Perovskite Solar Cells With Modified Carbon Electrode and CuSCN Interlayer Processed Under Ambient Conditions

Abstract

Carbon‐based perovskite solar cells (PSCs) have the advantages of a long lifetime and are compatible with highly scalable manufacturing processes. The use of carbon electrodes and the absence of a hole selective layer (HSL) promote a simplified fabrication process. However, the efficiency of HSL‐free carbon‐based PSCs is inferior to PSCs that utilize metal electrodes and HSL due to poor hole extraction at the perovskite/carbon interface. To overcome those issues, researchers added an interlayer on the perovskite/carbon interface or incorporated additive material into the carbon layer. However, there is limited research on utilizing both strategies to improve carbon‐based PSC performance. Here, we use CuSCN as an interlayer between the perovskite/carbon interface and a carbon additive in carbon‐based PSCs. By utilizing both strategies, the charge transfer of carbon‐based PSC was significantly improved compared to carbon‐based PSC utilizing only one improvement strategy. Confirmed by photoluminescence (PL) and electrochemical impedance spectroscopy (EIS) characterizations, the CuSCN interlayer and CuSCN‐incorporated carbon electrode enable more efficient hole transfer, resulting in an increased power conversion efficiency from 0.58% to 5.06%. The proposed PSC structure shows promising results for further improving carbon‐based PSC performance.