar¹ and Ar² independently from each other stand for

R⁶³ and R⁶⁴ independently from each other stand for hydrogen, -X¹-X²-X³, or C₆-C₂ -aryl, in particular phenyl,

R⁶⁵ and R⁶⁶ independently from each other stands for hydrogen, Cι-C₂₅-alkyl, Cι-C₂₅- alkoxy, -CR⁶¹R⁶²-(CH₂)_m-A¹, cyano, halogen, -OR⁵⁹, -S(O)_pR⁶⁰, -X¹-X²-X³, or phenyl, which can be substituted one to three times with C -C₈alkyl or Gι-C₈alkoxy,

R⁶⁸ and R⁶⁹ independently from each other stand for hydrogen, Gι-C₂₅-al yl, G5-C12- cycloalkyl, -CR⁶¹R⁶²-(CH₂)_m-A¹, C₆-C₂ -aryl, in particular A¹, or a saturated or unsaturated heterocyclic radical comprising five to seven ring atoms, wherein the ring consists of carbon atoms and one to three hetero atoms selected from the group consisting of nitrogen, oxygen and sulfur, or R⁶⁸ and R⁶⁹ together with the nitrogen atom to which they are bonded form a five or six membered heterocyclic ring which can be condensed by one or two optionally

substituted phenyl groups, such as

, wherein A¹, R⁵⁹, R⁶⁰, R⁶¹, R⁶², p and m are as defined above and X¹, X² and X³ are as defined below.

Fluorescent diketopyrrolopyrroles (including compositions and polymers) of formula I, which are suitable for the use as color changing material, are known and are described, for example, in EP-A-0133156, US-A- ,585,878,EP-A-0353184, EP-A-0787730, WO98/25927, US-A-5,919,944, EP-A-0787731, EP-A-0811625, WO98/25927, EP-A-1087005, EP-A- 1087006, WO03/002672, WO03/022848, PCT/EP03/00650, PCT/EP03/07638, and PCT/EP2004/050403, H. Langhals et al. Liebigs Ann. 1996, 679-682:

In a preferred embodiment, the diketopyrrolopyrrole compound is a compound the absoption peak of which is in the range of from about 440 to about 490 nm, especially of from about 450 to about 480 n , and which shows photoluminescence the peak of which is in the range of from about 510 to about 550 nm, especially from about 520 to about 540 nm, i.e. a blue-to- green color changing material (A) ("blue-to-green CCM").

In said embodiment, the diketopyrrolopyrrole is preferably a compound of formula

(I), wherein

R¹ and R² are independently of each other a C^-alkyl group, a C₂-₂ -alkenyl group, Ar⁷, especially phenyl which can be substituted up to three times with CrC₈alkyl, or a group of formula -CR³⁰R³¹-(CH₂)_m-Ar⁷or Y-R³², wherein R³⁰ and R³¹ independently of each other stand for hydrogen, or CrC₄alkyl, or phenyl which can be substituted up to three times with d- C₄alkyl,

Ar⁷ stands for aryl, C₅-C₈cycloalkyl, C₅-C₈cycloalkenyl or heteroaryl, which can be substituted one to three times with CrC₈alkyl, C C₈alkoxy- cyano, halogen or phenyl, which can be substituted with Cι-C₈alkyl or CrC₈alkoxy one to three times, m stands for 0, 1, 2, 3 or 4, Y is -C(O)-, -C(O)O-, -C(O)NH-, -SO₂NH- or -SO₂- and

R³² is CrC₁₈alkyl, Ar⁷, or aralkyl, or R¹ and R² are independently of each other a group -X²-X³,

Ar¹ and Ar² are independently of each other a group of formula

, w ,herein R³, R⁴ and R° are independently of each other a hydrogen atom, a

group, a C-i

Cι₈-alkoxy group, a fluorine atom, a chlorine atom, or a group -X¹-X²-X³, wherein

X¹ is -O-, -S-, -NH-, -CONH-, -COO-, -SO₂-NH-, or -SO₂-O-,

X² is an alkylene, arylene, aralkylene or cycloalkylene spacer containing optionally one or more groups -0-, -S-, -NR¹⁴-, -CO-, -CONH-, -CONR¹⁵-, or -COO- as linking bridge, X³ is OH, WH₂, -C(R¹¹)=CH₂, -OC(O)-C(R¹²)=CH₂, -C(O)-C(R¹²)=CH₂, C₅-C₇cycloalkenyl,

-OC(O)-N-X⁴-N-C(O)-O-X⁵-O-C(O)-C(R¹ )=CH₂ ; wherein R¹¹ is hydrogen, C C₄alkyl, or halogen, R ² is hydrogen, C C₄alkyl, or halogen, R¹³ is hydrogen, Cι-C₄alkyl, or G₆-Cι₂aryl,

R¹⁴ and R¹⁵ are independently of each other hydrogen, Cι-C₈alkyl, or C₆-Ci₂aryl, and X⁴ and X⁵ are independently of each other an alkylene, arylene, aralkylene or cycloalkylene spacer.

Ar¹ and Ar² are preferably the same and selected from the following groups:

or , wherein

R⁸¹, R⁸² and R⁸⁴ are a hydrogen atom and R⁸³ is a C-,-₈-alkyl group, a fluorine atom, or a chlorine atom, or

R⁸³, R⁸² and R⁸⁴ are a hydrogen atom and R⁸¹ is a Cι-₈-alkoxy group, or R⁸³, R⁸¹ and R⁸⁴ are a hydrogen atom and R⁸² is a C^-alkoxy group, or a C_1-3-alkyl group, or R⁸² and R⁸⁴ are a chlorine atom and R⁸¹ and R⁸³ are a hydrogen atom, and R⁸⁵ is a d-s-alkyl group.

The light-emitting compounds I usually exhibit a fluorescence quantum yield ("FQN') in the range of from 1 > FQY > 0.3 (measured in toluene). Further, in general, the compounds I exhibit a molar absorption coefficient in the range of from 5000 to 100000. The molar absorption coefficient and quantum yield of exemplary compounds of formula I are shown below:

The absorbance spectra are measured on a U-3300 spectrophotometer (Hitachi, Ltd.) and the fluorescence spectra on a F-4500 Fluorescence spectrophotometer (Hitachi, Ltd.). The measurements are carried out with a solution of toluene containing 0J-0.05 % by weight of the DPP compounds.

In a further embodiment, the diketopyrrolopyrrole compound is a compound the absorption of which is in the range of from about 440 to about 500 nm, especially in the range of from about 450 to about 490 nm, and which shows photoluminescence the peak of which is in the range of from 530 to 570 nm, especially in the range of from 540 to 570 nm, and is used in combination with a fluorescent compound the absorption peak of which is in the range of from about 530 to about 570 nm and which shows photoluminescence the peak of which is in the range of from about 580 to about 650 nm.

In this embodiment, the diketopyrrolopyrrole is preferably either a compound of formula (I) which shows photoluminescence the peak of which is in the range of from about 530 to about 550 nm or a compound of formula

wherein

R²¹ and R²² are independently of each other a d-₂₄-alkyl group, a C_2-24-alkenyl group, a group of formula -CR³⁰R³¹-(CH₂)_m-Ar⁷orY-R³², wherein R³⁰ and R³¹ independently of each other stand for hydrogen, or C₁-C alkyl, or phenyl which can be substituted up to three times with d-C₄alkyl,

Ar⁷ stands for aryl, C₅-C₈cycloalkyl, C₅-C₈cycloalkenyl or heteroaryl, which can be substituted one to three times with d-C₈alkyl, d-C₈alkoxy, cyano, halogen or phenyl, which can be substituted with d-C₈alkyl or d-C₈alkoxy one to three times, m stands for 0, 1 , 2, 3 or 4, Y is -C(O)-, -C(O)O-, -C(O)NH-, -SO₂NH- or -SO₂- and R³² is C C₁₈alkyl, Ar⁷, or aralkyl, or a group of the formula -X²-X³, Ar³ and Ar⁴ are independently of each other a group of formula

. or , wherein

R⁴¹, R⁴², R⁴⁴, R ^■54⁴5⁶, r R->₄ ⁴6⁶, R⁴⁷ and R⁴⁸ are independently of each other a hydrogen atom, a Cι.

Cι₈-alkyl group, a Cι-Cι₈-alkoxy group, or a group -X¹-X²-X³,

R⁴³ is a cyano group, a bromine atom, or a phenoxy group which can be substituted one to three times with d-C₈alkyl, or d-dalkoxy, or

R⁴³ is a hydrogen atom, or a Cι-C₈alkyl group, if Ar³ is not identical to Ar⁴, and

R⁴⁹ is hydrogen, or a phenyl group which can be substituted one to three times with d-

Csalkyl, or d-C₈alkoxy, wherein

X¹ is -O-, -S-, -NH-, -C NH-, -COO-, -SO₂-NH-, or -SO₂-O-,

X² is an alkylene, arylene, aralkylene or cycloalkylene spacer containing optionally one or more groups -O-, -S-, -NR¹⁴-, -CO-, -CONH-, -CONR¹⁵-, or -COO- as linking bridge,

X³ is OH, NH₂, -C(R¹¹)=CH₂, -OC(0)-C(R¹²)=CH₂, -C(O)-C(R¹²)=CH₂, C₅-C₇cycloalkenyl,

-OC(O)-N-X⁴-N-C(O)-O-X⁵-O-C(O)-C(R¹ )=CH₂ ; wherein R¹¹ is hydrogen, C C alkyl, or halogen, R¹² is hydrogen, d-C₄alkyl, or halogen,

R¹³ is hydrogen, Cι-C₄alkyl, or C₆-Cι₂aryl,

R¹⁴ and R¹⁵ are independently of each other hydrogen, d-C₈alkyl, or C₆-d₂aryl, and

X⁴ and X⁵ are independently of each other an alkylene, arylene, aralkylene or cycloalkylene spacer.

Ar³ and Ar⁴ are preferably the same and selected from the following groups:

, wherein

R⁸⁶ is a C_1-8-alkyl group and R⁸⁷ is a bromine atom, or R⁸⁶ is a cyano group and R⁸⁷ is a hydrogen atom, R⁸⁸ is a d-₈-alkoxy group, R⁸⁹ is a hydrogen atom, or a phenyl group, and R⁹⁰is a hydrogen atom, or a d-₈-alkyl group.

