To develop novel luminescent materials with optical thermometry and anti-counterfeiting functionalities, this work designed, prepared, and characterized a series of Sc2Mo3O12: Eu3+ (SMOE) phosphors and SMOE/g-C3N4 composites. Structural and optical analyses reveal that SMOE exhibits two-dimensional negative thermal expansion (NTE) behavior and high resistance to luminescence concentration quenching. Via vapor deposition, g-C3N4 was deposited onto SMOE particles, slightly enhancing their NTE performance. Upon UV excitation, SMOE/g-C3N4 shows dual-emission characteristics featuring blue luminescence from g-C3N4 and red-orange emissions from Eu3+, with different dependencies on excitation wavelength. Additionally, the g-C3N4 emission band undergoes spectral narrowing and fast thermal quenching with increasing temperature, in contrast to the relatively stable Eu3+ emissions. These divergent thermal responses enable five independent thermometric parameters (luminescence intensity ratios, spectral bandwidth, and individual emission intensities) to exhibit linear temperature dependence. A multi-parameter sensing strategy based on a multiple linear regression model yields a maximal relative sensitivity of an exceptional 30%/K, surpassing single-parameter approaches and outperforming most previously reported optical thermometers. Moreover, SMOE/g-C3N4 is proved to be highly suitable for anti-counterfeiting labels, as its luminescence color can be switched by controlling the excitation conditions. Overall, SMOE/g-C3N4 is a highly promising dual-functional material coupled with excellent thermal sensing and anti-counterfeiting capabilities.

Trivalent lanthanide (Ln3+)-doped negative thermal expansion (NTE) materials often suffer from humidity-induced luminescence quenching and degraded thermometric performance. To address these issues, this work reports a g-C3N4 surface modification strategy for Er3+: Yb2W3O12 phosphors. Er3+: Yb2W3O12/g‑C3N4 composites are fabricated via a liquid-phase adsorption method. Structural and morphological analyses confirm that g-C3N4 nanosheets coat the particles without altering the orthorhombic phase of Yb2W3O12. X-ray photoelectron spectroscopy and thermogravimetric analyses verify that the coating effectively suppresses water adsorption. Under 980 nm excitation, the optimal composite shows 1.4-, 1.8- and 3.3-fold enhancements in emission intensities at 532 nm, 554 nm and 658 nm, respectively, relative to the uncoated sample. It also exhibits bright blue emission from g-C3N4 under UV excitation. Benefiting from this excitation-dependent dual-mode emission, dynamic anti‑counterfeiting is realized by simply switching the excitation wavelength. Furthermore, a multiple linear regression model integrating seven thermometric parameters achieves a maximum relative sensitivity of 6.06% K−1, outperforming most previously reported luminescent thermometers. The present study provides a facile approach to optimize the Ln3+-doped NTE phosphors for high‑performance optical thermometry and anti‑counterfeiting applications.

Luminescent materials covering bands of Sn2+ and Mn2+ active ions have attracted extensive research interest due to their tunable emission properties. However, the susceptibility of both ions to oxidation during melting poses a significant challenge for precise valence states control. In this work, a series of highly transparent phosphate glasses modified by SnO and MnO ions were fabricated via the melt-quenching method. It is worthy noticed that the valence states of Sn and Mn can be effectively regulated by introducing reducing agents to achieve the better light-emitting property. Under ultraviolet excitation, full visible spectrum emission from dual emission centers spanning blue to red-white light was achieved by modulating concentration of Mn2+ ions. In addition, the glass sample with 0.8% Mn2+ contents exhibited quasi-white light emission from a single host matrix, characterized by the correlated color temperature (CCT) of 6754 K and CIE coordinates of (0.317, 0.276). Furthermore, energy transfer gradually occurred from the microsecond-lived Sn2+ ions to the millisecond-lived Mn2+ ions as the latter gradually increased, resulting in a progressive shift in CCT from cool to warm tones. This glass, exhibiting high spectral programmability, demonstrates significant potential as a promising candidate material for applications in plant lighting, environmental sensing, and bio-imaging.

