Origins of high mechanical property and donor-acceptor composition tolerance in all-polymer solar cells

Abstract

Here, we systematically design widely used all-PSCs systems consisting of PBDB-T:P(NDI(2OD)-T2) modulating molecular weight of P(NDI(2OD)-T2) from 9 to 115 Kg $mol^{-1}$ to thoroughly analyze the origin of D:A ratio tolerance in all-PSCs and correlation with mechanical properties of photoactive layers. Our work demonstrates all-PSCs incorporating polymer acceptor with high molecular weight shows much superior PCE tolerance and mechanical toughness around wide ranges of D:A ratio, which takes a step closer to application of all-PSC into large scale production and flexible devices.