Tailoring luminescent colour and life persistence of undoped CdSiO3

In this work, undoped CdSiO3 samples with different luminescence spectra and light persistence were obtained by controlling the parameters of sol-gel synthesis. The process of monoclinic phase formation was monitored through XRD and TG-DTA measurements, combined to microstructural characterization using FTIR and SEM. The optical energy bandgap (Eg) of CdSiO3 was estimated from Tauc equation and indicates the dependency of bandgap energy on the starting pH used for synthesis. Three main peaks could be identified from PL and XEOL spectra, at 590 nm, 490 nm and 406 nm. Their relative intensities yielded overall distinct luminescence colours, such as indigo or red. The luminescent mechanisms of CdSiO3 related to an intrinsic defect (VCd) were further investigated to show its key role in the charge trapping that causes long lasting luminescence.