A series of fluorotellurite glasses were prepared using the melt-quenching method, and the effects of adding moderate amounts of BaF2 on the structure and optical properties of the tellurite glasses were investigated. Furthermore, the luminescent properties of Er3+-doped fluorotellurite glasses were further analyzed. The results indicate that, when the BaF2 content reaches 15 mol%, the fluorotellurite glass exhibits high infrared transmittance (85.7 %), a low hydroxyl absorption coefficient (0.25 cm-1), and good thermal stability (Delta T = 129 degrees C). These findings suggest that moderate BaF2 incorporation effectively reduces the hydroxyl content of the glass while preserving good thermal stability. Further analysis of mid-infrared fluorescence spectra reveals that the luminescence intensity at 2.7 mu m reaches its maximum at an Er2O3 doping concentration of 6 mol%. The corresponding absorption and emission cross-sections are 5.93 x 10-21 cm2 and 7.15 x 10-21 cm2, respectively. These results demonstrate that the Er3+-doped fluorotellurite glass prepared in this study holds great potential as a gain medium for applications in mid-infrared fiber lasers.

Optical temperature sensors play a crucial role in noncontact temperature measurement, industrial process monitoring, biological diagnostics, and related applications. This work focuses on highly sensitive advanced sensing materials, particularly those suitable for high-temperature operation. ZnAl2O4 glass-ceramics co-doped with Tb3+ and Eu3+ were synthesized via melt quenching and continuous heat treatment. Increasing the Eu3+ doping concentration enhanced the energy transfer efficiency from Tb3+ to Eu3+, with the glass-ceramics exhibiting higher energy transfer efficiency than the precursor glass. The fluorescence intensity ratio (FIR) of the transitions from 5D4 to 7F5 of Tb3+ and from 5D0 to 7F2 of Eu3+ demonstrated relatively high temperature sensitivity. Based on this FIR, the optical thermometer achieved a maximum relative sensitivity of 0.597 %K- 1 at 583 K. Above 513 K, the glass-ceramic exhibited improved temperature sensitivity compared to the precursor glass and demonstrated outstanding high-temperature sensing performance. The prepared Tb3+/Eu3+ co-doped ZnAl2O4 glass-ceramic shows strong application potential in optical temperature sensing.

Plant photosynthesis relies on photosynthetic pigments to absorb red and far-red light. Cr3+-doped ZnAl2O4 exhibits superior red-light emission, holding great potential for plant illumination. Nevertheless, the luminescence efficiency of nanocrystalline glass-ceramics is limited by their crystal size. To address this issue, in this study, Cr3+-doped micron-sized ZnAl2O4 devitrified glasses were fabricated via a cooling-induced self-crystallization method. Cr3+ incorporation simultaneously modulates the crystallization kinetics of the devitrified glasses and significantly enhances the luminescent properties. The maximum luminescence intensity was obtained at the Cr3+ doping concentration of 0.1 mol%. Notably, the as-prepared devitrified glasses retain approximately 84% of its room-temperature photoluminescence intensity, even at an elevated temperature of 150 degrees C. The emission peak of the ZnAl2O4: Cr3+ devitrified glasses in the red spectral region closely matches the absorption spectrum of phytochrome far-red, effectively satisfying the red-light requirement for plant photosynthesis. Electroluminescence (EL) characterization confirms its suitability for plant lighting applications. This work is of great significance for promoting the development of the plant lighting industry.

The development of inorganic phosphor-in-glass film (PIGF) converters with both high brightness and excellent color quality for use as color conversion materials in high-power laser lighting sources has emerged as a research focus. However, when different types of phosphors are blended in a glass matrix, problems such as photon reabsorption and mismatched stability occur. Additionally, phosphors are susceptible to thermal erosion and degradation. To address these limitations, this study is aimed at establishing a double-sided PIGF framework using with glass matrices suited to individual phosphors, with the ultimate goal of achieving high-quality laser illumination. Specifically, a low-melting-point tellurate glass is selected as the matrix environment for YAG: Ce3+ phosphor, whereas a fluorophosphate glass is used for CASN: Eu2+ phosphor. These two glass films are coated on opposite sides of a sapphire substrate to form a sandwich bilateral-PIGF structure. The luminous flux of this novel system is 998.3 lm at a laser power density of 11.16 W/mm2, which is 2.31 times higher than that of a traditional mixed-PIGF converter. Additionally, high-quality white light with CRI of 80.5 and chromaticity coordinates of (0.3815,0.3434) is achieved. In addition, the double-layer film exhibits excellent high-temperature performance. These results demonstrate that the bilateral-PIGF increases the luminescence saturation threshold, positioning it as a promising reflective color converter for high-brightness laser lighting.

