Study of a Lead-Free Perovskite Solar Cell Using CZTS as HTL to Achieve a 20% PCE by SCAPS-1D Simulation

In this paper, a n-i-p planar heterojunction simulation of Sn-based iodide perovskite solar cell (PSC) is proposed. The solar cell structure consists of a Fluorine-doped tin oxide (FTO) substrate on which titanium oxide (TiO2) is placed; this material will act as an electron transporting layer (ETL); then, we have the tin perovskite CH3NH3SnI3 (MASnI(3)) which is the absorber layer and next a copper zinc and tin sulfide (CZTS) that will have the function of a hole transporting layer (HTL). This material is used due to its simple synthesis process and band tuning, in addition to presenting good electrical properties and stability; it is also a low-cost and non-toxic inorganic material. Finally, gold (Au) is placed as a back contact. The lead-free perovskite solar cell was simulated using a Solar Cell Capacitance Simulator (SCAPS-1D). The simulations were performed under AM 1.5G light illumination and focused on getting the best efficiency of the solar cell proposed. The thickness of MASnI(3) and CZTS, band gap of CZTS, operating temperature in the range between 250 K and 350 K, acceptor concentration and defect density of absorber layer were the parameters optimized in the solar cell device. The simulation results indicate that absorber thicknesses of 500 nm and 300 nm for CZTS are appropriate for the solar cell. Further, when optimum values of the acceptor density (N-A) and defect density (N-t), 10(16) cm(-3) and 10(14) cm(-3), respectively, were used, the best electrical values were obtained: J(sc) of 31.66 mA/cm(2), V-oc of 0.96 V, FF of 67% and PCE of 20.28%. Due to the enhanced performance parameters, the structure of the device could be used in applications for a solar energy harvesting system.

Automated summary

The paper proposes a n-i-p planar heterojunction simulation of Sn-based iodide perovskite solar cell, with CZTS as the hole transporting layer. The simulations focus on optimizing parameters such as absorber thickness, band gap, temperature, acceptor concentration, and defect density to achieve the best efficiency of the solar cell. The results show that with specific parameters, the solar cell can achieve high electrical values and be used in solar energy harvesting systems.