Thermal Degradation Mechanisms and Stability Enhancement Strategies in Perovskite Solar Cells: A Review

Abstract: Perovskite Solar Cells (PSCs) have garnered global research interest owing to their superior photovoltaic (PV) performance. The future of photovoltaic technology lies in PSCs since they can produce power with performance on par with the best silicon solar cells while being less expensive. PSCs have enormous potential; in just ten years, their efficiency increased from 3.8% to 25.2%, and research into new developments is still ongoing. Thermal instability is PSCs' main disadvantage, despite their high efficiency, flexibility, and lightweight nature. This paper looks at how temperature affects the ways that hole transport layers (HTLs) like spiro-OMeTAD and perovskite layers, especially MAPbI3, degrade. Elevated temperatures cause MAPbI3 to degrade into PbI2, CH3I, and NH3, with decomposition rates affected by moisture, oxygen, and environmental factors. Mixed cation compositions, such as Cs-MA-FA, have higher thermal stability, whereas MA+ cations break-down faster under heat stress. HTLs deteriorate due to morphological changes and the hydrophilicity of dopant additions like Li-TFSI and t-BP. Alternative dopant-free HTMs, such as P3HT and inorganic materials including CuSCN, NiOx, and Cu2O, have shown improved thermal stability and efficiency. Hybrid HTLs, dopant-free designs, and interface tweaks are all viable solutions for increasing the stability of PSC. Addressing thermal stability issues remains crucial for the development of more reliable and efficient PSC technology.