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arXiv · 2511.22136

Unraveling UV Stability in Metal Halide Perovskites: From Degradation Mechanisms to Molecular Passivation

Xin Wen·Zhiyi Yao·Wenzhuo Li·Zhijun Ning·Fan Zheng
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Abstract

Understanding the mechanisms of UV-induced degradation is crucial for enhancing the UV stability of perovskite solar cells. The UV-driven structural dynamics of CH3NH3PbI3 (MAPbI3) are investigated using real-time TDDFT simulations, revealing that under the electron and hole excitation, the distortion of the inorganic framework (PbI) is primarily driven by the electron occupation of Pb-p and I-p antibonding states, whereas in the hole case, it is mainly governed by the direct cooling induced distortion. We also find that UV accelerates the rotation of MA+ molecules. Further, a BDO molecule is introduced as a passivant, which suppresses structural distortions and provides multi-phonon channels to dissipate carrier cooling energy. Experimental results confirm the UV-protective role of BDO, with suppressed PbI2 formation and improved device stability. These results clarify the mechanism of the UV-induced degradation in the MAPbI3 perovskite and further elucidate how passivation molecules enhance UV stability.

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Xin Wen, Zhiyi Yao, Wenzhuo Li, Zhijun Ning, Fan Zheng. 2025-11-27. Unraveling UV Stability in Metal Halide Perovskites: From Degradation Mechanisms to Molecular Passivation. https://arxiv.org/abs/2511.22136

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