- 标题
- 摘要
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- 实验方案
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On the Blue Emitting Phosphor Na <sub/>3</sub> RbMg <sub/>7</sub> (PO <sub/>4</sub> ) <sub/>6</sub> :Eu <sup>2+</sup> Showing Ultra High Thermal Stability
摘要： This work concerns a novel blue emitting LED phosphor activated by Eu2+. It turned out that this luminescent material can be efficiently pumped by near UV or UV-A radiation sources while it exhibits a high quantum yield for a doping level between 0.3 and 3.0%. More impressively, the material has a very high quenching temperature T1/2 and will thus be applicable on-chip in high power phosphor converted LEDs or even in laser diodes. The emission and thermal stability is almost identical to that of BAM:Eu2+ while the absorption band is broader and reaches into the near UV range. Therefore, Na3RbMg7(PO4)6:Eu2+ is a promising candidate as a blue emitter in high CRI full conversion LEDs. To investigate the site preference of Eu2+, DFT and Ligand Field Theory based calculations were performed to successfully predict the emission spectrum. An unusual decay behavior was observed at low temperatures and the underlying mechanism involving spin-forbidden transitions of Eu2+ is discussed.
关键词： high thermal stability,solid state lighting,Eu2+ luminescence,near UV LED,high CRI,decay time,Blue photoluminescence
更新于2025-11-21 11:18:25
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Lead Halide Post-Perovskite-Type Chains for High-Efficiency White-Light Emission
摘要： Hybrid metal halides containing perovskite layers have recently shown great potential for applications in solar cells and light-emitting diodes. Such compounds exhibit quantum confinement effects leading to tunable optical and electronic properties. Thus, broadband white-light emission has been observed from diverse metal halides and, owing to high color rendering index, high thermal stability, and low-temperature solution processability, these materials have attracted interest for application in solid-state lighting. However, the reported quantum yields for white photoluminescence (PLQY) remain low (i.e., in the range 0.5–9%) and no approach has shown to successfully increase the intensity of this emission. Here, it is demonstrated that the quantum efficiencies of hybrid metal halides can be greatly enhanced if they contain a polymorph of the [PbX4]2? perovskite-type layers: the [PbX4]2? post-perovskite-type chains showing a PLQY of 45%. Different piperazines lead to a hybrid lead halide with either perovskite layers or post-perovskite chains influencing strongly the presence of self-trapped states for excitons. It is anticipated that this family of hybrid lead halide materials could enhance all the properties requiring the stabilization of trapped excitons.
关键词： trapped excitons,solid-state lighting,post-perovskite,photoluminescence
更新于2025-11-14 15:16:37
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Prediction of excitation wavelength of phosphors by using machine learning model
摘要： Luminescent materials are the integral part of green revolution helping us in saving the energy. Much effort been made to design and discover the novel phosphors for solid-state lighting. The current paper focuses on the development of machine learning (ML) model based on simple luminescent materials to predict the excitation to the closest possible accuracy using easily accessible key attributes using least absolute shrinkage and selection operator (LASSO) and artificial neural network (ANN) ML approach. These selected attributes expected to correlate with the excitation of material. The style for studying the material property has the potential to turn down the cost and time involved in an Edisonian approach to the lengthy lab experiment to identify excitation.
关键词： Solid-state lighting,Phosphor,Machine learning,Excitation wavelength,Luminescence
更新于2025-09-23 15:22:29
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[IEEE 2018 4th International Conference on Applied and Theoretical Computing and Communication Technology (iCATccT) - Mangalore, India (2018.9.6-2018.9.8)] 2018 4th International Conference on Applied and Theoretical Computing and Communication Technology (iCATccT) - A concept of energy efficient LED lighting using Power-over-Ethernet (PoE) technology
摘要： LED lighting is found universal acceptance for being affordable and energy ef?cient. The next big step for LED lighting is enabling LED ?xtures to work in Internet-of- Things (IoT) infrastructure. Power-over-Ethernet(PoE) standard delivers power and data via a Ethernet cable from a power source such as a hub directly to the network port of a connected powered device, in the case of lighting the powered device can be a LED bulb.In this paper the concept of energy ef?cient LED lighting using PoE technology is discussed in brief.The bene?ts PoE technology provides and challenges that needs to be addressed are highlighted.
