“…[ 9 , 10 ] The concept of semi-transparent solar cells becomes particularly interesting for window applications if mainly the infrared part of light is absorbed. In order to synthesize polymers with an extended absorption to the infrared, the concept of co-polymers with alternating electron rich and electron depleted units such as poly [2,7-(9,9-dioctylfluorene)-alt-5,5-(5',8'-di-2-thienyl-(2',3'-bis-(3''-octyloxyphenyl)-quinoxaline))] (APFO-15), [ 11 ] poly[N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)] (PCDTBT), [ 12 ] poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b']dithiophene)-alt-4,7-(2,1,3-benzothiadiazole)] (PCPDTBT) [ 13 ] or poly[(4,4'-bis(2-ethylhexyl) dithieno [3,2- [ 14 ] has proven itself benefi cial.…”