Investigating the theoretical performance of Cs2TiBr6-based perovskite solar cell with La-doped BaSnO3 and CuSbS2 as the charge transport layers

A lead-free, completely inorganic, and nontoxic Cs2TiBr6-based double perovskite solar cell (PSC) was simulated via SCAPS 1-D. La-doped BaSnO3 (LBSO) was applied as the electron transport layer (ETL) unprecedentedly in the simulation study of PSCs, while CuSbS2 was utilized as the hole transport layer (HTL). wxAMPS was used to validate the results of SCAPS simulations. Moreover, the first-principle density function theory (DFT) calculations were performed for validating the 1.6 eV bandgap of the Cs2TiBr6 absorber. To enhance the device performance, we analyzed and optimized various parameters of the PSC using SCAPS. The optimum thickness, defect density, and bandgap of the absorber were 1000 nm, 10(13) cm(-3), and 1.4 eV, respectively. Furthermore, the optimum thickness, hole mobility, and electron affinity of the HTL were 400 nm, 10(2) cm(2)V(-1) s(-1), and 4.1 eV, respectively. However, the ETL thickness had a negligible effect on the device's efficiency. The optimized values of doping density for the absorber layer, HTL, and ETL were 10(15), 10(20), and 10(21) cm(-3), respectively. Herein, the effect of different HTLs was analyzed by matching up the built-in voltage (V-bi) in respect of the open-circuit voltage (V-OC). It was found that the V-bi was directly proportional to the V-OC, and CuSbS2 was the champion in terms of efficiency for the PSC. The optimum work function of metal contact and temperature of the PSC were 5.9 eV and 300 K, respectively. After the final optimization, the device achieved an exhilarating PCE of 29.13%. Novelty Statement LBSO was used as the ETL for the very first time in the simulation study of PSCs, while CuSbS2 was utilized as the HTL. DFT calculations were performed to understand the electronic behavior of Cs2TiBr6 absorber and validation of the SCAPS simulation results was accomplished via wxAMPS. Different parameters of the absorber layer, ETL, and HTL were optimized using SCAPS and a PCE of 29.13% was achieved after the final optimization of the device.

Automated summary

For the first time, LBSO was used as the ETL in the simulation study of PSCs, and the device performance was improved through optimization of various parameters, achieving an exciting PCE of 29.13% after finalization.