Narrow-band green-emitting phosphor β-SiAlON:Eu has been widely used in advanced wide-gamut backlighting devices. However, the origins for unusual sharp lines in photoluminescence emission at room temperature and tunable narrow-bandemission tailored by reducing Al-O in β-SiAlON:Eu are still unclear. Here, the presence of sharp-line fine structure in the emission spectra of β-SiAlON:Eu is mainly due to purely electronic transitions (zero phonon lines) and their vibronic repetitions resulted from the multi-microenvironment around Eu 2+ ions that has been revealed by relative emission intensity of sharp line depends on excitation wavelength and monotonously increasing decay time. The specific features of the Eu 2+ occupying interstitial sites indicate that the effect of crystal field strength can be neglected. Therefore the enhanced rigidity and higher ordering structure of β-SiAlON:Eu with decreasing the substitution of Si-N by Al-O become the main factors in decreasing electron-lattice coupling and reducing inhomogeneous broadening, favouring the blue-shift and narrow of the emission band, the enhanced thermal stability, as well as the charge state of Eu 2+ . Our results provide new insights for explaining the reason for narrow-band-emission in β-SiAlON:Eu, which will deliver an impetus for the exploration of phosphors with narrow band and ordering structure.

A SrLiAl3 N4 :Eu(2+) (SLA) red phosphor prepared through a high-pressure solid-state reaction was coated with an organosilica layer with a thickness of 400-600 nm to improve its water resistance. The observed 4f(6) 5d→4f(7) transition bands are thought to result from the existence of Eu(2+) at two different Sr(2+) sites. Luminescence spectra at 10 K revealed two zero-phonon lines at 15377 (for Eu(Sr1)) and 15780 cm(-1) (for Eu(Sr2)). The phosphor exhibited stable red emission under high pressure up to 312 kbar. The configurational coordinate diagram gave a theoretical explanation for the Eu(2+/3+) result. The coated samples showed excellent moisture resistance while retaining an external quantum efficiency (EQE) of 70 % of their initial EQE after aging for 5 days under harsh conditions. White-light-emitting diodes of the SLA red phosphor and a commercial Y3 Al5 O12 :Ce(3+) yellow phosphor on a blue InGaN chip showed high color rendition (CRI=89, R9=69) and a low correlated color temperature of 2406 K.

Cs4PbBr6 is regarded as an outstanding luminescent material with good thermal stability and optical performance. However, the mechanism of green emission from Cs4PbBr6 has been controversial. Here we show that isolated CsPbBr3 nanoparticles embedded within a Cs4PbBr6 matrix give rise to a "normal" green luminescence while superfluorescence at longer wavelengths is suppressed. High-resolution transmission electron microscopy shows that the embedded CsPbBr3 nanoparticles are around 3.8 nm in diameter and are well-separated from each other, perhaps by a strain driven mechanism. This mechanism may enable other efficient luminescent composites to be developed by embedding optically active nanoparticles epitaxially within inert host lattices.

A new concept called "full-spectrum lighting" has attracted considerable attention in recent years. Traditional devices are usually combined with ultraviolet-light-emitting diode (LED), red, green, and blue phosphors. However, a cyan cavity exists in the 480-520 nm region. Hence, cyan phosphors are needed to compensate for the cavity. (Sr,Ba)(PO)Cl:Eu phosphors feature an extremely unique and tunable photoluminescence spectrum. Nevertheless, the tuning mechanisms of these phosphors remain unclear. In this study, we elucidate the mechanism of the cation size-controlled activator uneven-occupation and reoxidation in (Sr,Ba)(PO)Cl:Eu phosphors. This mechanism could help tune the optical properties of related apatite families and structures with multiple cation sites and strongly uneven occupation of activators and cations. Finally, the package of the LED device is constructed to show that both color rendering index Ra and R9 are higher than 95. Thus, the device could be a potential candidate for full-spectrum lighting.

A Ce 3+ --doped nitrodoagnesoaluminate Sr[Mg 2 Al 2 N 4 ] phosphor was prepared from all--nitride precur-sors using gas pressure sintering method. The effective excitation by green light (510 nm) that revealed a broad emission from 550--650 nm prompted an innovation in the assembly of the pc--LED by using a blue chip LED that is sequentially coated with a green--emitting phosphor (β--SiAlON:Eu 2+ ) that excites the upper Sr[Mg 2 Al 2 N 4 ]:Ce 3+ layer thereby producing white light. The use of this broadband emitting phosphor and the innovative configu-ration generates white light and puts forward two promising innovations for pc--LEDs.Efficiency in the conversion of electrical energy to light has been a paramount consideration in the search and development of energy--saving alternatives to convention-al incandescent bulbs. 1 Phosphor--converted white light-emitting diodes (pc--WLEDs) have emerged as a promis-ing technology to revolutionize modern day lighting. This technology ensures energy--efficiency and improves color rendition and luminous efficacies. 1

Here, we are reporting a halide precursors acid precipitation method to synthesize Cs2AgIn1–xBixCl6 (x = 0, 0.02, 0.04, 0.08, 0.16, 0.32, 0.64, and 1) microcrystals. Cs2AgInCl6 and Bi derivative double...

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.

Searching for a non-rare-earth-based oxide red-emitting phosphor is crucial for phosphor-converted light-emitting diodes (LEDs). In this study, we optimized a blue and UV-light excited SrAlO:Mn phosphor exhibiting red emission peaked at ∼653 nm, which was successfully synthesized by solid-state reaction. The crystal structure, micromorphology, and luminescent properties of SrAlO:Mn phosphors were characterized by X-ray Rietveld refinement, high-resolution transmission electron microscopy, and photoluminescence spectra. The band gap and electronic structure of SrAlO were analyzed by density functional theory calculations using the hybrid exchange-correlation functional. The crystal field environment effect of Al sites from introducing activator Mn ions was investigated with the aid of Raman Al nuclear magnetic resonance spectra and electron spin resonance. The pressure dependent luminescent properties and decay time of this compound were presented. The tricolor display spectrum by combining blue InGaN chips, commercial β-SiAlON:Eu green phosphor, and SrAlO:Mn red phosphor were evaluated for commercial applications: using the present SrAlO:Mn red phosphor converted LED as a backlighting source.