The light-emitting compounds II usually exhibit a fluorescence quantum yield ("FQY") in the range of from 1 > FQY > 0.3 (measured in toluene). Further, in general, the compounds II exhibit a molar absorption coefficient in the range of from 5000 to 100000. The molar absorption coefficient and quantum yield of exemplary compounds of formula II are shown below:

The diketopyrrolopyrrole compound of formula II or alternatively formula I is used in this case with a fluorescent compound the absorption peak of which is in the range of from about 530 to about 570 nm and which shows photoluminescence the peak of which is in the range of from about 580 to about 650 nm, i.e. a red fluorescent compound. Examples of such compounds are: diketopyrrolopyrrole compounds of formula III described below, cyanine dyes, such as DCM and DCJTB, Rhodamine dyes, such as Rhodamine B and Rhodamine 6G, pyridinium salt dyes, and oxazine dyes.

In a further embodiment, the diketopyrrolopyrrole compound is a compound the absorption peak of which is in the range of from about 530 to about 570 nm, especially in the range of from about 540 to about 560 nm, and which shows photoluminescence the peak of which is in the range of from about 580 to about 650 nm, especially in the range of from 590 to 630 nm, and is used in combination with a fluorescent compound the absorption peak of which is in the range of from about 440 to about 500 nm and which shows photoluminescence the peak of which is in the range of from about 530 to about 570 nm.

In this embodiment, the diketopyrrolopyrrole is preferably a compound of formula

wherein

R²³ and R²⁴ are independently of each other a C_1-24-alkyl group, a C₂-₂₄-alkenyl group, a group of formula -CR³⁰R³ -(CH₂)_m-Ar⁷orY-R³², wherein R³⁰ and R³¹ independently of each other stand for hydrogen, or Cι-C alkyl, or phenyl which can be substituted up to three times with d-dalkyl,

Ar⁷ stands for aryl, C₅-C₈cycloalkyl, C₅-C₈cycloalkenyl or heteroaryl, which can be substituted one to three times with d-C₈alkyl, C C₈alkoxy, cyano, halogen or phenyl, which can be substituted with d-C₈alkyl or C C₈alkoxy one to three times, m stands for 0, 1 , 2, 3 or 4, Y is -C(O)-, -C(O)O-, -C(O)NH-, -SO₂NH- or -SO₂- and R³² is Cι-C₁₈alkyl, Ar⁷, or aralkyl, or a group -X²-X³, wherein

X² is an alkylene, arylene, aralkylene or cycloalkylene spacer containing optionally one or more groups -O-, -S-, -NR¹⁴-, -CO-, -CONH-, -CONR¹⁵-, or -COO- as linking bridge, X³ is OH, NH₂, -C(R¹¹)=CH₂, -OC(0)-C(R¹²)=CH₂, -C(O)-C(R¹²)=CH₂, C₅-C₇cycloalkenyl,

-OC(O)-N-X⁴-N-C(O)-O-X°-O-C(O)-C(R¹ =CH₂ ; wherein

R¹ s hydrogen, or Cι-C alkyl, or halogen, R 12 is hydrogen, d-G alkyl, or halogen,

R 13 is hydrogen, CrC alkyl, or C₆-C₁₂aryl, R¹⁴ and R¹⁵ are independently of each other hydrogen, d-C₈alkyl, or C₆-Cι₂aryl, X⁴ and X⁵ are independently of each other an alkylene, arylene, aralkylene or cycloalkylene spacer,

Ar⁵ and Ar⁶ are independently of each other a group of formula

wherein R and R are independently of each other a C C₂₄alkyl group,

or a group of formula

or wherein R ^■>29 , _D R3⁴0^U and R^dη are independently of each other hydrogen, C C₈alkyl, C C₈alkoxy

or a group -NR³²R³³, wherein R³² and R³³ are independently of each other

or

, wherein R³⁴ is hydrogen, Cι-C₈alkyl or d-C₈alkoxy, R⁴¹ is a hydrogen atom, a d.C₁₃-alkyl group, a Cι-Ci₈-alkoxy group, or a group -X¹-X -X³ , wherein

X¹ is -O-, -S-, -NH-, -CONH-, -COO-, -SO₂-NH-, or -SO₂-O-,

X² is an alkylene, arylene, aralkylene or cycloalkylene spacer containing optionally one or more groups -O-, -S-, -NR¹⁴-, -CO-, -CONH-, -CONR¹⁵-, or -COO- as linking bridge, X³ is OH, NH₂, -C(R¹¹)=CH₂, -OC(O)-C(R¹²)=CH₂, -C(0)-C(R¹²)=CH₂, C₅-C₇cycloalkenyl,

; wherein

R¹¹ is hydrogen, d-C₄alkyl, or halogen, R¹² is hydrogen, d-C₄alkyl, or halogen, R¹³ is hydrogen, C C₄alkyl, or C₆-C₁₂aryl, R¹⁴ and R¹⁵ are independently of each other hydrogen, Ci-Csalkyl, or C₆-Cι₂aryl, and X⁴ and X⁵ are independently of each other an alkylene, arylene, aralkylene or cycloalkylene

spacer, or R and R s19 together form a five or six membered ring, in particular -O

Compounds of formula 111, wherei

are independently of each other a group of formula

, wherein

are especially preferred and the following compounds are most preferred:

The light-emitting compounds III usually exhibit a fluorescence quantum yield ("FQY') in the range of from 1 > FQY > 0.3 (measured in toluene). Further, in general, the compounds III exhibit a molar absorption coefficient in the range of from 5000 to 100000. The molar absorption coefficient and quantum yield of exemplary compounds of formula III are shown below:

The diketopyrrolopyrrole compound of formula III is used in this case with a fluorescent compound the absorption peak of which is in the range of from about 440 to about 500 nm and which shows photoluminescence the peak of which is in the range of from about 530 to about 570 nm, i.e. a yellow-green fluorescent compound. Examples of such compounds are: diketopyrrolopyrrole compounds of formula I or II described above, Coumarin dyes, such as Coumarin 5, Coumarin 7, Coumarin 30, Coumarin 153, and naphthalimide dyes, such as solvent yellow 11 and solvent yellow 116. If a diketopyrrolopyrrole compound of formula III is used with a diketopyrrolopyrrole compound of formula I or II the following combinations are especially preferred: Compound of Formula I Compound of Formula

The term "halogen" is generally iodine, fluorine, bromine or chlorine, preferably bromine or chlorine.

In a further embodiment the diketopyrrolopyrrole compound is a compound the absorption of which is in the range of from about 500 to about 530 nm, especially in the range of from about 500 to about 520 nrn, and which shows photoluminescence the peak of which is in the range of from 540 to 600 nm, especially in the range of from 550 to 580 nm, and is used in combination with a fluorescent compound the absorption peak of which is in the range of from about 530 to about 570 nm and which shows photoluminescence the peak of which is in the range of from about 580 to about 650 nm, and optionally with a fluorescent compound the absorption peak of which is in the range of from about 440 to about 500 nm and which shows photoluminescence the peak of which is in the range of from about 530 to about 570 nm.

In this embodiment the diketopyrrolopyrrole is preferably a compound of formula

R⁹ and R⁹² are independently of each other a C C₂ alkyl group, a C₂-C₂₄alkenyl group, a group of formula -CR³⁰R³¹-(CH₂)_m-Ar⁷orY-R³², wherein R³⁰ and R³¹ independently of each other stand for hydrogen, or C C₄alkyl, or phenyl which can be substituted up to three times with d-dalkyl,

Ar⁷ stands for C₆-C₂ aryl, C₅-C₈cycloalkyl, C₅-C₈cycloalkenyl, or heteroaryl, which can be substituted one to three times with C C₈alkyl, Cι-C₈alkoxy, cyano, halogen or phenyl, which can be substituted with Cι-C₈alkyl or C C₈alkoxy one to three times, m stands for 0, 1 , 2, 3 or 4, Y is -C(O)-, -C(0)O-, -C(O)NH-, -SO₂NH- or -SO₂-, R³² is C C₁₈alkyl, Ar⁷, or C₇-C₂₄aralkyl, or a group of the formula -X²-X³, Ar⁸ and Ar⁹ are independently of each other a group of formula

, wherein

R⁴³ is a CrCι₈alkoxy group, R⁴⁴, R⁴⁵, R⁵⁵, R⁶⁵ and R^6S are independently of each other a hydrogen atom, a G dsal l group, a C Ci₈-alkoxy group, or a group -X -X²-X³, wherein X¹ is -0-, -S-, -NH-, -CONH-, -COO-, -SO₂-NH-, or -SO₂-0-.

X² is an alkylene, arylene, aralkylene or cycloalkylene spacer containing optionally one or more groups -O-, -S-, -NR¹⁴-, -CO-, -CONH-, -CONR¹⁵-, or -COO- as linking bridge, X³ is -OH, -NH₂, -C(R¹¹)=CH₂, -OC(0)-C(R¹²)=CH₂, -C(O)-C(R¹²)=CH₂, C₅-C₇cycloalkenyl,

-OC(0)-N-X⁴-N-C(0)-O-X⁵-O-C(O)-C(R¹²)=CH₂ ; wherein R¹¹ is hydrogen, d-C₄alkyl, or halogen,

R¹² is hydrogen, C C alkyl, or halogen,

R¹³ is hydrogen, d-C₄alkyl, or C₆-C₁₂aryl,

R¹⁴ and R¹⁵ are independently of each other hydrogen, Cι-C₈alkyl, or C₆-C₁₂aryl, and

R⁹³ and R⁹⁴ are independently of each other a Cι-Cι₈alkyl group,

Y¹ is -O-, -S-, -SO₂-, -NR⁶⁸-, -CHR⁶⁸-, and ri_! is1, 2, or 3, especially 1, or 2, wherein R⁶⁸ is d-

C₁₈-alkyl, or C₆-C₁₂aryl.

