- 标题
- 摘要
- 关键词
- 实验方案
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Functionalizing Window Coatings with Luminescence Centers by Combinatorial Sputtering of Scatter-Free Amorphous SiAlON:Eu2+ Thin Film Composition Libraries
摘要： SiAlON window coatings are applied on an industrial scale to achieve e.g. scratch-resistance and anti-reflection. Doping these SiAlONs with rare-earths adds luminescent functionality, which could be applied in photovoltaics. By using a combinatorial reactive sputtering approach, an amorphous thin film composition library with a Si:Al ratio from 0:062 : 1 to 3:375 : 1 and a Eu doping from 4:8 at:% to 26 at:% is created. This library uniquely combines high absorption, strong emission and absence of light scattering. By combining position-dependent EDX measurements with transmission and emission spectra, properties like the index of refraction, absorption strength, emission wavelength and decay times of the library can directly be related to the composition. Throughout the library, an index of refraction of 1:63 ± 0:03 is observed, typical for a film with low nitrogen content. The library also shows a large absorption coefficient of 1294 ± 8 cm?1 at:%?1. Laser-excited emission spectra show that the library has a strong redshift from 500 nm to 550 nm with increasing Al concentration. An increase in Eu concentration also causes a shift of the emission to red. Decay spectra show that a high degree of Si greatly improves the luminescence intensity. These functionalized SiAlON coatings can be of great interest for transparent and scatter-free luminescent solar concentrators applied as windows.
关键词： Combinatorial Science,SiAlON,Sputter Deposition,Solar-Conversion
更新于2025-11-14 15:30:11
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Biotechnology for Biofuel Production and Optimization || Photobiohybrid Solar Conversion with Metalloenzymes and Photosynthetic Reaction Centers
摘要： Sunlight provides an abundant and sustainable supply of energy to the Earth's surface, at levels that far exceed the yearly human global energy demand. However, the intermittency and geographic variability of solar irradiation, combined with the need for storage, limits the ability to provide practical alternatives to use of conventional fossil fuels. To better utilize the available solar energy, current photovoltaic technologies must be integrated with conversion technologies that produce storable chemical energy (fuels) that are easily distributed to meet regional demand as needed. In biological photosynthesis, conversion of solar energy into chemical energy is accomplished by the water-splitting and CO2 fixation reactions. The molecular machinery of the natural system provides ideal models for the design and development of artificial solar-to-fuel systems. The theoretical limit of biological photosynthesis is ~12%, and under optimal conditions, efficiencies of 7% have been achieved; however, 1% is a more typical benchmark. Photosynthetic reactions rely on four key components which are integrated to act in concert as a highly functional energy transduction network: (i) the antenna, where photons are absorbed; (ii) the charge separation site, where high-energy excitons (electron-hole pairs) are separated into positive and negative charge carriers; (iii) the reduction catalyst, where electrons are utilized in a fuel-forming reaction (e.g., NAD+ → NADH formation used for CO2 fixation in photosynthesis); and (iv) the oxidation catalyst, where holes are utilized to drive an oxidation reaction (e.g., water oxidation by photosystem II during photosynthesis). Efforts are underway to translate photobiological design principles to develop artificial systems for solar fuel generation that circumvent or eliminate unwanted side reactions and attain higher efficiencies. These efforts include the development of photochemical devices, inorganic biomimetic and bioinspired catalysts and light-harvesting complexes, and organic hybrid materials for photo-driven fuel production. Here, we discuss research focused on the development of hybrid materials that incorporate artificial and natural molecular components into unified functional systems for light-harvesting and conversion into reduced chemical fuels.
关键词： solar conversion,photobiohybrid,metalloenzymes,CO2 reduction,hydrogen production,photosystem I,photosynthetic reaction centers
更新于2025-09-23 15:21:01
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Six-junction IIIa??V solar cells with 47.1% conversion efficiency under 143a??Suns concentration
摘要： Single-junction flat-plate terrestrial solar cells are fundamentally limited to about 30% solar-to-electricity conversion efficiency, but multiple junctions and concentrated light make much higher efficiencies practically achievable. Until now, four-junction III–V concentrator solar cells have demonstrated the highest solar conversion efficiencies. Here, we demonstrate 47.1% solar conversion efficiency using a monolithic, series-connected, six-junction inverted metamorphic structure operated under the direct spectrum at 143 Suns concentration. When tuned to the global spectrum, a variation of this structure achieves a 1-Sun global efficiency of 39.2%. Nearly optimal bandgaps for six junctions were fabricated using alloys of III–V semiconductors. To develop these junctions, it was necessary to minimize threading dislocations in lattice-mismatched III–V alloys, prevent phase segregation in metastable quaternary III–V alloys and understand dopant diffusion in complex structures. Further reduction of the series resistance within this structure could realistically enable efficiencies over 50%.
关键词： III–V solar cells,multijunction solar cells,concentrator solar cells,solar conversion efficiency
更新于2025-09-19 17:13:59
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Monolayer HfTeSe4: A promising two-dimensional photovoltaic material for solar cells with high efficiency
摘要： Currently, atomically thin materials with high photovoltaic performance are urgently needed for applications in solar cells. Herein, by using first-principles calculations, we propose an excellent two-dimensional photovoltaic material, monolayer HfTeSe4, which can be exfoliated feasibly from its layered bulk. It behaves the semiconductor character with a moderate direct gap of 1.48 eV and exhibits remarkable absorbance coefficient of ~105 cm-1 in visible-light region. Meanwhile, monolayer HfTeSe4 shows ultrahigh photocurrent and a long carrier recombination life-time. And strain engineering can further modulate the recombination time of carriers. Moreover, the heterostructure between HfTeSe4 and Bi2WO6 is proposed as potential solar cells with the solar conversion efficiency up to ~20.8%. These extraordinary properties combined with its experimental feasibility makes monolayer HfTeSe4 particularly promising for photovoltaic device applications.
关键词： absorbance coefficient,solar conversion efficiency,carrier recombination,photovoltaic,first-principles calculations,photocurrent
更新于2025-09-12 10:27:22
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Removing Defects in WSe <sub/>2</sub> via Surface Oxidation and Etching to Improve Solar Conversion Performance
摘要： Layered metal dichalcogenide materials (MX2) have great potential for solar energy conversion. However, as-grown MX2 materials often contain edge and terrace defects that degrade semiconducting properties and hinder their solar performance. Herein, we demonstrate a simple approach to removing surface defects and improving the solar performance by using UV-generated ozone to oxidize the surface of WSe2 nanoplates and single crystals, followed by a simple soak in aqueous solutions to remove the oxide. Structural characterizations reveal that defective edges and basal plane defect sites are selectively oxidized and subsequently etched, and the ratio of the non-stoichiometric WSex species is reduced. After this treatment, p-type WSe2 single crystals show increased electron accumulation on the surface and significantly enhanced photoelectrochemical solar conversion efficiency. These results and insights will be useful in the improvement and utilization of layered MX2 materials based on both Se and S for solar energy conversion and other device applications.
关键词： surface defects,oxidation,layered metal dichalcogenide,WSe2,UV-generated ozone,etching,solar conversion
更新于2025-09-10 09:29:36