Crosslinkable P3HT as Hole Transport Layer of Polymer Based Solar Cells

A photocrosslinkable bromine-functionalized poly(3-hexylthiophene) (P3HT-Br) copolymer was synthesized and used as the hole transport layer in polymer solar cells based on poly(3-hexylthiophene), and low band gap polymer, 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) with [6,6]-phenyl-C61-butyric acid methyl ester. Electrochemical stability of crosslinked P3HT-Br is superior to poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS), which has widely been used as the hole transport material in polymer solar cells.