As a next-generation high-power lighting technology, laser lighting has attracted great attention in high-luminance applications. However, thermally robust and highly efficient color converters suitable for high-quality laser lighting are scarce. Despite its versatility, the phosphor-in-glass (PiG) has been seldom applied in laser lighting because of its low thermal conductivity. In this work, we develop a unique architecture in which a phosphor-in-glass (PiG) film was directly sintered on a high thermally conductive sapphire substrate coated by one-dimensional photonic crystals. The designed color converter with the composite architecture exhibits a high internal quantum efficiency close to that of the original phosphor powders and an excellent packaging efficiency up to 90%. Furthermore, the PiG film can even be survived under the 11.2 W mm blue laser excitation. Combining blue laser diodes with the YAG-PiG-on-sapphire plate, a uniform white light with a high luminance of 845 Mcd m(luminous flux: 1839 lm), luminous efficacy of 210 lm W, and correlated color temperature of 6504 K was obtained. A high color rendering index of 74 was attained by adding a robust orange or red phosphor layer to the architecture. These outstanding properties meet the standards of vehicle regulations, enabling the PiG films with the composite architecture to be applied in automotive lighting or other high-power and high-luminance laser lighting.

the medical diagnostic fields than ever before. [1][2][3][4] There is a particular focus on materials operating in the 700-1100 nm region of the electromagnetic spectrum because this range covers the characteristic absorption signals of the CH, OH, and NH normal modes. Analyzing these vibrations enables the quick and nondestructive detection of biomolecules, including sugar, protein, fat, or the presence of harmful ingredients like pesticide residues. [5,6] Moreover, the NIR light in this energy region is known as the first biological window. It allows an appreciable penetration depth in biological tissues, making the NIR light suitable for radioisotope-free tissue imaging and noninvasive blood glucose sensing, among other uses. [7] Finally, NIR light can be detected by inexpensive silicon-based detectors, making sensors based on these wavelengths cost-effective and easily deployed. [8] The biggest challenge inhibiting the further deployment of this technology today is the limited capability to efficiently generate broadband NIR light. [9] Phosphor-converted NIR light-emitting diodes (pc-NIR LEDs) have been recently demonstrated to be the superior option for NIR production because of their outstanding output power, efficiency, durability, and compact size over other more traditional NIR light sources, including incandescent bulbs, tungsten halogen lamps, or even NIR LEDs. [10,11] These advantages make pc-NIR LEDs ideal for accessible, lowcost spectroscopic applications. However, these devices require efficient and thermally stable phosphors to convert the nearly monochromatic blue emission from commercially available InGaN chips into the requisite broadband NIR light.Generally, broadband NIR phosphors can be created by introducing an activator ion, like Eu 2+ , Bi 2+ , Mn 2+ , or Cr 3+ into an inorganic solid-state host compound. [12] Of the options available, Cr 3+ in a weak crystal field environment, with its unique 3d 3 electronic configuration, is considered the best option for broadband NIR emission. [13,14] Cr 3+ can be excited by blue light and emits between 700 and 1100 nm. This concept has led to the discovery of numerous Cr 3+ -substituted NIR phosphors. For example, garnets like Gd 3 Sc 2 Ga 3 O 12 :Cr 3+ (full width at half maximum (fwhm) = 110 nm, λ em = 756 nm) and Ca 3 Sc 2 Si 3 O 12 :Cr 3+ (fwhm = 92 nm, λ em = 783 nm) were both reported to have a quantum yield (QY) surpassing 90% and low thermal quenching, which is defined by the drop in emission Efficient broadband near-infrared (NIR) emitting materials with an emission peak centered above 830 nm are crucial for smart NIR spectroscopy-based technologies. However, the development of these materials remains a significant challenge. Herein, a series of design rules rooted in computational methods and empirical crystal-chemical analysis is applied to identify a new Cr 3+ -substituted phosphor. The compound GaTaO 4 :Cr 3+ emerged from this study is based on the material's high structural rigidity, suitable electronic environment, and relatively we...

