Preparation of colloidal submicrometre spheres with low-optical absorption via double laser-induced in liquid

The exciting properties of submicrometre sphere particles have been employed in many fields, such as the selective intervention characteristics and the size effect was widely used in the fields of biomedicine and sensing. However, the main synthesized methods at present were chemical or mechanical types, and several drawbacks existed. Recently, single pulsed laser irradiation in liquid has been confirmed as an innovative approach for fabrication of the submicrometre sphere particles due to the different optical absorption of precursor materials in a liquid phase, and many sphere particles for metal or alloy materials could be successfully synthesized. However, most of the semiconductor materials with low-optical absorption were disabled in this way, due to the laser energy under a proper wavelength was forbidden by the intrinsic wide bandgap of the semiconductor. Herein, based on the property of optical absorption, a double laser system was constructed to heat and assist fabrication by resonating wavelength matching. In the experiment section, the wide bandgap nanomaterials TiO2 was employed as the precursor and irradiated at the proper wavelength that originated from the optical absorption spectrum (532 nm for Nd: YAG laser and 324 nm for OPO laser, respectively). The results indicated that the submicrometre sphere particles could be well synthesized, and the morphology, optical absorption property was obtained improvement than that way of a single pulse.