Fotoluminescência do cromo trivalente na rede cristalina da cerâmica avançada Mg2Sn04

Abstract

In this work it is presented the synthesis and optical characterization of the Cr3+ doped Mg2SnO4 advanced ceramics. The sample was prepared from the raw oxides MgO, SnO2 e Cr2O3 to obtain the [Mg2(1−x)Cr2xSnO4 (x = 0, 001) compound by solid state reaction. The crystalline structure was analyzed by powder X-ray diffraction and the photoluminescent properties were investigated using photoluminescence measurements and excitation of the photoluminescence at room temperature. The diffractogram shows a profile that confirms the crystallinity of the system and the compound formation. The Mg2SnO4 crystallizes in cubic symmetry, with space group [Fd¯3m] and inverse spinel structure. In the photoluminescence experiments carried out with the excitation wavelengths [[...]exc] = 300, 450 and 532 nm it was identified a broad and intense band in the near infrared region with a maximum around 780 nm and a weak structure at 695 nm, both attributed to the presence of the Cr3+ ion in an octahedral coordination site. It was also identified an emission band around 612 nm, which it is believed to be related to the emission of the lattice. Excitation photoluminescence measurements show the presence of two bands at visible region located at 460 nm and 628 nm, attributed to octahedral Cr3+ transitions. Optical spectra were analyzed and interpreted according to the Crystal Field Theory and the Tanabe-Sugano energy matrices for d³ configuration. The broad and intense band observed in the near infrared in the emission spectra suggests that the system may be a promising material as a source of luminescence at room temperature.