Affiliation:
1. National and Local Joint Engineering Laboratory for Optical Conversion Materials and Technology of National Development and Reform Commission Department of Materials Science Cross‐Strait Research and Technology Transfer Center for Optoelectronic Materials and Devices of Lanzhou University and Taiwan Kun Shan University School of Materials and Energy Lanzhou University No. 222, South Tianshui Road Lanzhou Gansu 730000 P. R. China
Abstract
AbstractObtaining phosphors with higher quenching temperatures is a key scientific problem in developing high‐quality full‐spectrum white lighting devices. Herein, a near ultraviolet (NUV) activated orange‐yellow‐emitting single‐phase Li2Sr1‐ΔSiO4:Eu2+ phosphor is synthesized based on a nonstoichiometric ratio (Δ), and the relationship between local structure and photoluminescence (PL) is studied by electron spin resonance spectrum (ESR), Raman spectrum and density functional theory (DFT) calculations. Under the nonstoichiometric ratio effect, the local structure maintains stability by varying bond lengths, interatomic bond properties, and symmetry of coordination polyhedrons, which in turn modulates the crystal field and the PL spectra. Moreover, the optimum sample (Δ = 0.1%) specifically remains at 102%, 110%, and 114% of PL intensities at 150, 200, and 225 °C, respectively, compared with the initial at 25 °C, and the zero‐thermal‐quenching is mainly compensated by certain wide‐distributed self‐defect levels (300–550 K). Finally, a white light emitting diode with high luminous efficiency (89.61 lm W−1), low corresponding color temperature (5352 K), and good color rendering index (Ra = 95.8) is successfully fabricated. The strategy of designing self‐defect by nonstoichiometric synthesis provides a new insight for developing novel thermal‐quenching resistant phosphors and applying potential.
Funder
National Natural Science Foundation of China
Subject
Atomic and Molecular Physics, and Optics,Electronic, Optical and Magnetic Materials
Cited by
6 articles.
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