Efficient and stable organic solar cells enabled by a poly(carbazole phosphonic acid)hole transporter

Conventional self-assembled monolayer(SAM)hole transporters in organic solar cells(OSCs)generally suffer from poor uniformity and limited thickness tolerance,hindering their large-scale production.To overcome these limitations,we introduce a novel polymeric hole transporter synthesized by polymerizing carbazole phosphonic acid(PACz).The resultant Poly-2PACz material exhibits exceptional conductivity,high tolerance for variations in layer thickness,and improved film uniformity compared with conventional SAMs.Consequently,the OSCs utilizing Poly-2PACz achieve a remarkable power conversion efficiency of 19.1%and a high fill factor of 81.2%,surpassing the devices based on 2PACz.Moreover,Poly-2PACz-based OSCs demonstrate excellent operational stability,retaining over 80%of their initial efficiency after 1,400 h of continuous light exposure in ambient conditions.This work presents a novel strategy for designing hole transporters,paving the way for more efficient and stable OSCs.