Yang Xi, Ying Zhiqin, Yang Zhenhai, Xu Jia-Ru, Wang Wei, Wang Jiajia, Wang Zenggui, Yao Lingze, Yan Baojie, Ye Jichun
Ningbo Institute of Materials Technology and Engineering Chinese Academy of Sciences (CAS) Ningbo 315201 P. R. China.
Joint Key Laboratory of the Ministry of Education Institute of Applied Physics and Materials Engineering University of Macau Macao SAR 999078 P. R. China.
Adv Sci (Weinh). 2021 Jan 4;8(5):2003245. doi: 10.1002/advs.202003245. eCollection 2021 Mar.
Achieving efficient passivating carrier-selective contacts (PCSCs) plays a critical role in high-performance photovoltaic devices. However, it is still challenging to achieve both an efficient carrier selectivity and high-level passivation in a sole interlayer due to the thickness dependence of contact resistivity and passivation quality. Herein, a light-promoted adsorption method is demonstrated to establish high-density Lewis base polyethylenimine (PEI) monolayers as promising PCSCs. The promoted adsorption is attributed to the enhanced electrostatic interaction between PEI and semiconductor induced by the photo-generated carriers. The derived angstrom-scale PEI monolayer is demonstrated to simultaneously provide a low-resistance electrical contact for electrons, a high-level field-effect passivation to semiconductor surface and an enhanced interfacial dipole formation at contact interface. By implementing this light-promoted adsorbed PEI as a single-layered PCSC for type silicon solar cell, an efficiency of 19.5% with an open-circuit voltage of 0.641 V and a high fill factor of 80.7% is achieved, which is one of the best results for devices with solution-processed electron-selective contacts. This work not only demonstrates a generic method to develop efficient PCSCs for solar cells but also provides a convenient strategy for the deposition of highly uniform, dense, and ultra-thin coatings for diverse applications.
实现高效的钝化载流子选择性接触（PCSCs）在高性能光伏器件中起着关键作用。然而，由于接触电阻率和钝化质量对厚度的依赖性，在单一的中间层中同时实现高效的载流子选择性和高水平的钝化仍然具有挑战性。在此，展示了一种光促进吸附方法，以建立高密度的路易斯碱聚乙烯亚胺（PEI）单分子层作为有前景的PCSCs。这种促进吸附归因于光生载流子诱导的PEI与半导体之间增强的静电相互作用。所得到的埃级PEI单分子层被证明能同时为电子提供低电阻电接触、对半导体表面进行高水平的场效应钝化以及在接触界面增强界面偶极的形成。通过将这种光促进吸附的PEI用作晶硅太阳能电池的单层PCSCs，实现了19.5%的效率，开路电压为0.641 V，填充因子高达80.7%，这是采用溶液处理电子选择性接触的器件的最佳结果之一。这项工作不仅展示了一种开发高效太阳能电池PCSCs的通用方法，还为沉积高度均匀、致密且超薄的涂层以用于各种应用提供了一种便捷策略。