The following diketopyrrolopyrroles of formula IV are especially preferred:

The light-emitting compounds IV usually exhibit a fluorescence quantum yield ("FQY") in the range of from 1 > FQY > 0.3 (measured in toluene). Further, in general, the compounds of formula IV exhibit a molar absorption coefficient in the range of from 5000 to 100000. The molar absorption coefficient and quantum yield of exemplary compounds of formula IV are shown below:

The diketopyrrolopyrrole compound of formula IV is used in this case with a fluorescent compound the absorption peak of which is in the range of from about 530 to about 570 nm and which shows photoluminescence the peak of which is in the range of from about 580 to about 650 nm, i.e. a red fluorescent compound. Examples of such compounds are: diketopyrrolopyrrole compounds of formula III described above, cyanine dyes, such as DCM and DCJTB, Rhodamine dyes, such as Rhodamine B and Rhodamine 6G, pyridinium salt dyes, and oxa∑inβ dyes.

In this case a fluorescent compound can optionally be present, the absorption peak of which is in the range of from about 440 to about 500 nm and which shows photoluminescence the peak of which is in the range of from about 530 to about 570 nm, i.e. a yellow-green fluorescent compound. Examples of such compounds are: diketopyrrolopyrrole compounds of formula I or II described above, Coumarin dyes, such as Coumarin 5, Coumarin 7,

Coumarin 30, Coumarin 153, and naphthalimide dyes, such as solvent yellow 11 and solvent yellow 116.

d-dalkyl group is methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl or tert-butyl; C C₈alkyl is, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert- butyl, n-amyl, tert-amyl or hexyl; d-C₁₈alkyl is, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert- butyl, n-amyl, tert-amyl, hexyl, heptyl, octyl, 2-ethylhexyl, nonyl, decyl, dodecyl, tetradecyl, hexadecyl or octadecyl.

The term "alkylene" means in general linear or branched Cι-C₁₈alkylene, wherein examples of preferred linear representatives are for example -(CH₂)₄-, -(CH₂)₅-, -(CH₂)₆-, -(CH₂)₇-, - (CH₂)₈-, -(CH₂)9-,-(CH₂)ιo-. -(CH₂)ιι-, -(CH₂)ι -,-(CH₂)i3-, -(CH₂)ι -, -(CH₂)i5-, -(CH₂)₁₆-, - (CH₂)ι₇-, -(CH₂)ιs-, preferably C -d₆alkylene such as -(CH₂)₄-, -(CH₂)₅-, -(CH₂)₆-, -(CH₂) , - (CH₂)₈-, -(CH₂)₉-,-(CH₂)ιo-, -(CH₂)_ι , or -(CH₂)₁₂-.

The "alkoxy group" in d-Cι₈alkoxy can be linear or branched and is for example methoxy, ethoxy, n-propoxy, isopropoxy, butyloxy, hexyloxy, decyloxy, dodecyloxy, hexadecyloxy or octadecyloxy, preferably Cι-C₈alkoxy such as methoxy, ethoxy, n-propoxy, isopropoxy, butyloxy, hexyloxy, or octyloxy.

CrC₁₈alkylmercapto is, for example, methylmercapto, ethylmercapto, propylmercapto, butylmercapto, octyl mercapto, decylmercapto, hexadecylmercapto or octadecyl mercapto.

d-Cι₈alkylamino is, for example, methylamino, ethylamino, propylamino, hexylamino, decylamino, hexadecylamino or octadecylamino, preferably Cι-C₆alkylamino such as methylamino, ethylamino, propylamino or hexylamino.

The term "aryl group" is typically C_Θ-C₂₄aryl, such as phenyl, indenyl, azulenyl, naphthyl, biphenyl, as-indacenyl, s-indacenyl, acenaphthylenyl, phenanthryl, fluoranthenyl, triphenlenyl, chrysenyl, naphthacen, picenyl, perylenyl, pentaphenyl, heseacenyl, pyrenyl, or anthracenyl, preferably phenyl, 1-naphthyl, 2-naphthyl, 9-phenanthryl, 2- or 9-fluorenyl, 3- or 4-biphenyl, which may be unsubstituled or substituted. Examples of C₆-Cι₂aryl are phenyl, 1-naphthyl, 2-naphthyl, 3- or 4-biphenyl, which may be unsubstituted or substituted.

The term "aralkyl group" is typically C₇-C₂₄aralkyl, such as benzyl, 2-benzyl-2-propyl, β-phenyl-ethyl, ,α-dimethylbenzyl, ω-phenyl-butyl, ω,co-dimethyl-co-phenyl-butyl, ω-phenyl-dodecyl, ω-phenyl-octadecyl, ω-phenyl-eicosyl or o-phenyl-docosyl, preferably C₇-Cι₈aralkyl such as benzyl, 2-benzyl-2-propyl, β-phenyl-ethyl, α,α-dimethylbenzyl, ω-phenyl-butyl, ω,o>dimethyl-ophenyl-butyl, ω-phenyl-dodecyl or ω-phenyl-octadecyl, and particularly preferred C₇-d₂aralkyl such as benzyl, 2-benzyl-2-propyl, β-phenyl-ethyl, α,α-dimethylbenzyl, ω-phenyl-butyl, or ω,ω-dimethyl-ω-phenyl-butyl, in which both the aliphatic hydrocarbon group and aromatic hydrocarbon group may be unsubstituted or substituted.

The term "cycloalkyl group" is typically C₅-d₂cycloalkyl, such as cyclopentyl, cyclohexyl, cycloheptyl, cyciooctyl, cyclononyl, cyclodecyl, cycloundecyl, cyclododecyl, preferably cyclopentyl, cyclohexyl, cycloheptyl, or cyciooctyl, which may be unsubstituted or substituted. The term "cycloalkenyl group" means an unsaturated alicyclic hydrocarbon group containing one or more double bonds, such as cyclopentenyl, cyclopentadienyl, cyclohexenyl and the like, which may be unsubstituted or substituted. The cycloalkyl group, in particular a cyclohexyl group, can be condensed one or two times by phenyl which can be substituted one to three times with Cι-C₄-alkyl, halogen and cyano. Examples of such condensed

cyclohexyl groups are:

, wherein R⁵¹ , R⁵², R⁵³, R⁵⁴, R⁵⁵ and R⁵⁶ are independe of each other d-C₈-alkyl, CrC₈-alkoxy, halogen and cyano, in particular hydrogen.

The term "heteroaryl group" is a ring, wherein nitrogen, oxygen or sulfur are the possible hetero atoms, and is typically an unsaturated heterocyclic radical with five to 18 atoms having at least six conjugated π-electrons such as thienyl, benzo[b]thienyl, dibenzo[b,d]thienyl, thianthrenyl, furyl, furfuryl, 2H-pyranyl, benzofuranyl, isobenzofuranyl, 2H-chromenyl, xanthenyl, dibenzofuranyl, phenoxythienyl, pyrrolyl, imidazolyl, pyrazolyl, pyridyl, bipyridyl, triazinyl, pyrimidinyl, pyrazinyl, IH-pyrrolizinyl, isoindolyl, pyridazinyl, indolizinyl, isoindolyl, indolyl, 3H- indolyl, phthalazinyl, naphthyridinyl, quinoxalinyl, quinazolinyl, cinnolinyl, indazolyl, purinyl, quinolizinyl, chinolyl, isochinolyl, phthalazinyl, naphthyridinyl, chinoxalinyl, chinazolinyl, cinnolinyl, pteridinyl, carbazolyl, 4aH-carbazolyl, carbolinyl, benzotriazolyl, benzoxazolyl, phenanthridinyl, acridinyl, perimidinyl, phenanthrolinyl, phenazinyl, isothiazolyl, phenothiazinyl, isoxazolyl, furazanyl or phenoxazinyl, preferably the above-mentioned mono- or bicyclic heterocyclic radicals, which may be unsubstituted or substituted.

The term "alkylene (spacer)" is typically d-C₃₀alkylene, preferably CrCι₈alkylene, and embraces the linear as well as the branched representatives and can be, for example, -CH₂- and C₂-C₃₀alkylene, such as -(CH₂)₂-, -CH(Me)-, -(CH₂)₃-, -CH₂-CH(Me)-, -C(Me)₂-, -(CH₂)₄-, - (CH₂)₅-, -(CH₂)₆-, -(CH₂)₇-,-(CH₂)₈-, -(CH₂)₉-, -(CH₂)ι₀-, -(CH₂)₁₁-, -(CH₂)ι₂-, -(CH₂)ι₃-, -(CH₂)₁ - , -(CH₂)i5-, -(CH₂)₁₆-, -(CH₂)ι -, -(CH₂)ι₈-, -(CH₂)-ι₉-, -(CH₂)₂o , -(CH₂)₂ι-, -(CH₂)22-, -(CH₂)₂₃-, - (CH₂)₂₄-, -(CH₂)₂₅-,-(CH₂)26-, -(CH₂)₂₇-, -(CH₂)₂₈-, -(CH₂)₂₉-, -(CH₂)₃₀-, preferably -CH₂-, - (CH₂)₂-, -(CH₂)₃-, -(CH_Z)₄-, -(CH₂)5-. -(CH2)6-, -(CH₂)₇-, -(CH₂)_S-, -(CH₂)₉-, -(CH₂)ι₀-, -(CH₂)π-, - (CH₂)₁₂-, -(CH₂)₁₃-, -(CH₂)ι₄-, -(CH₂)₁₅-, -(CH₂)₁₆-, -(CH₂)₁₇-, -(CH₂)₁₈-, and also -CH(C₂- C₃₀alkylene)-. The "alkylene spacer" can optionally comprise one or more, in particular one or two groups selected from -O-, -S-, -NR¹¹⁴-, -CO-, -CONH-, -CON¹¹⁵-, or -COO- as linking group. d-C₃₀alkylene can, for example, be interrupted several times by -0-, -S-, -NH- or- C(O)NH-, such as -(CH₂)₂-0-(CH₂)-, -(CH₂)₂-0-(CH₂)₂-, -(CH₂)₂-S-(CH₂)₂-, -CH₂-CH-CH₂-0- (CH₂)_P-CH₃, wherein p is an integer from 1 to 10; or-CHX¹³CH₂-(X¹⁴)_n-OH, wherein X¹³ is C C₈alkyl, X¹⁴ is an alkylene oxide monomer, preferably ethylene oxide or propylene oxide, or alkylene amino monomer, preferably amino ethylene or amino propylene, and n is an integer from 1 to 10, preferably 1 to 5; or -(CH₂)₂-NH-(CH₂)₂- or -(CH₂)₂-C(0)NH-(CH₂)₂-, wherein R¹¹⁴ and R¹¹⁵ are independently of each other hydrogen, d-C₈alkyl, or C₈-C ₂aryl.

