Solvent-Mediated Crystallization of CH3NH3SnI3 Films for Heterojunction Depleted Perovskite Solar Cells
Solvent-Mediated Crystallization of CH3NH3SnI3 Films for Heterojunction Depleted Perovskite Solar Cells
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DOI：
10.1021/jacs.5b06658
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发表时间：
2015-09-09
影响因子：
15
通讯作者：
Kanatzidis, Mercouri G.
中科院分区：
文献类型：
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作者：
Hao, Feng;Stoumpos, Constantinos C.;Kanatzidis, Mercouri G.
有机卤化铅钙钛矿太阳能电池已经获得了巨大的意义，现在已经实现了接近20%的功率转换效率。然而，这些系统中铅的潜在毒性引发了广泛部署的环境问题。在这里，我们调查溶剂的无铅甲基铵三碘化锡（CH 3 NH3 SnI 3）钙钛矿薄膜的结晶在溶液生长过程中的影响。高度均匀的，无针孔的钙钛矿薄膜获得从二甲基亚砜（DMSO）溶液通过过渡SnI 2中心点3DMSO中间相。这种高质量的钙钛矿薄膜能够实现基于中孔TiO 2层的异质结耗尽太阳能电池，但不存在任何空穴传输材料，光电流高达21 mA cm（-2）。电荷提取和瞬态光电压衰减测量揭示了高载流子密度的CH 3 NH3 SnI 3钙钛矿型设备是一个数量级大于CH 3 NH3 PbI 3为基础的设备，但在这两个设备具有可比的复合寿命。与Pb基类似物相比，Sn基钙钛矿的相对高的背景暗载流子密度是导致较低光伏效率的原因。这些结果为实现溶液处理的高效无铅钙钛矿太阳能电池中实现改善的钙钛矿形态控制提供了重要进展。
Organo-lead halide perovskite solar cells have gained enormous significance and have now achieved power conversion efficiencies of similar to 20%. However, the potential toxicity of lead in these systems raises environmental concerns for widespread deployment. Here we investigate solvent effects on the crystallization of the lead-free methylammonium tin triiodide (CH3NH3SnI3) perovskite films in a solution growth process. Highly uniform, pinhole-free perovskite films are obtained from a dimethyl sulfoxide (DMSO) solution via a transitional SnI2 center dot 3DMSO intermediate phase. This high-quality perovskite film enables the realization of heterojunction depleted solar cells based on mesoporous TiO2 layer but in the absence of any hole-transporting material with an unprecedented photocurrent up to 21 mA cm(-2). Charge extraction and transient photovoltage decay measurements reveal high carrier densities in the CH3NH3SnI3 perovskite device which are one order of magnitude larger than CH3NH3PbI3-based devices but with comparable recombination lifetimes in both devices. The relatively high background dark carrier density of the Sn-based perovskite is responsible for the lower photovoltaic efficiency in comparison to the Pb-based analogues. These results provide important progress toward achieving improved perovskite morphology control in realizing solution-processed highly efficient lead-free perovskite solar cells.