Preparation and Bolometric Responses of MoS₂ Nanoflowers and Multi-Walled Carbon Nanotube Composite Network

Due to their broadband optical absorption ability and fast response times, carbon nanotube (CNT)-based materials are considered promising alternatives to the toxic compounds used in commercial infrared sensors. However, the direct use of pure CNT networks as infrared sensors for simple resistance read-outs results in low sensitivity values. In this work, MoS2 nanoflowers are composited with CNT networks via a facile hydrothermal process to increase the bolometric performance. The thermal diffusivity (alpha) against temperature (T) is measured using the transient electro-thermal (TET) technique in the range of 320 K to 296 K. The alpha-T curve demonstrates that the composite containing MoS2 nanoflowers provides significant phonon scattering and affects the intertube interfaces, decreasing the alpha value by 51%. As the temperature increases from 296 K to 320 K, the relative temperature coefficient of resistance (TCR) increases from 0.04%/K to 0.25%/K. Combined with the enhanced light absorption and strong anisotropic structure, this CNT-MoS2 composite network exhibits a more than 5-fold greater surface temperature increase under the same laser irradiation. It shows up to 18-fold enhancements in resistive responsivity ((R-on - R-off)/R-off) compared with the pure CNT network for a 1550 nm laser at room temperature (RT).