Developing laser-driven phosphor-in-glass film (PiGF) color converters with simultaneous excellent optical performance, color quality, and thermal management remains challenging. Herein, a novel sandwich converter of layered PiGF between dual sapphires (S@LPiGF@S) is fabricated via thermocompression bonding, with spatially separated yellow-emitting La₃Si₆N₁₁: Ce³ ⁺ (LSN) and red-emitting CaAlSiN₃: Eu²⁺ (CASN) PiGFs. The photothermal performance and color quality of the S@LPiGF@S-based white laser diodes (wLDs) are regulated by optimizing phosphor content and PiGF configuration. Benefiting from the decoupled photon reabsorption of layered PiGF and multiple heat-dissipation channels of dual sapphires, the optimized S@R-YPiGF@S-based wLDs achieve a high luminous flux of 1580 lm and an excellent color rendering index (CRI) of 89 at a laser power density of 33 W/mm², representing the best comprehensive result reported for bicolor PiGF-based wLDs. This work demonstrates that the dual-sapphire sandwich design of layered PiGF is a promising route toward high-quality laser-driven white lighting.

High-quality laser-driven lighting faces a critical bottleneck in the thermal-induced luminescence saturation of color converters, where conventional single-substrate phosphor-in-glass films (PiGFs) fail to dissipate heat efficiently under the intense irradiation. Herein, we systematically investigate a synergistic thermal management strategy by integrating a sapphire-capped PiGF architecture with dynamic rotational cooling. A yellow-emitting Y3Al5O12:Ce3+ (YAG) or red-emitting CaAlSiN3:Eu2+ (CASN) PiGF is sandwiched between a Al2O3 substrate and a sapphire cover plate, establishing bidirectional heat dissipation pathways. Under the rotation mode, the as-fabricated PiGFs deliver a high luminous flux (LF) of 6145 lm@50 W·mm-2 (unsaturated) for YAG and 347.4 lm@42 W·mm-2 for CASN, while the corresponding working temperatures are maintained at merely 172 and 222°C, respectively. Furthermore, the influence of phosphor spatial arrangement on photon reabsorption is briefly examined, revealing that physical separation of YAG and CASN offers marginal benefits in preserving conversion efficiency. This work provides a viable material platform that simultaneously achieves high LF and excellent thermal stability, holding great promise for next-generation high-quality laser lighting.

Laser-excited phosphor is a promising technology for new-generation laser lighting. However, traditional plain-like inorganic color converters exhibit limited thermal-optical performance. Herein, novel phosphor-in-glass film (PiGF) converters based on 3D-patterned Al2O3 ceramic substrate, including hill-like (PiGF-H) and valley-like (PiGF-V) configurations, were constructed. Conformal PiGF preparation was achieved by regulating the fluidity of La3Si6N11:Ce3+ phosphor-glass paste during printing and sintering on substrates. The thermal-optical performance was comprehensively evaluated and compared with conventional plain-like PiGF (PiGF-P). The inclined side walls of the 3D-patterned surface promote multiple reflections and enhance the light excitation of the blue laser, enabling the PiGF-H to substantially outperform the PiGF-V and the PiGF-P under 6-42 W blue laser excitation. The PiGF-H achieves a high luminous flux of 4123 lm@36 W, significantly exceeding the PiGF-V (2166@21 W) and the PiGF-P (1701@18 W). Moreover, the PiGF-H has the highest luminous efficacy with minimal attenuation, an optimal normalized spectral intensity distribution, and an appropriate white light with a correlated color temperature (CCT) of 4874 K. The operating temperature of PiGF-H (240 degrees C) is considerably lower than that of PiGF-V (335 degrees C) and PiGF-P (359 degrees C). This work provides valuable guidance for enhancing thermal-optical characteristics of color converters in advanced laser lighting applications.

Abstract Phosphor ceramic has been regarded as a promising color converter for high-quality laser illumination, but it often suffers from optothermal performance degradation during high-temperature sintering process. Herein, an optothermal-enhanced cold-sintered phosphor film@Cu (PF@Cu) converter is developed. A low-temperature (150℃) cold sintering process (CSP) was introduced and tunable composite pastes were prepared with geopolymer, alkali activator, and phosphor materials. High-performance yellow-emitting PF@Cu (Y-PF@Cu) and yellow/red-emitting PF@Cu (Y/R-PF@Cu) converters were prepared with densified PFs that tightly integrated with the Cu substrate while effectively preserving the intrinsic luminescent properties of phosphors. The optimized Y-PF@Cu converter achieves a record luminous flux (LF) of 9624.7 lm@35 W/mm2, a correlated color temperature (CCT) of 5931 K and a color rendering index (CRI) of 60.7. The further optimized Y/R-PF@Cu converter delivers excellent comprehensive performance, including a high thermal conductivity of 50.6 W/(m·K), a LF of 2652.2 lm@17.5 W/mm2, a CCT of 2604 K, and a significantly improved CRI of 91.2. This work demonstrates the feasibility of CSP for fabricating color converters and provides an efficient strategy for synergistic optothermal optimization in ultra-high-brightness laser-illumination applications.

