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Hybrid nanoparticle layers toward enhanced luminescence of phosphor plates for white LEDs
摘要： MgF2 porous nanoparticle-silica hybrid coating layers were utilized to enhance luminescence efficiency of phosphor plates for white light emitting diodes (wLEDs). Silica and chemically synthesized porous MgF2 nanoparticles were sequentially deposited by spin coating on the phosphor plate with phosphor-in-glass (PiG) configuration. Microscopic investigation the hybrid film suggested intermixing of silica and porous MgF2 nanoparticles. Numerical estimation based on transfer matrix method expected a significant reduction in reflectance and enhancement of transmission spectra by the hybrid coating. In accordance, the photoluminescence intensity of phosphor plates showed a drastic improvement and quantum yield were enhanced from 30% (for bare PiG plate) to 45% (for hybrid layer coated PiG plate). When assembled with blue LEDs, hybrid nanoparticle coating on the PiG phosphor plates improved luminescence efficacy from 40 lm/W to 49 lm/W without deterioration of chromaticity during operation. In addition, mechanical durability of the hybrid thin film was confirmed by abrasion test. Conformal coating of matching layer consisting of porous MgF2 nanoparticles and silica can provide an efficient route to highly luminescent white LEDs with mechanical stability.
关键词： refractive index,phosphor-in-glass,nanoparticles,Luminescence,Hybrid coating
更新于2025-09-23 15:21:01
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Performance analysis of a heat pump-based photovoltaic/thermal (PV/T) system
摘要： Photovoltaic/thermal (PV/T) system produces both heat and electricity simultaneously with the advantages of better space utilization and higher conversion efficiency over individual solar thermal and solar photovoltaic (PV) system when operated separately. The PV/T system can control the operating temperature of PV by passing a heat transfer fluid through a heat exchanger attached to the rear of the modules. The present study analyses the performance of one such in-house built system, where the heat transfer fluid is refrigerant. Refrigerant-based PV/T system involves the integration of evaporator coils of the heat pump and PV module to form a cogeneration type system known as photovoltaic/thermal–solar assisted heat pump (PV/T–SAHP). The prototype of the PV/T–SAHP was fabricated with a double glass PV module instead of a conventional module with polyvinyl fluoride backsheet. Initially, the performance characteristics of the system are analyzed in detail using the experimental observations under a typical clear sky condition during the transition season. Following, the year-round performance of the system is predicted using an already validated numerical model. It was found that the present system can improve the average electrical efficiency by 15.20% and can achieve a coefficient of performance of 2.96.
关键词： Refrigerant-based PV/T system,Thermal management of PV module,Double glass PV module,Heat pump
更新于2025-09-23 15:21:01
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Atomic picture of crack propagation in Li <sub/>2</sub> Oa??2SiO <sub/>2</sub> glassa??ceramics revealed by molecular dynamics simulations
摘要： Fundamental understanding of the interaction between glass and ceramic phases with a running crack and the mechanisms by which propagation is hindered or altered as compared to the precursor parent glasses remains elusive for the lithium disilicate glass-ceramics. We herein conduct extensive molecular dynamics simulations to reveal some atomic details that are otherwise extremely challenging to be probed by experiments. The results show that the crack propagation pathway in glass-ceramics is dramatically different as compared to the precursor parent glass. In glassy sample, clean crack branching seems to be triggered by multiple cavitation events ahead of crack tip. In glass-ceramic samples, however, branching is characterized by microcracks at multiple glass-nanocrystal interface sites, clean nanocrystal cleavage along certain crystalline plane, and even secondary cracks due to the percolation of multiple microcracks. Additionally, the nanocrystal distribution, total volume fraction, and aspect ratio also have pronounced effects on the propagation of a primary crack and can lead to very diverse crack patterns.
