周磊副教授/吴明娒教授团队最新Angew:单颗粒高效率全光谱发射荧光粉

一、研究背景

健康的全光谱照明是新一代固态照明的发展方向。目前，为了获得理想的全光谱发射，主要通过将不同颜色荧光粉混合。但是，物理混合通常导致不规则的发光分布。为了消除这种差异，在制备白光LED的过程中，往往需要经过严格把控，包括精确的荧光粉配比、充分的物理混合、严格的质量筛选，显著增加了制造成本。单一全光谱发射荧光粉能够简化混合荧光粉的工艺，利于全光谱照明器件的普及。然而，单一全光谱发射荧光粉通常受限于内在能量迁移的影响，发光效率较低，难以满足应用要求。鉴于此，周磊副教授/吴明娒教授团队和瑞士洛桑联邦理工学院Jean-Claude G. Bünzli教授通过原位生长构筑异质界面，阻隔这种有害的能量迁移过程，制备出了一种内外量子效率分别高达76.1%和56.2%的高效率单颗粒全光谱发射荧光粉SrLiPO₄/Sr₈MgLi(PO₄)₇:Eu²⁺。相关研究工作以Single-Grain High-Efficiency Full-Visible-Spectrum White Emitters为题发表在Angew. Chem. Int. Ed. DOI:10.1002/anie.202502100.

二、图文导读

Figure 1. a) Schematic of the manufacture of SPO/SMLPO:Eu²⁺-x single-grain phosphors. b) XRD patterns of SPO/SMLPO:Eu²⁺-x (x = 16%–22%) phosphors. ¨ and « refer to the main diffraction peaks of SPO and SMLPO, respectively. c) HAADF-STEM image and corresponding element mapping of Sr, Mg, P, and O for the SPO/SMLPO:Eu²⁺-18% phosphor. d) TEM and e) high-resolution TEM images of the SPO/SMLPO:Eu²⁺-18% phosphor. 

Figure 2. a) PL spectra normalized at 408 nm and b) CIE chromaticity coordinates of SPO/SMLPO:Eu²⁺-x (x = 0%–22%) phosphors under 365 nm excitation. The insets show the digital photographs of the phosphors (x = 0%, 18%, and 22%) under UV light excitation. c) PL spectrum of SPO/SMLPO:Eu²⁺-18% under 365 nm excitation. d–f) Fluorescence microscopy images of a single-grain SPO/SMLPO:Eu²⁺-18% upon excitation at 365 nm and monitoring of the wavelength d) below and e) over 500 nm, as well as f) full-visible emission.

Figure 3. a) XRD patterns of SLPO/SMLPO:Eu²⁺-y (y = 20%–50%) phosphors. ¨ and « refer to the main diffraction peaks of SLPO and SMLPO, respectively. b) TEM, c) HAADF-STEM image and corresponding element mapping of Sr, Mg, P, and O. d) High-resolution TEM image for the SLPO/SMLPO:Eu²⁺-35% phosphor.

Figure 4. a) PL spectra normalized at 450 nm and b) CIE chromaticity coordinates of SLPO/SMLPO:Eu²⁺-y (y = 0%–50%) phosphors under 365 nm excitation. The insets show the digital photographs of the phosphors (y = 0%, 35%, and 50%) under UV light excitation. c) PL spectrum of SLPO/SMLPO:Eu²⁺-35% under 365 nm excitation. d–f) Fluorescence microscopy images of a single-grain SLPO/SMLPO:Eu²⁺-35% upon excitation at 365 nm and monitoring of the wavelength d) below and e) over 500 nm, as well as f) full-visible emission. g) Excitation lines of BaSO₄ and SLPO/SMLPO:Eu²⁺-35%, and the emission spectrum of SLPO/SMLPO:Eu²⁺-35% collected by using an integrating sphere. The inset shows a magnification of the emission spectrum of SLPO/SMLPO:Eu²⁺-35%. h) Temperature-dependent integral intensity of SLPO/SMLPO:Eu²⁺-35% phosphor.

Figure 5. a) Electroluminescence spectra of the white LED driven by different currents (50–500 mA). b) General color rendering index (R1-R8) and special color rendering index (R9-R15) of the white LED driven by 500 mA current. c) CCT of the white LED driven by different currents (50–500 mA). d) CCT of the white LED in continuous operation at 500 mA current.