Synthesis and optical characterization of lanthanide-doped colloidal Ga2O3 nanoparticles

Abstract

We demonstrate the use of thermal decomposition reaction to obtain Ga2O3 nanoparticles with average size around 5nm. The obtained nanoparticles presented a good colloidal stability and high optical transparency. We were also able to incorporate Eu3+ and Tb3+ ions inside the crystal host. The synthesized nanomaterials exhibited dual mode emission upon UV excitation, consisting of a broad band in the blue region and a characteristic series of sharp lines. The former resulted from donor–acceptor pairs recombination in Ga2O3 host, while the latter from 4f–4f electronic transitions in lanthanide ions. For fuller optical characterization of the obtained nanoparticles, we have performed wide wavelength range Z-scan studies, and calculated the values of nonlinear absorption cross-sections. Gallium (III) oxide nanoparticles showed two-photon absorption in the range between 500nm and 700nm, with molecular weight scaled nonlinear optical parameters exceeding the values for other lanthanide-doped nanoparticles of similar size.