High‐Performance Graphene/GaInP Solar Cell Prepared by Interfacial Chemical Modification with Poly(3,4‐ethylenedioxythiophene):Poly(styrenesulfonate)

Graphene/semiconductor heterojunction based solar cell is realized as a promising candidate for high-efficiency solar cells. However, the interface between graphene and the semiconductor should be further explored to enhance the performance of the solar cell. As graphene is impermeable to water and gases, encapsulating hole conducting organic material poly(3,4-ethylene-dioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) at the interface is possible and can improve the surface passivation, p-dope graphene, increase the barrier height, and speed up the transfer of carriers. Herein, a novel graphene/PEDOT:PSS/GaInP organic/inorganic Schottky heterojunction solar cell is designed and assembled via interfacial chemical modification. The cell exhibits an open-circuit voltage (V-oc) of 0.90 V under AM1.5 illumination, while the counterpart solar cell without PEDOT:PSS interlayer only gives a V-oc of 0.49 V. In comparison with the PEDOT:PSS interlayer, indium tin oxide (ITO) film shows little effect on the improvement of V-oc. The V-oc of graphene/ITO/GaInP and ITO/PEDOT:PSS/GaInP solar cells is 0.11 and 0.37 V, respectively. As a result, the power conversion efficiency (PCE) of the Schottky junction solar cell with an interlayer reaches up to 4.55%, more than seven times that obtained without interlayer. The work has proven that integrating graphene/semiconductor heterostructure solar cells with organic conductive materials in the interface can achieve high PCE.