Ultrasonication effect on size distribution of functionalized porous silicon microparticles

Sponge-like luminescent mesoporous silicon microparticles are produced from crystalline silicon with a simple and cheap top-down fabrication process which, however, offers scarce control of structural features such size, size distribution and pore dimensions of the final product. Herein, we report on a post-fabrication procedure based on ultrasonic treatment to get more homogeneous size distribution and much more control on the average dimension of the microparticles. We investigated the effect of variable ultrasonic treatments on the structural and optical properties of the microparticles. The structure was analysed both at micro and nano scale and for microparticles in dried state and in solution. We proved that few minutes of sonication strongly limits the heterogeneity of the sample size, without affecting the optical properties and porous structure. This simple post-fabrication step offers new opportunities for successful use of silicon microparticles in biomedicine.