Anomalous 3D nanoscale photoconduction in hybrid perovskite semiconductors revealed by tomographic atomic force microscopy
Anomalous 3D nanoscale photoconduction in hybrid perovskite semiconductors revealed by tomographic atomic force microscopy
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DOI：
10.1038/s41467-020-17012-y
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发表时间：
2020-07-03
影响因子：
16.6
通讯作者：
Huey, Bryan D.
中科院分区：
文献类型：
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作者：
Song, Jingfeng;Zhou, Yuanyuan;Huey, Bryan D.
虽然传统无机半导体中的晶界（GB）经常被认为不利于光生载流子传输，但对于新兴的混合钙钛矿半导体来说，它们的确切作用仍然模糊。 GB 特性研究的主要挑战是，在实验上它们需要在顶部表面进行，这不仅对深度相关的不均匀性不敏感，而且还可能容易受到地形伪影的影响。因此，我们开发了一种基于层析原子力显微镜的独特方法，在混合钙钛矿中实现纳米级的全3D光生载流子传输图。这揭示了 GB 作为载流子传输的高度互连的传导通道。我们进一步发现杂化钙钛矿中存在两种GB类型的共存，一种表现出增强的载流子迁移率，而另一种则表现平淡。我们的方法揭示了原本难以接近的埋藏特征和之前未解决的传导路径，这对于优化太阳能电池和光电探测器等各种光电应用的混合钙钛矿至关重要。卤化物钙钛矿中晶界（GB）的作用是一个有趣的话题，但现有的研究仅限于顶面。这里宋等人。利用断层扫描 AFM 研究晶粒和 GB 的埋藏特征，揭示互连导电 GB 和惰性 GB 的共存。
While grain boundaries (GBs) in conventional inorganic semiconductors are frequently considered as detrimental for photogenerated carrier transport, their exact role remains obscure for the emerging hybrid perovskite semiconductors. A primary challenge for GB-property investigations is that experimentally they need to be performed at the top surface, which is not only insensitive to depth-dependent inhomogeneities but also could be susceptible to topographic artifacts. Accordingly, we have developed a unique approach based on tomographic atomic force microscopy, achieving a fully-3D, photogenerated carrier transport map at the nanoscale in hybrid perovskites. This reveals GBs serving as highly interconnected conducting channels for carrier transport. We have further discovered the coexistence of two GB types in hybrid perovskites, one exhibiting enhanced carrier mobilities, while the other is insipid. Our approach reveals otherwise inaccessible buried features and previously unresolved conduction pathways, crucial for optimizing hybrid perovskites for various optoelectronic applications including solar cells and photodetectors. The role of grain boundaries (GBs) in halide perovskite is an interesting topic but existing investigations are limited to the top surface. Here Song et al. employ tomographic AFM to study the buried features of grains and GBs, revealing coexistence of interconnected conducting and inert GBs.