Keywords: Alq3; tris(8-hydroxyquinolinato) aluminum(III); BCP; bathocuproine; BHJSCs; bulk heterojunction solar cells; BAlq-13; bis(2-methyl-quinolin-8-olato)(2,6-diphenylphenolato)aluminum(III); Bphen; bathophenanthroline; bpy; 2,2â²-bipyridine; bq; 2,2â²-biquin