Terminal group engineering of TiCT MXene on thermal emitter performance.

TiCT MXene has emerged as a promising material for diverse nanophotonics applications. In this study, we investigate how TiCT MXene terminal groups (-F, -O-, -OH) influence the performance of a planar thermal emitter with a VO/SiO/TiCT MXene structure. By examining four variants of TiCT MXene across the 2-20 µm spectral range, we demonstrate that the hysteresis loop threshold temperature remains constant for all MXene types due to the VO phase change material. The average differential emissivity (Δε) between the semiconductor and metallic states of VO varies significantly with terminal group composition. The VO/SiO/TiCF structure exhibits the highest differential emissivity of Δε = 0.42, while VO/SiO/TiC(OH) shows the lowest of Δε = 0.33. The remaining structures; VO/SiO/TiC and VO/SiO/TiCO, demonstrate intermediate differential emissivity values of Δε = 0.41 and 0.38, respectively. These findings establish a foundation for controlling emissivity in applications such as energy harvesting, thermophotovoltaics, and radiative cooling systems. The ability to tailor thermal emission through MXene terminal group engineering presents opportunities for designing tunable photonic devices with precise thermal control capabilities for the next-generation of energy management systems.