Phase (1T/2H) dependent electromagnetic wave absorbing performance of flower-like MoS₂ nanosheets

A study was carried out to determine the phase-dependent electromagnetic wave (EMW) absorption performance of MoS₂ particles via systematically diversified hydrothermal synthesis conditions such as time, temperature, precursor molarity, and oxalic acid concentration. The formation of mixed-phase structure was verified depending on the presence of the characteristic diffraction peaks belong to 1T (trigonal, P3̅m1 space group) and 2H (hexagonal, P63/mmc space group) phases in the X-ray diffraction (XRD) patterns. Phase-pure 2H-MoS₂ was obtained at 200 °C after 12 h of reaction and using 5 mmol oxalic acid. Microscopic examinations indicate that MoS₂ particles formed by assembling several nanosheets to create a flower-like morphology. The size, shape, and the distance between the nanosheets were observed to change with increasing temperature, time, and acid concentration. The band gap was found to be modified depending on the phase distribution and decreased from 1.54 eV (2H) to a minimum of 0.64 eV (1T/2H) with the formation of the 1T (metallic) phase. Finally, the minimum reflection loss was measured as − 67.73 dB (99.9999 % of absorption at 9.05 GHz) with an effective absorption bandwidth (EAB) of 3.52 GHz for the sample composed of 1T/2H mixed-phased structure.