"Arylene (spacer)" is an unsubstituted or substituted carbocylic or heterocyclic arylene group, preferably containing 6 to 14 carbon atoms, typically phenylene, naphthylene, anthracenylene, anthraquinonylene, pyridinylene, quinolinylene, preferably a group

wherein X¹¹ is a single bond in ortho-, meta- or para-position, or -O-, -S-, -NR¹¹⁴-, -CO-, -CONH-, -CON¹¹⁵-, or -COO- in ortho-, meta- or para-position; para-phenylene and para-phenylenoxy are preferred. "Aralkylene (spacer)" is an unsubstituted or substituted carbocylic or heterocyclic aralkylene

group, preferably containing 6 to 14 carbon atoms, preferably a group

wherein X¹¹ is a single bond in ortho-, meta- or para-position, or -O-, -S-, -NR¹¹⁴-, -CO-, -CONH-, -CON¹¹⁵-, or -COO- in ortho-, meta- or para-position, and

X¹² is alkylene, or a group , wherein X¹² is alkylene in ortho-, meta- or

para-position and X¹¹ is a single bond, -O-, -S-, -NR¹¹⁴-, -CO-, -CONH-, -CON¹¹⁵-, or -COO-.

"Cycloalkylene (spacer)" is an unsubstituted or substituted carbocylic or heterocyclic cycloalkylene group, preferably containing 6 to 14 carbon atoms, typically cyclohexylene,

preferably a group

wherein X¹¹ is a single bond in 2-, 3- or 4-position, or -O-, -S-, -NR¹¹⁴-, -CO-, -CONH-, -CON¹¹⁵-, or -COO- in 2-, 3- or 4-position;

4-cyclohexylene and 4-cyclohexylenoxy are preferred.

The above-mentioned groups can be substituted by a d-C₈alkyl, a hydroxyl group, a mercapto group, d-C₈alkoxy, Cι-C₈alkylthio, halogen, ha!o-d-C₈alkyl, a cyano group, an aldehyde group, a ketone group, a carboxyl group, an ester group, a carbamoyl group, an amino group, a nitro group, a silyl group or a siloxanyl group.

The term "carbamoyl group" is typically a Cι_ι₈carbamoyl radical, preferably d.gcarbamoyl radical, which may be unsubstituted or substituted, such as, for example, carbamoyl, methylcarbamoyl, ethylcarbamoyl, n-butylcarbamoyl, tert-butylcarbamoyl, dimethylcarbamoyloxy, morpholinocarbamoyl or pyrrol idinocarbamoyl.

The term "silyl group" means a group of formula -SiR⁷²R⁷³R⁷⁴, wherein R⁷², R⁷³ and R⁷⁴ are independently of each other a d-C₈alkyl group, in particular a C C₄ alkyl group, a C₆-C₂₄aryl group or a C₇-Ci₂aralkylgroup, such as a trimethylsilyl group. The term "siloxanyl group" means a group of formula -O-SiR⁷²R⁷³R⁷⁴, wherein R⁷², R⁷³ and R⁷⁴ are as defined above, such as a trimethylsiloxanyl group. The terms "haloalkyl, haloalkenyl and haloalkynyl" mean groups given by partially or wholly substituting the above-mentioned alkyl group, alkenyl group and alkynyl group with halogen, such as trifluoromethyl etc. The "aldehyde group, ketone group, ester group, carbamoyl group and amino group" include those substituted by an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group or a heterocyclic group, wherein the alkyl group, the cycloalkyl group, the aryl group, the aralkyl group and the heterocyclic group may be unsubstituted or substituted.

The light emitter for use in the invention is not specifically defined, including, for example, EL (electroluminescent) devices, LEDs (light emitting diodes), VFDs (visual fluorescence displays), PDP (plasma display panels) etc.

The light emitter is preferably an organic or inorganic electroluminescent element, which comprises an organic or inorganic electroluminescent material part which emits blue light.

An example of an inorganic electroluminescent material part which emits blue light, comprises a substrate, a metal, a thick film dielectric which consists of a lead magnesium niobate (PMN) combined with a lead zirconate titanate (PZT) based material, a blue phosphor, such as, for example, SrS:Ce, BaAI₂S₄:Eu (L₆₀ = 200 cd/m² with CIE x, y coordinates 0J35 and 0J05, respectively) or Mg_xBaι-_xAI₂S :Eu (x = 0 to 1.0), and an indium tin electrode (MgχBaι-_xAI₂S :Eu Blue Phosphor on iFire Thick Dielectric Substrates - Dan Cheong et al., December 2002; Self-Aligned Phosphor Patterning Techniques for IEL Displays - D. Seale et al., May 2002; WO007091 , WO02100978, WO02098180, especially WO0223957, which discloses a blue phosphor comprising a composition of the formula M'_aBai a M"₂ M™ : RE, where iW is at least one element selected from the group consisting of magnesium and calcium, M" is at least one element selected from the group consisting of aluminum, gallium and indium, '" is at least one element selected from the group consisting of sulphur, selenium and tellurium, RE is at least one rare earth element, and 0 < a < 1.). In case of an inorganic electroluminescent material part comprising in addition to the blue phosphor a green phosphor, for example (Zn,Mg)S:Mn, the diketopyrrolopyrrole compounds of formula III can be applied as green-to-red CCM.

Next the present invention is illustrated in more detail on the basis of an organic electroluminescent material part. "Bottom electrode," as used herein, means an electrode that is deposited directly onto the substrate.

"Top electrode," as used herein, means an electrode that is deposited at the end of the

OLED that is distal to the substrate. "Hole-injection layer," as used herein, is a layer into which holes are injected from an anode when a voltage is applied across an OLED.

"Hole-transport layer," as used herein, is a layer having high hole mobility and high affinity for holes that is between the anode and the emitter layer. It will be evident to those of skill in the art that the hole-injection layer and the hole-transport layer can be a single layer ("hole-injection/hole-transport layer"), or they can be distinct layers comprising different chemical compounds.

"Electron-injection layer," as used herein, is a layer into which electrons are injected from a cathode when a voltage is applied across an OLED.

"Electron-transport layer," as used herein, is a layer having high electron mobility and high affinity for electrons that is between the cathode and the emitter layer. It will be evident to those of skill in the art that the electron-injection layer and the electron-transport layer can be a single layer ("electron-injection/electron-transport layer"), or they can be distinct layers comprising different chemical compounds.

"Down-emitting," as used herein, refers to an OLED in which light is transmitted through the transparent or semi-transparent bottom electrode, which is typically an anode.

"Up-emitting," as used herein, refers to an OLED in which light is transmitted through the transparent or semi-transparent top electrode, which is typically a cathode.

High energy (i. e., blue) light in full-color OLED display devices may be produced by any source, but is preferably produced by an emissive monochromatic OLED display device, such as the one described below. The monochromatic OLED display device may or may not be pixelated. Preferably the OLED display is pixelated and is of high resolution, for example, with sub-pixel sizes less than about 50 μm, preferably less than about 25 μm, more preferably less than about 10 μm.

The device comprises a substrate, which can be transparent or opaque (and which may further comprise driving electronics), a patterned bottom electrode, which is a cathode or an anode, a first charge transport layer, which is a hole-transport layer if the bottom electrode is an anode and which is an electron-transport layer if the bottom electrode is a cathode, an emitter layer, a second transport layer, which is a hole-transport layer if the bottom electrode is a cathode and which is an electron-transport layer if the bottom electrode is an anode, a top electrode, which is a cathode if the bottom electrode is an anode and which is an anode if the bottom electrode is a cathode, and which may be patterned (i. e., in passive matrix displays) and a protective layer. Each element of the patterned bottom electrode represents one pixel in the matrix. When current is applied to the elements of the patterned bottom electrode, holes are transported through the hole-transport layer and electrons are transported through the electro ntransport layer and holes and electrons recombine in the light emitting layer to produce light of the same wavelength, e. g., blue light, at each pixel. "Patterning,"as used herein, means that the materials are formed into stripes, squares, rectangles, triangles, hexagons, circles, or any other shape known in the art. Preferably, each individual OLED is rectangular and the color changing materials are patterned in parallel stripes, or rectangular dots. The patterning of color changing materials provides for the formation of discrete red, green and blue sub-pixels, without having the colors mix together.

Electrodes can be patterned by any method known in the art, including, but not limited to lithographic, particularly photolithographic techniques, laser ablation, and masking during deposition. Each element of the patterned electrode represents one sub-pixel in the matrix. A first patterned color changing material (A) is aligned with a first element of the patterned bottom electrode, so that the first patterned color changing material (A) is directly above a specified element. In a similar fashion, the second patterned color changing material (B) is aligned with a second element of the patterned bottom electrode adjacent to the first element. A third element of the patterned bottom electrode adjacent to the second element is not aligned with a patterned color changing material. When a current is applied between the top electrode and the patterned bottom electrode, holes are transported through the hole-transport layer and electrons are transported through the electron-transport layer and holes and electrons recombine in the emitter layer to produce light of a particular wavelength, e. g., blue light, at each sub-pixel. For a green sub-pixel, when blue light is emitted from the emitter layer at the first element of the patterned electrode, it is absorbed by the first patterned color changing material (A) ("blue-to-green CCM") that is aligned with the first element. The first patterned color changing material (A) then emits green light by fluorescence. For a red sub-pixel, when blue light is emitted from the emitter layer at the second element of the patterned bottom electrode, it is absorbed by the second patterned color changing material (B) ("blue-to-red CCM") that is aligned with the second element. The second patterned color changing material (B) then emits red light by fluorescence. For a blue sub-pixel, when blue light is emitted by the emitter layer at the third element of the patterned bottom electrode, the blue light is transmitted through the various layers substantially without being absorbed. The patterning of the first and second color changing materials are repeated every fourth element, resulting in an array of pixels each comprising a red, a green and a blue sub-pixel. An embodiment of a down-emitting full-color OLED display device, comprises a first color changing layer comprising a first patterned color changing material (A) deposited on a substrate, a first protective layer covering the first color changing layer formed on a transparent or semi transparent substrate. A second color changing layer comprises a second patterned color changing material (B) adjacent to the first protective layer, a second protective layer covering the second color changing layer, a patterned bottom electrode, which is a cathode or an anode, a first charge transport layer, which is a hole-transport layer if the bottom electrode is an anode and which is an electron-transport layer if the bottom electrode is a cathode, an emitter layer, a second charge transport layer, which is a hole-transport layer if the bottom electrode is a cathode and which is an electron-transport layer if the bottom electrode is an anode, a top electrode, which is a cathode if the bottom electrode is an anode and which is an anode if the bottom electrode is a cathode, and an encapsulation layer.

