Mapping Electric Field-Induced Switchable Poling and Structural Degradation in Hybrid Lead Halide Perovskite Thin Films
Mapping Electric Field-Induced Switchable Poling and Structural Degradation in Hybrid Lead Halide Perovskite Thin Films
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DOI：
10.1002/aenm.201500962
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发表时间：
2015-10-21
影响因子：
27.8
通讯作者：
Petrozza, Annamaria
中科院分区：
文献类型：
--
作者：
Leijtens, Tomas;Hoke, Eric T.;Petrozza, Annamaria
对于考虑用于大规模商业应用的卤化铅钙钛矿型太阳能电池，必须证明活性材料在相关的操作条件下基本稳定，例如暴露在光、热、环境和偏压下。确定了在不同环境条件下施加电场时的可逆和不可逆效应。在惰性条件下施加电场只能在几分钟的时间尺度上产生可逆极化，其分布被绘制在整个半导体薄膜中。研究还发现，在存在电场的情况下，水分的存在以及通常存在的小的极性和氢键分子会导致不可逆的降解，在与光伏相关的条件下，这种降解发生在几个小时的时间尺度上。这里的测量表明，空气中不可逆场致降解是通过水合相发生的，在水合相中，有机阳离子松散结合，可以随电场漂移，最终将材料降解为PbI2。这与钙钛矿太阳能电池有直接关系；电流-电压曲线中的滞后行为因湿度的存在而加剧，而器件在负载下老化会加速退化。
For lead halide perovskite solar cells to be considered for large-scale commercial applications, the active material must be proven to be fundamentally stable under relevant operating conditions, such as exposure to light, heat, ambient environment, and electrical bias. Reversible and irreversible effects upon applying an electric field under different environmental conditions are identified. The application of an electric field in inert conditions leads only to a reversible poling on a time scale of minutes, whose distribution is mapped throughout the semiconductor film. It is also found that the presence of moisture, and in general of small polar and hydrogen-bonding molecules, results in an irreversible degradation in the presence of the electric field, which happens in a time scale of hours under conditions relevant for photovoltaic operation. The measurements here suggest that the irreversible field-induced degradation in air occurs via a hydrated phase, in which the organic cation is loosely bound and can drift in response to an electric field, finally degrading the material to PbI2. This has direct relevance to perovskite solar cells; hysteretic behavior in current-voltage curves is aggravated by the presence of moisture while devices aged under load accelerates degradation.