Summary: A series of cross‐linked polythiophene derivatives ( P1 – 4 ) are synthesized by adding different ratio (0, 2, 5, and 10%) of conjugated cross‐linker via a Stille coupling reaction. From P1 – 4 , with the increase of the content of the conjugated bridges, the UV‐visible absorption peaks of the polymers were shifted towards blue and their electrochemical bandgap increased. The hole mobilities of P1 – 4 as determined from the SCLC model are 5.23 × 10−6, 1.28 × 10−4, 7.01 × 10−3, and 2.34 × 10−5 cm2 · V−1 · s−1, respectively. The PCEs of the polymer solar cells based on P1 – 4 are 0.37, 1.05, 1.26, and 0.78%, respectively. The improvement of PCE of the devices based on P2 – 4 compared with that of P1 may be due to the increase of hole mobility.
Molecular structure of the polythiophene derivatives ( P1 – 4 ).
