Partial cation substitution reduces iodide ion transport in lead iodide perovskite solar cells
Partial cation substitution reduces iodide ion transport in lead iodide perovskite solar cells
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DOI：
10.1039/c9ee00476a
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发表时间：
2019-07-01
影响因子：
32.5
通讯作者：
Cameron, Petra J.
中科院分区：
文献类型：
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作者：
Ferdani, Dominic W.;Pering, Samuel R.;Cameron, Petra J.
含有a位阳离子混合物的卤化物钙钛矿太阳能电池由于其改善的稳定性和高功率转换效率而引起了相当大的兴趣。众所周知，离子传输是钙钛矿行为的重要预测因素，但部分a位取代对碘离子扩散的影响尚不清楚。在这里，我们结合从头算模型、阻抗谱和μ子自旋弛豫来研究将七种不同大小的阳离子（从小铷到大胍）中的每一种低浓度的离子加入碘化铅甲基铵中对碘离子输运的影响。实验结果与模拟结果吻合较好，表明这些阳离子取代增加了碘离子扩散的活化能。我们首次表明，部分胍取代成甲基碘化铅强烈抑制碘离子运输。从这项多技术研究中获得的见解对未来设计具有增强性能的混合阳离子钙钛矿太阳能电池具有重要意义。
Halide perovskite solar cells containing a mixture of A-site cations are attracting considerable interest due to their improved stability and high power conversion efficiencies. Ionic transport is known to be an important predictor of perovskite behaviour, but the impact of partial A-site substitution on iodide ion diffusion is poorly understood. Here, we combine ab initio modelling, impedance spectroscopy and muon spin relaxation to investigate the effect on iodide ion transport of incorporating a low concentration of each of seven different sized cations (from small rubidium to large guanidinium) into methylammonium lead iodide. Experimental and simulation results are in good agreement, indicating that these cation substitutions increase the activation energy for iodide ion diffusion. We show for the first time that partial guanidinium substitution into methylammonium lead iodide strongly suppresses iodide ion transport. The insights gained from this multi-technique study are important for the future design of mixed-cation perovskite solar cells with enhanced performance.