CuSCN modified PEDOT:PSS to improve the efficiency of low temperature processed perovskite solar cells

The energy structure of PEDOT:PSS limits the perovskite solar cell (PSC) performance based on inverted FTO/PEDOT:PSS/perovskite/PCBM structure. Here, inorganic CuSCN is modified on PEDOT:PSS using spin-coating method under low temperature, which is compatible with the low temperature fabrication of PSC. Modification CuSCN guarantees the light harvesting of perovskite layer because of the transparency of CuSCN and good crystalline of perovskite film on CuSCN/PEDOT:PSS substrate. Furthermore, CuSCN effectively changes the energy states of PEDOT:PSS to decrease the energy loss during charge transport, promoting the charge transfer at the same time. Based on the improved charge transport and reduced energy loss, the photovoltaic property of PSC based on CuSCN/PEDOT:PSS reaches the optimized efficiency of 10.9%, much better than the control PEDOT:PSS-based device with 9.1% performance (AM1.5, 1sun).