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

Abstract Nd 3+ doped ZnV 2 O 6 and Zn 2 V 2 O 7 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 ZnV 2 O 6 and Zn 2 V 2 O 7 were detected. Electron dispersive spectroscopy (EDS) analysis shows that the Nd 3+ incorporation into the ZnV 2 O 6 and Zn 2 V 2 O 7 hosts is around 0.9±0.1 and 0.2±0.1 at%, respectively. The micrographs obtained by Scanning Electron Microscopy, reveal that the Nd 3+ doped ZnV 2 O 6 sample is predominantly composed by micro-rods, whereas the Nd 3+ doped Zn 2 V 2 O 7 one is only composed by irregular blocks. The band gap energies (E g ) were calculated from the diffuse reflectance spectra by the Kubelka–Munk equation; E g values resulted to be 2.24 and 2.86 eV for the Nd 3+ doped ZnV 2 O 6 and Zn 2 V 2 O 7 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) −1 range for the Nd 3+ doped ZnV 2 O 6 and Zn 2 V 2 O 7 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 Nd 3+ characteristics emissions. For instance, the Nd 3+ doped ZnV 2 O 6 sample displayed the Nd 3+ 4 F 5/2 → 4 I 9/2 and 4 F 3/2 → 4 I 9/2 emissions; while the Nd 3+ doped Zn 2 V 2 O 7 one showed the Nd 3+ characteristic emissions associated with the 4 G 7/2 , 4 F 9/2 , 4 F 5/2 and 4 F 3/2 → 4 I 9/2 transitions. The lifetimes were 80 and 130 µs for the Nd 3+ doped ZnV 2 O 6 and Zn 2 V 2 O 7 samples, respectively. All these results suggest a successful synthesis of Nd 3+ doped zinc vanadate compounds by the melt-quenching technique.