Synthesis of TiO2 nanoparticles and spectroscopic upconversion luminescence of Nd3+-doped TiO2-SiO2 composite glass

► We prepare both pure and PMMA embedded TiO2 thin films. ► We prepare Nd3+-doped TiO2-SiO2 composite glass samples. ► The 600 nm absorption band in the TiO2 film appears because of defects. ► UV and blue upconversion emissions with 578 nm excitation for the composites. ► Intense and rare 341 nm UV upconversion emission with 532 nm excitation.