关键词： lithium disilicate glass-ceramics,crack branching,microcracks,crack propagation
更新于2025-09-23 15:21:01
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An investigation on determinants of silver paste metallization contact performance on crystalline silicon solar cells
摘要： Since the application of silver (Ag) electrodes is of vital importance to the power output of crystalline silicon (c-Si) solar cells, the factors affecting Ag paste metallization contact performance on Si wafers need to get well understood. Herein, the correlation of Ag/Si contact resistivity and glasses used in Ag paste was studied comprehensively. Here taken for exemplification are three types of glass samples used in Ag paste, because the application of them can result in obvious differences in the contact interface characteristics as well as in the contact resistivity. It was found that the factors affecting contact resistivity include the formation of Ag colloids in the glass phase, the doping concentration in the contacted Si surface, and the fixed charge density and defect states density at the interface. In terms of these issues, the key functions and mechanisms of glasses used in Ag paste are elucidated, and also their effects on electrical performance of cells are discussed in this article.
关键词： glass frit,metallization contact,contact resistivity,crystalline silicon solar cells,silver paste
更新于2025-09-23 15:21:01
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Enhanced 2???μm Mida??Infrared Laser Output from Tm <sup>3+</sup> a??Activated Glass Ceramic Microcavities
摘要： Transparent glass ceramics (GCs) consisting of an homogeneous glass phase and a well-dispersed crystal phase are considered as ideal optical gain materials potentially applied in optoelectronic devices due to the combination of facile processability of glass and the intense crystal ?eld of nanocrystals. Here, a heat-induced nanocrystal-in-glass method is employed to integrate the active ions Tm3+ into Bi2Te4O11 nanocrystals with an intense crystal ?eld to realize an enhanced microlaser output. This strategy endows the e?cient tellurate GC microcavity laser operating at ≈2 μm. Compared with the laser properties of as-prepared glass microcavities, the pump threshold (260 μW) is as low as less than a quarter and the slope e?ciency (0.0296%) is 5.5 times higher. Furthermore, by carefully engineering the heat treatment temperature and duration, the crystal size and distribution can be precisely controlled. Thus, the Rayleigh scattering loss that is detrimental to quality (Q) factor is e?ectively suppressed and the GC microcavities with high Q factors up to 105 are successfully obtained. This work provides useful insight on the development of optical functional materials and expands the practical applications of GC microcavities in various optoelectronic ?elds.
关键词： mid-infrared lasers,glass-ceramic microspheres,microcavities,whispering gallery mode
更新于2025-09-23 15:21:01
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Study on high-efficiency separation of laminated glass by skillfully combining laser-induced thermal-crack propagation and laser thermal melting
摘要： Laminated glass has a wide range of applications, but the cutting process is too cumbersome. In this paper, a novel laser composite separation method was proposed to separate the laminated glass by one time and simplify the cutting process from five steps to two steps for the first time by skillfully combining laser-induced thermal-crack propagation and laser thermal melting. This method generated three laser foci, and each laser focus is acting on one layer of laminated glass. Then, the composite mechanism combining laser-induced thermal-crack propagation for glass layers and laser thermal melting separation for PVB layer was realized to separate entire laminated glass. The experiments of separating laminated glass with thickness of 5 + 0.38 + 5 mm were carried out by laser composite separation successfully, and the separation side wall was very smooth (roughness of glass layer reached 10.24 nm) without any separation defects such as chipping, micro-cracks or subsurface damage. A mathematical model was also established to analyze the separation mechanism.
关键词： Laser melting,Numerical simulation,Laser-induced thermal-crack propagation,Laser separation,Laminated glass
更新于2025-09-23 15:21:01
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Particulars of Femtosecond Laser Modification of Antimony-Silicate Glass
摘要： The particulars of the effect of focused femtosecond laser pulses on antimony silicate glass with the composition 25Sb2O3–75SiO2 % (molar content) in thermal and athermal regimes were studied. It was found that in contrast to quartz, alkali silicate, and some borosilicate glasses the birefringence of the form characteristic for the formation of nanogratings does not arise in the laser-modified zones of the studied glass. Weak birefringence with slow axis parallel to the polarization plane of the writing laser beam, accompanied by precipitation of crystalline phases, seemingly including the cubic modification of Sb2O3, arises in the modified zones under irradiation by 106 pulses with energy > 100 nJ and repetition frequency 10 and 200 kHz.
