Spanning the Solar Spectrum: Azopolymer Solar Thermal Fuels for Simultaneous UV and Visible Light Storage

2016 ◽  
Vol 7 (3) ◽  
pp. 1601622 ◽  
Author(s):  
Andrew K. Saydjari ◽  
Philipp Weis ◽  
Si Wu
Keyword(s):  
Visible Light ◽  
Solar Spectrum ◽  
Solar Thermal ◽  
Light Storage

scholarly journals The Influence of Calcination Temperature on Photocatalytic Activity of TiO2-Acetylacetone Charge Transfer Complex towards Degradation of NOx under Visible Light

Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1463
Author(s):  
Lucas A. Almeida ◽  
Margarita Habran ◽  
Rafael dos Santos Carvalho ◽  
Marcelo E. H. Maia da Costa ◽  
Marco Cremona ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Charge Transfer ◽  
Visible Light ◽  
Calcination Temperature ◽  
Charge Transfer Complex ◽  
Light Exposure ◽  
Sol Gel ◽  
Solar Spectrum ◽  
Photocatalytic Efficiency ◽  
Nanocrystalline Tio2

The improvement of photocatalytic activity of TiO2-based nanomaterials is widely investigated due to the tentative of their industrialization as environmental photocatalysts and their inherently low solar spectrum sensitivity and rapid recombination of charge carriers. Coupling of oxygen-based bidentate diketone to nanocrystalline TiO2 represents a potential alternative for improving the holdbacks. Formation of TiO2-acetylacetone charge transfer complex (CTC) by sol-gel route results in a hybrid semiconductor material with photodegradation activity against toxic NOx gas. In this research, the influence of the chelating agent acetylacetone (ACAC) content on the CTC photocatalytic efficiency under visible light was evaluated. A high content of ACAC in the CTC is not a decisive factor for efficiency of photocatalytic reactions. In fact, the highest efficiency for NOx degradation (close to 100%, during 1 h of visible light exposure) was reported for the material calcined in air at 300 °C with the content of strongly bonded acetylacetone not higher than 3 wt.%. Higher calcination temperature (400 °C) left TiO2 almost completely depleted in ACAC, while at the highest applied temperature (550 °C) a portion of anatase was transformed into rutile and the sample is free of ACAC. The analyses pointed out that superoxide anion radical (O2−) plays an active role in photo-oxidation of NOx. Our findings indicate that this CTC has both high visible light spectral sensitivity and photocatalytic efficiency.

scholarly journals Water-soluble ZnSe/ZnS:Mn/ZnS quantum dots convert UV to visible light for improved Si solar cell efficiency

2021 ◽  
Author(s):  
Hisaaki Nishimura ◽  
Takaya Maekawa ◽  
Kazushi Enomoto ◽  
Naoteru Shigekawa ◽  
Tomomi Takagi ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Solar Cells ◽  
Solar Cell ◽  
Visible Light ◽  
Solar Spectrum ◽  
Water Soluble ◽  
Solar Cell Efficiency ◽  
Cell Efficiency ◽  
Si Solar Cell ◽  
Si Solar Cells

The sensitivity of Si solar cells to the UV portion of the solar spectrum is low, and must be increased to further improve their efficiencies.

scholarly journals New Solar Thermal Materials

2021 ◽  
Vol 1 (1) ◽  
pp. 154-157
Author(s):  
Baghdad Science Journal
Keyword(s):  
Solar Radiation ◽  
Solar Energy ◽  
Absorption Spectra ◽  
Wavelength Range ◽  
Solar Spectrum ◽  
The Other ◽  
Solar Thermal

A number of ehemical ion materials were used as an absorber against solar energy. These materials were selected according to their absorption spectra in the wavelength range 300-800nm where the solar spectrum is coventrated. A solar olleetorw^esigd and The ability of each material inside the collector for absorbing the solar radiation was examined by a converter parameter “R”.According to the “R” parameter, the cohaltous and copperic ions material seems to be of higher capability for absorbing solar energy than the other materials.All the results were analyzed by means of a least-squared fitting program.

