Non-ferroelectric nature of the conductance hysteresis in CH3NH3PbI3 perovskite-based photovoltaic devices
Non-ferroelectric nature of the conductance hysteresis in CH3NH3PbI3 perovskite-based photovoltaic devices
复制标题
DOI：
10.1063/1.4919109
复制
发表时间：
2015-04-27
影响因子：
4
通讯作者：
Radaelli, P. G.
中科院分区：
文献类型：
--
作者：
Beilsten-Edmands, J.;Eperon, G. E.;Radaelli, P. G.
我们使用双波方法测量了CH3NH3PbI3钙钛矿薄膜上的电导滞后，以研究铁电响应的可能性。在0.1 Hz至150 Hz范围内，观察到迟滞的频率依赖性很强，在低于0.4 Hz的频率下，迟滞电荷密度超过1000 μ C cm(-2)，这是非铁电响应的特征。我们表明，观察到的滞后电导，以及阻抗谱中双弧的存在，可以完全解释为在秒的时间尺度下偏压下移动离子的迁移。我们的测量将任何与频率无关的固有极化的上限约为1 μ C cm(-2)，排除了铁电性作为电流-电压滞后的主要原因，并进一步证明了离子迁移在改变CH3NH3PbI3器件效率中的重要性。(C) 2015 AIP出版有限责任公司
We present measurements of conductance hysteresis on CH3NH3PbI3 perovskite thin films, performed using the double-wave method, in order to investigate the possibility of a ferroelectric response. A strong frequency dependence of the hysteresis is observed in the range of 0.1 Hz to 150 Hz, with a hysteretic charge density in excess of 1000 mu C cm(-2) at frequencies below 0.4 Hz-a behaviour uncharacteristic of a ferroelectric response. We show that the observed hysteretic conductance, as well as the presence of a double arc in the impedance spectroscopy, can be fully explained by the migration of mobile ions under bias on a timescale of seconds. Our measurements place an upper limit of approximate to 1 mu C cm(-2) on any intrinsic frequency-independent polarisation, ruling out ferroelectricity as the main cause of current-voltage hysteresis and providing further evidence of the importance of ionic migration in modifying the efficiency of CH3NH3PbI3 devices. (C) 2015 AIP Publishing LLC.