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SrZn2(PO4)2 (SZP) and Mn2+ doped SrZn2(PO4)2 (SZP: Mn) nanophosphors are prepared through solution combustion synthesis at a moderate temperature of 823 K. The nanophosphors are characterized by structural and spectral investigations systematically. X-ray diffraction (XRD) analysis confirms the monoclinic phase of SrZn2(PO4)2 with average crystallite size around 60-65 nm. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images of the samples have shown irregular morphology. The fundamental vibrational modes of different phosphate groups are confirmed by Fourier transform infrared (FT-IR) spectroscopic analysis. Optical absorption spectrum exhibits Mn2+ characteristic bands are in visible region. Electron paramagnetic resonance (EPR) study describes octahedral environment of Mn2+ ions around the ligands in the host. Photoluminescence (PL) spectra show peaks in blue and yellow-orange region. Commission Internationale de l'Eclairage (CIE) and color correlation temperature (CCT) values indicate that SZP and SZP:Mn nanophosphors are potentially good for solid state lightening and white light emitting diodes (WLEDs). [ABSTRACT FROM AUTHOR]

In the present work, VO2+ doped ZnS nanocrystals have been synthesized by simple co-precipitation method at room temperature. X-ray diffraction result reveals cubic structure of VO2+ doped ZnS nanocrystals. Micro-structural properties such as grain size, strain, dislocation density and texture coefficient are calculated. Both SEM and TEM images represent the non-uniformly distributed spherical like structures. Optical absorption spectrum vanadyl ions exhibits three characteristic peaks 516, 647 and 863 nm suggesting C4V symmetry and their evaluated crystal field and tetragonal field parameters are Dq = 1545 cm− 1, Ds = − 2215 cm− 1 and Dt = 987 cm− 1. From EPR spectrum the calculated spin Hamiltonian parameters are g║= 1.9423, g┴ = 1.980 and A║= 167 × 10− 4 cm− 1, A┴ = 62 × 10− 4 cm− 1. By correlating Optical and EPR studies confirm the tetragonally compressed octahedral site symmetry for VO2+ ions and the nature bonding between VO2+ and its ligands is covalent. The PL spectrum exhibits the violet, blue, green and strong orange emission bands and the corresponding CIE chromaticity coordinates are evaluated to be in white region. VO2+ doped ZnS nanocrystals showed the room temperature ferromagnetic property and their saturation, remnant magnetization values are 12.9 × 10− 3, 2.59 × 10− 3 emu/g respectively. TG-DTA curves indicate the thermal decomposition of the prepared sample at different temperatures and the corresponding total weight loss is 24.94%. The present results revealed that VO2+ doped ZnS nanocrystals may applications in white LED and spintronic devices. [ABSTRACT FROM AUTHOR]

Cu(II) ions doped Calcium borophosphates were prepared by solid state reaction method. In this study, we investigate the structural and optical properties of CuCaBPO (x = 0.01, 0.03, 0.05) nanophosphors, depending on copper content. The xCuCaBPO nanophosphor shows high-quality powder characteristics by XRD and exhibited stillwellite like structure. Field emission scanning electron microscopy micrographs showed the presence of several irregular shaped particles. FT-IR spectrum revealed the characteristic vibrational bands of the prepared nanophosphor material. From optical absorption and electron paramagnetic resonance spectral data the doped Cu(II) ions are ascribed to distorted octahedral site symmetry. The synthesized phosphor exhibits emission bands in ultraviolet, blue and green regions under the excitation wavelength of 325 nm. The CIE chromaticity coordinates are also calculated for the prepared sample from the emission spectrum. [ABSTRACT FROM AUTHOR]

Mn doped ZnO nanopowder was prepared by simple sonochemical method. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, optical absorption (UV-Vis), photoluminescence (PL), Electron Paramagnetic Resonance (EPR), Fourier transform infrared (FT-IR) spectroscopy and magnetization have been used to characterize the sample. XRD study revealed that Mn doped ZnO had wurtzite hexagonal structure. Composition analysis by EDX indicated the presence of small amounts of manganese. Crystal field (Dq) and interelectronic repulsion (B, C) parameters are evaluated from optical absorption. Spin-Hamiltonian and bonding parameters are evaluated from the EPR study. Optical and EPR confirms that the Mn entered into ZnO lattice as distorted octahedral site symmetry. FT-IR spectrum exhibited vibrational bands of Zn-O bonds. PL spectrum shows the emission bands in UV and visible region. Magnetization loop was measured and clearly shows typical ferromagnetic saturation behavior. The results suggest oxygen vacancies, especially singly ionized oxygen vacancies, play a crucial role in mediating ferromagnetism in the Mn doped ZnO system. [ABSTRACT FROM AUTHOR]