Light‐Promoted Electrostatic Adsorption of High‐Density Lewis Base Monolayers as Passivating Electron‐Selective Contacts. Issue 5 (4th January 2021)

• Record Type: Journal Article
• Authors: Yang, Xi; Ying, Zhiqin; Yang, Zhenhai; Xu, Jia‐Ru; Wang, Wei; Wang, Jiajia; Wang, Zenggui; Yao, Lingze; Yan, Baojie; Ye, Jichun
• Is Part Of: Advanced science. Volume 8:Issue 5(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-01-04
• Subjects: carrier‐selective contact -- electrostatic adsorption -- Lewis bases -- passivating contact -- silicon solar cells; Science -- Periodicals; 505
• DOI: 10.1002/advs.202003245
• Languages: English
• ISSNs: 2198-3844

Abstract

Abstract: 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 n‐ 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. Abstract : A light‐promoted adsorption method is introduced to establish high‐density Lewis‐base polyethylenimine monolayers, which simultaneously provide a low‐resistance contact for electrons, a high‐quality field‐effect passivation to semiconductor and an enhanced dipole formation at semiconductor/cathode interface, as promising passivating carrier‐selective contacts for solar cells. This work also provides a convenient strategy to deposit highly uniform, dense, and ultra‐thin coatings for diverse applications.