Amino-Terminated Ti3C2Tx MXene Prepared via Ammonia Treatment Boosts Efficiency and Stability of Perovskite Solar Cells.

Abstract

Defect-mediated non-radiative recombination and progressive material degradation impose fundamental limits on the power conversion efficiency (PCE) and operational durability of perovskite solar cells (PSCs). To address this issue, we synthesized amino-terminated Ti3C2Tx MXene (denoted as A-MXene) nanosheets through LiF/HCl etching and subsequent ammonia post-treatment and incorporated them into PSCs. Characterization results reveal that ammonia treatment modifies the surface/interlayer chemistry of Ti3C2Tx and introduces amino-related nitrogen species, accompanied by increased interlayer spacing, reduced lateral flake dimensions, and enhanced dispersibility. In PSCs, A-MXene regulates both Pb- and I-related chemical environments, improves perovskite crystallization, suppresses non-radiative recombination, and promotes interfacial hole extraction. Consequently, the A-MXene-modified device delivers a PCE of 23.49%. Moreover, the encapsulated device retains 94.9% of its initial PCE after 720 h of uninterrupted 1-sun illumination at 85 °C in a N2 atmosphere. These findings establish ammonia-treated MXene as a versatile additive capable of concurrently governing defect chemistry and charge transport, thereby enabling high-efficiency, stable PSCs.