High-power chip arrays and multi-chip modules in modern electronic systems often experience severe local heat accumulation and temperature non-uniformity, posing significant reliability challenges. To address this issue, a multi-objective topology optimization framework for microchannel cooling structures is developed to achieve efficient and uniform heat dissipation under high heat flux. A density-based formulation simultaneously considers heat transfer and hydraulic resistance while accounting for heat-source characteristics, coolant properties, and material attributes. Coupled fluid–thermal–solid simulations are performed to analyze the velocity, pressure, and temperature fields. Multi-objective Pareto frontiers are constructed to quantify the trade-off between heat transfer and pressure drop, and an analytical expression dependent on inlet velocity facilitates rapid prediction under varying operating conditions. Furthermore, the temperature gradient is introduced as an auxiliary evaluation metric during the post-processing stage, allowing for a comprehensive assessment of temperature uniformity among the Pareto-optimal designs. For an array heat flux of 1.0 × 106 W/m2 at an inlet velocity of 0.5 m/s, the optimized design achieves reductions of 3.26 °C in peak temperature and 2.23 °C in average temperature compared with a straight-channel cold plate, while reducing pressure drop by 228.97 Pa and increasing the Nusselt number by 42.79%. Compared with a topology-optimized design obtained under uniform heat flux, further reductions of 1.82 °C (peak) and 2.02 °C (average) are achieved. These results demonstrate that incorporating realistic array-type heat-source distributions yields superior thermal regulation without sacrificing hydraulic performance.

Laser diode (LD) displays high power density, high brightness, and collimated illumination, which can be integrated with phosphor converters to construct laser light source, showing application potential in laser lighting, projection and display, communication, and medical healthcare. Herein, the developments of advanced phosphor converters for laser-driven light source are summarized, and the corresponding research objectives of high luminescence saturation threshold, high light extraction and uniformity, and high color quality are discussed. Typical all-inorganic phosphor converters, such as single crystal, phosphor ceramic, phosphor-in-glass (PiG), and PiG film (PiGF), are presented in detail. Then, the computer-assisted methods for laser-driven phosphor converters development are concluded. Correspondingly, the applications in laser illumination, laser projection and display, medical healthcare, visible light communication (VLC), and inspection and detection are exhibited. Finally, the research progress is summed up and the design rules of phosphor converters are concluded. The outlook of further work about laser-driven phosphor converters is highlighted. This review will promote the development and applications of phosphor converters for laser-driven light source technology.

Laser diode (LD) lighting, as an emerging solid-state lighting technology, holds significant promise for obtaining high-power white light by exciting Y3Al5O12:Ce3+ (YAG)-based phosphor-in-glass films (PiGFs). While optimizing materials and architectures of phosphor converters remains the primary approach for enhancing the saturation threshold, the influence of the laser path should not be overlooked. In this study, the optical performances of remote laser-excited light sources were effectively regulated by adjusting the laser incidence distance and angle between YAG PiGFs and blue LD. The results indicate that the threshold saturation improves with the increase of both incidence distance and angle. At a tilt angle of 51.4° and a distance of 107.5 mm, a high saturation threshold of 43 W and a luminous flux of 6527 lm were achieved, representing 2.5 and 2.3 times the values under the conditions of 0° and 92.7 mm, respectively. Furthermore, increasing the excitation distance and tilt angle significantly reduces the operating temperature of PiGFs, thereby enhancing their long-term operational stability. These opto-thermal improvements are the consequence of a reduced power density, which is caused by the enlarged spot area resulting from an increased excitation distance and angle. The findings demonstrate that the optimizing laser path can effectively enhance the optical performances of PiGFs, offering new perspectives for the packaging technology of white laser lighting sources.

