Alkoxyphenyl-thiophene, -selenophene and -furan substituted benzodithiophene based 2D pi-conjugated polymers for polymer solar cells and effect of chalcogen on optoelectronic properties

摘要

In order to analyze the correlation between the optpelectronic properties and chalcogen present in the conjugated side chain of benzodithiophene (BDT) based 2D pi-conjugated polymers, we synthesized a new series of 2D pi-conjugated polymers P1 (S), P2 (Se), and P3 (0), in which alkoxyphenyl-thiophene, alkoxyphenyl-selenophene and alkoxyphenyl-furan substituted BDT as an electron rich donor unit and thieno[3,4-c]pyrrole-4,6-dione as an "electron deficient acceptor unit, respectively. The P1-P3 showed varied optoelectronic properties with respect to the chalcogen present in the conjugated side chains of donor unit. The bulk heterojunction (BHJ) polymer solar cells (PSCs) based on P1-P3 showed maximum power conversion efficiency of 3.37, 3.53 and 1.54%, respectively. In particular, open-circuit voltages (V-OC) of P1-P3 based PSCs were (0.92, 0.96 and 0.80 V) significantly affected upon chalcogen exchange, which was further analyzed by Mott-Schottky analysis and, the obtained flat-band potential values are well matched with the V-OC of P1-P3 based devices. (C) 2016 Elsevier B.V. All rights reserved.