Blue luminescence of nanocrystalline CaZrO3:Tm phosphors synthesized by a modified Pechini sol-gel method

This paper reports the photoluminescence (PL) properties of nanocrystalline CaZrO₃:Tm phosphor synthesized by the polymerizable complex method based on the Pechini-type reaction. Nanosized phosphors with paving stone morphology were prepared at a relatively low temperature about 800 °C with the particle size being about 30 nm. The transmission electron microscope (TEM) images showed that further heat treatment at higher temperature could increase the particle size to 50 nm, but its morphology remained unchanged. The luminescence spectra indicated that the blue emission of CaZrO₃:Tm could be produced by four kinds of excitation energies, i.e. the charge transfer (CTS) between Tm³⁺-O²⁻, band-band absorption of host, the absorption defects in the host and the ³H₆-¹D₂ transition. The luminescent mechanism of CaZrO₃:Tm was deduced tentatively based on the luminescence spectra.