Laser-induced formation of photocatalytic TiO 2 micro networks on a UV-absorbing glass surface

Abstract

Laser-induced formation of functional materials from glasses has a great potential for creation of monolithic and highperformance glass-based devices, such as optical circuit and micro-TAS. We have recently developed a laser-induced formation technique of photocatalytic titanium oxide on a UV-absorbing TiO 2 -SiO 2 -based glass surface by excimer laser irradiation under a specific condition, which we term laser-induced superficial phase separation. The laser-induced structure has the shape of micro-cones, growing into micro-sized network after accumulating laser pulses, which we call TiO 2 micronetwork. The TiO 2 micronetwork exhibited the rutile crystalline phase and photocatalytic ability. Moreover, the crystalline phase can be controlled from the rutile to the anatase by post-treatments. Utilizing this technique, we were able to make a site-selective growth of TiO 2 micronetworks: a microwell array and a microchannel modified with the TiO 2 network only on the bottom. This flexible formation of photocatalytic TiO 2 onto a glass surface without any heattreatments and/or adhesives opens a new way to develop a monolithic glass device like micro-fluidics with lightcatalyzed reactions.