Intense photoluminescence emission at room temperature in calcium copper titanate powders

A novel method to synthesize CaCu3Ti4O12 with acetylacetonate precursor

“…The F g symmetry mode at 573 cm À 1 is characteristic for Ti-O-Ti anti stretching vibration of TiO 6 octahedron. They are matching with other reported results for CCTO [19].…”

Photoluminescence emission in zirconium-doped calcium copper titanate powders

“…Thus, the PL behavior at room temperature can be related to the degree of order in the CCTO lattice, controlled by the [TiO 5 ] and [TiO 6 ] clusters. In a previous study, our group investigated the influence of the annealing temperature on the PL of CCTO powders [26]. In the current work, CCTZO powders were prepared with the aim of improving the lattice defects and phase transformations as well as increasing the surface area, which affects the crystallization process of the main phase.…”

Red shift and higher photoluminescence emission of CCTO thin films undergoing pressure treatment

“…Intermediate levels are created inside the band gap by an overlap between the 2p orbital of oxygen vacancies to the 4d orbital of titanium. Moura et al [22] reported an E gap of about 1.63 eV to a ordered film comparable to the CCTO CF-700°C of this study. Similar to temperature effect described by Moura et al [22], the smaller E gap observed to the CF + PT reported here indicates that the increase in oxygen pressure can also break the Ti-O bond leading to the origin of TiO 5 V z 0 cluster which resulted in an overlap of 2p orbitals from the oxygen vacancies to the conduction band.…”

“…Moura et al [22] reported an E gap of about 1.63 eV to a ordered film comparable to the CCTO CF-700°C of this study. Similar to temperature effect described by Moura et al [22], the smaller E gap observed to the CF + PT reported here indicates that the increase in oxygen pressure can also break the Ti-O bond leading to the origin of TiO 5 V z 0 cluster which resulted in an overlap of 2p orbitals from the oxygen vacancies to the conduction band. The band gap reduction (about 1.1 eV) obtained after the air pressure treatment favors the red shift in the PL emission which involves lower PL emission energy.…”

“…Moura et al [22] proposed that an increase in PL emission is caused by a decrease in the CCTO band gap originated from structural defects. Intermediate levels are created inside the band gap by an overlap between the 2p orbital of oxygen vacancies to the 4d orbital of titanium.…”