Molecular Optimization on Polymer Acceptor Enables Efficient All‐Polymer Solar Cell with High Open‐Circuit Voltage of 1.10 V

Abstract

Currently, rational design of polymer acceptors is desirable but there is still a challenge to develop high-performance all-polymer solar cells (all-PSCs). In this work, brominated thienyl-fused malononitrile-based monomer is employed to copolymerize with indacenodithiophene (IDT) and benzodithiophene (BDT)-based linking units to develop two polymerized small molecule acceptors (PSMAs) PIDT and PBDT, respectively, for all-PSCs. The two PSMAs show similar absorption edges, while PBDT shows a slightly higher lowest unoccupied molecular orbital (LUMO) energy level than PIDT. Benefitted from the relatively high LUMO levels of the two polymer acceptors, notable open-circuit voltage (V oc ) values over 1.0 V are achieved when using them as acceptor to blend with PTQ10 as polymer donor. Particularly, the all-PSC based on PTQ10:PIDT demonstrates a power conversion efficiency of 10.19%, with an outstanding Voc of 1.10 V benefitted from the higher LUMO energy level of PIDT acceptor. The results demonstrate a feasible strategy to design PSMAs by selecting appropriate linking units for increasing the V oc and improving the efficiency of all-PSCs.

Perovskite and Polymeric Solar Cells: A Comparison of Advances and Key Challenges

“…In the same year, Yang et al [ 78 ] synthesized two different polymerized small molecule acceptors (PSMAs), PIDT, and PBDT, based on indacenedithiophene (IDT) and benzodithiophene (BDT). In addition, PTQ10 was used as a donor polymer to form PTQ10 active layers: (PIDT or PBDT):PTQ10.…”

Isomeric Monomer Engineering of Regioregular Polymer Acceptors for Efficient All-Polymer Solar Cells

“…Therefore, deeply understanding the correlation between the molecular structure and performance of PSMAs is imperative for further advancing the development of all-PSCs. 29,30 Herein, we report the synthesis of two regioregular PSMAs (namely, PBTP-α and PBTP-β, see Figure 1a) that consist of isomeric thiophene-fused ending-groups TCN-α and TCN-β, respectively, with the same central block and thiophene πbridge. To gain a comprehensive understanding of the effect of terminal group isomerism on the photoelectric and photovoltaic properties of PSMAs, the regiorandom analogue PBTPm was also developed by copolymerization of thiophene with unpurified mixed monomers (M1, M2, and M3) (Figure 1b).…”

“…The aforementioned examples exemplify the significance of isomeric thiophene terminal groups in the design of efficient PSMAs. Therefore, deeply understanding the correlation between the molecular structure and performance of PSMAs is imperative for further advancing the development of all-PSCs. , …”