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

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 2.5wt% 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. The power conversion efficiency (PCE) of the device with PANI/GO(2.5) is enhanced up to 4.23%, which 20% higher than the device with the conventional HTL material, PEDOT:PSS. [Display omitted] •We prepared a new class of hole transport layer material by adding GO in PSSA-g-PANI.•The device of P3HT with the new hole transport material exhibits a PCE of 4.23%.•The enhancement of PCE arises mainly from an increase of Jsc.