Graphene oxide/PEDOT:PSS composite hole transport layer for efficient and stable planar heterojunction perovskite solar cells.
UNLABELLED We investigated a graphene oxide (GO)/poly(3,4 ethylenedioxythiophene):poly(styrene sulfonate) PEDOT PSS) composite as a promising candidate for the practical application of a 2 D carbonaceous hole transport layer (HTL) to planar heterojunction perovskite solar cells (PeSCs) consisting of a transparent electrode/HTL/perovskite/fullerene/metal electrode. Both the insulating properties of GO and the non uniform coating of the transparent electrode with GO cause the poor morphology of perovskite induced low power conversion efficiency (PCE) of 6.4% On the other hand, PeSCs with a GO/PEDOT:PSS composite HTL, exhibited a higher PCE of 9.7% than that of a device fabricated with conventional PEDOT PSS showing a PCE of 8.2% The higher performance is attributed to the decreased series resistance (RS) and increased shunt resistance (RSh) The well matched work function between GO (4.9 eV) and PEDOT PSS (5.1 eV) probably results in more efficient charge transport and an overall decrease in RS. The existence of GO with a large bandgap of ~3.6 eV might induce the effective blocking of electrons, leading to an increase of RSh. Moreover, improvement in the long term stability under atmospheric conditions was observed.
Nanoscale