High-Efficiency Continuous-Luminescence-Controllable Performance and Antithermal Quenching in Bi³⁺-Activated Phosphors

Abstract

Recently, Bi 3+ -activated phosphors have been widely researched for phosphor-converted light-emitting diode (pc-LED) applications. Herein, novel fullspectrum A 3 BO 7 :Bi 3+ (A = Gd, La; B = Sb, Nb) phosphors with a luminescence-tunable performance were achieved by a chemical substitution strategy. In the La 3 SbO 7 host material, a new luminescent center was introduced, with Gd 3+ replacing La 3+ . The photoluminescence (PL) spectra show a large blue shift from 520 to 445 nm, thus achieving regulation from green to blue lights. Moreover, a series of solid solution-phase phosphors La 3 Sb 1−x Nb x O 7 :Bi 3+ were prepared by replacing Sb with Nb, and a PL spectral tunability from green (520 nm) to orange-red (592 nm) was realized. Temperaturedependent PL spectra show that La 3−x Gd x SbO 7 :Bi 3+ phosphors have excellent thermal stability. Upon 350 nm excitation, the PL intensity of La 3−x Gd x SbO 7 :Bi 3+ phosphors at 150 °C remained at more than 93% at room temperature. With Gd 3+ doping, the thermal stability gradually improved, and LaGd 2 SbO 7 :0.03Bi 3+ represents splendid antithermal quenching (135.2% at 150 °C). Finally, a full-visible spectrum for pc-LED with a high color-rendering index (Ra = 94.4) was obtained. These results indicated that chemical substitution is an effective strategy to adjust the PL of Bi 3+ , which is of great significance in white-light illumination and accurate plant lighting.

Novel color tunable LaCaGaO4:Bi3+,Eu3+ phosphors for high color rendering warm white LEDs

“…This band is attributed to the 3 P 1 → 1 S 0 transition of the Bi 3+ ions. When monitored at 445 nm, there is a strong broad excitation band in the region of 280–400 nm region with two excitation peaks at 325 and 365 nm, respectively, due to the partial overlap of the 1 S 0 → 3 P 1 transition bands of Bi 3+ (I) and Bi 3+ (II), while there are two weaker excitation bands in the 200–280 nm region with two excitation peaks at 230 and 265 nm, respectively, due to the 1 S 0 → 1 P 1 transitions of Bi 3+ (I) and Bi 3+ (II) 28 . In support of the above, a series of normalized emission spectra for different excitation wavelengths were tested.…”

“…When monitored at 445 nm, there is a strong broad excitation band in the region of 280-400 nm region with two excitation peaks at 325 and 365 nm, respectively, due to the partial overlap of the 1 S 0 → 3 P 1 transition bands of Bi 3+ (I) and Bi 3+ (II), while there are two weaker excitation bands in the 200-280 nm region with two excitation peaks at 230 and 265 nm, respectively, due to the 1 S 0 → 1 P 1 transitions of Bi 3+ (I) and Bi 3+ (II). 28 In support of the above, a series of normalized emission spectra for different excitation wavelengths were tested. As the excitation wavelength was changed from 310 to 390 nm, one can clearly see that the emission spectrum shows a clear red shift with the emission peak moving from 410 to 445 nm (Figure S4), demonstrating that the Bi 3+ ions occupy more than one site.…”

Surface Optics and Color Effects of Liquid Metal Materials

“…As shown in Figure 19c, colorful liquid metals are obtained by mixing liquid metals with different substances. [ 159 ] 4)Liquid metals and their composites can be achieved with colorful functionalization under external stimuli, including electrical stimulation, acoustic stimulation, optical stimulation, magnetic stimulation, thermal stimulation, mechanical stimulation, solution stimulation, etc. Liquid metals exhibit different color appearance with diverse stimulation methods, times and environments.…”

“…c) Reproduced with permission. [ 159 ] Copyright 2021, Elsevier. d) SEM images of the four kinds of Cu‐Ga‐In/fibers.…”

“…c) Optical images of the pure liquid metal droplets (LMD), magnetic liquid metal droplet with Fe particles (S-LMD), large-sized NdFeB particles (H-LMD1) and small-sized NdFeB particles (H-LMD). c) Reproduced with permission [159]. Copyright 2021, Elsevier.…”