Ti3AlC2 MAX and Ti3C2 MXene Quantum Sheets for Record-High Optical Nonlinearity

• Published in: The journal of physical chemistry letters 2022-05, Vol.13 (17), p.3929-3936
• Main Authors: Chen, Zhexue, Sui, Xinyu, Li, Yueqi, Liu, Xinfeng, Zhang, Yong
• Format: Article
• Language: English
• Subjects: Physical Insights into Materials and Molecular Properties
• ISSN: 1948-7185; 1948-7185
• DOI: 10.1021/acs.jpclett.2c00711

Two-dimensional (2D) transition-metal carbides (MXenes) have attracted great interest owing to their unique structures and superior properties compared to those of traditional 2D materials. The transformation of 2D MXenes into sub-5-nm quantum sheets (QSs) is urgently required but rarely reported. Herein, the Ti3AlC2 MAX and Ti3C2 MXene QSs with monolayer structures and sub-5-nm lateral sizes are demonstrated. Exceptionally high yields (>15 wt %) are obtained through an all-physical top-down method. The QS dispersions present unique photoluminescence, and the QSs-poly­(methyl methacrylate) (PMMA) hybrid thin films demonstrate remarkable nonlinear saturation absorption (NSA). Absolute modulation depths of 30.6 and 49.9% and saturation intensities of 1.16 and 1.25 MW cm–2 (i.e., 116 and 125 nJ cm–2) are achieved for Ti3AlC2 QSs and Ti3C2 QSs, respectively. Such record-high NSA performances of MXene QSs would boost the application of MAX/MXene materials in nonlinear optics.