Sacrificial Template Synthesis and Photothermal Conversion Enhancements of Hierarchical and Hollow CuInS₂ Microspheres

Hierarchical and hollow CuInS 2 microspheres are synthesized on the basis of sacrificial templates with solid and hollow CuS microspheres as sacrificial templates, respectively. Transformations from CuS solid microspheres to CuInS 2 hierarchical microspheres and CuS hollow microspheres to CuInS 2 hollow microspheres can be achieved by a solvothermal process at 180 °C for 24 h with N, N -dimethylformamide as both solvent and reductant. The products are well characterized, and the formation mechanisms are proposed. The as-synthesized products have strong optical absorption from 1000 to 2000 nm in addition to normal absorption from 400 to 800 nm, which has not be reported in the literature. The as-synthesized products exhibit a significant photothermal conversion effect under an irradiation of a 1064 nm laser. At a laser power of 0.05 W·cm –2, up to 30% and 20% enhancement of photothermal conversion is observed in the aqueous suspension containing 0.1 wt % CuInS 2 hollow microspheres and hierarchical microspheres, respectively. The mechanisms for the enhancements of photothermal conversion in the as-synthesized products are also discussed.