Investigation of efficient photoconduction and enhanced luminescence characteristics of Ce-doped ZnO nanophosphors for UV sensors.

ABSTRACT

This study involves the single-step, mass-scale productive synthesis, photoconduction, and luminescence characteristics of pure and cerium rare-earth-ion-doped ZnO (CZO) nanophosphors with different Ce concentrations (Ce 0, 2, 4, 6, and 8 wt.%) synthesized using the solid-state reaction method. The synthesized nanophosphors were characterized for their structural, morphological, optical, and photoconductivity (PC) properties using X-ray diffraction (XRD), field-effect scanning electron microscopy (FE-SEM), energy dispersive spectroscopy, Fourier-transform infrared (FT-IR), photoluminescence (PL), and PC measurements. The sharp diffraction peaks of XRD results exhibit the formation of crystalline hexagonal wurtzite ZnO nanostructures. The decrease in diffraction peak intensities of CZO with an increase in Ce concentrations signifies the deterioration of the ZnO crystal. FE-SEM images exhibit the good crystalline quality of nanophosphors composed of spherical- and elongated-shaped nanoparticles that are distributed consistently on the surface. The energy dispersive X-ray pattern of the 4 wt.% Ce-doped ZnO (CZO4 ) sample confirms the doping of Ce in ZnO. The presence of chemical bonds and functional groups corresponds to transmittance peaks established using FT-IR spectroscopy. Deconvoluted PL spectra show two major emission peaks, one in the UV region, which is near-band-edge, and the other in the visible region ranging from ~456 to 561 nm. In PC studies, current-voltage (I-V) and current-time (I-T) characteristics, that is, rise/decayin current under dark as well as UV light conditions, are also investigated. Efficient photoconduction is observed in CZO samples. The obtained results indicate the suitability to luminescent and photosensor applications.