Study on the structure, energy transfer, and color-tunable photoluminescence of the stable BaY2Si3O10: Bi/Tb/Sm phosphors

With the growing concern about energy consumption, white light-emitting diodes(wLEDs), as the fourth generation of lighting sources, are highly scrutinized by researchers. A series of Bi3+/Tb3+/Sm3+ (co)doped BaY2Si3O10 phosphors were prepared by traditional solid-state method, and the phase purity was analyzed by X-ray diffraction. In this work, Bi3+/Tb3+/Sm3+ theoretically occupies the Ba/Y sites, and this conjecture is also proved by spectral analysis. Under near ultraviolet (nUV) light excitation, Bi3+/Tb3+/Sm3+ is respectively used as the blue (3P1 → 1S0)/green (5D4 → 7Fj)/red (4G5/2 → 6Hj) luminescence center. Due to the energy transfer (ET) efficiency between Bi3+/Sm3+ is not ideal, Tb3+ is introduced as a bridge to improve the ET efficiency of the whole system to achieve spectral tunability and application in wLEDs. And at different excitation wavelengths, Bi3+ emits a wide range of blue to cyan light because it occupies two cation sites. We selected a proper excitation wavelength and obtained an emission spectrum covering the whole visible region. The CIE color coordinates (0.3487, 0.3313), the correlated color temperature (CCT, 4773.61 K), quantum efficiency (QE, 47.62 %), and thermal stability (T50 = 537 K) of BaY2Si3O10: Bi3+/Tb3+/Sm3+ are discussed in depth, Lu3+ was used instead of Y3+ to improve the thermal stability of BYS. Its excellent luminescence performance indicates that this phosphor has potential applications in nUV wLEDs. The BYS: Bi/Tb/Sm phosphors emit white light under 335 nm excitation and energy level transition schematic of Bi/Tb/Sm. [Display omitted] •A small amount of Bi/Tb/Sm entered the lattice of Ba and a large quantity of Bi/Tb/Sm entered the Y site in BaY2Si3O10.•The cascading ET occurs with high efficiency and probability from Bi .→ Tb → Sm and Tb acts as ET bridge.•The tunable spectra were obtained by ET and adjusting the amount of (co)doping content.•A wide spectral range covering the entire visible spectrum is realised under excitation at specific wavelengths.•Replacing partial Y by Lu improves the thermal stability.