Design and control of the luminescence in Cr3+-doped NIR phosphors via crystal field engineering

Near-infrared (NIR) light-emitting diodes (LEDs) have currently attracted increasing attention owing to high efficiency and longevity. Accordingly, NIR phosphor, as the indispensable role in NIR LEDs, needs to be enriched to meet widespread applications worldwide. Benefitting from structural tunability of LaSc3B4O12(LSB), a sequence of broadband phosphors, with continuous-tunable luminescence toward longer wavelength, can be designed by regulating the crystal field environment of the Cr3+ via substituting the Sc3+ by Y(3+ )in LSB host. The correlations among structural evolution, crystal field environment, and luminescence properties of LaSc3-xYxB4O12(LSYB): Cr3+ (0 <= x <= 1.3) have been discussed in detail. Furthermore, substitution Y3+ for Sc3+ in LSB causes band gap variation of host lattice, demonstrated by the diffuse reflectance spectra, consequently resulting in improved quantum yield (QY), and mitigated thermal quenching behavior of LSYB: Cr(3+ )compared to that of Y3+-free sample. The above results demonstrate the superiority of crystal field engineering in exploring broadband NIR phosphors with modified luminescence performance for potential application in NIR pc-LEDs. (C) 2020 Elsevier B.V. All rights reserved.