The thermo-optical response of nanoparticles embedded in a glass matrix

CSI XLI, Mexico, 10 de Junio de 2019Nanoparticles of materials having a low melting point can be embedded in a high melting point glass matrix. This configuration suggests that the system can be heated up or slightly above the melting point of the nanoparticles and subsequently cooled down in order to get back to its original state. This behavior actually occurs. In this work two types of glasses have been studied in detail, the first one is composed of Bi nanoparticles embedded in a germanate matrix. The second one involves CuCl semiconductor nanocrystals embedded in an aluminoborosilicate matrix. In both cases reversible thermo-optical effects are evidenced upon heating and cooling cycles. Optical transmission measurements reveal a great amount of information regarding the melting and crystallization of the nanoparticles that can happen at very different temperatures giving rise to hysteresis effects. However the underlying mechanisms governing the effects in the two types of the studied glasses are fundamentally different. The observed changes have been evidenced in a variety of experimental situations by X-rays, Raman spectroscopy, UV-Vis, among others. Finally we discuss some possible applications for these systems in the design of spectral-selective thermo-optical devices that could be used for optical switching purposes1. References: [1] Jimenez de Castro M., Serna R., Toudert J., Fernández Navarro J. M., Haro-Poniatowski E. ¿Thermo-optical properties of Bi nanoparticles embedded in germanate glasses and alumina thin films¿, Ceram. Int., Vol. 41, No. 6, 8216¿8222, 2015