Achieving high color rendering index (CRI) in white LEDs requires the use of red-emitting phosphors. With the expanding application range of high-power LEDs and laser diodes, the demand for thermal stability of phosphor has become increasingly stringent. In this study, a series of novel red-emitting phosphors Sr2-xLiAlO4: xSm3+ (x = 0.01-0.18) were synthesized by a solid-state reaction. Under 407 nm excitation, this phosphor displays a prominent red emission (608 nm) characterized by the dominant 4G -> 6H transition of Sm3+. The phosphor maintains 98.5 % of its luminescence intensity at 200 degrees C compared to room temperature (30 degrees C). This indicates that Sr1.91LiAlO4: 0.09Sm3+ phosphor has excellent thermal stability, which is attributed to the high rigidity of its crystal structure. A white LED was fabricated by coating a 365 nm near-UV chip with a blend of phosphors: the red Sr1.91LiAlO4: 0.09Sm3+, a yellow-green (Sr, Ba)2SiO4: Eu2+ and a blue BaMgAl10O17: Eu2+ phosphors. The device emits white light with a high color rendering index (CRI) of 94.4 and a correlated color temperature (CCT) of 5625 K. The results demonstrate the promising application potential of the Sr1.91LiAlO4: 0.09Sm3+ red phosphor in white LED applications.

In the realm of luminescent glass, Sn2+ ions have garnered considerable attention for their unique electronic transition properties and highly tunable luminescent performance, offering significant promise for novel optoelectronic devices and high-efficiency phosphor materials. However, challenges such as the regulation of Sn ion valence states, structural instability of the glass, and its susceptibility to hydrolysis present significant barriers to progress in this field. This study explores an innovatively designed phosphate glass system, modified with chloride, which provides an optimized substrate environment for luminescence. By incorporating a reducing agent, the prepared samples exhibit consistent and tunable valence state transformations of Sn ions, resulting in enhanced luminescence intensity and high transparency that effectively minimizes optical losses. Furthermore, co-doping with Dy3+and Sm3+ ions yielded chromaticity coordinates of (0.21, 0.21) and (0.23, 0.19), respectively, demonstrating a tunable emission spectrum ranging from blue to pale yellow and orange-red. The findings indicate that this material holds substantial potential for applications in optoelectronic devices, advanced lighting systems, and other optical materials.

A series of TeO2-Ga2O3-BaF2-La2O3 glasses were prepared via the conventional melt quenching method. The structure and thermal properties were systematically investigated via Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and differential scanning calorimetry (DSC). The results indicate that the addition of La2O3 raises the glass transition temperature (Tg) to 426°C and improves resistance to crystallization of fluorotellurite glass, simultaneously maintaining a high mid-infrared (MIR) transmittance (~85%) and a low hydroxyl content (0.30 cm-1). Furthermore, the addition of La2O3 also enhances the emission intensity of fluorotellurite glass doped with an identical Er2O3 concentration. On the basis of the optimized composition (6 mol% La2O3), the maximum Er2O3 doping concentration of fluorotellurite glass reaches 6 mol%, which corresponds to absorption and emission cross-sections of 5.54 × 10-21 cm2 and 6.63 × 10-21 cm2, respectively. These results suggest that the prepared fluorotellurite glass is a viable gain medium for MIR fiber lasers.

ABSTRACT A series of TeO 2 ‐Ga 2 O 3 ‐BaF 2 ‐La 2 O 3 glasses were prepared via the conventional melt quenching method. The structure and thermal properties were systematically investigated via Raman spectroscopy, X‐ray photoelectron spectroscopy (XPS), and differential scanning calorimetry (DSC). The results indicate that the addition of La 2 O 3 raises the glass transition temperature ( T g ) to 426°C and improves resistance to crystallization of fluorotellurite glass, simultaneously maintaining a high mid‐infrared (MIR) transmittance (~85%) and a low hydroxyl content (0.30 cm −1 ). Furthermore, the addition of La 2 O 3 also enhances the emission intensity of fluorotellurite glass doped with an identical Er 2 O 3 concentration. On the basis of the optimized composition (6 mol% La 2 O 3 ), the maximum Er 2 O 3 doping concentration of fluorotellurite glass reaches 6 mol%, which corresponds to absorption and emission cross‐sections of 5.54 × 10 −21 cm 2 and 6.63 × 10 −21 cm 2 , respectively. These results suggest that the prepared fluorotellurite glass is a viable gain medium for MIR fiber lasers.

