Cd-doped ZnO-based electron transport layer for organic-inorganic hybrid perovskite cells: Experimental and numerical study

Organic-inorganic solar cells (PSCs) are considered emergent photovoltaics (PV) technology. For better performance and stability of the PSCs, the selection of the electron transport layer (ETL) is vital. In this study, Cd doped ZnO (CZO) nanoparticles (NPs) are synthesized using the solution process. The optical properties of the CZO NPs were determined experimentally. With Cd doping, the optical bandgap was reduced and the lowest bandgap was obtained for 2% Cd doping. With further increase of Cd doping concentrations, the bandgap was slightly increased. However, the highest values of refractive index were obtained for Cd doping of 1%. The optical parameters were used to simulate the n-i-p (FTO/ETL/MAPbI₃/HTL/Au)-structured PSCs using gpvdm solar simulator. The simulated parameters viz. short circuit current density (J_sc), open circuit voltage (V_oc), fill factor (FF), and power conversion efficiency (η) of the CZOs-based PSCs were compared with the parameters obtained for ZnO ETL. An efficiency of 26.07% was achieved for PSC with 1% Cd-doped ZnO, which is 9.72% higher than the efficiency of ZnO-based PSC (η ∼ 23.76%). These experimental results proved an opportunity to improve the performance of the PSCs via Cd doping.