An organic light emitting device (100, 200), comprising an organic layer positioned between an anode layer (115, 230) and a cathode layer (160, 215), said organic layer comprising an organoselenium material selected from the group consisting of wherein each of R 1 R 2, R 3, R 4, R 5, R 6 and R 7 indicates an optional substituent to any possible position in the relevant moiety, and each line linking two molecular moieties indicates attachment between the two moieties at any possible positions on the respective moieties, wherein each of said optional substituents represented by R 1, R 2, R 3, R 4, R 5, R 6 and R 7 consists of halo, alkyl, heteroalkyl, cycloalkyl, alkenyl, alkynyl, arylalkyl, heterocyclic group, aromatic group, and heteroaryl; wherein said aromatic group consists of benzene, benzocyclopropene, benzocyclopropane, benzocyclobutadiene, and benzocyclobutene, naphthalene, anthracene, tetracene, pentacene, phenanthrene, triphenylene, helicenes, corannulene, azulene, acenaphthylene, furan, benzofuran, isobenzofuran, pyrrole, indole, isoindole, thiophene, benzothiophene, benzo[c]thiophene, imidazole, benzimidazole, purine, pyrazole, indazole, oxazole, benzoxazole, isoxazole, benzisoxazole, thiazole, benzothiazole, pyridine, quinoline, isoquinoline, pyrazine, quinoxaline, acridine, pyrimidine, quinazoline, pyridazine and cinnoline; or wherein the organoselenium material is: wherein each of R 1 and R 2 indicates an optional substituent to any possible position in the relevant moiety, selected from the group consisting of halo, alkyl, heteroalkyl, cycloalkyl, alkenyl, alkynyl, arylalkyl, benzene, benzocyclopropene, benzocyclopropane, benzocyclobutadiene, and benzocyclobutene, naphthalene, anthracene, tetracene, pentacene, phenanthrene, triphenylene, helicenes, corannulene, azulene, acenaphthylene, furan, benzofuran, isobenzofuran, pyrrole, indole, isoindole, thiophene, benzothiophene, benzo[c]thiophene, imidazole, benzimidazole, purine, pyrazole, indazole, oxazole, benzoxazole, isoxazole, benzisoxazole, thiazole, benzothiazole, pyridine, quinoline, isoquinoline, pyrazine, quinoxaline, acridine, pyrimidine, quinazoline, pyridazine and cinnoline. wherein each of R 1 R 2, R 3, R 4, R 5, R 6 and R 7 indicates an optional substituent to any possible position in the relevant moiety, and each line linking two molecular moieties indicates attachment between the two moieties at any possible positions on the respective moieties, wherein each of said optional substituents represented by R 1, R 2, R 3, R 4, R 5, R 6 and R 7 consists of halo, alkyl, heteroalkyl, cycloalkyl, alkenyl, alkynyl, arylalkyl, heterocyclic group, aromatic group, and heteroaryl; wherein said aromatic group consists of benzene, benzocyclopropene, benzocyclopropane, benzocyclobutadiene, and benzocyclobutene, naphthalene, anthracene, tetracene, pentacene, phenanthrene, triphenylene, helicenes, corannulene, azulene, acenaphthylene, furan, benzofuran, isobenzofuran, pyrrole, indole, isoindole, thiophene, benzothiophene, benzo[c]thiophene, imidazole, benzimidazole, purine, pyrazole, indazole, oxazole, benzoxazole, isoxazole, benzisoxazole, thiazole, benzothiazole, pyridine, quinoline, isoquinoline, pyrazine, quinoxaline, acridine, pyrimidine, quinazoline, pyridazine and cinnoline; or wherein the organoselenium material is: wherein each of R 1 and R 2 indicates an optional substituent to any possible position in the relevant moiety, selected from the group consisting of halo, alkyl, heteroalkyl, cycloalkyl, alkenyl, alkynyl, arylalkyl, benzene, benzocyclopropene, benzocyclopropane, benzocyclobutadiene, and benzocyclobutene, naphthalene, anthracene, tetracene, pentacene, phenanthrene, triphenylene, helicenes, corannulene, azulene, acenaphthylene, furan, benzofuran, isobenzofuran, pyrrole, indole, isoindole, thiophene, benzothiophene, benzo[c]thiophene, imidazole, benzimidazole, purine, pyrazole, indazole, oxazole, benzoxazole, isoxazole, benzisoxazole, thiazole, benzothiazole, pyridine, quinoline, isoquinoline, pyrazine, quinoxaline, acridine, pyrimidine, quinazoline, pyridazine and cinnoline.