Cyanoesterthiophene Based Low‐Cost Polymer Donors for High Efficiency Organic Solar Cells

Abstract

To achieve commercial application of organic solar cells (OSCs), it is necessary to reduce material costs and improve device efficiency. This paper reports on the utilization of a multifunctional building block, namely 3‐cyanoesterthiophene, which exhibits simple structure and accessibility of synthetic for cost‐effective and high‐performance polymer donors (PDs). Meanwhile, ternary and terpolymerization strategies have been studied. Two similar PDs, PBTCl0‐TCA and PBTCl100‐TCA, are synthesized, and the devices exhibit less‐than‐satisfactory efficiency of 13.21% and 11.53% due to mismatching energy level and imperfect morphology. The two PDs with comparable structures and commendable compatibility easily form alloy‐like phase in active layer, which can effectively boost the efficiency of ternary devices to 14.17% with retained high JSC and significant improved open‐circuit voltage (VOC) and fill factor (FF). Encouraged by the ternary blending phenomenon, a polymer donor (PBTCl50‐TCA) with same ratio by random terpolymerization is designed. And over 17% efficiency binary OSCs using terpolymerization donor are demonstrated. The synergies of incorporation of the cyanoester‐group and terpolymer endow the developed PDs with deep‐lying energy levels, face‐on orientation, thermodynamic miscibility with the prevailing nonfullerene acceptor and appropriate polymer crystallinity. The findings study provide valuable insights and support for the advancement of cost‐effective and high‐performance PDs.

Cost-effective polymer donors with simple structure for organic solar cells

“…Polymer donors are mainly composed of alternating electron-deficient units and electron-rich units, which usually have a complex fused-ring structure and synthesis process, leading to excessive production costs. 36,37 Therefore, it is necessary to develop cost-effective and efficient donor materials with simple structures by avoiding tedious synthetic methods 37 and employing cost-effective raw materials. 38,39 The polymer donors with a simple structure mentioned in this paper are mainly polymer donors based on non-fused-ring electron-deficient units, and the cost-effectiveness mainly refers to the reduction of synthetic cost, which is beneficial for the commercial application of OSCs due to the simple synthesis process and purification of polymer donors, as well as the low-cost and easy availability of synthetic raw materials.…”