Near-infrared (NIR) phosphor-converted light-emitting diode (pc-LED) technology has attracted considerable interest as a next-generation light source for emerging NIR spectroscopic applications. However, discovering efficient broadband NIR phosphors necessary to access the desired long-wavelength (λem ≥ 800 nm) energy window remains a challenge. Here, a new phosphate phosphor, KGaP2O7:Cr3+, emerged from a fundamental study of the AMP2O7 (A = Li, Na, K; M = Al, Ga, Sc, In) family. This material combines all of the requisite properties for the efficient generation of NIR photons, including limited defect formation, minimal electron–phonon coupling, a subtle octahedral site distortion, and well-separated transition metal substitution sites. Photoluminescence spectroscopy indicates that this material emits from 700 to 1100 nm (λmax = 815 nm) with a full width at half-maximum (fwhm) of 127 nm or 1874 cm–1. Exciting the material with a blue LED reveals a quantum yield of 74.4% with an absorption efficiency of 44.8%, resulting in an excellent external quantum efficiency as high as 33.3% from the as-prepared sample. A prototype NIR pc-LED device generated an output power of 473.8 mW and a high photoelectric conversion efficiency (10.7% under 500 mA), demonstrating the potential of applying this phosphor in blue LED-based NIR spectroscopy.

Clarification of thermal saturation helps to guide the design of high-brightness yellow and green components for laser lighting and displays.

Color converter is a key luminescent material in the laser‐driven solid state lighting, which must bear high‐density excitation and serious thermal attack from the incident laser. Here, a thermally robust yellow‐emitting La3Si6N11:Ce‐in‐glass (LSN:Ce‐PiG) film for laser lighting is reported by co‐firing the LSN:Ce and glass powders on a thermally conductive sapphire substrate. No detectable interfacial reaction occurs between the LSN:Ce particle and glass matrix, enabling the film to fully inherit the original thermal robustness and high quantum efficiency. The optical performance of LSN:Ce‐PiG‐converted white laser light has been effectively optimized by changing the phosphor‐to‐glass (PtG) ratio and the film thickness. The highest light conversion efficiency is respectively achieved at PtG = 2:3 and the thickness of 70 µm, and the saturation threshold is found to decrease with either a higher PtG ratio or a thicker film. The optimized LSN:Ce‐PiG film (P2G3‐50) can withstand a maximum laser power density of 12.91 W mm−2 and produce a cool white light with a high luminous flux of 1076 lm (luminance of 773 Mcd m−2), a luminous efficiency of 166.05 lm W−1, a color rendering index of 70. These results make the LSN:Ce‐PiG film a considerably promising color converter for laser lighting.

There is a significant need to identify cyan-emitting phosphors capable of filling the “cyan-gap” (480-520 nm) in full-visible-spectrum phosphor-converted white light-emitting diodes (pc-wLEDs). Here, a new broadband cyan-emitting phosphor enabling...

The laminated PiG films are promising color converters for use in high-power and wide-color-gamut laser-driven display applications.

Traditionally, phosphors are developed by doping activators on standard crystallographic sites of selected inorganic hosts, thus enabling the prediction of their luminescence with some empirical models or theoretical calculations. Here, we propose the idea of interstitial site engineering as a totally different way to design phosphors with promising properties. In detail, a red-emitting phosphor La3Si6N11:Ce3+,Al3+ was developed by engineering the interstitial Ce3+ site, which produces an unusual red emission band (λem = 600–665 nm) under blue light excitation. The origin of this red emission was assigned from the first-principle calculation to the Ce3+ ion occupying the [Si8N8] void in the c∼1/2 layer of which the calculated transition energies matching with experiment within 0.1 eV. Such an interstitial Ce3+ site was created as a charge compensator for the aliovalent substitution of Si4+ by Al3+ ions. The red-enhanced La3Si6N11:Ce3+,Al3+ phosphor showed great potentials for improving the optical quality (i.e., color temperature and color rendition) of laser-driven white light. This work indicates that the interstitial site engineering is an efficient way for generating new luminescence centers and opens up an avenue for designing phosphors with appealing properties.