Photoluminescent and electrical properties of novel Nd3+ doped ZnV2O6 and Zn2V2O7

Nd3+ doped ZnV2O6 and Zn2V2O7 samples were synthetized by using melt-quenching method. X-ray diffraction patterns indicate that both samples are polycrystalline. The crystallinity was also verified by Raman scattering, from which the different vibrational modes of ZnV2O6 and Zn2V2O7 were detected. Electron dispersive spectroscopy (EDS) analysis shows that the Nd3+ incorporation into the ZnV2O6 and Zn2V2O7 hosts is around 0.9±0.1 and 0.2±0.1 at%, respectively. The micrographs obtained by Scanning Electron Microscopy, reveal that the Nd3+ doped ZnV2O6 sample is predominantly composed by micro-rods, whereas the Nd3+ doped Zn2V2O7 one is only composed by irregular blocks. The band gap energies (Eg) were calculated from the diffuse reflectance spectra by the Kubelka-Munk equation; Eg values resulted to be 2.24 and 2.86 eV for the Nd3+ doped ZnV2O6 and Zn2V2O7 samples, respectively. By means of two points dark conductivity measurements, conductivity values in the 10−4-10−6 and 10−6-10−8(Ω cm)−1range for the Nd3+ doped ZnV2O6 and Zn2V2O7 samples were measured, respectively. The conductivity as a function of the temperature indicated a semiconductor behavior. The photoluminescence spectra upon Ar+ laser excitation at 488 nm, exhibited the Nd3+ characteristics emissions. For instance, the Nd3+ doped ZnV2O6 sample displayed the Nd3+ 4F5/2→4I9/2 and 4F3/2→4I9/2 emissions; while the Nd3+ doped Zn2V2O7 one showed the Nd3+ characteristic emissions associated with the 4G7/2, 4F9/2, 4F5/2 and 4F3/2→4I9/2 transitions. The lifetimes were 80 and 130 µs for the Nd3+ doped ZnV2O6 and Zn2V2O7 samples, respectively. All these results suggest a successful synthesis of Nd3+ doped zinc vanadate compounds by the melt-quenching technique.