Department of Mechanical and Materials Engineering, University of Nebraska, Lincoln, NE 68588, USA.
Nuclear Engineering Program, Department of Mechanical and Aerospace Engineering, Ohio State University, Columbus, OH 43210, USA.
Science. 2015 Feb 27;347(6225):967-70. doi: 10.1126/science.aaa5760. Epub 2015 Jan 29.
Long, balanced electron and hole diffusion lengths greater than 100 nanometers in the polycrystalline organolead trihalide compound CH3NH3PbI3 are critical for highly efficient perovskite solar cells. We found that the diffusion lengths in CH3NH3PbI3 single crystals grown by a solution-growth method can exceed 175 micrometers under 1 sun (100 mW cm(-2)) illumination and exceed 3 millimeters under weak light for both electrons and holes. The internal quantum efficiencies approach 100% in 3-millimeter-thick single-crystal perovskite solar cells under weak light. These long diffusion lengths result from greater carrier mobility, longer lifetime, and much smaller trap densities in the single crystals than in polycrystalline thin films. The long carrier diffusion lengths enabled the use of CH3NH3PbI3 in radiation sensing and energy harvesting through the gammavoltaic effect, with an efficiency of 3.9% measured with an intense cesium-137 source.
长而平衡的电子和空穴扩散长度大于 100 纳米的多晶有机铅三卤化物化合物 CH3NH3PbI3 对于高效的钙钛矿太阳能电池至关重要。我们发现，通过溶液生长法生长的 CH3NH3PbI3 单晶在 1 个太阳（100 mW cm(-2))下的扩散长度可以超过 175 微米，在弱光下电子和空穴的扩散长度都超过 3 毫米。在弱光下，3 毫米厚的单晶钙钛矿太阳能电池的内量子效率接近 100%。这些长的扩散长度归因于单晶中的载流子迁移率更高、寿命更长、陷阱密度远小于多晶薄膜。长的载流子扩散长度使得 CH3NH3PbI3 能够通过伽马伏效应用于辐射感应和能量收集，用强铯-137 源测量的效率为 3.9%。
