Contactless Visualization of Fast Charge Carrier Diffusion in Hybrid Halide Perovskite Thin Films
Contactless Visualization of Fast Charge Carrier Diffusion in Hybrid Halide Perovskite Thin Films
复制标题
DOI：
10.1021/acsphotonics.5b00562
复制
发表时间：
2016-02-01
期刊：
影响因子：
7
通讯作者：
Hartschuh, Achim
中科院分区：
文献类型：
--
作者：
Handloser, Kathrin;Giesbrecht, Nadja;Hartschuh, Achim
有机-无机金属卤化物钙钛矿太阳能电池最近引起了相当大的关注，报道的器件效率接近多晶硅中实现的那些。有效提取光生载流子的关键是低非辐射弛豫速率的组合，导致长载流子寿命和快速扩散传输。然而，后者难以直接评估，报告的数值差异很大。在这里，我们提出了一种实验方法的非接触式可视化的电荷载流子的扩散长度和速度在薄膜的基础上，在不同的距离从激发位置的光致发光的时间分辨共焦检测。我们对氯化物处理的甲基铵碘化铅薄膜的测量表明，电荷载流子扩散长度为5.5-7.7 μ m，第一微米的输运时间为100 ps，对应于扩散常数约为5-10 cm（2）s（-1），类似于GaAs薄膜。
Organic-inorganic metal halide perovskite solar cells have recently attracted considerable attention with reported device efficiencies approaching those achieved in polycrystalline silicon. Key for an efficient extraction of photogenerated carriers is the combination of low nonradiative relaxation rates leading to long carrier lifetimes and rapid diffusive transport. The latter, however, is difficult to assess directly with reported values varying widely. Here, we present an experimental approach for a contactless visualization of the charge carrier diffusion length and velocity in thin films based on time-resolved confocal detection of photoluminescence at varying distances from the excitation position. Our measurements on chloride-treated methylammonium lead iodide thin films, the material for which the highest solar cell efficiencies have been reported, reveal a charge carrier diffusion length of 5.5-7.7 mu m and a transport time of 100 ps for the first micrometer corresponding to a diffusion constant of about 5-10 cm(2) s(-1), similar to GaAs thin films.