p-Type Conjugated Polymers Containing Electron-Deficient Pentacyclic Azepinedione

Qiao He; Jessica Shaw; Yuliar Firdaus; Xiantao Hu; Bowen Ding; Adam V Marsh; Alexandre S Dumon; Yang Han; Zhuping Fei; Thomas D Anthopoulos; Christopher R McNeill; Martin Heeney

doi:10.1021/acs.macromol.3c00843

p-Type Conjugated Polymers Containing Electron-Deficient Pentacyclic Azepinedione

Macromolecules. 2023 Jul 26;56(15):5825-5834. doi: 10.1021/acs.macromol.3c00843. eCollection 2023 Aug 8.

Authors

Qiao He¹, Jessica Shaw¹, Yuliar Firdaus^{2

3}, Xiantao Hu¹, Bowen Ding¹, Adam V Marsh², Alexandre S Dumon¹, Yang Han⁴, Zhuping Fei⁵, Thomas D Anthopoulos², Christopher R McNeill⁶, Martin Heeney^{2

7}

Affiliations

¹ Department of Chemistry and Centre for Processable Electronics, Imperial College London, White City Campus, London W12 0BZ, U.K.
² KAUST Solar Center (KSC), Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.
³ Research Center for Electronics, National Research and Innovation Agency (BRIN), Komplek BRIN Jl. Sangkuriang Cisitu, Bandung 40135, Indonesia.
⁴ School of Materials Science & Engineering, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin 300072, China.
⁵ Institute of Molecular Plus, Department of Chemistry, Tianjin Key Laboratory of Molecular Optoelectronic Science, Tianjin University, Tianjin 300072, China.
⁶ Department of Materials Science and Engineering, Monash University, Clayton, Victoria 3800, Australia.
⁷ Department of Chemistry and Centre for Processable Electronics, Imperial College London, London W12 0BZ, U.K.

Abstract

Bisthienoazepinedione (BTA) has been reported for constructing high-performing p-type conjugated polymers in organic electronics, but the ring extended version of BTA is not well explored. In this work, we report a new synthesis of a key building block to the ring expanded electron-deficient pentacyclic azepinedione (BTTA). Three copolymers of BTAA with benzodithiophene substituted by different side chains are prepared. These polymers exhibit similar energy levels and optical absorption in solution and solid state, while significant differences are revealed in their film morphologies and behavior in transistor and photovoltaic devices. The best-performing polymers in transistor devices contained alkylthienyl side chains on the BDT unit (pBDT-BTTA-2 and pBDT-BTTA-3) and demonstrated maximum saturation hole mobilities of 0.027 and 0.017 cm² V^-1 s^-1. Blends of these polymers with PC₇₁BM exhibited a best photovoltaic efficiency of 6.78% for pBDT-BTTA-3-based devices. Changing to a low band gap non-fullerene acceptor (BTP-eC9) resulted in improved efficiency of up to 13.5%. Our results are among the best device performances for BTA and BTTA-based p-type polymers and highlight the versatile applications of this electron-deficient BTTA unit.