Naphtho[1,2-b:5,6-b′]dithiophene-based conjugated polymer as a new electron donor for bulk heterojunction organic solar cells

Abstract

We report for the first time the synthesis and photovoltaic application of a naphtho[1,2-b:5,6-b′]dithiophene (NDT) containing donor–acceptor conjugated copolymer. The combination of a thiophene-bridge NDT building block with a quinoxaline acceptor unit results in a new copolymer that has an optical band gap of 1.77 eV, a HOMO level of −5.24 eV, and a hole mobility of 5.0 × 10⁻⁵ cm² V⁻¹ s⁻¹. Preliminary characterization of the bulk-heterojunction solar cell device exhibits a PCE of around 1.5%.