In this embodiment, for a red sub-pixel, blue light is emitted downward from the emitter layer at the first element of the patterned bottom electrode, and is absorbed by the first patterned color changing material (A) ("blue-to-red CCM") that is aligned with the first element. The first patterned color changing material then emits red light by fluorescence (or phosphorescence). For a green sub-pixel, when blue light is emitted from the emitter layer at the second element of the patterned bottom electrode, it is absorbed by the second patterned color changing material (B) ("blue-to-green CCM") that is aligned with the second element. The second patterned color changing material (B) then emits green light by fluorescence or phosphorescence. For a blue sub-pixel, when blue light is emitted by the emitter layer at the third element of the patterned bottom electrode, the blue light is transmitted through the various layers substantially without being absorbed. The patterning of the first and second color changing materials are repeated every fourth element, resulting in an array of pixels each comprising a red, a green and a blue sub-pixel.

OLEDs can be fabricated by any method known in the art. The OLED layers may be formed by evaporation, spin casting, self-assembly or other appropriate filmforming techniques. Thicknesses of the layers typically range from a few monolayers to about 2,000 Angstroms. In one embodiment, OLEDs are formed by vapor deposition of each layer. In a preferred embodiment, OLEDs are formed by thermal vacuum vapor deposition. The OLEDs described above are by way of example, and any type can be used. For example, an OLED may comprise a hole-injection layer adjacent to the anode and at least two hole-transport layers, a first hole-transport layer adjacent to the hole-injection layer and a second hole-transport layer adjacent to the first holetransport layer. The hole-injection layer and the at least two hole-transport layers may be deposited separately. Alternately, at least two of the layers may be inter-deposited.

An OLED may comprise an electron-injection layer and at least one electrontransport layer, or the OLED can further comprise an additional layer adjacent to the top electrode. In a preferred embodiment, the layer comprises indium tin oxide.

An OLED may comprise a light emitting layer or two light emitting layers, optionally which contain electron-injection layer and/or one electron transport layer, and/or hole-injection layer and one or two hole-transport layers.

The organic EL device usable in the invention is basically so constructed that a light emission layer is sandwiched between a pair of electrodes.

Concretely, it may have any of the following structures:

(1) Anode/light emission layer/cathode,

(2) Anode/hole injection layer/light emission layer/cathode,

(3) Anode/light emission layer/electron injection layer/cathode, (4) Anode/hole injection layer/light emission layer/electron injection layer/cathode.

Organic EL devices emitting blue light and their fabrication are described, for example, in US-B-6,464,898, column 10, line 24 to column 20, line 48. The organic EL device disclosed in Example 1 of US-B-6,464,898 having the following structure: ITO anode/4,4',4"-tris[N-(3- methylphenyl)-N-phenylamino]triphenylamine (MTDATA; hole-injecting material)/4,4'-bis[N- (1 -naphthyl)-N-phenylamino]biphβnyl NPD(hole-injecting material)/4,4'-bis(2,2- diphenylvinyl)biphenyl (DPVBi; light emitting layer)/tris(8-quinolinol)aluminium (Alq; electron injection layer)/magnesium and silver cathode, is preferred. Other OLED structures will be evident to those skilled in the art.

A substrate may be made from any material known in the art, including glass, silicon, plastic, quartz and sapphire. If the OLED display is formed on a silicon chip, the chip preferably includes drive electronics and one of the sub-pixel electrodes. The top electrode may be common to all sub-pixels. An anode is typically about 800 A thick and can have one layer comprising a metal having a high work function, a metal oxide and mixtures thereof. Preferably, the anode comprises a material selected from the group consisting of a conducting or semiconducting metal oxide or mixed metal oxide such as indium zinc tin oxide, indium zinc oxide, ruthenium dioxide, molybdenum oxide, nickel oxide or indium tin oxide, a metal having a high work function, such as gold or platinum, and a mixture of a metal oxide and a metal having a high work function. In one embodiment, the anode further comprises a thin layer (approximately thick) of dielectric material between the anode and the first hole-injection/hole-transport layer. Examples of such dielectric materials include, but are not limited to, lithium fluoride, cesium fluoride, silicon oxide and silicon dioxide. In another embodiment, the anode comprises a thin layer of an organic conducting material adjacent to the hole injection/hole-transport layer. Such organic conducting materials include, but are not limited to polyaniline, PEDOT-PSS, and a conducting or semi-conducting organic salt thereof.

A semi-transparent cathode is typically between 70 and 150 A thick. In one embodiment, the cathode comprises a single layer of one or more metals, at least one of which has a low work function. Such metals include, but are not limited to, lithium, aluminum, magnesium, calcium, samarium, cesium and mixtures thereof. Preferably, the low work function metal is mixed with a binder metal, such as silver or indium. In another embodiment, the cathode further comprises a layer of dielectric material adjacent to the electron-injection/electron-transport layer, the dielectric material including, but not limited to, lithium fluoride, cesium fluoride, lithium chloride and cesium chloride. Preferably, the dielectric material is lithium fluoride or cesium fluoride. In preferred embodiments, the cathode comprises either aluminum and lithium fluoride, a mixture of magnesium and silver, a mixture of lithium and aluminum, or calcium followed by aluminum. In yet another embodiment, the cathode comprises magnesium, silver and lithium fluoride. In one embodiment, the hole-injection/hole-transport layer is about 750 A thick. Hole-injection/hole-transport layers typically comprise at least one material with good hole mobility. Examples of such materials include, but are not limited to, copper phthalocyanine (CuPc), and aromatic amine compounds such as N,N'-bisnaphthyl)-N,N'-diρhenyl-1 ,r~biphenyl-4,4'-diamine (NPD), bis(N, N'-1-naphthyl-phenyl-amino-biphenyl)-biphenyl amine (BPA-DNPB) and bis(carbazol-M-biphenyl)-biphenyl amine (BPA-BCA).

An OLED may further comprise an emitter layer between the electron-injection/electron-transport layer and the hole-injection/hole-transport layer in which electrons from the electron-injection/electron-transport layer and holes from the hole injecting/hole-transport layer recombine. Depending on the composition of the emitter layer, OLEDs emit visible light of different colors. Emitter layers typically comprise at least one host compound, either alone or together with at least one dopant compound, which is a luminophor. Examples of host compounds include, but are not limited to, 2,2', 7,7'-naphthyl-9₁9'-spirobifluorene (N-SBF), ALQ, IDE-120 and IDE140 (Idemitsu Kosan Co., Ltd., Tokyo, Japan). Examples of dopant compounds include, but are not limited to, Coumarin 6, Coumarin 485, Coumarin, 487, Coumarin 490, Coumarin 498, Coumarin 500, Coumarin 503, Coumarin 504, Coumarin 504T, Coumarin 510, Coumarin 515, Coumarin 519, Coumarin 521, Coumarin 521T, Coumarin 522B, Coumarin 523, Coumarin 525, Coumarin 535, Coumarin 540A, Coumarin 545, Coumarin 545T, quinacridone derivatives such as diethyl pentyl quinacridone and dimethyl quinacridone, distyrylamine derivatives, such as IDE-102, IDE-105 (Idemitsu Kosan Co., Ltd., Tokyo, Japan), rubrene, DCJTB, pyrromethane 546, and mixtures thereof. The structure of DCJTB is shown below:

In one embodiment, the emitter layer emits blue light and comprises IDE-102 and IDE-120.

The emitter layer may be between 200-400 A thick.

The electron-injectioπ/electron-transport layer is typically about 350 A thick and comprises a compound such as ALQ, or a suitable oxadiazole derivative. In a preferred embodiment, the electron-injection/electron-transport layer is N-SBF, ALQ, or a mixture of N-SBF and ALQ.

In one embodiment, a blue-emitting OLED for use in color OLED displays comprises an anode comprising indium tin oxide, a hole-injection layer adjacent to the anode comprising CuPc, a hole-transport layer adjacent to the hole-injection layer comprising NPD, an emitter layer adjacent to the hole-transport layer comprising DCJTB, IDE-102 and IDE-120, an electron-transport layer adjacent to the emitter layer comprising ALQ, and a cathode comprising lithium fluoride and aluminum.

A method for forming patterned color changing materials on or under an OLED display device will now be described. In the first step step, a blue-to-green CCM layer, for example, is deposited on the protective layer of an up-emitting monochromatic OLED display device. In the case of a down-emitting device the layer would be deposited on the substrate. CCM layers can be deposited by any method known in the art, including spin-coating, meniscus-coating, spray-coating, dip-coating, blade-coating, from solution or suspension or by sublimation in a vacuum. When a voltage is applied, the monochromatic OLED display emits blue light, which is either transmitted through the protective layers at a blue sub-pixel or is absorbed by the patterned blue-to-green CCM or by the patterned blue-to-red CCM, which in turn emit green or red light, respectively, to form a green sub-pixel and a red sub-pixel, respectively. Thus, a full-color OLED display device is formed.

In addition, although the method of the present invention has been illustrated for generating red and green sub-pixels, one of skill in the art will recognize that subpixels of any color can be generated simply by altering the color changing materials. For example, only one CCM layer can be used on a monochromatic OLED display device. Alternatively, many CCM layers can be used and the CCM emission colors may vary, e. g., one could have a monochromatic OLED display that emits deep blue light in combination with CCM films patterned as described herein that emit, for example, yellow/green and orange light.

