Study of photoluminescence and electronic states in nanophase strontium titanate

The role of oxygen vacancy in the photoluminescence property at room temperature of the CaTiO3

“…Moreover, this line shape indicates that the confinement effect cannot be considered as the predominant mechanism of the luminescence. 40 The rearrangement of the lattice was clearly detected through PL experimental measurements and is a strong indication that this measurement is highly sensitive to structural changes.…”

Presence of excited electronic state in CaWO4 crystals provoked by a tetrahedral distortion: An experimental and theoretical investigation

“…The decrease in the bandgap can be attributed to defects, local bond distortion, intrinsic surfaces states and interfaces which yield localized electronic levels in the forbidden bandgap. 105,106 We believe that this significant difference is attributed to surface and interface intrinsic defects generally expected in the MH processing. 107,108 F. PL emission analyses Figure 7 illustrates the PL spectra recorded at room temperature for the CaWO 4 crystals processed at 140 C for different time (from 30 to 480 min) in MH system.…”

Negative pressure effects in strontium titanate nanoparticles

“…SrTiO 3 is a perovskite-type quantum paraelectric metaloxide where large quantum fluctuations make the ferroelectric state unstable in favor of the paraelectric state. It has been found that the reduction of grain size for SrTiO 3 into the nanoscale regime makes distinct properties from the bulk [2][3][4]. For example, the optical energy gap E g [2] and the photoluminescence (PL) intensity [3] were observed to increase with SrTiO 3 particles when the grain size reaches the nanoscale regime, which were ascribed to the formation of the intrinsic surface states and defect centers in the nanoparticles.…”