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Accordingly, phosphor-converted (pc) NIR light-emitting diodes (LEDs) have received extensive scientific attention as lighting sources, owing to their conspicuous characteristics and range of applications. [8] The integration of blue InGaN LED chips with NIR phosphors is considered a promising strategy for yielding novel high-performance NIR light sources with broadband spectra. [9][10][11][12] Since NIR phosphors are key parts of these devices, affecting their overall luminescence performance and emission spectrum, selecting the appropriate phosphor is paramount. In this regard, for the design of efficient broadband NIR phosphors, applying a suitable activator as an ideal luminescence center is of vital importance.Chromium (Cr) exhibits a broadband absorption in the visible spectral range stemming from its distinctive 3d 3 electronic configuration. Besides, Cr 3+ ions can display a tunable narrowband or broadband spectrum (from deep red to the NIR region) depending on whether they are in a strong or weak crystal field environment, respectively. [9][10][11] Correspondingly, garnets possess a stable cubic crystal structure with a complex arrangement of different cations in the unit cell and exhibit several advantages, including a high thermal stability and long distances between alkali ions. The specific physicochemical Broadband near-infrared (NIR) luminescent materials have received notable attention due to their distinct photophysical properties for designing NIR light-emitting diodes (NIR LEDs). Here, a series of Ca 3−x Lu x Ga 2+x Ge 3−x O 12 :Cr 3+ (CLGGG:Cr 3+ ) (x = 0-1) NIR-emitting garnet phosphors with an emission range of 660-1200 nm are successfully developed and their lattice parameters are structurally analyzed. Upon 460 nm blue light excitation, the NIR phosphors exhibit both a substantial spectral broadening (FWHM: 129→267 nm) and a redshift of 37 nm (766→803 nm) with cosubstitution of [Lu 3+ -Ga 3+ ] pairs for [Ca 2+ -Ge 4+ ] sites. Furthermore, their luminescence thermal stability is substantially improved, maintaining ≈90% of the original photoluminescence intensity at 150 °C, owing to shrinkage of the second coordination sphere and rigid lattice, which are strongly associated with Cr 3+ trade-off occupancy and local structure evolutions. The relation between the trade-off site occupation of Cr 3+ in GaO 6 /CaO 8 polyhedrons and the NIR emission is also clarified by evaluating the decay and electron paramagnetic resonance behavior of Cr 3+ at different sites. The broadband NIR phosphors investigated here can serve as auspicious luminescent converters for phosphor-converted NIR LEDs and can provide an inspiring platform for future studies.

Cyan-emitting phosphors are important for near-ultraviolet (NUV) light-emitting diodes (LEDs) to gain high-quality white lighting. In the present work, a Bi3+-doped BaScO2F, R+ (R = Na, K, Rb) perovskite, which emits 506 nm cyan-green light under 360 or 415 nm excitation, is obtained via a high-temperature solid-state method for the first time. The obtained perovskite shows improved photoluminescence and thermal stability due to the charge compensation of Na+, K+, and Rb+ co-doping. Its spectral broadening is attributed to two centers Bi (1) and Bi (2), which are caused by the zone-boundary octahedral tilting due to the substitution of Bi3+ for the larger Ba2+. Employing the blend phosphors of Ba0.998ScO2F:0.001Bi3+,0.001K+ and the commercial BAM:Eu2+, YAG:Ce3+, and CaAlSiN3:Eu2+, a full-spectrum white LED device with R a = 96 and CCT = 4434 K was fabricated with a 360 nm NUV chip. Interestingly, a novel strategy is proposed: the cyan-green Ba0.998ScO2F:0.001Bi3+,0.001K+ and orange Sr3SiO5:Eu2+ phosphors were packaged with a 415 nm NUV chip to produce the white LED with R a = 85 and CCT = 4811 K.