Synthesis and Characterization of Photocatalytic TiO2-ZnFe2O4 Nanoparticles

2005 ◽  
Vol 876 ◽  
Author(s):  
Sesha S. Srinivasan ◽  
Jeremy Wade ◽  
Elias K. Stefanakos
Keyword(s):  
Visible Light ◽  
Low Cost ◽  
Anatase Phase ◽  
Solar Spectrum ◽  
Rutile Phase ◽  
Oxidation Potential ◽  
Narrow Bandgap ◽  
Visible Wavelengths ◽  
Indoor Lighting

AbstractThe wide bandgap semiconductor TiO2 has become the dominant UV-activated photocatalyst in the field of air and water detoxification because of its high stability, low cost, high oxidation potential and chemically favorable properties. The demand for visible-light activated photocatalytic systems is increasing rapidly; however, currently, the efficiency and availability of photocatalysts that can be activated effectively by the solar spectrum and particularly indoor lighting is severely limited. In this paper, a new coprecipitation/hydrolysis synthesis route is used to create a TiO2-ZnFe2O4 nanocomposite that is directed towards extending the photoresponse of TiO2 from UV to visible wavelengths (>400nm). The effect of TiO2's accelerated anatase-rutile phase transformation due to the presence of the coupled ZnFe2O4 narrow bandgap semiconductor is evaluated. The transformation's dependence on pH, calcination temperature, particle size, and ZnFe2O4 concentration has been analyzed using XRD, SEM, and UV-Visible spectrometry. The requirements for retaining the highly photoactive anatase phase present in a ZnFe2O4 nanocomposite are outlined. The visible-light activated photocatalytic activity of the TiO2-ZnFe2O4 nanocomposites have been compared to an Aldrich TiO2 reference catalyst, using a solar-simulated photoreactor for the degradation of phenol.

scholarly journals Virtual screening of norbornadiene-based molecular solar thermal energy storage systems using a genetic algorithm

2021 ◽  
Author(s):  
Nicolai Ree ◽  
Mads Koerstz ◽  
Kurt V. Mikkelsen ◽  
Jan H. Jensen
Keyword(s):  
Genetic Algorithm ◽  
Energy Storage ◽  
Storage Systems ◽  
Chemical Space ◽  
Tight Binding ◽  
Solar Spectrum ◽  
High Energy ◽  
Solar Thermal ◽  
Solar Thermal Energy ◽  
Energy Storage Systems

We present a computational methodology for the screening of a chemical space of 10²⁵ substituted norbornadiene molecules for promising kinetically stable molecular solar thermal (MOST) energy storage systems with high energy densities that absorb in the visible part of the solar spectrum. We use semiempirical tight-binding methods to construct a dataset of nearly 34,000 molecules and train graph convolutional networks to predict energy densities, kinetic stability, and absorption spectra and then use the models together with a genetic algorithm to search the chemical space for promising MOST energy storage systems. We identify 15 kinetically stable molecules, five of which have energy densities greater than 0.45 MJ/kg and the main conclusion of this study is that the largest energy density that can be obtained for a single norbornadiene moiety with the substituents considered here, while maintaining a long half-life and absorption in the visible spectrum, is around 0.55 MJ/kg.

Selective Infrared Energy Harvesting by Nanoparticle Dispersions in Solar Thermal Desalination Systems

2020 ◽  
Author(s):  
James S. Hammonds ◽  
Kimani A. Stancil ◽  
Olalekan S. Adewuyi
Keyword(s):  
Light Harvesting ◽  
Volume Fraction ◽  
Radiation Transport ◽  
Near Field ◽  
Solar Spectrum ◽  
Solar Thermal ◽  
Infrared Light ◽  
Chain Model ◽  
Nanoparticle Dispersions ◽  
Thermal Desalination

Abstract A significant portion of the infrared solar spectrum is either unused, or wasted by inefficient solar energy conversion. In this paper, we show that infrared light harvesting can also be accomplished by dispersions of polar nanoparticles. Polar nanoparticle dispersions in a selective absorber may result in Solar Thermal Desalination (STD) systems that aim to maximize the solar-to-heat conversion efficiency by managing the thermal radiative and conduction losses. In noting that irregular dispersions of polar nanoparticles are less costly than regularly spaced nanostructures to manufacture at large scales, we describe the solar absorptivity as a function of a nanoparticle chain model determined emissivity and thermal conductance. The near-field interactions between nanoparticles are explained by modeling the nanoparticles as dispersed electromagnetic dipole oscillations that interact with solar light. An FDTD model of polar nanodispersions near an optical cavity is used to demonstrate infrared harvesting. With this model, we show that the infrared light-harvesting mechanisms of silica nanoparticles involve local and propagating surface phonon polaritons and varying the volume fraction changes radiation transport properties by several orders of magnitude. In discussing STD systems, we demonstrate a potential to use nanoparticle chains to create novel selective absorbers with tunable solar absorptivity.

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