Real-space observation of unbalanced charge distribution inside a perovskite-sensitized solar cell
Real-space observation of unbalanced charge distribution inside a perovskite-sensitized solar cell
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DOI：
10.1038/ncomms6001
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发表时间：
2014-09-01
影响因子：
16.6
通讯作者：
Berger, Ruediger
中科院分区：
文献类型：
--
作者：
Bergmann, Victor W.;Weber, Stefan A. L.;Berger, Ruediger
钙钛矿敏化太阳能电池已经达到了与商业太阳能电池相当的电力转换效率，例如用于太阳能发电场。与硅太阳能电池不同，钙钛矿敏化太阳能电池可以通过廉价材料的溶液工艺制成。这些电池的功率转换效率在很大程度上取决于界面上的电荷转移。在这里，我们使用开尔文探针力显微镜来研究高效介观甲基铵铅三碘化铅太阳电池内电势的真实空间横截面分布。我们证明了通过这些器件的电场是均匀的，类似于p-i-n型结的电场。在短路条件下照明时，由于器件中电荷传输的不平衡，空穴在空穴传输层前面积累。光照后，我们发现俘获的电荷仍然留在有源器件层内。消除这些陷阱和不平衡的电荷注入可以进一步提高钙钛矿敏化太阳能电池的性能。
Perovskite-sensitized solar cells have reached power conversion efficiencies comparable to commercially available solar cells used for example in solar farms. In contrast to silicon solar cells, perovskite-sensitized solar cells can be made by solution processes from inexpensive materials. The power conversion efficiency of these cells depends substantially on the charge transfer at interfaces. Here we use Kelvin probe force microscopy to study the real-space cross-sectional distribution of the internal potential within high efficiency mesoscopic methylammonium lead tri-iodide solar cells. We show that the electric field is homogeneous through these devices, similar to that of a p-i-n type junction. On illumination under short-circuit conditions, holes accumulate in front of the hole-transport layer as a consequence of unbalanced charge transport in the device. After light illumination, we find that trapped charges remain inside the active device layers. Removing these traps and the unbalanced charge injection could enable further improvements in performance of perovskite-sensitized solar cells.