A Polycyclic Aromatic Hydrocarbon random Copolymer (PAHC) comprising a mixture of at least one benzochalcogenophenobenzochalogenophene (BXBX) monomer unit having the Formula, and at least one fluorene monomer unit having the Formula, and at least one triarylamine monomer unit having the Formula: wherein, Y 1 and Y 2 are independently S or Se; k is 0 or 1; I is 0 or 1; n' is 0,1, 2 or 3; wherein each of R 1, R 2, R 3, R 4, R 5, R 6, R 7, R 8, R 9, R 10, R 11 and R 12, which may be the same or different, independently represents hydrogen; a branched or unbranched, substituted or unsubstituted C 1 -C 40 alkyl group; a branched or unbranched, substituted or unsubstituted C 2 -C 40 alkenyl group; a branched or unbranched, substituted or unsubstituted C 2 -C 40 alkynyl group; an optionally substituted C 3 -C 40 cycloalkyl group; an optionally substituted C 6 -C 40 aryl group; an optionally substituted C 1 -C 40 heterocyclic group; an optionally substituted C 1 -C 40 heteroaryl group; an optionally substituted C 1 -C 40 alkoxy group; an optionally substituted C 6 -C 40 aryloxy group; an optionally substituted C 7 -C 40 alkylaryloxy group; an optionally substituted C 2 -C 40 alkoxycarbonyl group; an optionally substituted C 7 -C 40 aryloxycarbonyl group; a cyano group (-CN); a carbamoyl group (-C(=O)NR 15 R 16); a carbonyl group (-C(=O)-R 17); a carboxyl group (-CO 2 R 18) a cyanate group (-OCN); an isocyano group (-NC); an isocyanate group (-NCO); a thiocyanate group (-SCN) or a thioisocyanate group (-NCS); an optionally substituted amino group; a hydroxy group; a nitro group; a CF 3 group; a halo group (Cl, Br, F, I); -SR 19; -SO 3 H; -SO 2 R 20; -SF 5; an optionally substituted silyl group; wherein at least two of R 1, R 3, R 4, R 6, R 7, R 9, R 10, and R 12, are a bond, represented by -*, to another monomer unit having the Formula,,or; and wherein each R 1', R 2', R 3' and R 4', each of which may be the same or different, is selected from the same group as R 1, R 2, R 3, R 4 already defined above for monomer and for the monomer group, -* represents a bond to another monomer unit having the Formula, or wherein Ar 1, Ar 2 and Ar 3, which may be the same or different, each represent, independently, an optionally substituted C 6-40 aromatic group (mononuclear or polynuclear), wherein preferably at least one of Ar 1, Ar 2 and Ar 3 is substituted with at least one polar or polarising groups and for the monomer group, -* represents a bond to another monomer unit having the Formula, or. Y 1 and Y 2 are independently S or Se; k is 0 or 1; I is 0 or 1; n' is 0,1, 2 or 3; wherein each of R 1, R 2, R 3, R 4, R 5, R 6, R 7, R 8, R 9, R 10, R 11 and R 12, which may be the same or different, independently represents hydrogen; a branched or unbranched, substituted or unsubstituted C 1 -C 40 alkyl group; a branched or unbranched, substituted or unsubstituted C 2 -C 40 alkenyl group; a branched or unbranched, substituted or unsubstituted C 2 -C 40 alkynyl group; an optionally substituted C 3 -C 40 cycloalkyl group; an optionally substituted C 6 -C 40 aryl group; an optionally substituted C 1 -C 40 heterocyclic group; an optionally substituted C 1 -C 40 heteroaryl group; an optionally substituted C 1 -C 40 alkoxy group; an optionally substituted C 6 -C 40 aryloxy group; an optionally substituted C 7 -C 40 alkylaryloxy group; an optionally substituted C 2 -C 40 alkoxycarbonyl group; an optionally substituted C 7 -C 40 aryloxycarbonyl group; a cyano group (-CN); a carbamoyl group (-C(=O)NR 15 R 16); a carbonyl group (-C(=O)-R 17); a carboxyl group (-CO 2 R 18) a cyanate group (-OCN); an isocyano group (-NC); an isocyanate group (-NCO); a thiocyanate group (-SCN) or a thioisocyanate group (-NCS); an optionally substituted amino group; a hydroxy group; a nitro group; a CF 3 group; a halo group (Cl, Br, F, I); -SR 19; -SO 3 H; -SO 2 R 20; -SF 5; an optionally substituted silyl group; wherein at least two of R 1, R 3, R 4, R 6, R 7, R 9, R 10, and R 12, are a bond, represented by -*, to another monomer unit having the Formula,,or; and wherein each R 1', R 2', R 3' and R 4', each of which may be the same or different, is selected from the same group as R 1, R 2, R 3, R 4 already defined above for monomer and for the monomer group, -* represents a bond to another monomer unit having the Formula, or wherein Ar 1, Ar 2 and Ar 3, which may be the same or different, each represent, independently, an optionally substituted C 6-40 aromatic group (mononuclear or polynuclear), wherein preferably at least one of Ar 1, Ar 2 and Ar 3 is substituted with at least one polar or polarising groups and for the monomer group, -* represents a bond to another monomer unit having the Formula, or.