Combined Experimental and DFT Study on 2D MoSe₂ toward Low Infrared Emissivity

Abstract

Low infrared emissivity materials play a key role in thermal camouflage or retardation. Among these, fillers can be easily shaped into various flexible forms and normally provide an omnidirectional and polarization-insensitive emissivity. However, conventional fillers suffer from drawbacks of full-waveband ultrahigh reflectivity, unsatisfactory thermal camouflage performances, or poor chemical/thermal stabilities. Herein, 2D MoSe 2 is discovered as a new semiconductor with intrinsic low infrared emissivity after first-principle density functional theory calculation and experimental demonstration on eight types of two-dimensional materials (2DMs). Mechanisms of electron-photon reflection and phonon-photon absorption for the low infrared emissivity are proposed. A two-step microwave-assisted amination process is developed to exfoliate the nanosheets and obtain a desired low infrared emissivity. The as-obtained chitosan modified MoSe 2 (CS@MoSe 2 ) has an ultrahigh spectral reflectivity of 78%-86% in 8-14 µm, and its resin-based coating still exhibits a low infrared emissivity of 0.32 and shows a dramatic reduction in radiation temperature of 28 °C for a hot object at 70 °C. Besides, CS@MoSe 2 can endure a high temperature of 220 °C and is demonstrated with a long-term thermal camouflage efficiency in hot environments. This work will guide 2DMs selection and preparation toward desired infrared radiation properties to satisfy numerous applications.

Recent progress in microwave-assisted preparations of 2D materials and catalysis applications

“…In recent years, microwave-assisted methods have been widely used in 2DMs exfoliation [17,18], chemical synthesis [19,20], doping [21][22][23][24] and modification [25][26][27][28][29] and construction of 2D-based hierarchical hybrid structures [30,31] to perform excellent catalysis activities. The good catalytic activities of as-obtained 2DMs nanomaterials strongly depend on the desired chemical compositions and fine microstructures benefiting a lot from the microwave effects [30,[32][33][34].…”