Reversible Healing Effect of Water Molecules on Fully Crystallized Metal–Halide Perovskite Film

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• 作者：Wenke Zhou ; Yicheng Zhao ; Chenglong Shi ; Haonan Huang ; Jing Wei ; Rui Fu ; Kaihui Liu ; Dapeng Yu ; Qing Zhao
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：March 10, 2016
• 年：2016
• 卷：120
• 期：9
• 页码：4759-4765
• 全文大小：494K
• ISSN：1932-7455

文摘

Water molecules have been reported to cause the degradation of perovskite crystals by forming a hydrated intermediate structure and then lead iodide irreversibly. Here, the quality of fully crystallized perovskite films is found to be improved by spraying water vapor with an appropriate time. Moreover, this healing effect was found to be reversible and would disappear when the water molecules escaped. Through measuring the steady-state and time-resolved photoluminescence of perovskite film before and after water vapor spray, we found that water molecules can deactivate the nonradiative recombination centers due to hydrogen bonding with uncoordinated ions on the surface of perovskite film. Furthermore, by analyzing the capacitance of devices without and with water vapor spray, the healing or deactivation effect was clearly seen in the significantly decreased density of defect states. This work emphasized the effectiveness of hydroxyl to heal the defects due to dangling bonds on the material surface, and close attention should be paid on searching for more stable healing agent with hydroxyl to increase the efficiency of perovskite solar cells.