High-speed shearing prepare Bi2Se3 dispersions and effect of size on photothermal conversion

•The size distribution of Bi2Se3 nanoparticles depends on the excellent photothermal conversion and heat stability of aqueous solutions.•The broad wavelength range and localized surface plasmons resonance of Bi2Se3 nanoparticles improve the photothermal conversion efficiency.•Excellent cycling stability testifies high photothermal conversion of Bi2Se3 aqueous solutions.•The temperature of Bi2Se3 aqueous solutions can increase up to 41.4 °C. Bi2Se3, as an important photothermal conversion semiconductor material, has been widely studied to realize the heat energy application. The Bi2Se3 nanoparticles (NPs) dispersion is prepared by the combined technology of grinding and high-speed shearing. The different size distribution of Bi2Se3 has been selected by tuning centrifugal rates and mechanism is discussed in detail. The NPs dispersion with radius of 330 nm has the best photothermal conversion, which selected at centrifugal rates of 3000 rpm. The Steady-state temperature of NPs dispersions at centrifugal rates of 1000 rpm can reaches 41.4 °C under 1.6 W laser irradiation. These show that the quantum confinement effect and the localized surface plasmon resonances (LSPR) of Bi2Se3 NPs play crucial roles for excellent photothermal conversion, which are in good agreement with the numerically theoretical calculation investigated using the finite difference time domain (FDTD) method.