Design and efficiency optimization of Cs 2 AgBiBr 6 double perovskite solar cells via SCAPS-1D modelling

Abstract This work presents a SCAPS-1D simulation based design for PSC with cesium silver bismuth bromide (Cs 2 AgBiBr 6 ) absorber layer and tries to find out the best possible combination of charge transport layers and optimum values of physical parameters which can point out the right direction towards an actual laboratory synthesis of perovskite solar cells with the most efficient configuration. The work also explores the properties of the optimized design by analyzing both its DC response through JV characteristics and AC response through Mott Schottky and Nyquist plots. The quantum efficiency profile is also plotted to understand the photon to exciton conversion efficiency at different regions of electromagnetic spectrum. This work suggests the structure ITO/C 60 /Cs 2 AgBiBr 6 /SpiroOMeTAD/Au as a feasible combination of solar cell with lead free double perovskite absorber layer, after analyzing the effect of different charge transport layers. The work also determines the optimum thickness for HTL, ETL and absorber layer involved in the structure and the maximum efficiency is found to be 7.4%. The effect of temperature and total defect density in the power conversion efficiency of the solar cells is studied. The AC simulations of the optimized configuration is carried out by obtaining Mott Schottky and Nyquist plots. The quantum efficiency profile is also determined predicting good absorption in the UV, blue and green region of electromagnetic spectrum. Further the effect of incorporating CdS as an electron extractor in the structure is analyzed to find out theoretically how far the efficiency can be improved in spite of its toxicity. The work also shows how interfacial defect density becomes a major factor limiting the power conversion efficiency of Cs 2 AgBiBr 6 double perovskite solar cells.