Preferably, the monochromatic OLED display device emits blue light (close to CIE (0J55; 0.07)) and there are two CCM layers, one emitting red light (close to CIE (0.625; 0.34)) and the other emitting green light (close to CIE (0.28; 0.595)) to form a proper red-green-blue ("RGB") display. If multiple CCM or filter layers are deposited on a single substrate and sequentially on top of each other, then a protective layer is deposited over each patterned layer. The protective layer preferably comprises inert materials that are transparent and have low or no luminescence. The protective layer is preferably not patterned. Without being bound by any theory, the protective layer absorbs the radiation used in the patterning method and/or prevents ambient oxygen from penetrating to the lower layers in order to prevent the already-patterned underlying layers from being re-exposed.

Suitable materials for the protective layer are preferably able to absorb light used in the methods of the present invention (usually ultraviolet light), are able to block oxygen penetration into the other layers, are transparent to visible light (usually red, green and blue), are non-fluorescent and are easily deposited onto the CCM layers without harming thern.

Preferably, such materials are deposited onto the CCM layers by heat or e-beam evaporation or are sputtered (reactive DC or RF). Suitable protective layer materials are known in the art and include, but are not limited to, metal oxides such as Si0₂, SiN, MgO, and ITO, organic polymers, conjugated polymers, additives such as benzophenones, heat and/or ultraviolet curing epoxy compounds, spin-on-glass materials, siloxanes and combinations thereof.

Color changing materials may comprise any material known in the art. For example, CCM layers may comprise compounds including, but not limited to, pure sublimed fluorescent compounds, sublimed host molecules that are doped (co-evaporated) with other materials in order to improve quantum efficiency of photoluminescence, purely organic or organometallic materials, or unconjugated, conjugated or partially conjugated polymers or co-polymers. If a CCM is a doped layer, the host can be chosen to optimize its absorption of the wavelength of light emitted by the monochromatic OLED display (usually blue light), and the dopant can be chosen to emit the desired wavelength of light (usually red or green light).

Instead of the DPP compounds of formula I known blue-to-green CCM and instead of the DPP compounds of formula I or II and III known blue-to-red CCM can be used. The DPP compounds of formula I or II and 111 may be contained in one layer or may be contained in two different layers, i.e. a green fluorescence conversion film may be laminated with another fluorescence conversion film capable of converting green into red.

An example of an alternative blue-to-green CCM is, for example, a coumarin-type coloring matter such as Coumarin 153 (2,3,5,6-1 H,4H-tetrahydro-8-trifluoromethylquinolidino- (9,9a,1-gh)coumarin), Coumarin 6, Coumarin 485, Coumarin, 487, Coumarin 490, Coumarin 498, Coumarin 500, Coumarin 503, Coumarin 504, Coumarin 504T, Coumarin 510, Coumarin 515, Coumarin 519, Coumarin 521, Coumarin 521T, Coumarin 522B, Coumarin 523, Coumarin 525, Coumarin 535, Coumarin 540A, Coumarin 545, Coumarin 545T, quinacridone derivatives such as diethyl pentyl quinacridone and dimethyl quinacridone, or the following CCM materials:

especially

An example of an alternative blue-to-red CCM is, for example, distyrylamine derivatives, such as IDE-102, IDE-105 (Idemitsu Kosan Co., Ltd., Tokyo, Japan), rubrene, DCJTB, pyrromethane 546, and mixtures thereof, or cyanine-type coloring matters such as 4-dicyanomethylene-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran (DCM), etc.; pyridine-type coloring matters such as 1-ethyl-2-[4-(p-dimethylaminophenyI)-1,3-butadienyl]-pyridinium perchlorate (Pyridine 1), etc.; xanthene-type coloring matters such as Rhodamine B, Rhodamine 6G, etc.; as well as oxazine-type coloring matters.

Color changing materials can alternatively also comprise pure polymers or polymer blends, fluorescent polymers or fluorescent compounds doped into conjugated or partly conjugated fluorescent or nonfluorescent polymers. A wide range of polymers and copolymers are available as CCMs because different side groups can be attached to a particular backbone. In addition, co-polymers can be used. Examples of useful polymers in CCMs are known in the art and include, but are not limited to, PPV polymers, thiophene-based polymers, inert polymers with attached luminophor side groups, fluorene-based polymers, phenylene-based polymers, furylene-based polymers, oligomers, oligomers with spiro centers, and combinations and co-polymers thereof. A blue-to red CCM is, for example, a PPV copolymer with cyano-groups attached to the vinyl groups of the polymer backbone or a poly-alkyl-thiophene polymer. A blue-to-green CCM is, for example, a polyfluorene-based copolymer, a PPV polymer with discontinuous conjugation (i. e., with electrically and optically inert spacer groups) or a PPV polymer with solubilising side groups, such as a di-alkyl PPV. CCMs that emit red light preferably have an absolute quantum efficiency of photoluminescence that is greater than about 20%, preferably greater than about 30%, and more preferably greater than about 40%. Such efficiencies can be achieved by multi-component color changing materials, wherein the major component (comprising about 70-98% of the material) absorbs blue light efficiently, the minor component (dopant) has high quantum efficiency of photoluminescence in the desired wavelength range, and there is efficient energy transfer from the major component to the dopant.

If the CCMs are used without binder polymer, the CCM layers are preferably less than about 3 μm thick, more preferably less than about 2 μm thick, and most preferably less than about 1 μm thick. As the thickness of the CCM layers increases, the layers may waveguide or scatter the light they emit, which in turn may lead to loss of brightness and contrast in the displays.

The invention also provides a fluorescence conversion medium which comprises at least a fluorescent diketopyrrolopyrrole compounds and a binder resin and which can absorb light from a light emitter and can emit visible fluorescence.

The fluorescent conversion medium optionally contains a UV absorbent and a light stabilizer in order to improve the light resistance of the fluorescence conversion medium.

In general, the UV absorbent is grouped into salicylate-type ones, benzophenone-type ones, benzotriazole-type ones, cyanoacrylate-type ones, and other types of UV absorbents. Examples of salicylate-type UV absorbents are phenyl salicylate, p-octylphenyl salicylate, p-t-butylphenyl salicylate, etc.; and examples of benzophenone-type UV absorbents are 2,2'- dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2',4,4'- tetrahydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2,4-dihydroxybenzo- phenone, 2-hydroxy-4-octoxybenzophenone, etc. Examples of benzotriazole-type UV absorbents are 2-(2'-hydroxy-3^l,5'-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3'- tert-butyI-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3'-tert-arnyl-5'- isobutylphenyl)-5-chlorobenzotriazole, 2-(2^,-hydroxy-3'-isobutyl-5'-methylphenyl)-5- chloroben∑otriazole, 2-(2'-hydroxy-3'-isobutyl-5'-propylphenyl)-5-chlorobenzotriazole, 2-(2'- hydroxy-3',5'-di-tert-butylphenyl)benzotriazole, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-[2'-hydroxy-5'-(1J,3,3-tetramethyl)phenyl]benzotriazole, etc.; and examples of cyanoacrylate-type UV absorbents are ethyl 2-cyano-3,3-diphenylacrylate, 2-ethylhexyl 2- cyano-3,3-diphenylacrylate, etc. Other types of UV absorbents include, for example, resorcinol monobenzoate, 2,4-di-t-butyl phenyl 3,5-di-t-butyl-4-hydroxybenzoate, N-(2-ethylphenyl)-N'-(2-ethoxy-5-t-butylphenyl)oxalic acid diamide, etc.

In addition to the above-mentioned low-molecular compounds serving as a UV absorbent, further employable herein are reactive UV absorbents having a reactive functional group such as an acrylic group or the like bonded thereto, polycondensate-type UV absorbents, and polymer-type UV absorbents having an UV absorbent moiety bonded to the polymer main chain.

The light stabilizer includes hindered amines and nickel compounds. Hindered amine-type light stabilizers include, for example, bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, dimethyl succinate-1 -(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, poly[6- (1 ,1 ,3,3-tetramethylbutyl)imino-1 ,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4- piperidyl)imino]hexamethylene[2,2,6,6-tetramethyl-4-piperidyl) imide], tetrakis(2,2,6,6- tetramethyl-4-piperidyl) 1,2,3,4-butane-tetracarboxylate, 2,2,6,6-tetramethy!-4-piperidyl benzoate, bis-(1 ,2,6,6-pentamethyl-4-piperidyl) 2-(3,5-di-t-butyl-4-hydroxybenzyl)-2-n-butyl malonate, bis- (N-methyl-2,2, 6,6-tetramethyl-4-piperidyl) sebacate, 1-1'-(1,2- ethanediyl)bis(3,3,5,5-tetramethylpiperazinone), (mixed 2,2,6,6-tetramethyl-4- piperidyl/tridecyl) 1,2,3,4-butane-tetracarboxylate, (mixed 1,2,2,6,6-pentamethyl-4- piperidyl/tridecyl) 1 ,2,3,4-butane-tetracarboxylate, mixed [2,2,6,6-tetramethyl- -piperidyl/ β.β,β', β'-tetramethyl-^θ-PAδ, 10-tetroxaspiro(5,5)undecane]diethyl] 1 ,2,3,4-butane- tetracarboxylate, mixed [1 ,2,2,6,6-pentamethyl-4-piperidyl/β,β,β', β'-tetramethyl-3,9-[2,4,8J0- tetroxaspiro(5,5)undecane]diethyl] 1 ,2,3,4-butane-tetracarboxylate, N,N'-bis(3- aminopropyl)ethylenediamine-2,4-bis[N-butyl-N-(1 ,2,2,6,6-pentamethyl-4-piperidyl)amino]-6- chloro-1,3,5-triazine condensate, poly[6-N-morpholyl-1 ,3,5-triazine-2,4-diyl][(2,2,6,6- tetramethyl-4-piperidyl)imino]hexamethylene[(2,2,6,6-tetramethyl-4-piperidyl)imide], N,N'- bis(2,2,6,6-tetramethyl-piperidyl)hexamethylenediamine/ 1 ,2-dibromoethane condensate, [N- (2,2,6,6-tetramethyl-4-piperidyl)-2-methyl-2-(2,2,6,6-tetramethyl-4- piperidyl)imino]propionamide, etc.

Examples of nickel compounds serving as a light stabilizer are nickel bis(octylphenyl)sulfιde, [2,2'-thiobis(4-tert-octylphenolato)]-n-butylamine nickel, nickel dibutyldithiocarbamate, nickel complex-3,5-di-tert-butyl-4-hydro ybenzyl phosphate monoethylate, etc.