关键词： energy,lighting,ef?ciency,light emitting diode,solid state lighting,Power over Ethernet,POE,LED,SSL
更新于2025-09-23 15:21:01
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High Emission Quantum Yield Tb <sup>3+</sup> -Activated Organic-Inorganic Hybrids for UV-Down-Shifting Green Light-Emitting Diodes
摘要： Solid-state light-emitting diodes (LEDs) are driving the lighting industry towards efficient and environmentally friendly lighting and displays. Current challenges encompass efficient and low-cost down-shifting phosphors with tuned emission colors. Green light lies on the low-loss optical transmission window in plastic optical fibers and plays a special role in human and plants circadian rhythm regulation. Moreover, green-emitting phosphors may suppress the ‘green gap’ found in semiconductor-based LEDs. In this work, a UV-photostable Tb(NaI)3(H2O)2, with (1-ethyl-1,4-dihydro-7-methyl-4-oxo-1,8-NaI= nalidixic naftiridine-3-carboxylic acid), was incorporated into tripodal organic-inorganic hybrid materials. The hybrid hosts boost the absolute emission quantum yield from ~0.11 (isolated complex) to ~0.82 (doped hybrid), being the largest value reported for Tb3+-based hybrid phosphors. A green-emitting LED was fabricated by coating a near-UV LED (365 nm) with a Tb3+-activated organic-inorganic hybrid showing pure-green light with Commission International de l’Eclairage color coordinates and an efficacy value of (0.33, 0.59) and 1.3 lm·W?1, respectively.
关键词： near-UV light-emitting diodes,green light-emitting diodes,lanthanides,solid-state lighting,organic-inorganic hybrids
更新于2025-09-23 15:21:01
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Photoluminescence properties of Ca3B2O6: RE3+ (RE = Dy and Eu) phosphors for ecofrindly solid state lighting
摘要： The phosphors Ca3B2O6:Dy3+ and Ca3B2O6:Eu3+ were prepared by a combustion method. The phosphor was characterized for X- ray diffraction and photoluminescence. The XRD is well matched with the standard JCPDS. Ca3B2O6:Dy3+ phosphor shows two emission bands centered at 481nm and 577nm corresponding to transitions 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2 respectively. Eu3+ doped Ca3B2O6 phosphor gives emission centered at 588nm, 597nm, 614nm and 627 nm having excitation at 396nm. Concentration quenching effect was observed in both the phosphors. Photoluminescence results suggest that phosphor could be used as ecofriendly solid state lighting applications.
关键词： Combustion method,Borate,solid state lighting
更新于2025-09-23 15:21:01
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Illuminating homes with LEDs in India: Rapid market creation towards low-carbon technology transition in a developing country
摘要： Near-term climate change mitigation calls for technological innovation and widespread implementation of appropriate technologies. This is salient in emerging economies, where impending socio-economic and infrastructural transitions hold immense potential for locking-in low-carbon development pathways. Yet, little is understood about how developing countries can scale appropriate technology transitions, given their often underdeveloped technological innovation capabilities and supporting infrastructures and finances. This paper examines a recent, rapid, and ongoing transition of India's lighting market to light emitting diode (LED) technology, from a negligible market share to LEDs becoming the dominant lighting products within five years, despite the country's otherwise limited visibility in the global solid-state lighting industry. Annual sales of LED bulbs grew more than 130 times to over 650 million bulbs between 2014–2018, with over 30 billion kWh of estimated annual energy savings. Focusing on this striking story of technology transition, this paper analyzes India's LED uptake using semi-structured interviews and drawing on the technology innovation systems literature. The results show that the success of transition coexists with its share of shortfalls, and that there is an important tension between the lowering of upfront costs of low-carbon technologies and the efforts to enhance domestic technological capabilities. The paper discusses the results for the Indian LED case and emphasizes the importance of consistent strategic action taking into account all (and not limited) parts of the technology innovation system, while also providing insights on how mitigation technologies can be developed and deployed in developing countries.
