Electrodeposition of nanostructured bilayer CuI@CuSCN as hole transport material for highly efficient inverted perovskite solar cells

Highlights: : • Electrodeposition of bilayer CuI@CuSCN by two step electrodeposition technique. • The film thickness and morphology was controlled by changing electrochemical potential. • The effectiveness of bilayer CuI@CuSCN thin-films on the photovoltaic performance is demonstrated. • The highest power conversion of 20.35% was achieved with bilayer HTLs grown for 2 min deposition time. -- Abstract: In this article, we implemented a new two-step electrodeposition method for preparing bilayer CuI@CuSCN thin films. The film thickness and optical transparency are controlled by varying electrochemical potential and time. The inverted perovskite solar cells are fabricated using electrodeposited bilayer CuI@CuSCN thin films as a hole transport material (HTM) and carbon as a back electrode. The best performing device showed short circuit current (J_sc) of 20.26 mA/cm², open-circuit voltage(V_oc) of 1.10 V, fill factor (FF) of 0.78 and power conversion efficiency of 20.35% with 2 min grown bilayer CuI@CuSCN HTMs. The electrodeposited bilayer CuI@CuSCN thin films showed a 7.6% enhancement in power conversion efficiency than the previously reported CuI/CuSCN composites. From the observed results, moderate film thickness and uniform morphology of bilayer CuI@CuSCN HTMs provide better photovoltaic performance. The robust nanoclusters of bilayer CuI@CuSCN and used carbon back electrode provides remarkable device stability and charge extraction.