Blue thermoluminescence emission of annealed lithium rich aluminosilicates

Abstract

The blue thermoluminescence (TL) emission of different thermally annealed (i) β-eucryptite (LiAlSiO 4 ), (ii) virgilite-petalite (LiAlSi 5 O 12 ) and (iii) virgilite-petalite-bikitaite (LiAlSi 10 O 22 ) mixed crystals have been studied. The observed changes in the TL glow curves could be linked to simultaneous processes taking place in the lithium aluminosilicate lattice structure (phase transitions, consecutive breaking linking of bonds, alkali self-diffusion, redox reactions, etc). The stability of the TL signal after four months of storage performed at RT under red light, shows big differences between annealed (12 hours at 1200 o C) and non-annealed samples. The fading process in non-annealed samples can be fitted to a first-order decay mathematical expression; however preheated samples could not be reasonably fitted due to the highly dispersion detected. The changes observed in the X-ray diffractograms are in the intensity of the peaks that denote modifications in the degree of crystallinity and, in addition, there are some differences in the appeareance of new peaks that could suppose new phases (e.g. β-spodumene).

Thermo- and cathodoluminescence properties of lepidolite

“…According to Itoh and coworkers [20], the 397 nm emission can be attributed to [AlO 4 ] -centers, through electron-hole mechanisms [21]. Due to the exposure to the electron beam, the electrons are released from the oxygen atoms closed through the bulk and interfaces due to changes in the temperature of the lattice [22,23].…”

Role of phonons in negative thermal expansion and high pressure phase transitions in β-eucryptite: An ab-initio lattice dynamics and inelastic neutron scattering study

“…The layered compounds are found to exhibit particularly high diffusion coefficients for Li-ion 1,23,24 . βeucryptite (LiAlSiO 4 ) finds application as a battery material [25][26][27][28][29] as well as a humidity sensor. It is used in the manufacturing of domestic cookware, high-precision machines and optical devices, solid electrolytes for Li-ion batteries and pressure sensitive switches.…”