An organic semiconductor layer comprising: - a compound of formula 1: wherein X is O, S or Se; Ar 1 is selected from unsubstituted C 6 to C 24 aryl or unsubstituted C 3 to C36 heteroaryl ; R 1 , R 2 are independently selected from substituted or unsubstituted C 6 to C 24 aryl, substituted or unsubstituted C 3 to C 24 heteroaryl, or R 1 and R 2 are selected from substituted or unsubstituted C 6 to C 24 aryl and substituted or unsubstituted C 3 to C 24 heteroaryl and linked with each other via a single bond such that a five-membered ring is formed, wherein the substituents of the substituted C 6 to C 24 aryl and substituted C 3 to C 24 heteroarylene are selected from H, D, C 1 to C 16 alkyl, partially or perfluorinated C 1 to C 16 alkyl, partially or perdeuterated C 1 to C 16 alkyl, C 1 to C 16 alkoxy, C 1 to C 16 thioalkyl, C 3 to C 16 branched alkyl, C 3 to C 16 cyclic alkyl, C 3 to C 16 branched alkoxy, C 3 to C 16 cyclic alkoxy, C 3 to C 16 branched thioalkyl, C 3 to C 16 cyclic thioalkyl, C 6 to C 24 aryl and C 3 to C 25 heteroaryl; and - a dopant selected from an organic metal complex or metal halide. - a compound of formula 1: wherein X is O, S or Se; Ar 1 is selected from unsubstituted C 6 to C 24 aryl or unsubstituted C 3 to C36 heteroaryl ; R 1 , R 2 are independently selected from substituted or unsubstituted C 6 to C 24 aryl, substituted or unsubstituted C 3 to C 24 heteroaryl, or R 1 and R 2 are selected from substituted or unsubstituted C 6 to C 24 aryl and substituted or unsubstituted C 3 to C 24 heteroaryl and linked with each other via a single bond such that a five-membered ring is formed, wherein the substituents of the substituted C 6 to C 24 aryl and substituted C 3 to C 24 heteroarylene are selected from H, D, C 1 to C 16 alkyl, partially or perfluorinated C 1 to C 16 alkyl, partially or perdeuterated C 1 to C 16 alkyl, C 1 to C 16 alkoxy, C 1 to C 16 thioalkyl, C 3 to C 16 branched alkyl, C 3 to C 16 cyclic alkyl, C 3 to C 16 branched alkoxy, C 3 to C 16 cyclic alkoxy, C 3 to C 16 branched thioalkyl, C 3 to C 16 cyclic thioalkyl, C 6 to C 24 aryl and C 3 to C 25 heteroaryl; and X is O, S or Se; Ar 1 is selected from unsubstituted C 6 to C 24 aryl or unsubstituted C 3 to C36 heteroaryl ; Ar 1 is selected from unsubstituted C 6 to C 24 aryl or unsubstituted C 3 to C36 heteroaryl ; R 1 , R 2 are independently selected from substituted or unsubstituted C 6 to C 24 aryl, substituted or unsubstituted C 3 to C 24 heteroaryl, or R 1 and R 2 are selected from substituted or unsubstituted C 6 to C 24 aryl and substituted or unsubstituted C 3 to C 24 heteroaryl and linked with each other via a single bond such that a five-membered ring is formed, wherein the substituents of the substituted C 6 to C 24 aryl and substituted C 3 to C 24 heteroarylene are selected from H, D, C 1 to C 16 alkyl, partially or perfluorinated C 1 to C 16 alkyl, partially or perdeuterated C 1 to C 16 alkyl, C 1 to C 16 alkoxy, C 1 to C 16 thioalkyl, C 3 to C 16 branched alkyl, C 3 to C 16 cyclic alkyl, C 3 to C 16 branched alkoxy, C 3 to C 16 cyclic alkoxy, C 3 to C 16 branched thioalkyl, C 3 to C 16 cyclic thioalkyl, C 6 to C 24 aryl and C 3 to C 25 heteroaryl; - a dopant selected from an organic metal complex or metal halide. <EOS>