Enhanced performance of polymer solar cells with PSSA?g?PANI/Graphene oxide composite as hole transport layer

Abstract

A new class of hole transport layer (HTL), which is composed of poly(styrene sulfonic acid) grafted with polyaniline (PSSA?g?PANI) and graphene oxide (GO), was prepared by adding GO into PSSA?g?PANI aqueous solution. The PSSA?g?PANI/GO composites exhibit high optical transparency and high electrical conductivity. When the composite with 2.5 wt% GO loading was used as HTL material for the device based on poly(3-hexylthiophene)/PC61BM blend, the device exhibits an enhanced power conversion efficiency (PCE) of 4.23%, which is 23% higher than the PCE of device with the conventional HTL material, PEDOT:PSS (3.44%). This enhancement of PCE arises mainly from an increase of the short-circuit current density due to higher optical transparency and higher electrical conductivity of PSSA?g?PANI/GO composite. When the PSSA?g?PANI/GO composite is applied as HTL to a low bandgap polymer-based solar cell, PTB7:PC71BM blend, the PCE is also enhanced as compared to the device with PEDOT:PSS, providing us with the possibility to use PSSA?g?PANI/GO as a hole transport layer for various polymer-based solar cells to enhance the photovoltaic performance.