White light-emitting organic electroluminescent devices

A light-emitting device comprising:

• a light-emitting member that comprises a first electrode, a second electrode, at least two organic EL materials disposed in separate layers between said first and second electrodes, and a charge blocking layer disposed between said layers of said organic PL materials, said light-emitting member being disposed on a substrate and emitting first EM radiation having a first spectrum when an electrical voltage is applied across said electrodes;
• and
• at least one PL material disposed in a path of light emitted by said light-emitting member, said PL material absorbing a portion of said first EM radiation and emitting second EM radiation having a second spectrum having a wavelength range from about 500 nm to about 600 nm;
• wherein at least a first organic EL material is selected from the group consisting of poly(N-vinylcarbazole);
• poly(alkylfluorene);
• poly(paraphenylene);
• polysilanes;
• derivatives of poly(N-vinylcarbazole);
• derivatives of poly(alkylfluorene);
• derivatives of poly(paraphenylene);
• derivatives of polysilanes;
• mixtures comprising at least two of poly(N-vinylcarbazole), poly(alkylfluorene), poly(paraphenylene), and polysilanes;
• copolymers comprising structural units found in at least two of poly(N-vinylcarbazole), poly(alkylfluorene), poly(paraphenylene), and polysilanes;
• 1,3,5-tris{n-(4-diphenylaminophenyl) phenylamino} benzene;
• phenylanthracene;
• tetraarylethene;
• coumarin;
• rubrene;
• tetraphenylbutadiene;
• anthracene;
• perylene;
• coronene;
• aluminum-(picolymethylketone)-bis[2,6-di(t-butyl)phenoxides;
• scandium-(4-methoxypicolymethylketone)-bis(acetylacetonate);
• aluminum-acetylacetonate;
• gallium-acetylacetonate;
• and indium-acetylacetonate;
• and
• at least a second organic EL material is selected from the group consisting of
• wherein each of R1, R2, R3, and R4 is independently selected from the group consisting of aromatic, substituted aromatic, heteroaromatic, or substituted heteroaromatic groups;
• wherein R1 and R2 are independently represented by
• wherein R′ an R″ are independently selected from the group consisting of alkylaryl, alkenylaryl, and heteroaryl groups;
• Q is a radical selected from aryl group and fused ring aromatic groups;
• and n is from 1 to 3, inclusive;
• where A is selected from the group consisting of Br− and naphthyl radical;
• said PL material is selected from the group consisting of organic PL materials and inorganic PL material;
• said organic PL materials are selected from the group consisting of azo dyes, anthraquinone dyes, nitrodiphenylamine dyes, iron (II) complexes of 1-nitroso-2-naphthol and 6-sulphol-1-nitroso-2-naphthol, coumarin dyes, and xanthene dyes;
• said inorganic PL materials are selected from the group consisting of Ca8Mg(SiO4)4Cl2:Eu2+,Mn2+;
• GdBO3:Ce3+, Tb3+;
• CeMgAl11O19:Tb3+;
• Y2SiO5:Ce3+,Tb3+;
• and BaMg2Al16O27:E2+,Mn2+;
• (Ca,Sr)S:Ce;
• Sr2Si3O8.2SrCl2:Eu2+;
• Sr4Al11O25:Eu2+;
• Y(Cd,Tb,Lu,)3(Al,Ga)5O12:Ce3+, and Mn-doped magnesium fluorogermanate;
• and
• said charge blocking layer comprises a material selected from the group consisting of poly(N-vinyl carbazole), bathocuproine (“BCP”), bis(2-methyl-8-quinolinato)triphenylsilanolate aluminum (III), bis(2-methyl-8-quinolinato)4-phenolate aluminum (III), and bis(2-methyl-8-quinolinato)4-phenylphenolate aluminum (III), N,N′-diphenyl-N,N′-(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine and poly(3-octyl-4-methylthiophene).

A method of making a light-emitting device that comprises at least two organic PL materials, each of which emits EM radiation having one of two wavelength ranges, said method comprising:

• (1) forming a light-emitting member in a process comprising the steps of:
• providing a first electrode comprising a first electrically conducting material, and a second electrode comprising a second electrically conducting material;
• disposing said at least two organic EL materials between said first and second electrodes;
• and
• disposing a charge blocking material between said at least two organic EL;
• and
• (2) disposing at least one PL material adjacent to said light-emitting member.