During the past decade, natural melanin and melanin-like polymers have garnered significant attention due to their unique light absorption properties. However, the regulation of their light absorption, particularly for the simultaneous enhancement across the full-spectrum absorption from ultraviolet (UV) to near-infrared (NIR) regions within melanin-like polymers, remains a challenge. Herein, we have successfully boosted the light absorption capacity of melanin-like polymers by introducing substituents ortho to the phenolic groups through the phenolic-aldehyde reactions between melanin monomers/oligmers and aldehyde molecules. Detailed structural analysis revealed that the introduction of the substituents played a dual role in enhancing the full-spectrum absorption of melanin-like polymers: On one hand, it could suppress the oxidation of phenolic groups, which disrupted intramolecular conjugation, and consequently enhanced UV absorption; On the other hand, the steric effect impeded the tight packing of it-conjugated oligomers, reducing the density of nanoparticles and thereby boosting their visible and near-infrared absorption. These resulting melanin-like polymers with enhanced light absorption properties were further incorporated into polyvinyl alcohol (PVA) to fabricate composite films, which exhibited exceptional heating, defrosting, defogging properties, and plant photoprotection performances, highlighting their significant potential for agricultural applications.

A core bottleneck for high-brightness white laser lighting lies in developing phosphor converters that must satisfy stringent requirements for efficient heat dissipation and superior optical properties under high power laser excitation. Herein, a novel configuration of reflective Y3Al5O12: Ce3+ (YAG) phosphor-in-glass film (PiGF) integrated with an alumina (Al2O3) heat sink (PiGF@heat sink) was proposed and demonstrated in laser-driven lighting. Benefiting from the superior thermal dissipation capacity of the heat sink and optimized substrate area, PiGF@heat sink achieves a laser power saturation threshold of 30 W with a corresponding luminous flux of 6264 lm (30 W@6264 lm), which exhibits a significant enhancement over the conventional PiGF@plain Al2O3 (21 W@4482 lm). Furthermore, following 1200 s irradiation under 15 W laser power, the working temperature of PiGF@heat sink plateaus at 340 degrees C, which is 120 degrees C lower than that of the traditional PiGF@plain Al2O3. These findings indicate that the proposed PiGF@heat sink paves a promising pathway for high-brightness white laser lighting.

High-power laser-driven projection display demands that the phosphor converters possess excellent thermal handling capacity and stably efficient light output; however, simultaneously enhancing opto-thermal performance is still full of challenges. Herein, a novel universal architecture of phosphor-in-glass film (PiGF) on sapphire substrate with MgO-in-glass (MiG) layer coated on the other side is developed. Owing to the high refractive index of 1.74 and thermal conductivity of 50 Wm-1K-1 of MgO, the MiG layer not only recycles the backscattering light but also improves the heat dissipation, leading to synergistically enhanced opto-thermal properties of PiGF. Taking Y3Al5O12: Ce3+ (YAG) PiGF-sapphire-MiG (YSM) as a representative example, the optimized composite enables a high luminous flux (LF) of 5515 lm and luminous efficiency (LE) of 196.9 lmW-1 at a luminescence saturation threshold (ST) of 28 Wmm-2. After introducing red-emitting CaAlSiN3: Eu2+ (CASN) component, the YAG-CASN PiGF-sapphire-MiG (YCSM) converter yields warm white light with a color rendering index (CRI) up to 90.6, enabling to realization of more details and more vivid color rendition of the laser projection system. This study provides a cost-effective, easy-prepared, and universal strategy for advancing high-efficiency PiGF-based color converters and high-power laser-driven applications.

Phosphor-converted laser lighting is a new generation of high-brightness solid-state light source, and its spatial light uniformity is of crucial importance for actual applications. Herein, the spatial light distribution of a laser-driven phosphor-in-glass film (PiGF) with a transmissive type was systematically studied for the first time, and its spatial light uniformity was enhanced by integrating an aluminum reflective cup. The YAG:Ce PiGFs with various thicknesses were printed and sintered on sapphire substrates. The PiGF was tightly bonded on the sapphire and maintains a high quantum yield (QY) of 91.9%. With the increase in PiGF thickness, the luminous flux of laser-driven PiGFs initially increases and then decreases, while the correlated color temperature (CCT) gradually decreases. The spatial irradiance and CCT of common laser-driven PiGFs show a strong central peak and rapid radial attenuation. By integrating the aluminum reflective cup, the laser-driven PiGFs emit white laser light with uniform irradiance. The related CCT increases from 6164 K at 0 degrees to 9493 K at 25 degrees, corresponding to a balanced warm-to-cold white emission. The work provides valuable guidance for testing and optimizing of spatial light distribution in high-brightness laser-driven lighting.

