Poly(4-Vinylpyridine)-Based Interfacial Passivation to Enhance Voltage and Moisture Stability of Lead Halide Perovskite Solar Cells
Poly(4-Vinylpyridine)-Based Interfacial Passivation to Enhance Voltage and Moisture Stability of Lead Halide Perovskite Solar Cells
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DOI：
10.1002/cssc.201700271
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发表时间：
2017-06-09
期刊：
影响因子：
8.4
通讯作者：
Miyasaka, Tsutomu
中科院分区：
文献类型：
--
作者：
Chaudhary, Bhumika;Kulkarni, Ashish;Miyasaka, Tsutomu
众所周知，溶液法制备的CH3NH3PbI3钙钛矿薄膜的表面陷阱态和电子紊乱对太阳能电池的性能影响很大，光活性钙钛矿材料的水分敏感性限制了其实际应用。在此，我们展示了用溶液可加工疏水性聚合物（聚（4-乙烯基吡啶）PVP）对钙钛矿薄膜进行表面改性，该聚合物通过其吡啶路易斯碱侧链钝化钙钛矿表面的欠配位铅原子，从而消除了表面陷阱态和非辐射重组。此外，它作为钙钛矿和空穴传输层（HTL）之间的电子屏障，减少了界面电荷复合，导致开路电压（V-oc）提高了120至160 mV，而在相同条件下制造的标准电池，由于主要的界面复合过程，Voc低至0.9 V。结果表明，当V-oc大于1.05 V且J-V曲线无迟滞时，聚合物修饰器件的功率转换效率（PCE=15%）提高了3 ~ 5%。有利的是，聚合物链的疏水性可以保护钙钛矿表面免受水分的影响，并提高了非封装电池的稳定性，使其在开放大气（50%湿度）下暴露30天仍能保持其设备性能。
It is well known that the surface trap states and electronic disorders in the solution-processed CH3NH3PbI3 perovskite film affect the solar cell performance significantly and moisture sensitivity of photoactive perovskite material limits its practical applications. Herein, we show the surface modification of a perovskite film with a solution-processable hydrophobic polymer (poly(4-vinylpyridine), PVP), which passivates the undercoordinated lead (Pb) atoms (on the surface of perovskite) by its pyridine Lewis base side chains and thereby eliminates surfacetrap states and non-radiative recombination. Moreover, it acts as an electron barrier between the perovskite and hole-transport layer (HTL) to reduce interfacial charge recombination, which led to improvement in open-circuit voltage (V-oc) by 120 to 160 mV whereas the standard cell fabricated in same conditions showed Voc as low as 0.9 V owing to dominating interfacial recombination processes. Consequently, the power conversion efficiency (PCE) increased by 3 to 5% in the polymer-modified devices (PCE=15%) with V-oc more than 1.05 V and hysteresis-less J-V curves. Advantageously, hydrophobicity of the polymer chain was found to protect the perovskite surface from moisture and improved stability of the non-encapsulated cells, which retained their device performance up to 30 days of exposure to open atmosphere (50% humidity).