关键词： senarmontite,Raman scattering spectroscopy,crystallization,antimony silicate glass,femtosecond laser modification
更新于2025-09-23 15:21:01
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Concurrent Formation of Metallic Glass During Laser Forward Transfer 3D Printing
摘要： In recent years, bulk metallic glasses (BMGs) have drawn much research attention and are shown to be of industrial interest due to their superior mechanical properties and resistance to corrosion. In spite of the interest in harnessing MG for microelectromechanical systems devices, there are limitations in manufacturing such micrometer-scale structures. A novel approach for the fabrication of 3D MG structures using laser-induced forward transfer (LIFT) is demonstrated. Inherent tremendous cooling rates associated with the metal LIFT process (≈1010 k s?1) make the formation of a variety of BMGs accessible, including also various binary compositions. In this work, it is demonstrated that LIFT printing of ZrPd-based metallic glass microstructures can also be performed under ambient conditions. X-ray diffraction analysis of the printed structures reveals > 95% of amorphous metal phase. Taking advantage of the properties of BMG, high quality printing of high aspect ratio BMG pillars, and microbridges are demonstrated. It is also shown how a composite, amorphous-crystalline metal structure with a required configuration can be fabricated using multimaterial LIFT printing. The inherent high resolution of the method combined with the noncontact and multimaterial printing capacity makes LIFT a valuable additive manufacturing technique to produce metallic glass-based devices.
关键词： mixed metal structures,3D metal printing,metal glass,additive manufacturing
更新于2025-09-23 15:21:01
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Perovskite Photovoltaics on Roll-To-Roll Coated Ultra-thin Glass as Flexible High-Efficiency Indoor Power Generators
摘要： Indoor perovskite photovoltaics can help power the internet of things revolution, being highly ef?cient, low-cost, printable, and compatible with ?exible substrates. Castro-Hermosa et al. develop ?exible perovskite cells on roll-to-roll coated ultra-thin glass with excellent optoelectrical and mechanical properties, delivering ef?ciencies of 20.6%–22.6% under 200–400 lx LED illumination.
关键词： Flexible high-efficiency indoor power generators,Perovskite photovoltaics,LED illumination,Roll-to-roll coated ultra-thin glass
更新于2025-09-23 15:21:01
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Pulsed Laser Deposition Films Based on CdSe-Doped Zinc Aluminophosphate Glass
摘要： A composite material with applications in optoelectronics has been investigated. Pulsed laser deposition CdSe-doped glass film was prepared by the combinatorial deposition from two targets, namely pure CdSe and glass belonging to the 20Li2O-10Al2O3-7BaO-2La2O3-2ZnO-59P2O5 system. Exciton peaks in the Vis domain, related to electron–hole pairs transitions from the valence band to the conduction band, were revealed in the optical absorption spectra of the CdSe-doped film. CdSe quantum dots (QDs) band gap energy depends on the CdSe quantum confinement effect. CdSe-doped film photoluminescence exhibits peaks in the red domain assigned to CdSe transitions from the excited state to the ground state. The size of CdSe nanoclusters, determined from x-ray diffraction is correlated with scanning electron microscopy–energy dispersive x-ray spectroscopy and atomic force microscopy results. Vibration modes specific both to CdSe QDs and to the vitreous network have been evidenced by Fourier transform infrared and Raman spectroscopy.
关键词： quantum dots,optoelectronics,zinc aluminophosphate glass,pulsed laser deposition,CdSe
更新于2025-09-23 15:21:01