Lead‐free chalcogenide BaZrS 3 (BZS) perovskite materials unveil a promising pathway toward the fabrication of nontoxic, stable, and efficient photovoltaic solar cells. Unlike lead‐halide perovskite‐based solar cells (PSCs), which suffer from moisture instability and lead toxicity, BZS exhibits robust stability in ambient atmosphere, making it a compelling candidate for next‐generation photovoltaic technologies. While the optoelectronic properties of BZS perovskite materials have been studied to some extent, the integration of BZS in solar cells and their optimized cell performances are yet to be fully explored. Using SCAPS‐1D simulation software, we systematically optimized the performances of BZS‐based photovoltaic solar cells by varying the doping levels, charge transport properties, thickness, alloying compositions, and defect densities of BZS materials as well as charge transport materials. In particular, p‐type doping in BZS outperforms its n‐type counterpart, offering superior defect tolerance due to enhanced charge carrier mobility and reduced recombination rates. The results showed that the FTO/ZnO/BaZrS 3 /MoO 3 structure demonstrated resilience to interface defects, maintaining a high efficiency of 26.72% at interface defect densities of 10 11 cm −3 . This study further optimizes lead‐free BaZrS 3 (BZS) perovskite solar cells through SCAPS‐1D simulations, achieving a power conversion efficiency (PCE) of 34.47% with Ti alloying (Ba(Zr 0 . 96 Ti 0 . 04 )S 3 ) at a tuned bandgap of 1.51 eV. Alloying with Ti, Se, and Ca was explored to reduce the inherent 1.7 eV bandgap, with Ti preferred for its minimal defect formation (0.1 atom% vs. 1% for Se) and structural stability compared to Ca. Se alloying yielded a higher PCE of 36.54% at 1.26 eV, but at the cost of increased recombination and reduced open‐circuit voltage (V OC ). The optimal configuration—FTO/ZnO/Ba(Zr 0 . 96 Ti 0 . 04 )S 3 /MoO 3 /Au with a 1300 nm absorber—delivers a PCE of 32.11%, a V oc of 1.2794 V, a short‐circuit current density (J sc ) f 27.98 mA/cm 2 , and a fill factor (FF) of 90.16% at interface defect densities of 10 11 cm −3 . High shunt resistance (up to 10,000 Ω·cm 2 ) enhances efficiency to 31.97% for Ti‐alloyed BZS, while low series resistance (1 Ω·cm 2 ) minimizes losses. Thermal stability is notable, retaining 88% efficiency (28.24%) at 400 K. These findings position Ti‐alloyed BaZrS 3 as a high‐efficiency, stable, and sustainable alternative to lead‐based perovskites, offering a robust foundation for future experimental advancements in photovoltaic technology.
Chowdhury et al. (Thu,) studied this question.