Conjugated polymer consisting of benzothiadiazole and phenazine as donor materials for organic photovoltaics

Abstract

Two new polymers, poly(thiophene-benzothiadiazole) (PThBT) and poly(thiophene-dibenzophenazine) (PThFQ), were successfully polymerized through a Stille coupling reaction. PThBT exhibited the formation of an ordered lamellar structure with conventional edge-on pi-stacking. In contrast, the PThFQ backbones were oriented face-on relative to the substrate. For solar cells using a 1:6 ratio of PThFQ to PC71BM, the resulting Voc, Jsc, FF and PCE were 0.73 V, 3.4 mA/cm(2), 30.5% and 0.76%, respectively. The value of the FF for PThFQ increased by 22% compared to PThBT due to the effects of the backbone planarity of the polymers and the face-on orientation. (C) 2014 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.