化学
荧光粉
密度泛函理论
兴奋剂
猝灭(荧光)
热的
零(语言学)
氟化物
财产(哲学)
物理化学
计算化学
无机化学
热力学
光电子学
量子力学
荧光
物理
语言学
哲学
认识论
作者
Shaokun Ling,Yaxiong Wang,Xiaoyan Qin,Chang Chen,Cuicui Lu,Jidong Chen,Sen Liao,Yingheng Huang,Lei Hou
标识
DOI:10.1021/acs.inorgchem.3c04524
摘要
Although being applied in various fields, white light emitting diodes (WLEDs) still have drawbacks that urgently need to be conquered: the luminescent intensity of commercial phosphors sharply decreases at working temperature. In this study, we calculated the forming energy of defects and confirmed that the VNa defect state can stably exist in β-NaGdF4, by density functional theory (DFT) calculation. Furthermore, we predicted that the VNa vacancies would provide a zero thermal quenching (ZTQ) property for the β-NaGdF4-based red-light phosphor. Then, a series of β-NaGdF4:xEu3+ and β-NaGdF4:0.25Eu3+,yYb3+ red-light phosphors were synthesized by the hydrothermal method. We found that β-NaGdF4:0.25Eu3+ and β-NaGdF4:0.25Eu3+,0.005Yb3+ phosphors possess ZTQ properties at a temperature range between 303–483 K and 303–523 K, respectively. The thermoluminescence (TL) spectra were employed to calculate the depth and density of the VNa vacancies in β-NaGdF4:0.25Eu3+ and β-NaGdF4:0.25Eu3+,0.005Yb3+. Combining the DFT calculation with characterization results of TL spectra, it is concluded that electrons stored in VNa vacancies are excited to the exited state of Eu3+ to compensate for the loss of Eu3+ luminescent intensity. This will lead to an increase of luminescent intensity at high temperatures and facilitate the samples to improve ZTQ properties. WLEDs were obtained with CRI = 83.0, 81.6 and CCT = 5393, 5149 K, respectively, when phosphors of β-NaGdF4:0.25Eu3+ and β-NaGdF4:0.25Eu3+,0.005Yb3+ were utilized as the red-light source. These results indicate that these two phosphors may become reliable red-light sources with high antithermal quenching properties for WLEDs.
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