Relation between photoluminescence emission and local order-disorder in the CaTiO3 lattice modifier

Abstract

In this letter, the authors propose that photoluminescence emission in CaTiO3 is affected not only by disorder in the lattice former but also by structural disorder in the lattice modifier. Structural disorder was evaluated by Ti, Ca K-edge x-ray absorption near-edge structure experiments and by photoluminescence emission. The preedge feature of the Ca K edge was related to the intensity of photoluminescence emission. The results of the preedge feature of the Ca K-edge x-ray absorption near-edge structure confirm the presence of different Ca coordination numbers, namely, Ca–O11 and Ca–O12.

Structural refinement and photoluminescence properties of irregular cube-like (Ca1−xCux)TiO3 microcrystals synthesized by the microwave–hydrothermal method

“…Fig. 6(a) illustrates the pre-edge region ( ) situated at around 4.040 eV and the XANES spectra of the CaTiO 3 and (Ca 1Àx Cu x )TiO 3 microcrystals presents a similar profile as reported by our research group [31,32].…”

“…The XANES analyses were usually performed as a semiquantitative technique to get information about changes in the coordination of titanates lattice formers as well as the lattice modifiers [11,31,32]. Fig.…”

Structural conditions that leads to photoluminescence emission in SrTiO3: An experimental and theoretical approach

“…This explanation of vector displacement takes into account previous work on the perovskite structure. 23,24 Recently, Lazaro et al 51 reported results of a pre-edge feature of Ti and Ca K-edge XANES in a disordered CaTiO 3 perovskitelike structure. Their findings indicated two types of environments for the calcium, namely, 11-fold and 12-fold calcium coordinations.…”

Europium-doped calcium titanate: Optical and structural evaluations

“…This forbidden electronic transition dipole is normally allowed by the mixture of the p states from the surrounding oxygen atoms into the unfilled d states of the titanium atoms [39]. The increase in the intensity of this peak indicates that the local environment of the Ti atom is non-centrosymmetric which, distorts the octahedral configuration [24,40,41]. In fact, the intensity of the pre-edge feature also is attributed to presence of fivefold coordinated [TiO 5 ] clusters [24,41] [19].…”

“…According to de Lazaro et al [40], the PL emission can be related to the order-disorder in the calcium coordination which indicates that the lattice modifier affects the PL emission intensity.…”