关键词： Technology innovation systems,Light emitting diode (LED),Developing countries,India,Solid state lighting,Climate change mitigation,Energy efficiency
更新于2025-09-23 15:19:57
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A Study of Eu Doping in Nanolayers of CsPbBr <sub/>3</sub> using Ab Initio Calculations to Understand <i>fa??f</i> Transitions in Eu <sup>3+</sup> -Doped Nanocrystals for Light-Emitting Diodes
摘要： Recent experiments on Eu doped nanocrystals of CsPbX3 (X = Cl, Br) show that Eu exists in 3+ oxidation state even though it substitutes Pb which is in 2+ state in these perovskites. Therefore, the question arises, what is it that leads to the formation of Eu3+ in nanocrystals of these materials? In order to understand this, we have studied the doping of Eu in a slab (~1.8 nm thick) of CsPbBr3 from ab initio calculations and explored various possibilities that could lead to the formation of Eu3+ and the occurrence of f-f transitions. These include: 1) the presence of a Cs vacancy, 2) the existence of H or OH due to moisture, 3) substitution of O at a surface halogen site, and 4) the possibility of excess halogen around Eu. It is found that the presence of surface oxygen is the most likely reason for the observation of Eu3+ in these nanolayers. Our results show the presence of partially occupied spin-up f states and 6.48 μB magnetic moment on Eu that could lead to the possibility of f-f transition in these doped systems. A similar result has also been obtained for Eu doped in CsPbCl3 nanolayers. The calculated change in energy when defects/impurities are present gives favourable indication of finding H, OH, and Br as interstitials and O as substitutional entities, but Cs vacancy is unlikely. Additionally, we find that the doping of Eu in nanolayers does not affect the atomic structure and the cost of doping is also very small making these perovskites very promising materials for light emitting diodes and other solid-state lighting applications.
关键词： Two-dimensional systems,Light emitting diodes,Solid state lighting,Density functional theory,Metal-halide perovskites,Nanolayers,Defects,f-f transitions
更新于2025-09-23 15:19:57
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Conversionless efficient and broadband laser light diffusers for high brightness illumination applications
摘要： Laser diodes are efficient light sources. However, state-of-the-art laser diode-based lighting systems rely on light-converting inorganic phosphor materials, which strongly limit the efficiency and lifetime, as well as achievable light output due to energy losses, saturation, thermal degradation, and low irradiance levels. Here, we demonstrate a macroscopically expanded, three-dimensional diffuser composed of interconnected hollow hexagonal boron nitride microtubes with nanoscopic wall-thickness, acting as an artificial solid fog, capable of withstanding ~10 times the irradiance level of remote phosphors. In contrast to phosphors, no light conversion is required as the diffuser relies solely on strong broadband (full visible range) lossless multiple light scattering events, enabled by a highly porous (>99.99%) non-absorbing nanoarchitecture, resulting in efficiencies of ~98%. This can unleash the potential of lasers for high-brightness lighting applications, such as automotive headlights, projection technology or lighting for large spaces.
关键词： high-brightness illumination,solid-state lighting,light diffusers,laser diodes,hexagonal boron nitride
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Paths for maximal light incoupling and excellent electrical performances in silicon heterojunction solar cells
摘要： This paper presents the implementation of an automated roll-to-roll ?uidic self-assembly system based on the surface tension driven self-assembly with applications in the ?eld of macroelectronics. The reported system incorporates automated agitation, web motion, component dispensing, and recycling. The process enables the assembly and electrical connection of semiconductor dies/chips in a continuous and parallel method achieves an assembly rate of 15 000 chips per hour and an assembly yield exceeding 99%, testing assembly of standard square-shaped dies, 300–1000 μm size. Scaling the system to any desired throughput is possible due to the parallel manner of self-assembly. The identi?cation and the modeling of the relationship between process parameters and forces have been studied and experimentally veri?ed by testing the effect of the web angle, agitation on assembly, and detachment rates. As an application, we demonstrate the realization of a solid-state lighting module. This particular application requires the assembly of a conductive multilayer sandwich structure, which is achieved by combining the introduced assembly process with a novel lamination step.
关键词： solid state lighting,Roll-to-roll,fluidic self-assembly,flexible electronics
更新于2025-09-19 17:13:59