Low temperature processed inverted planar perovskite solar cells by r-GO/CuSCN hole-transport bilayer with improved stability

•Novel r-GO/CuSCN bilayer HTL was fabricated for inverted planar perovskite solar cells (PSCs).•The r-GO/CuSCN bilayer HTL based PSC showed power conversion efficiency up to 14.28%.•The r-GO/CuSCN bilayer HTL based PSC showed stable photovoltaic performance for 100 h. Low temperature processed Perovskite solar cells (PSCs) are popular due to their potential for scalable production. In this work, we report reduced Graphene Oxide (r-GO)/copper (I) thiocyanate (CuSCN) as an efficient bilayer hole transport layer (HTL) for low temperature processed inverted planar PSCs. We have systematically optimized the thickness of CuSCN interlayer at the r-GO/MAPbI3 interface resulting in bilayer HTL structure to enhance the stability and photovoltaic performance of low temperature processed r-GO HTL based PSCs with a standard surface area of 1.02 cm2. With matched valence band energy level, the r-GO/CuSCN bilayer HTL based PSCs showed high power conversion efficiency of 14.28%, thanks to the improved open circuit voltage (VOC) compared to the only r-GO based PSC. Moreover, enhanced stability has been observed for the r-GO/CuSCN based PSCs which retained over 90% of its initial efficiency after 100 h light soaking measured under continuous AM 1.5 sun illumination.