Side-chain optimization of perylene diimide-thiophene random terpolymer acceptors for enhancing the photovoltaic efficiency of all-polymer solar cells

摘要

Development of n-type polymer semiconductor materials for all-polymer solar cells (all-PSCs) receives increasingly attention. A series of new n-type random terpolymers with identical perylene diimide-thiophene alternating copolymer backbone and different composition of the side chains 2-octyldodecanyl and 2-ethylhexanyl have been designed and applied as the acceptor materials in all-PSCs. The all-PSCs based on bulk heterojunction blends with side-chain engineered random terpolymer P(l/1) as acceptor and PTB7-Th as donor give a high power conversion efficiency value of 6.18% with an open-circuit voltage of 0.74 V, a short-circuit current density of 14.71 mA cm~(-2), and a fill factor of 0.57. The results demonstrate that design of the poly(perylenediimide-alt-thiophene) random terpolymer acceptors via side-chain engineering is an alternative strategy for obtaining high-performance photovoltaic acceptor materials.