Parameters Affecting I鈥?i>V Hysteresis of CH3NH3PbI3 Perovskite Solar Cells: Effects of Perovskite Crystal Size and Mesoporous TiO2 Layer

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• 作者：Hui-Seon Kim ; Nam-Gyu Park
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2014
• 出版时间：September 4, 2014
• 年：2014
• 卷：5
• 期：17
• 页码：2927-2934
• 全文大小：539K
• ISSN：1948-7185

文摘

Current鈥搗oltage (I鈥?i>V) characteristics of CH₃NH₃PbI₃ perovskite solar cells are studied using a time-dependent current response with stepwise sweeping of the bias voltage. Compared with the crystalline Si solar cell showing time-independent current at a given bias voltage, the perovskite solar cells exhibit time-dependent current response. The current increases with time and becomes steady at forward scan from short-circuit to open-circuit, whereas it is decayed and saturated with time at reverse scan from open-circuit to short-circuit. Time-dependent current response eventually leads to I鈥?i>V hysteresis depending on the scan direction and the scan rate. Crystal size of CH₃NH₃PbI₃ and the mesoporous TiO₂ (mp-TiO₂) film are found to influence I鈥?i>V hysteresis, where the I鈥?i>V hysteresis is alleviated as crystal size increases and in the presence of mp-TiO₂. The capacitance observed at low frequency (0.1 to 1 Hz), associated with dipole polarization, tends to diminish as size of perovskite and mp-TiO₂ layer thickness increases, which suggests that the origin of hysteresis correlates to the capacitive characteristic of CH₃NH₃PbI₃ and the degree of hysteresis depends strongly on perovskite crystal size and mesoporous TiO₂ layer.

Keywords:

hysteresis; perovskite; CH₃NH₃PbI₃; solar cell; crystal size; mesoporous TiO₂; relaxation; polarization; capacitive current