Device Optimization of a Lead-Free Perovskite/Silicon Tandem Solar Cell with 24.4% Power Conversion Efficiency

• Main Authors: Khaoula Amri, Rabeb Belghouthi, Michel Aillerie, Rached Gharbi
• Format: Article
• Language: English
• Published: MDPI AG 2021-06-01
• Series: Energies
• Subjects: tandem solar cell; lead-free perovskite; SCAPS simulation; high efficiency
• Online Access: https://www.mdpi.com/1996-1073/14/12/3383

In this work, simulations were performed to optimize the parameters of a lead-free perovskite/silicon tandem solar cell for the improved efficiency and stability of commercial devices. The top sub-cell is based on a lead-free perovskite with a large bandgap of 1.8 eV, an electron transport layer of SnO₂/PCBM, which is known for its anti-hysteresis effect, and a hole transport layer of NiO to improve stability, whereas the bottom sub-cell is based on n-type silicon to increase the efficiency of the whole cell. First, the two sub-cells were simulated under standalone conditions for calibration purposes. Then, the current matching condition was obtained by optimizing the thicknesses of the absorber layers of both sub-cells and the doping concentration of the back surface field (BSF) layer of the silicon sub-cell. As a result of this optimization phase, thicknesses of 380 nm and 20 µm for the top and bottom sub-cells, respectively, and a doping concentration of 10²² cm^–3 were used in the configuration of the tandem cell, yielding a large open-circuit voltage of 1.76 V and a power conversion efficiency of 24.4% for the whole cell. Finally, the effect of the working temperature was evaluated, and the results reveal that the high performance of lead-free perovskite sub-cells is less affected by an increase in temperature compared to lead-based solar cells, such as those based on CH₃NH₃PbI₃ perovskite.