Recently, infrared (IR) light-emitting diodes (LEDs) have attracted considerable interest in the research field worldwide. IR phosphors, the basic materials utilized in LEDs, have become a research hotspot as well. Here, we introduce the high-quantum-efficiency IR ScBO 3 :Cr 3+ phosphor, which provides a spectral range of emission from 700 to 1000 nm with a peak maximum at 800 nm. Electron paramagnetic resonance spectroscopy, with high element selectivity, was used to elucidate the unusual small peak in the photoluminescence spectrum. Phonon structure and electron−lattice interaction were well observed and discussed via temperature-dependent measurements. Moreover, the high quantum efficiency of 72.8% was achieved. To evaluate their potential practical application, phosphor-converted LED packages were designed, which revealed high stability and high output power of 39.11 mW. Furthermore, the fabricated IR LED demonstrated a remarkable ability to penetrate biological tissues. This study provides insights into the luminescent properties and the practical applications of IR LEDs.

We aim to conduct a complete study on the unexpected structure evolution behavior in Cr 3+ -doped phosphors. A series of Ga 2−x Sc x O 3 :Cr 3+ phosphors are successfully synthesized and confirmed through structural studies, while the lattice parameters change unexpectedly. The unique partial substitution (∼87%) of Sc 3+ in the octahedral site is demonstrated via Rietveld refinement. Therefore, the bond valence sum calculation explains the reason for this particular Sc 3+ concentration. The photoluminescent bandwidth and electron−lattice coupling energy initially increase and then decrease, implying an inhomogeneous broadening effect. Time-resolved spectra and electron paramagnetic resonance are utilized to further examine the subtle change in the microstructures and the second coordination sphere effect of Cr 3+ . Ga 1.594 Sc 0.4 O 3 :0.006Cr 3+ exhibits high internal quantum efficiency (99%) and high phosphor-converted light-emitting diode output power (66.09 mW), demonstrating its capability as an outstanding infrared phosphor. This work will motivate further research on unexpected partial substitution during the solid solution process.

Portable near-infrared (NIR) light sources are in high demand for applications in spectroscopy, night vision, bioimaging, and many others. Typical phosphor designs feature isolated Cr 3+ ion centers, and it is challenging to design broadband NIR phosphors based on Cr 3+ −Cr 3+ pairs. Here, we explore the solidsolution series SrAl 11.88−x Ga x O 19 :0.12Cr 3+ (x = 0, 2, 4, 6, 8, 10, and 12) as phosphors featuring Cr 3+ −Cr 3+ pairs and evaluate structure−property relations within the series. We establish the incorporation of Ga within the magentoplumbite-type structure at five distinct crystallographic sites and evaluate the effect of this incorporation on the Cr 3+ −Cr 3+ ion pair proximity. Electron paramagnetic measurements reveal the presence of both isolated Cr 3+ and Cr 3+ − Cr 3+ pairs, resulting in NIR luminescence at approximately 650−1050 nm. Unexpectedly, the origin of broadband NIR luminescence with a peak within the range 740−820 nm is related to the Cr 3+ −Cr 3+ ion pair. We demonstrate the application of the SrAl 5.88 Ga 6 O 19 :0.12Cr 3+ phosphor, which possesses an internal quantum efficiency of ∼85%, a radiant flux of ∼95 mW, and zero thermal quenching up to 500 K. This work provides a further understanding of spectral shifts in phosphor solid solutions and in particular the application of the magentoplumbites as promising next-generation NIR phosphor host systems.

Phosphor-converted light-emitting diodes (LEDs) have recently become a promising candidate for next-generation agricultural and horticultural-use devices. In principle, they can overcome the limitations of regular daily sunshine. Here, the principle...

Mini-light-emitting diodes (mini-LEDs) are regarded as a promising light source for future high-end electronic products. Phosphors with a small size and high efficiency have been reported to achieve this goal. Here, we demonstrate that an easily synthesized Ga 2 O 3 :Cr 3+ -embedded mesoporous silica nanoparticle (GOC@ MSN) is an outstanding nanophosphor with a superb internal quantum efficiency (91.4%) and a good thermal stability. Structural studies have determined the mesostructure and intermolecular transfer of free electrons. Meanwhile, spectral studies have demonstrated detailed luminescent and thermal properties. A mini-LED package using a GOC@MSN nanophosphor and covering 650−900 nm exhibits its potential for practical applications. This work provides insight into the space-limited ship-in-a-bottle synthesis method for achieving a high quantum efficiency in nanosized phosphors and motivates further research on luminescent materials that use mini-LEDs.

A chemical and mechanical pressure-induced photoluminescence tuning method was developed through the structural evolution and hydrostatic pressure involving phase transition. A series of Ga 1.98−x Al x O 3 :0.02Cr 3+ phosphors were synthesized. Structural evolution reveals a crystal phase change with the incorporation of Al ions. The luminescent analysis shows the broad-to-sharp emission process with a high internal quantum efficiency value (>90%). The high-pressure study reveals the emission from the exchange-coupled Cr 3+ pairs and the phase transition under high pressure. Electron paramagnetic resonance indicates the distortion in the microstructures of the emission center. Finally, an ultra-broadband phosphor-converted lightemitting diode is achieved by utilizing the mixture of Ga 1.18 Al 0.8 O 3 :0.02Cr 3+ and Ga 1.18 Sc 0.8 O 3 :0.02Cr 3+ phosphors with a bandwidth of 209 nm and an output power of 119 mW. This study provides insights into the effect of chemical and mechanical pressure on the Cr 3+ -doped materials and the development of high-quality near-infrared luminescent materials.

Organic–inorganic hybrid metal halides have recently attracted attention in the global research field for their bright light emission, tunable photoluminescence wavelength, and convenient synthesis method. This study reports the detailed properties of (C10H16N)2MnBr4, which emits bright green light with a high photoluminescence quantum yield. Results of powder X-ray diffraction, photoluminescence, thermogravimetric analysis, and Raman spectra show the phase transition of (C10H16N)2MnBr4 at 430 K. This phase transition was identified as the solid to liquid state of (C10H16N)2MnBr4. Moreover, the pressure- and temperature-induced relationship between structural and optical properties in (C10H16N)2MnBr4 can be identified. This investigation provides deep insights into the luminescent properties of metal halide crystals and promotes further research.

Phosphor materials are promising candidates for white-light-emitting diode applications. High-quality phosphor materials must be synthesized under extreme conditions. In this study, a series of SrLi­(Al1–x Ga x )3N4:Eu2+ (GSLA) narrow-band emission red phosphors are successfully synthesized under 1000 atm nitrogen gas atmosphere through the hot isostatic press, which cannot be achieved under low pressure. Successful Ga incorporation is confirmed by X-ray diffraction and Rietveld refinement. Phonon repetition structure and detailed thermal properties are analyzed by temperature-dependent photoluminescence intensity and lifetime. The structural ordering and rigidity are comprehensively evaluated by Raman spectra. The blue shift of the photoluminescence spectra enhances the luminous efficacy of radiation, making GSLA a potential candidate for practical application. This study promotes the research on materials synthesized under extreme conditions and the development of novel phosphor materials.