Metal-ion doped luminescent thin films for optoelectronic applications

Nitride phosphors have drawn much interest because of their outstanding thermal and chemical stability and interesting photoluminescence properties. Currently, it remains a challenge to synthesize these phosphors through a convenient chemical route. Herein we propose a general and convenient strategy based on hydrothermal-ammonolysis reaction to successfully prepare zinc germanium nitride (ZnGeN 2 ) and Mn 2+ doped ZnGeN 2 phosphors. The crystal structure, composition, morphology, luminescence and reflectance spectra, quantum efficiency, and the temperature-dependent photoluminescence behavior were studied respectively. The phase formation and crystal structure of ZnGeN 2 were confirmed from powder X-ray diffraction and Rietveld refinement. EDX analysis confirmed the actual atomic ratios of Zn/Ge and N/Ge and suggested the presence of Ge vacancy defects in the ZnGeN 2 host, which is associated with its yellow emission at 595 nm with a FWHM of 143 nm under UV light excitation. For Mn 2+ doped ZnGeN 2 phosphor, it exhibits an intense red emission due to the 4 T 1g -6 A 1g transition of Mn 2+ ions. The unusual red emission of Mn 2+ at the tetrahedral Zn 2+ sites is attributed to the strong nephelauxetic effect and crystal field between Mn 2+ and the tetrahedrally coordinated N 3À . Moreover, the PL intensity of ZnGeN 2 :Mn 2+ phosphors can be enhanced by Mg 2+ ions partially substituting for Zn 2+ ions in a certain concentration range. The optimal Mn 2+ doping concentration in the ZnGeN 2 host is 0.4 mol%. The critical energy transfer distance of this phosphor is calculated to be about 27.99 Å and the concentration quenching mechanism is proved to be the dipole-dipole interaction. With increasing temperature, the luminescence of ZnGeN 2 :Mn 2+ phosphors gradually decreases and the FWHM of the emission band broadens from 54 nm to 75 nm. The corresponding activation energy E a was reckoned to be 0.395 eV. And the nonradiative transition probability increases with the increasing temperature, finally leading to the lifetime decrease with the increase of the temperature.

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“…72,73 Fig. S8 (ESI †) shows the CIE chromaticity of the prepared ZnGeN 2 and ZnGeN 2 :Mn 2+ phosphors.…”

Section: Diffuse Reflectance Spectra and Density Function Theory (Dftmentioning

confidence: 99%

ZnGeN₂ and ZnGeN₂:Mn²⁺ phosphors: hydrothermal-ammonolysis synthesis, structure and luminescence properties

et al. 2015

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“…[1][2][3][4][5][6]. The optical temperature sensing, based on the UC emission of RE ions, by means of the fluorescence intensity ratio (FIR) technique has received significant attention as a result of its high sensitivity and accuracy [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Low-temperature thermometry based on upconversion emission of Ho/Yb-codoped Ba0.77Ca0.23TiO3 ceramics

Luo

2015

Journal of Alloys and Compounds

133

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“…Titanium dioxide (TiO 2 ) has many interesting physical properties which make it suitable for different coating applications 3,4 . Among the different phases, anatase phase of TiO 2 is widely investigated because of its wide band gap ≈3.2 eV and stability.…”

Section: Introductionmentioning

confidence: 99%

Oxygen partial pressure induced effects on the microstructure and the luminescence properties of pulsed laser deposited TiO2 thin films

et al. 2017

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In this work, the influence of oxygen partial pressure on structural, morphological, and optical properties of TiO2 thin films grown on fused quartz substrate at different oxygen partial pressure by pulsed laser deposition were examined. X-Ray diffraction (XRD) patterns show the formation of TiO2 anatase phase deposited at high oxygen pressure. Atomic Force Microscopy (AFM) reveals that surface roughness of the films increases with oxygen pressure. Variation of surface morphology of films with increasing oxygen partial pressure was studied by AFM. It is observed that energy band gap of the films increases from 3.27 eV to 3.52 eV with the increase of oxygen pressure and is attributed to the decrease of oxygen defects. TiO2 thin films exhibited blue emission under the excitation of 320 nm wavelength. De-convoluted photoluminescence (PL) peaks showed that defect states are responsible for visible emission in TiO2 thin films. The intensity of PL emission associated with oxygen vacancies decreases with increasing oxygen pressure. Photometric characteristic analysis shows that the films deposited 1x10-4 mbar oxygen pressure exhibited intense blue emission with high luminescence efficacy of radiation.

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Metal-ion doped luminescent thin films for optoelectronic applications

Cited by 113 publications

References 75 publications

ZnGeN₂ and ZnGeN₂:Mn²⁺ phosphors: hydrothermal-ammonolysis synthesis, structure and luminescence properties

ZnGeN₂ and ZnGeN₂:Mn²⁺ phosphors: hydrothermal-ammonolysis synthesis, structure and luminescence properties

Low-temperature thermometry based on upconversion emission of Ho/Yb-codoped Ba0.77Ca0.23TiO3 ceramics

Oxygen partial pressure induced effects on the microstructure and the luminescence properties of pulsed laser deposited TiO2 thin films

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Metal-ion doped luminescent thin films for optoelectronic applications

Cited by 113 publications

References 75 publications

ZnGeN2 and ZnGeN2:Mn2+ phosphors: hydrothermal-ammonolysis synthesis, structure and luminescence properties

ZnGeN2 and ZnGeN2:Mn2+ phosphors: hydrothermal-ammonolysis synthesis, structure and luminescence properties

Low-temperature thermometry based on upconversion emission of Ho/Yb-codoped Ba0.77Ca0.23TiO3 ceramics

Oxygen partial pressure induced effects on the microstructure and the luminescence properties of pulsed laser deposited TiO2 thin films

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Product

Resources

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ZnGeN₂ and ZnGeN₂:Mn²⁺ phosphors: hydrothermal-ammonolysis synthesis, structure and luminescence properties

ZnGeN₂ and ZnGeN₂:Mn²⁺ phosphors: hydrothermal-ammonolysis synthesis, structure and luminescence properties