Impact of HTM on lead-free perovskite solar cell with high efficiency

Abstract

The Scaps-1d simulator was used to simulate a lead-free perovskite CH3NH3SnI3 based solar cell devices fabricated from different hole transport materials (HTM). This research looks at two organic and two inorganic HTM layers. The cell structure used in this study is FTO/TiO2/CH3NH3SnI3/HTM (variable)/Au(variable). Spiro-OMeTAD, PEDOT:PSS, CuO and Cu2O are the HTM materials used. The results show that utilizing CuO as an HTM produces better outcomes than other HTMs, with an efficiency of 28.45%. The thickness, acceptor concentration (NA), and defect density (Nt) of the perovskite layer on optoelectronic properties of the solar cell are focus of simulation studies. According to this study, an perovskite layer thickness of 1000 nm is suitable for a decent photovoltaic cell. Furthermore, by adjusting the HTM thickness and the defect density of HTM and absorber layer, promising findings of Jsc of 34.38 mAcm−2, Voc of 1.011 V, FF of 80.85% and PCE of 28.10% were obtained for Spiro-OMeTAD based PSC. Finally, in order to improve the device's performance, an anode material with high work function is required. Our findings reveal that using a thin absorber layer results in low photo generated charge carriers due to less absorption, but high carrier extraction. Although more carriers are created in the cell due to increased absorption, decreased collection efficiency is related to recombination, which decreases Voc for thick perovskite layers. Device efficiency is improved by increasing the doping density up to 1018 cm−3 in the perovskite layer due to built-in electric field across the solar cell. Again a very thin or thick HTL is not ideal for high PCE. For low recombination and a high fill factor, an HTM (Spiro-OMeTAD) of 1–100 nm is necessary. The great power conversion efficiency of organic HTM based lead-free PSC brings up the new possibilities for obtaining renewable energy.