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High-performance white light-emitting diodes (WLEDs) used for backlighting display applications require innovative and thermally stable narrow-band emission phosphors, particularly non-rare-earth Bi3+-activated phosphors. In this study, we demonstrate a defect-engineering strategy to create novel anti-thermal quenching phosphors Ca 3 Sc 2 Si 3 O 12 : x Bi3+ (CSSO: x Bi3+). Through structure refinement of CSSO: 0.06Bi3+ phosphor, we found that Bi occupies both Ca and Sc sites in the CSSO lattice. Direct visualization of atomic-resolution TEM and thermoluminescence spectra confirmed the formation of point defects due to the non-equivalent substitution of Ca2+ for Bi3+. Fluorescent-decay analysis revealed that two luminescence sites contribute to the blue-emitting of CSSO:Bi3+ phosphors. CSSO: 0.06Bi3+ phosphor exhibits outstanding thermal stability, with an integrated emission intensity of 103.6% at 423 K compared to that at 298 K. However, the addition of Li or Na as charge compensators reduced cationic defects, leading to a decrease in thermal stability. We believe that V C a ″ defects are primarily responsible for the anti-thermal quenching behavior of CSSO: x Bi3+ phosphors. An optimized CSSO: 0.06Bi3+ phosphor-based WLED displays a high color rendering index (CRI) of 90 and a wide color gamut (90% National Television System Committee (NTSC) standard), indicating its potential for use in industrial applications as a backlighting display. [ABSTRACT FROM AUTHOR]

Eu3+-activated luminous materials play important roles in WLEDs and optical temperature sensors, etc. While most Eu3+-activated phosphors have suffered from notable problems including low thermal quenching (TQ) temperature and quantum efficiency (QE). Here, we report a serial of Ba 3 Eu 2 (BO 3) 4 : xF (BEB: xF) (x = 0–0.7) phosphors covering high QE (97.3%) and excellent thermal stability (83.6%@423 K). Structural and spectral analysis indicate that Eu3+ in the 8 d lattice site dominantly attributes to the red emission. F- ions substitution induces more distorted inversion asymmetry for Eu3+ and results in stronger luminescence. Comparing serials of reported red phosphors under ∼393 nm excitation, these newly developed red phosphors present outstanding QE. Using the new excellent BEB: xF phosphors, two representative WLEDs have been fabricated with a satisfactory color-rendering index and luminous efficacy, demonstrating their potential performance for WLEDs. Meanwhile, a highly sensitive non-contacted optical thermometer has also been designed with the maximum relative sensor sensitivities of about 2.23% and 2.42% K−1 for BEB: xF (x = 0, 0.5) phosphors, respectively. This kind of single-activator doped phosphors provides a new and effective way for realizing dual-functional applications. In addition, the strategy of anion substitution can be adopted to develop optimal phosphors. [Display omitted] • Crystal structure for BEB: F has been determined, with the efficient luminous center Eu3+ located in a 8 d site • F- ions enhanced UV light absorption, leading to the enhanced luminescence intensity of Eu3+ in BEB. • BEB: xF phosphors exhibit intense red emission, high QE and good thermal stability, using for WLED. • 5D 0 and 5D 1 of Eu3+ exhibit different TQ behavior, making BEB: xF phosphors as the promising optical temperature sensor. [ABSTRACT FROM AUTHOR]