Bi Shiqing, Zhang Xuning, Qin Liang, Wang Rong, Zhou Jiyu, Leng Xuanye, Qiu Xiaohui, Zhang Yuan, Zhou Huiqiong, Tang Zhiyong
CAS Key Laboratory of Nanosystem, and Hierachical Fabrication CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, No. 11, ZhongGuanCun BeiYiTiao, Beijing, 100190, P. R. China.
School of Chemistry, Beihang University, No. 37, Xueyuan Road, Beijing, 100191, P. R. China.
Chemistry. 2017 Oct 17;23(58):14650-14657. doi: 10.1002/chem.201703382. Epub 2017 Sep 18.
The hysteresis effect and instability are important concerns in hybrid perovskite photovoltaic devices that hold great promise in energy conversion applications. In this study, we show that the power conversion efficiency (PCE), hysteresis, and device lifetime can be simultaneously improved for methylammoniumlead halide (CH NH PbI Cl ) solar cells after incorporating poly(methyl methacrylate) (PMMA) into the PC BM electron extraction layer (EEL). By choosing appropriate molecular weights of PMMA, we obtain a 30 % enhancement of PCE along with effectively lowered hysteresis and device degradation, adopting inverted planar device structure. Through the combinatorial study using Kelvin probe force microscopy, diode mobility measurements, and irradiation-dependent solar cell characterization, we attribute the enhanced device parameters (fill factor and open circuit voltage) to the surface passivation of CH NH PbI Cl , leading to mitigating charge trapping at the cathode interface and resultant Shockley-Read-Hall charge recombination. Beneficially, modified by inert PMMA, CH NH PbI Cl solar cells display a pronounced retardation in performance degradation, resulting from improved film quality in the PC BM layer incorporating PMMA which increases the protection for underneath perovskite films. This work enables a versatile and effective interface approach to deal with essential concerns for solution-processed perovskite solar cells by air-stable and widely accessible materials.
滞后效应和不稳定性是混合钙钛矿光伏器件中的重要问题，这类器件在能量转换应用中具有巨大潜力。在本研究中，我们表明，将聚甲基丙烯酸甲酯（PMMA）掺入到PC BM电子提取层（EEL）后，甲脒铅卤化物（CH₃NH₃PbI₃₋ₓClₓ）太阳能电池的功率转换效率（PCE）、滞后现象和器件寿命可同时得到改善。通过选择合适分子量的PMMA，采用倒置平面器件结构，我们实现了PCE提高30%，同时有效降低了滞后现象和器件退化。通过结合开尔文探针力显微镜、二极管迁移率测量以及依赖辐照的太阳能电池表征研究，我们将器件参数（填充因子和开路电压）的提高归因于CH₃NH₃PbI₃₋ₓClₓ的表面钝化，这减轻了阴极界面处的电荷俘获以及由此产生的肖克利-里德-霍尔电荷复合。有益的是，经惰性PMMA改性后，CH₃NH₃PbI₃₋ₓClₓ太阳能电池的性能退化明显减缓，这是由于掺入PMMA的PC BM层中薄膜质量得到改善，增强了对下层钙钛矿薄膜的保护。这项工作通过空气稳定且易于获取的材料，为解决溶液处理钙钛矿太阳能电池的关键问题提供了一种通用且有效的界面方法。
