Enhanced Crystallinity in Organic鈥揑norganic Lead Halide Perovskites on Mesoporous TiO2 via Disorder鈥揙rder Phase Transition

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• 作者：Byung-wook Park ; Bertrand Philippe ; Torbj枚rn Gustafsson ; K谩ri Sveinbj枚rnsson ; Anders Hagfeldt ; Erik M. J. Johansson ; Gerrit Boschloo
• 刊名：Chemistry of Materials
• 出版年：2014
• 出版时间：August 12, 2014
• 年：2014
• 卷：26
• 期：15
• 页码：4466-4471
• 全文大小：371K
• ISSN：1520-5002

文摘

Organic鈥搃norganic halide perovskite (OIHP) compounds are very interesting materials for device application in, for example, solar cells, electro-optics, and electronic circuits. In this report, we investigated OIHPs reported as CH₃NH₃PbI_3鈥?i>xCl_x (MAPbI_3鈥?i>xCl_x) and CH₃NH₃PbI₃ (MAPbI₃) prepared from solution on mesoporous TiO₂/glass substrates. A long-term conversion from disordered to more crystalline OIHPs was observed for both types of samples from XRD patterns over 5 weeks. The conversion rate to more crystalline OIHPs could be increased by increasing the temperature of the sample. SEM analyses of the two types of OIHPs show remarkably different surface microstructures. The X-ray diffractograms suggest that both samples are dominated by the similar crystal structure, although the preferential orientation for the crystal structure is different. Moreover, the results suggest that the material reported as MAPbI_3鈥?i>xCl_x is a combination of MAPbI₃ and MAPbCl₃. The crystal structure and exact nature of the material is important for the understanding and optimization of devices, and the possibility for enhanced crystallinity of the OIHPs shown in this report will therefore be important for further improvement and understanding of the devices.