Micron-Ag pressureless sintering faces grave challenges in high power SiC device packaging with simultaneously possessing low sintering temperature and excellent bonding strength and thermal conductivity. Herein, a costeffective micron-Ag paste with high sintering driving force was designed and prepared by solvent engineering and preheating temperature regulation. Consequently, the optimized Ag sintered joint yields a record shear strength of 43.9 MPa at a sintering temperature of 250 degrees C. Furthermore, the packaged SiC device with micron-Ag paste possesses power cycle numbers of 4525 cycles, which is 1.6 times higher than that of SiC device packaged by the traditional SAC solder. The findings provide valuable guidelines to develop high quality micron-Ag paste for high power electronics packaging.

The thermomechanical behavior of through ceramic via (TCV) interconnect structure significantly influences the 3-D package reliability. However, existing studies have largely overlooked the pivotal role of defects induced by laser drilling-specifically recast layers and rough interfaces-on the regulation of thermal stresses in high-power devices. In this work, a novel thermodynamic analysis of TCV interconnect structure incorporating the recast layers and rough interfaces was proposed. A ceramic-recast layer-copper model with tunable interface roughness was established employing the Weierstrass-Mandelbrot (W-M) fractal function. The experimental results agree well with the simulation results, with a maximum error of only 11.1%. The thermodynamic simulation results reveal a nonmonotonic relationship between thermal stress and interfacial roughness: thermal stress first decreases, reaching a minimum at 0.2 mu m roughness across all temperatures ( 200 degrees C similar to 500 degrees C), before increasing with additional roughness. Thermal deformation decreases slightly with increasing roughness. Further analyses demonstrate that the aforementioned laws are consistent both with and without a recast layer and across varying TCV aspect ratios (AR =3.13 similar to 8.33 ), thereby substantiating the model's universality. This study establishes quantitative correlations between process-induced defects and thermomechanical performance, offering insights for optimizing laser drilling parameters and TCV structural designs in high-density 3-D packaging applications.

Next-generation laser lighting requires color converters with high luminescence saturation and efficient heat dissipation. Herein, a concentration-gradient phosphor-in-glass film coated on an Al2O3 ceramic substrate (CG-PiGF@Al2O3) is proposed and fabricated via a simple multilayer printing and low-temperature sintering approach. By designing the highest phosphor concentration layer adjacent to the thermally conductive Al2O3 substrate, the heat transfer path is shortened, thereby reducing thermal resistance and enhancing optical performance. The CG-PiGF@Al2O3 converter with optimized gradient structure achieves a highest luminous flux (LF) of 2164 lm at a laser power saturation threshold (LP-ST) of 14 W, which is 1.44 times of conventional uniform-concentration (UC) PiGF@Al2O3 (1501 lm@9 W). At an excitation LP of 7 W, the operating temperature of CG-PiGF@Al2O3 converter is suppressed to 86℃, corresponding to a significant decrease of 94℃ (∼52.22%) compared with the UC-PiGF@Al2O3 (180℃). The practical illumination demonstrates a high-brightness, well-collimated white-light beam with high luminous intensity. These results provide a promising strategy for improving the performance of high-saturation white laser lighting.

Deep-ultraviolet light-emitting diodes (DUV LEDs) have significant potential for applications in disinfection and water treatment. However, their widespread commercialization is limited by challenges in light extraction efficiency (LEE) and wall-plug efficiency (WPE). This study focuses on optimizing fluoropolymer packaging to enhance the optoelectronic performance of high-power DUV LEDs. By implementing an experimentally optimized, dam-free fluoropolymer sidewall-encapsulated structure in combination with a simulation-optimized lens, the internal reflection and absorption losses of DUV LED chips are effectively reduced, which significantly boosts light output power (LOP). The optimized fluoropolymer packaging enables the DUV LED with a light output power of 69.35mW at 200 mA, representing a 68.15% improvement over the reference DUV LED, and the related WPE is increased by 60.60%. Furthermore, the emission angle is reduced drastically from 130° to 22°, resulting in a tenfold increase in on-axis ( $\sim 0^{\circ }\text {)}$ radiant intensity. This work demonstrates that substantial improvements in DUV LED light output and far-field directionality can be realized through packaging optimization, offering a practical approach for the fabrication of high-irradiance DUV LED module.

