Photo-thermoelectric conversion and photo-induced thermal imaging using 2D/3D ReS2@carbon framework with enhanced photon harvesting

Solar energy is a promising renewable energy with the potential for the sustainable development of the world. Efficient photo-thermal conversion is essential for harvesting and conversion of solar energy, therefore, the main challenge is the development of efficient and low-cost photothermal conversion materials. Carbon framework can be considered as a candidate but somehow its application potential can be still constrained due to the limited absorption of near-infrared (NIR) light. Herein, we propose a general strategy for preparing two-dimensional (2D) transition metal dichalcogenides nanosheets and three-dimensional (3D) carbon framework composites (2D/3D ReS 2 @C) as a photothermal material, which has an excellent broadband light absorption performance (in the wavelength range from 200 to 2500 nm). A small thermoelectric (TE) module with an area of 4 × 4 cm 2 is integrated with annealed ReS 2 @C as a light absorber for the investigation of photo-thermoelectric conversion. The open-circuit voltage of the assembled device increases clearly under solar illumination and reaches the maximum value of 136.3 mV, which is ∼ five times larger than that without the absorber. In addition, 20 TE modules coated with ReS 2 @C absorber layers are connected in series, which can produce a maximum open-circuit voltage of 2.12 V (∼66.25 V/m 2 ) to light up a red light-emitting diode (LED) under natural sunlight. Moreover, the annealed ReS 2 @C powder demonstrates a rapid and strong photothermal response under NIR light (wavelength ＞800 nm), which indicates a great application potential in photothermal imaging and photothermal cancer therapy.