Unveiling Charge Carrier Recombination Dynamics in Tin-Lead (Sn-Pb) Perovskite Solar Cells—A Pathway to Enhanced Performance and Stability

Tin-lead (Sn-Pb) perovskite solar cells are at the forefront of photovoltaic research, offering an exciting balance of high efficiency and reduced environmental impact. Despite their promising attributes, the optimization of Sn-Pb perovskites has been hindered by inconsistent reports of carrier lifetimes, crucial for device performance. Our comprehensive study tackles these inconsistencies head-on by integrating state-of-the-art transient photovoltage (TPV) and transient photocurrent (TPC) techniques, along with time-resolved photoluminescence (TRPL) measurements under diverse operational conditions. Enhanced by rigorous simulation and analytical methods, our research provides novel insights:<br/><b>1. Elucidation of Trap-Assisted Recombination Mechanisms:</b> Dominant under low-light conditions, this finding is crucial for understanding device performance under real-world lighting.<br/><b>2. Quantification of the Radiative Recombination Coefficient:</b> Dominant at high illumination levels, it can influence the design of high-efficiency solar cells.<br/><b>3. Effective Carrier Lifetimes:</b> Specifically under standard 1 sun illumination, offering a realistic perspective on device operation.<br/><b>4. Correlation Between TPV and TRPL Data:</b> This establishes a robust methodological framework for predicting device performance.<br/><b>5. Validation and Reproduction of Open-Circuit Voltages:</b> confirms the accuracy of TPV-derived parameters, reinforcing the reliability of our measurements and data analysis.<br/><b>6. Impact of Device Degradation on Carrier Lifetime:</b> We identify the significant effects of device stability (during the measurement) on data integrity, underscoring the importance of robust testing environments.<br/><br/>Our findings not only clarify the previously reported discrepancies in carrier lifetime data but also provide a deeper understanding of the intrinsic carrier dynamics within Sn-Pb perovskites. By addressing both fundamental science and practical challenges, this work sets the stage for next-generation solar cells that combine enhanced performance with increased reliability, marking a significant stride toward sustainable energy solutions.