In this paper, the crystallization kinetics of the sample were systematically investigated, ultimately leading to the successful precipitation of CdS QDs within the borosilicate glass matrix through meticulously designed thermal processing protocols and compositional optimization. Structural and morphological analyses confirmed the in-situ precipitation of crystals with an average diameter of approximately 10 nm embedded in the glass matrix. Notably, the glass sample exhibited a remarkably broad emission band spanning the entire visible spectrum when excited at 396 nm. Additionally, incorporating Eu3+ into the glass matrix and subjecting it to heat treatment at 500 degrees C resulted in a significant enhancement of photoluminescence intensity and an improved quantum yield. Furthermore, integrating Eu3+-co-doped CdS QD glass with a 395 nm blue LED chip produced yellow light emission. This emission demonstrated a color purity of up to 97% and a correlated color temperature of 3402 K. These findings strongly indicate the potential application of CdS:Eu QD glass in micro-LED lighting technologies.

Significant challenges in developing color-converting materials with high thermal conductivity and luminous efficiency lie ahead for laser lighting. In this study, it is reported for the first time that tetragonal SiO2 crystals prepared via high-temperature thermal treatment are skillfully combined with tellurite phosphor-in-glasses into composite materials. The establishment of an internal and external dual heat dissipation system allows the composite material to achieve effective thermal management and maintain stable luminescence. It's worth mentioning the enhancement of thermal stability and luminescence performance of the composite material, which result from the effect of t-SiO2 as both heat dissipation factors and scattering centers. After optimizing the formulation and dimensions, the material achieves a bright and dazzling white light output of 1823 lm, with the maximum laser damage threshold increased to 16 W mm-2. As a consequence, this phosphor-in-glass film based on TeO2 glass@t-SiO2 holds promising commercial prospects for applications in high-power white light laser illumination.

In this study, a novel optical thermometer based on a phosphor-in-glass (PiG) composite was designed, incorporating 9 mol% Nd3+:Yb2W3O12 and 0.5 mol% Ho3+:Yb2W3O12 phosphors into a silicate glass matrix. Upon excitation at 980 nm, the 9 mol% Nd3+:Yb2W3O12 phosphor exhibited a thermal enhancement in the nearinfrared anti-Stokes emissions of Nd3+ with an increase in temperature, whereas the up-conversion luminescence of Ho3+ in the 0.5 mol% Ho3+:Yb2W3O12 phosphor decreased. Utilizing the luminescence intensity ratio of Nd3+ to Ho3+ (I720-920 nm/I520-580 nm), a maximal relative sensing sensitivity of approximately 4.86 %K-1 was achieved. Moreover, the glass matrix effectively prevented the invasion of water molecules, thereby mitigating the deleterious effects of the hygroscopicity of Yb2W3O12. This work provides useful information for developing novel high-performance ratiometric luminescence thermometers.

Laser-driven lighting offers high brightness and excellent directivity and is widely employed in laser projection and automobile headlights. However, the phosphor conversion materials currently used in laser-driven lighting suffer from low light-extraction efficiency and poor thermal conductivity. Herein, a unique phosphor-in-glass(PiG)–silver (Ag)–copper (Cu) (referred to as PAC) converter that comprises a four-layer structure is reported: high-doped phosphor-in-glass (PiG) layer, high-reflectivity silver film, sealing silver paste, and copper substrate. Due to its unique design, the sample with an 85 wt% doping concentration and a 0.2 mm thickness exhibits outstanding luminescent performance, achieving a LE of 298 lm W−1 and a luminous flux (LF) of 2873 lm at an input power of 11.54 W. Furthermore, in the rotational mode, a high LF of 3920 lm is achieved. These results demonstrate that the PAC converter holds promise for applications in high-power laser lighting.

