Design, Preparation, and Characterization of a Novel Red Long-Persistent Perovskite Phosphor: Ca3Ti2O7:Pr3+

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• 作者：Bo Wang ; Hang Lin ; Ju Xu ; Hui Chen ; Zebin Lin ; Feng Huang ; Yuansheng Wang
• 刊名：Inorganic Chemistry
• 出版年：2015
• 出版时间：December 7, 2015
• 年：2015
• 卷：54
• 期：23
• 页码：11299-11306
• 全文大小：674K
• ISSN：1520-510X

文摘

Currently, the development of efficient red-emitting persistent phosphor is still an ongoing challenge. Herein, a novel red-emitting LPL phosphor Ca₃Ti₂O₇:Pr³⁺ is successfully prepared by a high-temperature solid-state method. XRD Rietveld refinement analyses demonstrate the high phase purity of the sample which crystallizes in an orthorhombic Ccm2₁ space group with lattice parameters of a = 5.7702(5) 脜, b = 19.4829(7) 脜, and c = 5.1214(2) 脜. Electronic structure of the host matrix is analyzed by the first-principle calculation using CASTEP code. The calculation results show that Ca₃Ti₂O₇ has a direct band gap with CB and VB mainly composed of the Ti-3d and O-2p states, respectively. On the basis of the DR spectrum, the band gap is determined to be 3.6 eV. It is demonstrated that the 612 nm red-emitting persistent luminescence of Ca₃Ti₂O₇:Pr³⁺ can be either activated by Ti⁴⁺鈥揙^{2鈥?/sup> 鈫?Ti3+鈥揙鈥?/sup> host absorption and Pr3+鈥揙鈥揟i4+ 鈫?Pr4+鈥揙鈥揟i3+ IVCT in the UV region, or Pr3+:3H₄ 鈫?3P_J transition in the blue region. The red afterglow can last for 鈭? min observed by the naked eyes in the dark after ceasing the irradiation source. On the basis of the TL analyses, the trap is found exponentially distributed in the host with the depth of 0.69鈥?.92 eV. Finally, a possible LPL mechanism for Ca₃Ti₂O₇:Pr3+ is proposed.}