Oxide Derivatives of Nb2CTx MXene and Their Application as Electron Transport Layers in Perovskite Solar Cells: Unraveling the Oxidation Process and Functionalization

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 20; no. 43; pp. e2403460 - n/a
• Main Authors: Yang, Lin, Liu, Ziyan, Zheng, Tianfang, Li, Peng, Ma, Jiangang, Zhang, Xintong, Zhu, Hancheng, Wang, Xiao‐Feng, Liu, Yichun
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01.10.2024
• Subjects: 2D Nb2CTx MXene; AIMD simulations; Atomic structure; Composite materials; DFT calculations; Dissolved oxygen; Electron transfer; Electron transport; electron transport layer; Energy levels; Metal carbides; MXenes; Oxidation; perovskite solar cells; Perovskites; Photoelectricity; Photovoltaic cells; Solar cells; Synergistic effect; Tin dioxide; Transition metals
• ISSN: 1613-6810; 1613-6829; 1613-6829
• DOI: 10.1002/smll.202403460

In the realm of photovoltaic research, 2D transition metal carbides (MXenes) have gained significant interest due to their exceptional photoelectric capabilities. However, the instability of MXenes due to oxidation has a direct impact on their practical applications. In this work, the oxidation process of Nb2CTx MXene in aqueous systems is methodically simulated at the atomic level and nanosecond timescales, which elucidates the structural variations influenced by the synergistic effects of water and dissolved oxygen, predicting a transition from metal to semiconductor with 44% C atoms replaced by O atoms in Nb2CTx. Moreover, Nb2CTx with varying oxidation degrees is utilized as electron transport layers (ETLs) in perovskite solar cells (PSCs). Favorable energy level alignments with superior electron transfer capability are achieved by controlled oxidation. By further exploring the composites of Nb2CTx to its derivatives, the strong interaction of the nano‐composites is demonstrated to be more effective for electron transport, thus the corresponding PSC achieves a better performance with long‐term stability compared with the widely used ETLs like SnO2. This work unravels the oxidation dynamics of Nb2CTx and provides a promising approach to designing ETL by exploiting MXenes to their derivatives for photovoltaic technologies. The oxidation process of Nb2CTx MXene is methodically simulated at the atomic level and nanosecond timescales, predicting a transition from metal to semiconductor with 44% C atoms replaced by O atoms in Nb2CTx. By exploiting MXenes to their derivatives, a promising approach to designing ETL for photovoltaic technologies is demonstrated.