Naphthodithieno[3,2-b]thiophene-based donor-acceptor copolymers: Synthesis, characterization, and their photovoltaic and charge transport properties

摘要

Herein, we report the synthesis, characterization, and their photovoltaic and field-effect properties of two dialkoxyl-substituted naphthodithieno[3,2-b]thiophene (NDTT)-based copolymers, namely P1 and P2. The NDTT-based copolymers exhibit broad absorption profiles throughout the visible spectrum up to ca. 800 nm. The copolymers have HOMO/LUMO energy levels of ca. -5.14 eV/-3.52 eV. The dialkoxyl-substituted NDTT units endow the copolymers with enhanced solution processability, and crystalline stacking thin films with small pi-pi distances of down to 3.59 angstrom. Polymer-fullerene bulk heterojunction solar cells that fabricated from a blend of P2/PC71BM using diiodooctane as a solvent additive, afforded the highest power conversion efficiency of 3.54%. Solution-processed polymer field-effect transistors based on P1 with bottom-gate bottom-contact geometry exhibited promising hole mobilities of 0.070 cm(2) V-1 s(-1). (C) 2016 Elsevier Ltd. All rights reserved.