Aiming to explore novel dual-functional phosphors integrating temperature sensing and anti-counterfeiting capabilities, HfScMo2VO12: Eu3+ (HSMVO: Eu3+), La2MgTiO6: Bi3+ (LMTO: Bi3+) and their binary composite were synthesized and characterized. XRD analysis confirmed the orthorhombic structure of both HSMVO and LMTO. Notably, HSMVO exhibited two-dimensional negative thermal expansion (NTE) with a volume thermal expansion coefficient (alpha V) of-6.258 x 10-6 K-1. Under UV excitation, the 613 nm emission of HSMVO: Eu3+ displayed a unique anti-thermal quenching behavior, while the 403 nm emission of LMTO: Bi3+ suffered from severe thermal quenching. A ratiometric luminescent thermometer fabricated with a HSMVO: Eu3+-LMTO: Bi3+ composite achieved a maximum relative sensitivity of 2.22 % K-1. Furthermore, the composite system enabled multi-modal anti-counterfeiting applications through excitation-wavelength-dependent color tuning and thermally-induced chromaticity shifts, offering multi-parameter encryption for dynamic visual authentication. This work demonstrates an effective approach for achieving dual functionalities of highly sensitive temperature sensing and dynamic anti-counterfeiting in luminescent materials.

The color rendering index (CRI) of white light-emitting diodes (LEDs) is very important for lighting quality. Currently, high-CRI white LEDs are typically fabricated by combining multiple-color phosphors. Therefore, the realization of multipeak-emission phosphors in a single phosphor is valuable. The Sr2LiAlO4: Eu2+ phosphor exhibits an obvious double-peak emission in the yellow-green spectral range and has excellent luminescence properties, suggesting its potential application in white LEDs. In this study, a series of Sr2LiAlO4-1.5xNx: Eu2+ (x = 0-0.7) phosphors were successfully synthesized by introducing N3- ions to replace O2- ions. The luminescence intensity was significantly enhanced by increasing the N3- concentration. Upon reaching a concentration of 0.7, the intensity of the yellow emission exceeded that of the green emission, indicating a shift in emission color from green to yellow. The emission peak of the Sr2LiAlO2.95N0.7: Eu2+ phosphor is at 568 nm, which exhibited broader yellow light emission. Finally, Sr2LiAlO2.95N0.7: Eu2+ was fabricated with a CaAlSiN3: Eu2+ red phosphor on 450 nm blue LED chips. The fabricated white LEDs was observed to be white light with a high CRI of 92.1 and an adjustable color temperature (4938-6665k), showing its potential application in white LEDs.

Developing a stable optical thermometric material with high sensitivity at elevated temperatures is a major challenge. In this study, a new glass component was designed to obtain a self-crystallizing glass ceramic with distinct optical thermometry properties by utilizing the properties of Cr3+ ions as a nucleating agent, demonstrating their potential in fluorescence intensity ratio (FIR) thermometry. Notably, the 4T2 -> 4A2 transition of Cr3+ ions intensify at high temperatures, causing the sample color to change from dark red to bright orange-red. The sample's maximum relative sensitivity within the physiological range was 3.48 % K-1, remaining above 1 % K-1 at the end of the measured temperature range. This study suggests that one-step-molded self-crystallized ZnAl2O4: Cr3+ microcrystalline glass is an ideal candidate for optical thermometers owing to its low cost, simple preparation, and efficient performance.

A novel tricolor phosphor-in-glass film (PiGF) with high luminous efficiency (LE) and color rendering index (Ra) was designed and fabricated by optimizing the glass layer thickness, phosphor ratio, film structure, and sintering process.

Advanced laser phosphor display (ALPD) technology based on phosphor converters offers high brightness, a wide colour gamut and no speckle. However, the glass matrix's relatively low thermal conductivity and red phosphor's poor thermal stability present key challenges for developing high-efficiency red converters with remarkable luminescence saturation for next-generation ALPD technology. Herein, several novel phosphor-in-glass ceramics (PiGCs) were prepared using spark plasma sintering (SPS) with glass ceramic (GC) powder and CaAlSiN3: Eu2 + (CASN) red phosphor as raw materials. The satisfactory crystallinity of the GC powder and the low temperature of SPS enabled these PiGCs to exhibit excellent luminescence performance and tolerate elevated laser power. When fabricated into a phosphor wheel, the high-speed rotating device achieved a luminous flux of 427 lm, with the luminescence saturation threshold exceeding 13.48 W. These results verify that the CASN-PiGC red converter possesses considerable potential for use in high-power laser displays.