Using Cu2O/ZnO as Two-Dimensional Hole/Electron Transport Nanolayers in Unleaded FASnI3 Perovskite Solar Cells

A Pb-free FASnI3 perovskite solar cell improved by using Cu2O/ZnO as two-dimensional-based hole/electron transport nanolayers has been proposed and studied by using a SCAPS-1D solar simulator. To calibrate our study, at first, an FTO/ZnO/MAPbI3/Cu2O/Au multilayer device was simulated, and the numerical results (including a conversion efficiency of 6.06%, an open circuit potential of 0.76 V, a fill factor parameter of 64.91%, and a short circuit electric current density of 12.26 mA/cm2) were compared with the experimental results in the literature. Then, the conversion efficiency of the proposed FASnI3-based solar cell was found to improve to 7.83%. The depth profile energy levels, charge carrier concentrations, recombination rate of electron/hole pair, and the FASnI3 thickness-dependent solar cell efficiency were studied and compared with the results obtained for the MAPbI3-containing device (as a benchmark). Interestingly, the FASnI3 material required to obtain an optimized solar cell is one-half of the material required for an optimized MAPbI3-based device, with a thickness of 200 nm. These results indicate that developing more environmentally friendly perovskite solar cells is possible if suitable electron/hole transport layers are selected along with the upcoming Pb-free perovskite absorber layers.

Effects of electron transport layer type on the performance of Pb-free Cs2AgBiBr6 double perovskites: a SCAPS-1D solar simulator-based study

Recently, due to the superior stability and lower risk of toxicity, the development of Pb-free halide double perovskite materials has revived excellent interest. In this work, Pb-free perovskite solar cells (PSCs) with ITO/ETL/Cs2AgBiBr6/Cu2O/Au multilayer structures with Cs2AgBiBr6 double perovskite as the solar light absorber layer, some electron transport layers (ETLs) and Cu2O as a hole transport layer have been introduced. Then, the effects of various thicknesses of the absorber layer and also ETL materials, like ZnO, C60, CdS, SnO2, phenyl-C61-butyric acid methyl ester (PCBM), and TiO2, on the device performance (including photoelectronic conversion efficiency (PCE), fill factor (FF%), short circuit current density (Jsc), and open-circuit voltage (VOC)) were examined with the help of a solar cell simulator (SCAPS-1D). It is noteworthy that, in the case of all ETL materials, the optimal thickness of the absorber layer was determined to be 400 nm. Then, the maximum PCE values of 20.08%, 17.63%, 14.07%, 12.11%, 14.94%, and 18.83% were obtained for the solar cells containing ZnO, C60, CdS, SnO2, PCBM, and TiO2 as the ETL, respectively. These results show that designing/developing Pb-free halide double perovskite devices having comparable PCEs with the Pb-based PSCs is feasible, provided that proper/compatible materials will be used in the multilayer structure of the next generations of solar cells.