To develop continuous broadband emission near-infrared (NIR) phosphors compatible with blue LED chips, numerous Cr 3+ -Yb 3+ co-doped phosphors have been synthesized. However, the emission spectra of Cr 3+ vary significantly across different matrix materials, while Yb 3+ maintains a relatively stable emission spectrum. This variation leads to notable luminescence depressions between 850 and 900 nm in many Cr 3+ -Yb 3+ co-doped phosphors. To address this emission spectrum gap, we utilized Cr 3+ as a sensitizer and introduced Nd 3+ as the luminescence center within the La 3 Sc 2 Ga 3 O 12 matrix material, establishing a Cr 3+ -Nd 3+ energy transfer channel. Under 480 nm excitation, we tuned emission peaks at 800 nm (Cr 3+ ) and 881 nm (Nd 3+ ). The stable NIR emission of Nd 3+ effectively compensates for the missing spectrum in Cr 3+ -Yb 3+ co-doping. The Cr 3+ -Nd 3+ energy transfer process was thoroughly analyzed using diffuse reflection spectrum, excitation spectrum, and fluorescence decay curves. The LSGO:0.125Cr 3+ , 0.03Nd 3+ compound with the best optical performance was packaged with a 480 nm LED chip to create a NIR light source. At a working current of 10 mA, it achieved a photoelectric conversion efficiency of 9.45 %, demonstrating its potential for applications in non-destructive detection and luminescence thermometry. This work presents a novel strategy for tuning NIR spectral distribution and developing continuous broadband NIR phosphors.
Jinning Wang,Qiufeng Shi,Konstantin V. Ivanovskikh,Lei Wang,Jianwei Qiao,Haijie Guo,Ping Huang
A series of Mn 4+ -doped NaSr 10 Y 5 W 4 O 30 (NSYWO) phosphors have been successfully synthesized and further characterized to estimate their potentials for application as a far-red emitting component of pc-LED. An XRD analysis and crystal structure refinement have been carried out to characterize its quality. The doping concentration and temperature (80–500 K) dependent luminescence properties as well as decay kinetics have been studied and analyzed. It has been found that Mn 4+ substitutes for W 6+ sites resulting in far-red emission at 688 nm. The temperature quenching is attributed to thermal activation of an electron from Mn 4+ 2 E g to 4 A 2g state via crossover, yielding an activation energy of 0.35 eV. Furthermore, to assess practical application of the novel phosphor, a blue-emitting LED chip combined with NSYWO: 0.8 mol% Mn 4+ has been packaged. The light from both the blue-emitting LED chip and NSYWO: Mn 4+ phosphor was shown to be effectively utilized, revealing a good promise for application of the phosphor in the field of plant growth lighting.
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