An efficient photothermal conversion material based on D-A type luminophore for solar-driven desalination

Abstract

Solar-driven interfacial evaporation is a promising technology for desalination. The photothermal conversion materials are at the core and play a key role in this field. Design of photothermal conversion materials based on organic dyes for desalination is still a challenge due to lack of efficient guiding strategy. Herein, a new D (donor)-A (acceptor) type conjugated tetraphenylpyrazine (TPP) luminophore (namely TPP-2IND) was prepared as a photothermal conversion molecule. It exhibited a broad absorption spectrum and strong π-π stacking in the solid state, resulting in efficient sunlight harvesting and boosting nonradiative decay. TPP-2IND powder exhibited high photothermal efficiency upon 660 nm laser irradiation (0.9 W cm⁻²), and the surface temperature can reach to 200°C. Then, an interfacial heating system based on TPP-2IND is established successfully. The water evaporation rate and the solar-driven water evaporation efficiency were evaluated up to 1.04 kg m⁻² h⁻¹ and 65.8% under 1 sunlight, respectively. Thus, this novel solar-driven heating system shows high potential for desalination and stimulates the development of advanced photothermal conversion materials.

Keywords

luminophore / photothermal conversion materials / seawater desalination / solar energy / tetraphenylpyrazine