One or more of these UV absorbents and light stabilizers may be used either singly or as mixture.

According to the present invention the fluorescent diketopyrrolopyrrole compounds and optional components, UV absorbent and light stabilizer, can optionally be held by fine particles as described in US-B-6,464,898. The fine particles include fine particles of various polymers (latexes) and fine particles of inorganic compounds. To produce the fluorescence conversion medium of the invention, the fluorescent diketopyrrolopyrrole compounds optionally along with a UV absorbent and a light stabilizer is combined with a binder resin, and the resulting dispersion is formed into a film, preferably into a thin film, which is then cured.

One or a multiple number of diketopyrrolopyrroles may be contained in a CCM layer. The total amount of the fluorescent diketopyrrolopyrrole compounds is between 0J and 20 % by weight, preferably between 0.3 and 10 % by weight, most preferably between 0.5 and 7 % by weight of the total of the fluorescence conversion medium .

In the above formulations, CCM layers are preferably about 100 μm to 0.5 μm thick, more preferably 50 μm to 2 μm thick, and most preferably 30 μm to 5 μm thick.

The binder resin includes oligomer-type or polymer-type melamine resins, phenolic resins, alkyd resins, epoxy resins, polyurethane resins, maleic acid resins, polyamide resins, as well as polymethyl mβthacrylate, polyacrylates, polycarbonates, polyvinyl alcohols, polyvinyl pyrrolidones, hydroxyethyl celluloses, carboxymethyl celluloses, etc. One or more of these may be employed either singly or as mixture.

For patterning the fluorescence conversion film, photosensitive resins may be used. The photosensitive resins may be any of photopolymerizable polyacrylates or polymethacrylates having reactive vinyl groups, or photocrosslinkable polyvinyl cinnamates, etc. In general, they are combined with a photosensitizer. If desired, thermosetting resins may also be used, and they are not mixed with a photosensitizer. Anyhow, it is desirable that the binder resin for use in the invention is highly transparent to visible light.

The dispersion liquid for forming the fluorescence conversion medium of the invention is prepared by mixing an appropriate solvent, the fluorescent diketopyrrolopyrrole, optionally along with a UV absorbent and a light stabilizer, and a binder resin in such a manner that the viscosity of the resulting mixture is suitable to forming the intended fluorescence conversion film and to patterning the film. Optionally, the mixture is exposed to ultrasonic waves or is further dispersed by the use of a dispersing machine such as a ball mill, a sand mill, a three-roll mill or the like. The fluorescence conversion medium, especially the fluorescence conversion film of the invention is produced from the fluorescence conversion film-forming dispersion liquid generally prepared in the manner mentioned above. For example, the dispersion liquid is formed into a film having a predetermined thickness through spin coating, roll coating, 5 casting, electrodeposition or the like, then patterned (into plural layers planarly spaced from each other), and thereafter cured. Alternatively, the fluorescence conversion medium may be incorporated into polymer plates to give fluorescence conversion plates.

To pattern it, the fluorescent conversion film containing a photosensitive resin (resist) as the 10 binder resin may be processed through photolithography. Containing any of photosensitive or non-photosensitive resin, the fluorescent coloring matter dispersion liquid may be applied to a suitable substrate through ordinary printing (relief printing, screen printing, offset printing, intaglio printing).

15 After having been thus formed, the film or the patterned film may be cured by drying or baking it at a temperature falling between room temperature and 250 °C. In that manner, the intended fluorescence conversion film of the invention that contains a fluorescent coloring matter is obtained.

20 The following examples further describe some preferred embodiments of the invention, but do not limit the scope of the invention. In the examples, all parts are by weight unless otherwise indicated.

Examples

X Example i 0.02 g of compound A-18 and 2.0 g of acryl polymer (PMMA: Wako Pure Chemicals Industries, Ltd.) are added to 18 g of toluene and dissolved. The solution is then spin coated on a borosilicate glass plate at 1000 rpm. The coated glass plate is dried for 5 minutes at 30 80°C on a hot plate, giving a uniform and transparent film. Film property: Abs.: 472 nm, Fluores.: 528 nm

Example 2 Example 1 is repeated except using compound A-45 instead of compound A-18. 35 Film property: Abs.: 475 nm, Fluores.: 532 nm Example 3

0.007 g of compound A-45, 0.003 g of compound C-9 and 1.0 g of acryl polymer (PMMA: Wako Pure Chemicals Industries, Ltd.) are added to 10 g of toluene and dissolved. The solution is then spin coated on a borosilicate glass plate at 1000 rpm. The coated glass plate is dried for 5 minutes at 80°C on a hot plate, giving a uniform and transparent film. Film property: Abs.: 475 nm, Fluores.: 597 nm

Example 4

0.006 g of compound A-45, 0.004 g of compound C-20 and 1.0 g of acryl polymer (PMMA: Wako Pure Chemicals Industries, Ltd.) are added into 10 g of toluene and dissolved. The solution is then spin coated on a borosilicate glass plate at 1000 rpm. The coated glass plate is dried for 5 minutes at 80°C on a hot plate, giving a uniform and transparent film. Film property: Abs.: 475 nm, Fluores.: 605 nm

Example 5

Example 3 is repeated except using compound B-40 instead of compound A-45. Film property: Abs.: 487 nm, Fluores.: 598 nm

Claims

1. An electroluminescent element comprising an organic or inorganic electroluminescent material part which emits a blue light and at least one fluorescent material part which absorbs said blue light and emits a fluorescence in a visible light range from bluish green to red light said fluorescent material part exists outside of the electroluminescent material part and comprises a diketopyrrolopyrrole compound.

2. An electroluminescent element according to claim 1 , wherein the diketopyrrolopyrrole compound is a compound the absoption peak of which is in the range of from about 440 to about 490 nm and which shows photoluminescence the peak of which is in the range of from about 510 to about 550 nm.

3. An electroluminescent element according to claim 2, wherein the diketopyrrolopyrrole is a compound of formula

(I), wherein R¹ and R² are independently of each other a d-₂₄-alkyl group, a C₂-₂ -alkenyl group, Ar⁷, especially phenyl which can be substituted up to three times with d-C₈alkyl, or a group of formula -CR³⁰R³¹-(CH₂)_m-Ar⁷ or Y-R³², wherein R³⁰ and R³¹ independently of each other stand for hydrogen, or d-dalkyl, or phenyl which can be substituted up to three times with d-G₄alkyl, Ar⁷ stands for aryl, C₅-C₈cycloalkyl, C₅-C₈cycloalkenyl or heteroaryl, which can be substituted one to three times with d-dalkyl, Cι-C₈alkoxy, cyano, halogen or phenyl, which can be substituted with d-G₈alkyl or d-Csalkoxy one to three times, m stands for 0, 1 , 2, 3 or 4, Y is -C(O)-, -C(O)O-, -C(O)NH-, -SO₂NH- or -S0₂- and R³² is Cι-Cι₈alkyl, Ar⁷, or aralkyl, or R¹ and R² are independently of each other a group -X²-X³, Ar¹ and Ar² are independently of each other a group of formula

. or , , wherein R³, R⁴ and R⁵ are independently of each other a hydrogen atom, a d-Ci₈-alkyl group, a d-C₁₈-alkoxy group, a fluorine atom, a chlorine atom, or a group -X¹-X²-X³, wherein X¹ is -O-, -S-, -NH-, -CONH-, -COO-, -SO₂-NH-, or -SO₂-O-,

X² is an alkylene, arylene, aralkylene or cycloalkylene spacer containing optionally one or more groups -O-, -S-, -NR¹⁴-, -CO-, -CONH-, -CONR¹⁵-, or -COO- as linking bridge, X³ is OH, NH₂, -C(R¹¹)=CH₂, -OC(0)-C(R¹²)=CH₂, -C(O)-C(R¹²)=CH₂,

C₅-C₇cycloalkenyl, - r

-OC(0)-N-X⁴-N-C(0)-0-X⁵-0-C(0)-C(R¹²)=CH₂ ; wherein

R¹¹ is hydrogen, Cι-C₄alkyl, or halogen,

R¹² is hydrogen, Cι-C alkyl, or halogen,

R¹³ is hydrogen, C C₄alkyl, or C₆-d₂aryl,

R¹⁴ and R¹⁵ are independently of each other hydrogen, C C₈alkyl, or C₆-C₁₂aryl, and

An electroluminescent element according to claim 3, wherein the diketopyrrolopyrrole is a compound of formula I, wherein

An electroluminescent element according to claim 1 , wherein the diketopyrrolopyrrole compound is a compound the absorption of which is in the range of from about 440 to about 500 nm and which shows photoluminescence the peak of which is in the range of from 530 to 570 nm and is used in combination with a fluorescent compound the absorption peak of which is in the range of from about 530 to about 570 nm and which shows photoluminescence the peak of which is in the range of from about 580 to about 650 nm.

