Synthesis and photovoltaic characteristics of push-pull organic semiconductors containing an electron-rich dithienosilole bridge for solution-processed small-molecule organic solar cells

Abstract

The synthesis and characterization of unprecedented push-pull organic semiconductors, TPA-Th-DTSi-[HxTh](2)-HCA (1), TPA-Th-DTSi-[HxTh](2)-MMN (2), bisDMFA-Th-DTSi-[HxTh](2)-HCA (3), and bisDMFA-Th-DTSi-[HxTh](2)-MMN (4) possessing a pi-conjugated thiophene bridge incorporating electron-rich dithienosiole (DTSi) moieties-are described, along with an investigation of their photovoltaic performances in solution-processed SMOSCs. Results showed that the greater intensities of pi-pi* transitions from the electron-rich Th-DTSi-[HxTh](2) bridge to [HxTh](2)-MMN (or[HxTh](2)-HCA) acceptors provide superior photocurrent efficiencies from absorbed photons compared to those via ICT transition in SMOSCs fabricated with these new material's coupled with PC71BM BHJ films. The most efficient SMOSCs fabricated based on this pi-conjugation bridge-containing electron-rich DTSi motif exhibited a moderate PCE of 2.34% from skeleton comprising of bisDMFA donor and MMN acceptor. (C) 2013 Elsevier B.V. All rights reserved.