Long-Range Balanced Electron- and Hole-Transport Lengths in Organic-Inorganic CH3NH3PbI3
Long-Range Balanced Electron- and Hole-Transport Lengths in Organic-Inorganic CH3NH3PbI3
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DOI：
10.1126/science.1243167
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发表时间：
2013-10-18
期刊：
影响因子：
56.9
通讯作者：
Sum, Tze Chien
中科院分区：
文献类型：
--
作者：
Xing, Guichuan;Mathews, Nripan;Sum, Tze Chien
由于激子或电子空穴扩散长度（通常约为10纳米）较差，低温溶液处理光伏电池的效率较低。最近，基于ch3nh3pbi3的高效太阳能电池在各种结构下的报道，为理解这些材料的基本光物理机制提供了一个令人信服的案例。通过将飞秒瞬态光学光谱应用于钙钛矿与选择电子或选择空穴萃取材料的界面双层，我们发现了溶液处理的CH3NH3PbI3中平衡的远程电子-空穴扩散长度至少为100纳米的具体证据。这些系统的高光转换效率源于可比的光吸收长度和电荷载流子扩散长度，超越了溶液处理半导体的传统限制。
Low-temperature solution-processed photovoltaics suffer from low efficiencies because of poor exciton or electron-hole diffusion lengths (typically about 10 nanometers). Recent reports of highly efficient CH3NH3PbI3-based solar cells in a broad range of configurations raise a compelling case for understanding the fundamental photophysical mechanisms in these materials. By applying femtosecond transient optical spectroscopy to bilayers that interface this perovskite with either selective-electron or selective-hole extraction materials, we have uncovered concrete evidence of balanced long-range electron-hole diffusion lengths of at least 100 nanometers in solution-processed CH3NH3PbI3. The high photoconversion efficiencies of these systems stem from the comparable optical absorption length and charge-carrier diffusion lengths, transcending the traditional constraints of solution-processed semiconductors.