Synthesis and Photoluminescence Properties of Deep-Red-Emitting CaYAlO 4 :Cr 3+ Phosphors
- PDF / 1,817,789 Bytes
- 8 Pages / 593.972 x 792 pts Page_size
- 50 Downloads / 202 Views
https://doi.org/10.1007/s11664-020-08457-4 Ó 2020 The Minerals, Metals & Materials Society
Synthesis and Photoluminescence Properties of Deep-Red-Emitting CaYAlO4:Cr3+ Phosphors L.Q. DUONG,1 N.T. TUAN,2 N.V. QUANG,3 P.T. HUY,4 D.Q. TRUNG,4 N. TU,4 N.V. DU,4 N.N. HA,5 N.D.T. KIEN,1 and D.H. NGUYEN 1,6 1.—Advanced Institute for Science and Technology, Hanoi University of Science and Technology, 1 Dai Co Viet, Hai Ba Trung, Hanoi, Vietnam. 2.—College of Natural Sciences, Can Tho University, Can Tho, Vietnam. 3.—Hanoi Pedagogical University 2, Phuc Yen, Vinh Phuc, Vietnam. 4.—Phenikaa University, Yen Nghia, Ha-Dong, Hanoi, Vietnam. 5.—International Training Institute for Materials Science, Hanoi University of Science and Technology, 1 Dai Co Viet, Hai Ba Trung, Hanoi, Vietnam. 6.—e-mail: [email protected]
Deep-red-emitting CaYAlO4:Cr3+ phosphors were synthesized by the sol–gel method followed by heat treatment. The effects of sintering temperature on the phase structure, morphology, and luminescence properties of the phosphors were investigated by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), Raman scattering spectroscopy, energy-dispersive X-ray spectroscopy, steady-state photoluminescence (PL), and timeresolved luminescence spectroscopy. The XRD patterns showed that tetragonal CaYAlO4 crystals with space group I4/mmm were obtained after sintering at > 900°C. These experimental data were consistent with Raman spectra and FESEM images. A deep-red emission band at approximately 742 nm from CaYAlO4:Cr3+ phosphors was observed. This band was attributed to the transitions between the 2Eg and 4A2g energy levels of Cr3+ ions located at the CaYAlO4 host’s lattice sites with D3d symmetry. Two absorption bands were recorded at near-ultraviolet and yellow regions. The highest PL intensity was obtained for phosphors with a Cr3+ doping concentration of about 0.7 mol.%. The PL decay dynamics of the materials with different doping Cr3+ concentrations were further investigated. All decay dynamics were featured with multiple decay components. The longest decay component with a lifetime of about 5.5 ms was obtained for the sample with the highest PL intensity. These optical behaviors were correlated with the critical distances of Cr3+ ions for energy transfers. Finally, the temperature dependence of deep-red PL emission was also investigated and discussed. Key words: CaYAlO4:Cr3+ phosphor, far-red emission, sol–gel, plant growth LEDs
INTRODUCTION Solid-state lighting (SSL) materials using semiconductor light-emitting diodes (LEDs) have significant advantages in industries because of their small volume, high efficiency, long lifetime,
(Received June 10, 2020; accepted August 27, 2020)
energy-saving ability, cost-effectiveness, and environmental friendliness.1–5 SSL can replace most conventional light sources such as those for homes and industries, modern vehicles, indicators, building exteriors, decorations, and entertainment systems, among others. In indoor agriculture, lighting is an essen
Data Loading...