The complete replacement of toxic mercury lamps requires III-nitride deep-ultraviolet (DUV) light emitters with high wall-plug efficiency (WPE at least 20%) under high-current operation, but their WPE is seriously limited by difficult forward light emission and low light extraction. Herein, a high-power DUV light emitter with a record 21.2% WPE is proposed by a cooperative photon-redirection strategy. The DUV chip architecture synergistically integrates an in situ nano-porous AlN scattering layer with an optimized reflective mesa and a double-sided patterned sapphire substrate. This strategy efficiently redirects laterally propagating photons into the escape cone through coupled reflection and multi-stage scattering, thereby increasing the TM-mode light extraction efficiency by 252.1%. Consequently, the fabricated DUV light emitter achieves a record-high WPE of 21.2% at an injected current of 70 mA, maintaining a WPE exceeding 16% over a wide current range from 10 to 350 mA. Furthermore, a DUV light emitter array module with a high irradiance of 1.33 W/cm(2) is integrated in a large-flow water-treatment system, making >99.999% inactivation of bacteria under an ultra-high water flow rate of 20 m(3)/h. This work will definitely accelerate the large-scale commercialization of the new-generation solid-state DUV source.

A key obstacle in advancing high-brightness lighting technology is the creation of laser-driven color-converting materials capable of integrated enhancement of optical and thermal performance. Herein, an omnidirectionally encapsulated color converter of phosphor-in-glass film (PiGF) was proposed, in which a hemispherical sapphire lens was integrated on the top surface of a BN-in-glass (BiG) layer-surrounded PiGF coated on a sapphire substrate (L@PiGF@S). The L@PiGF@S converters with different YAG contents were prepared by thermocompression sintering, which display enhanced forward light extraction from lens integration and efficient heat dissipation from an omnidirectional heat conduction structure. This remarkable opto-thermal cooperative effect enables an ultra-high luminous efficacy (LE) of 268 lm/W and a maximum luminous flux (LF) of 6129 lm@36 Wmm-2 for the laser-driven L@PiGF@S, which is 3 times of the common laser-driven PiGF@S of 2022 lm@12 Wmm-2. Importantly, the L@PiGF@S can produce a collimating and uniform white laser irradiation up to 1000 m, addressing the tough issues of large beam divergence and poor color distribution for the common PiGF@S. The developed L@PiGF@S converter demonstrates superior opto-thermal performances, showing a great potential for a high-brightness laser-driven lighting source.

All uniform and continuous wafer-scale sp2-hybridized boron nitride (sp2-BN) is one of the most promising candidate materials for vacuum ultraviolet photodetectors (VUV PDs). However, the fabrication of large-area, high-efficiency sp2-BN VUV PDs remains challenging. This study systematically investigates the role of high-temperature annealing-assisted metal-organic chemical vapor deposition (MOCVD) in enhancing thin-film quality and device performance. Through optimized annealing treatment, we achieved significant improvements in the crystalline uniformity of sp2-BN films and reduced dislocation density. Raman, FTIR, and XRD analyses consistently showed a narrowed full-width-at-half-maximum (FWHM) of characteristic peaks, while TEM cross-sectional imaging confirmed enhanced structural ordering. Mechanistic studies revealed that during annealing, nitridation of the sapphire substrate generated AlN interlayers, which guided the epitaxial rearrangement of BN molecules along the AlN crystallographic planes, thereby promoting defect annihilation. Device characterization demonstrated remarkable performance enhancements: response time (tau r/tau d) decreased from 356.16/142.27 ms to 39.34/41.34 ms, responsivity increased by 193% to 0.79 mA/W, and detectivity improved by 267% to 3.45 x 1010 Jones. This work establishes high-temperature annealing-assisted MOCVD as an effective strategy for optimizing sp2-BN VUV PDs, providing a viable pathway for advanced ultraviolet detection applications.

This study addresses fabrication challenges in hexagonal boron nitride (h-BN)-based vacuum ultraviolet photodetectors (VUV PDs) by implementing platinum nanoparticle (Pt NP)-induced localized surface plasmon resonance (LSPR) effects to enhance photoresponse characteristics. Size-controlled Pt NPs (32 nm, 50 nm, 85 nm) are synthesized on metalorganic chemical vapor deposition (MOCVD)-derived h-BN surfaces through a cost-effective dewetting process, with systematic evaluation under 185 nm VUV irradiation. The 32-nm Pt NP-enhanced device demonstrates optimal performance, achieving 1.02 mA/W responsivity (143% improvement) and 2.95 & times; 1011 Jones specific detectivity (117% enhancement) at 20 V bias. Numerical simulations confirm that LSPR mechanisms intensify localized electric fields and photon absorption efficiency. This work presents the first LSPR-enhanced h-BN VUV photodetector utilizing Pt nanoparticles (NPs). The proposed design effectively addresses responsivity limitations in two-dimensional material-based detectors. Furthermore, it creates new opportunities for advancing extreme-environment sensing and imaging technologies. The methodology maintains compatibility with scalable MOCVD fabrication processes, with performance improvements directly correlating to precise NP size optimization, suggesting plasmonic engineering as a critical pathway for next-generation optoelectronic devices.