Bisbenzothiadiazole-based Donor-Acceptor Copolymers for Bulk-Heterojunction Solar Cells

Abstract

On the basis of theoretical considerations of intramolecular charge transfer (ICT) effect, we have designed a series of donor (D)-acceptor (A) conjugated polymers based on bisbenzothiadiazole (BBT). A PPP type copolymer of electron-rich 2,7-carbazole (CZ) and electron-deficient BBT units poly(N-(2-decyltetradecyl)-2,7-carbazole-co-7,7'-(4,4′-bis(2,1,3-benzothiadiazole))) (PCZ-BBT), a PPV type copolymer poly(N-(2-decyltetradecyl)-2,7-carbazolevinylene-co-7,7'-(4,4′-bis(2,1,3-benzothiadiazolevinylene))) (PCZV-BBTV), and a tercopolymer based on carbazole, thiophene and BBT poly(N-(2-decyltetradecyl)-2,7-(di-2-thienyl)carbazole-co-7,7'-(4,4′-bis(2,1,3-benzothiadiazole))) (PDTCZ-BBT) have been synthesized to understand the influence of BBT acceptor structure and linkage on the photovoltaic characteristics of the resulting materials.