An electroluminescent element according to claim 5, wherein the diketopyrrolopyrrole is a compound of formula (I) which shows photoluminescence the peak of which is in the range of from about 530 to about 550 nm or a compound of formula

wherein R²¹ and R²² are independently of each other a Cι-₂₄-alkyl group, a C₂-₂ -alkenyl group, a group of formula -CR³⁰R³¹-(CH₂)_m-Ar⁷or Y-R³², wherein R³⁰ and R³¹ independently of each other stand for hydrogen, or d-C alkyl, or phenyl which can be substituted up to three times with C C₄alkyl, Ar⁷ stands for aryl, C₅-C₈cycloalkyl, C₅-C₈cycloalkenyl or heteroaryl, which can be substituted one to three times with C C₈alkyl, d-C₈alkoxy, cyano, halogen or phenyl, which can be substituted with C C₈alkyl or d-C₈alkoxy one to three times, m stands for 0, 1 , 2, 3 or 4, Y is -C(O)-, -C(0)0-, -C(O)NH-, -SO₂NH- or -S0₂- and R³² is d-Cι₈alkyl, Ar⁷, or aralkyl, or a group -X²-X³, Ar³ and Ar⁴ are independently of each other a group of formula

wherein

R⁴¹, R⁴², R⁴⁴, R⁴⁵, R⁴⁶, R⁴⁷ and R⁴⁸ are independently of each other a hydrogen atom, a d-Cis-alkyl group, a Cι-Cι₈-alkoxy group, or a group -X¹-X²-X³, R⁴³ is a cyano group, a bromine atom, or a phenoxy group which can be substituted one to three times with C C₈alkyl, or d-C₈alkoxy, or R⁴³ is a hydrogen atom, or a C -C₈alkyl group, if Ar³ is not identical to Ar⁴, and R⁴⁹ is hydrogen, or a phenyl group which can be substituted one to three times with d-C₈alkyl, or d-dalkoxy, wherein X¹ is -O-, -S-, -NH-, -CONH-, -COO-, -S0₂-NH-, or -S0₂-0-,

X² is an alkylene, arylene, aralkylene or cycloalkylene spacer containing optionally one or more groups -0-, -S-, -NR¹⁴-, -CO-, -CONH-, -CONR¹⁵-, or -COO- as linking bridge, X³ is OH, NH₂, -C(R¹¹)=CH₂, -OC(0)-C(R¹²)=CH₂, -C(0)-C(R¹²)=CH₂, _ H₂ "C C -C CH

C₅-C₇cycloalkenyl, -CO — ^ Vc = C - ¹³ , °_{\ /}° ' °_{\ /}° ' ^or ^⁼^ ^H CO co -OC(O)-N-X⁴-N-C(O)-O-X⁵-O-C(O)-C(R¹²)=CH₂; wherein

R¹¹ is hydrogen, C C alkyl, or halogen, R¹² is hydrogen, d-C alkyl, or halogen, R¹³ is hydrogen, d-C₄alkyl, or C₆-d₂aryl, R¹⁴ and R¹⁵ are independently of each other hydrogen, d-C₈alkyl, or C₆-C₁₂aryl, and X⁴ and X⁵ are independently of each other an alkylene, arylene, aralkylene or cycloalkylene spacer.

An electroluminescent element according to claim 6, wherein the diketopyrrolopyrrole is a compound of formula II. wherein

An electroluminescent element according to claim 1 , wherein the diketopyrrolopyrrole compound is a compound the absorption peak of which is in the range of from about 530 to about 570 nm and which shows photoluminescence the peak of which is in the range of from about 580 to about 650 nm and is used in combination with a fluorescent compound the absorption peak of which is in the range of from about 440 to about 500 nm and which shows photoluminescence the peak of which is in the range of from about 530 to about 570 nm.

An electroluminescent element according to claim 8, wherein the diketopyrrolopyrrole is a compound of formula

wherein R²³ and R²⁴ are independently of each other a Cι-₂₄-alkyl group, a C₂-₂₄-alkenyl group, a group of formula -CR³⁰R³¹-(CH₂)_m-Ar⁷or Y-R³², wherein R³⁰ and R³¹ independently of each other stand for hydrogen, or C C₄alkyl, or phenyl which can be substituted up to three times with d-C alkyl,

Ar⁷ stands for aryl, C₅-C₈cycloalkyl, C₅-C₈cycloalkenyl or heteroaryl, which can be substituted one to three times with C C₈alkyl, d-C₈alkoxy, cyano, halogen or phenyl, which can be substituted with d-C_aalkyl or C -C₈alkoxy one to three times, m stands for 0, 1 , 2, 3 or 4, Y is -C(O)-, -C(O)0-, -C(O)NH-, -SO₂NH- or -S0₂- and R³² is C Cι₈alkyl, Ar⁷, or aralkyl, or a group of the formula -X²-X³, wherein X² is an alkylene, arylene, aralkylene or cycloalkylene spacer containing optionally one or more groups -0-, -S-, -NR¹⁴-, -CO-, -CONH-, -CONR¹⁵-, or-COO- as linking bridge, X³ is OH, NH₂, -C(R¹¹)=CH₂, -OC(O)-C(R¹²)=CH₂, -C(0)-C(R¹²)=CH₂,

C₅-C₇cycloalkenyl, -

-OC(O)-N-X⁴-N-C(0)-O-X⁵-0-C(0)-C(R¹²)=CH₂ ; wherein R¹¹ is hydrogen, or C C₄alkyl, or halogen, 1₂ s hydrogen, d-C₄alkyl, or halogen, 13 Is hydrogen, CrC alkyl, or C₆-C₁₂aryl, R¹⁴ and R¹⁵ are independently of each other hydrogen, d-C₈alkyl, or C₆-Cι₂aryl, X⁴ and X⁵ are independently of each other an alkylene, arylene, aralkylene or cycloalkylene spacer, Ar⁵ and Ar⁶ are independently of each other a group of formula

wherein R ⁸ and R ⁹ are independently of each other a C C₂ alkyl

group, or a group of formula

, wherein R , R³⁰ and R are independently of each other hydrogen, d-C₈alkyl, d-C₈alkoxy or a group -NR^R , wherein R^ and R are

independently of each other

or , wherein R is hydrogen, d-C₈alkyl or C C₈alkoxy, R⁴¹ is a hydrogen atom, a d-Cι₈-alkyl group, a C Cι₈-alkoxy group, or a group -X¹-X²-X³ , wherein X¹ is -0-, -S-, -NH-, -CONH-, -COO-, -SO₂-NH-, or -SO₂-O-, X² is an alkylene, arylene, aralkylene or cycloalkylene spacer containing optionally one or more groups -0-, -S-, -NR¹⁴-, -CO-, -CONH-, -CONR¹⁵-, or-COO- as linking bridge, X³ is OH, NH₂, -C(R¹¹)=CH₂, -OC(0)-C(R¹²)=CH₂, -C(0)-C(R¹²)=CH₂,

C₅-C₇cycloal kenyl , -

-OC(0)-N-X⁴-N-C(0)-0-X⁶-O-C(O)-C(R¹²)=CH₂ ; wherein R¹¹ is hydrogen, C C alkyl, or halogen, R¹² is hydrogen, d-dalkyl, or halogen, R ³ is hydrogen, d-C₄alkyl, or C₆-d₂aryl, R¹⁴ and R¹⁵ are independently of each other hydrogen, d-C₈alkyl, or C₆-C₁₂aryl, and X⁴ and X⁵ are independently of each other an alkylene, arylene, aralkylene or cycloalkylene spacer, or R¹⁸ and R¹⁹ together form a five or six membered ring, in

particular -o

10. An electroluminescent element according to claim 9, wherein the diketopyrrolopyrrole is a compound of formula 111, wherein Ar⁵ and Ar⁶ are independently of each other a

group of formula

, wherein

1 . An electroluminescent element according to claim 1 , wherein the diketopyrrolopyrrole compound is a compound the absorption of which is in the range of from about 500 to about 530 nm, especially in the range of from about 500 to about 520 nm, and which shows photoluminescence the peak of which is in the range of from 540 to 600 nm, especially in the range of from 550 to 580 nm, and is used in combination with a fluorescent compound the absorption peak of which is in the range of from about 530 to about 570 nm and which shows photoluminescence the peak of which is in the range of from about 580 to about 650 nm, and optionally with a fluorescent compound the absorption peak of which is in the range of from about 440 to about 500 nm and which shows photoluminescence the peak of which is in the range of from about 530 to about 570 nm.

12. An electroluminescent element according to claim 11, wherein the diketopyrrolopyrrole is a compound of formula

(IV), wherein R⁹¹ and R⁹² are independently of each other a d-C₂₄alkyl group, a C -C₂₄alkenyl group, a group of formula -CR³⁰R³¹-(CH₂)_m-Ar⁷orY-R³², wherein R³⁰ and R³ independently of each other stand for hydrogen, or d-dalkyl, or phenyl which can be substituted up to three times with d-dalkyl, Ar⁷ stands for

Cs-Cβcycloalkyl, Cs-Cscycloalkenyl, or heteroaryl, which can be substituted one to three times with d-G₈alkyl, CrCβalkoxy, cyano, halogen or phenyl, which can be substituted with C C₈alkyl or d-C₈alkoxy one to three times, m stands for 0, 1, 2, 3 or 4, Y is -C(O)-, -C(0)O-, -C(0)NH-, -S0₂NH- or -SO₂-, R³² is C C₁₈alkyl. Ar⁷, or C₇-C₂ aralkyl, or a group of the formula -X²-X³, Ar⁸ and Ar⁹ are independently of each other a group of formula

wherein R⁴⁶ is a C Cι₈alkoxy group, R⁴⁴, R⁴⁵, R⁵⁵, R⁶⁵ and R⁶⁶ are independently of each other a hydrogen atom, a C Cι₈alkyl group, a Cι-Ci₈-alkoxy group, or a group -X¹-X²-X³, wherein X¹ is -0-, -S-, -NH-, -CONH-, -COO-, -S0₂-NH-, or -S0₂-O-. X² is an alkylene, arylene, aralkylene or cycloalkylene spacer containing optionally one or more groups -O-, -S-, -NR¹⁴-, -CO-, -CONH-, -CONR¹⁵-, or -COO- as linking bridge, X³ is -OH, -NH₂, -C(R ¹)=CH₂, -OC(O)-C(R¹²)=CH₂, -C(0)-C(R¹²)=CH₂,

C₅-C₇cycl oalkenyl, - CO or

-OC(0)-N-X⁴-N-C(0)-0-X⁵-0-C(0)-C(R¹²)=CH₂ ; wherein R¹¹ is hydrogen, d-dalkyl, or halogen, R¹² is hydrogen, d-C alkyl, or halogen, R¹³ is hydrogen, d-dalkyl, or C₆-Ci₂aryl, R¹⁴ and R¹⁵ are independently of each other hydrogen, d-C₈alkyl, or C₆-C₁₂aryl, and X⁴ and X⁵ are independently of each other an alkylene, arylene, aralkylene or cycloalkylene spacer. R⁹³ and R⁹⁴ are independently of each other a Cι-C₁₈alkyl group, Y¹ is -0-, -S-, -SO₂-, -NR⁶⁸-, -CHR⁶⁸-, and ni is1, 2, or 3, especially 1, or 2, wherein R⁶⁸ is Ci.Cis-alkyl, or C₆-d₂aryl.

13. An An electroluminescent element according to claim 12, wherein the diketopyrrolopyrrole of formula IV is selected from