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solar energy

Mohamad Mohsen Momeni, Yousef Ghayeb, Farzaneh Ezati
Tungsten-copper co-sensitized TiO2 nanotube films on titanium substrate, used as photoanodes in photoelectrochemical (PEC) water splitting to produce hydrogen, have been synthesized via anodization and chemical bath deposition (CBD) methods. Field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) were used to study the morphology and elemental composition of the synthetic samples. UV-Vis diffuse reflection spectroscopy (UV-Vis DRS) was sued to investigate the optical features of the samples...
December 6, 2017: Journal of Colloid and Interface Science
Xiaoyun Yu, Néstor Guijarro, Melissa Johnson, Kevin Sivula
Few-atomic-layer nanoflakes of liquid-phase exfoliated semiconducting transition metal dichalcogenides (TMDs) hold promise for large-area, high-performance, low-cost solar energy conversion, but their performance is limited by recombination at defect sites. Herein, we examine the role of defects on the performance of WSe2 thin film photocathodes for solar H2 production by applying two separate treatments, a pre-exfoliation annealing and a post-deposition surfactant attachment, designed to target intraflake and edge defects, respectively...
December 15, 2017: Nano Letters
Vânia Jesus, Diana Martins, Tatiana Branco, Nádia Valério, Maria G P M S Neves, Maria A F Faustino, Luís Reis, Esther Barreal, Pedro P Gallego, Adelaide Almeida
In the last decade, the worldwide production of kiwi fruit has been highly affected by Pseudomonas syringae pv. actinidiae (Psa), a phytopathogenic bacterium; this has led to severe economic losses that are seriously affecting the kiwi fruit trade. The available treatments for this disease are still scarce, with the most common involving frequently spraying the orchards with copper derivatives, in particular cuprous oxide (Cu2O). However, these copper formulations should be avoided due to their high toxicity; therefore, it is essential to search for new approaches for controlling Psa...
December 15, 2017: Photochemical & Photobiological Sciences
Jinlei Wu, Baosheng Cao, Luis Rino, Yurui Fang, Li Hu, Zhenyi Zhang, Yingzhou Huang, Bin Dong
Up-conversion luminescence (UCL) from rare-earth doped oxide (RE) films has great potential for application in fields such as solar cells, bioanalysis, or display technologies. However, the relatively high phonon energy of oxide matrices usually facilitates nonradiative relaxation leading to low UCL efficiency. Herein, we report a three-layer hierarchical structure of Ag/ZnO nanowires (nw-ZnO)/RE composite films, which enhances the UCL of rare-earth doped oxide films. An optimization of the geometric structure of the composite films demonstrated an increase of UCL by up to almost two orders of magnitude in Er3+ and Tm3+ doped YbMoO4 films...
December 15, 2017: Nanoscale
Norma F Santos-Sánchez, Raúl Salas-Coronado, Rogelio Valadez-Blanco, Beatriz Hernández-Carlos, Paula C Guadarrama-Mendoza
The food industry is becoming more specialized and processing methods are continuously being developed to meet consumer needs. Consumers demand products that are safe and preferably free of synthetic additives. These additives are associated with health effects, in most cases without reasonable justification. Consequently, consumers are looking for clearly labelled products that guarantee the absence of synthetic additives. This has led to the need to search for natural additives, which the food industry claims arenatural antioxidant preservatives...
October 2017: Acta Scientiarum Polonorum. Technologia Alimentaria
Juan Li, Shijie Zhang, Di Shao, Zhenqing Yang, Wansong Zhang
Auxiliary acceptor groups play a crucial role in D-A-π-A structured organic dyes. In this paper, we designed three D-A-π-A structured organic molecules based on the prototype dye QT-1, named ME18-ME20, and further investigated their electronic and optical properties with density functional theory (DFT) and time-dependent DFT (TDDFT). The calculated results indicate that the scope and intensity of dyes' absorption spectra have some outstanding changes by inserting auxiliary groups. ME20 has not only 152nm redshifts to long wave orientation, but also 78% increased oscillator strength compared to QT-1, and its absorption spectrum broadens region even up to 1400nm...
December 5, 2017: Spectrochimica Acta. Part A, Molecular and Biomolecular Spectroscopy
Aditya Kulkarni, Wiel H Evers, Stanko Tomic, Matthew C Beard, Daniël Vanmaekelbergh, Laurens D A Siebbeles
Carrier multiplication (CM) is a process in which a single photon excites two or more electrons. CM is of interest to enhance the efficiency of a solar cell. Until now, CM in thin films and solar cells of semiconductor nanocrystals (NCs) has been found at photon energies well above the minimum required energy of twice the band gap. The high threshold of CM strongly limits the benefits for solar cell applications. We show that CM is more efficient in a percolative network of directly connected PbSe NCs. The CM threshold is at twice the band gap and increases in a step-like fashion with photon energy...
December 14, 2017: ACS Nano
Tuan Anh Pham, Xueqiang Zhang, Brandon C Wood, David Prendergast, Sylwia Ptasinska, Tadashi Ogitsu
Many energy storage and conversion devices rely on processes that take place at complex interfaces, where structural and chemical properties are often difficult to probe under operating conditions. A primary example is solar water splitting using high-performance photoelectrochemical cells, where surface chemistry, including native oxide formation, affects hydrogen generation. In this perspective, we discuss some of the challenges associated with interrogating interface chemistry, and how they may be overcome by integrating high-level first-principles calculations of explicit interfaces with ambient-pressure X-ray photoelectron spectroscopy and direct spectroscopic simulations...
December 14, 2017: Journal of Physical Chemistry Letters
Stephanie Loeb, Chuanhao Li, Jae-Hong Kim
A simple heat treatment, perhaps the most globally recognized point-of-use water sterilization method, is seemingly effective against all major pathogens of concern, but bulk water boiling is not energy efficient or sustainable. Herein, we present the first application of solar-to-thermal converting nanomaterials for the direct inactivation of bacteria and viruses in drinking water through the application of Au nanorods, carbon black, and Au nanorod-carbon black composite materials as light absorbers. With broad absorption bands spanning the visible and near-infrared wavelengths, at sufficient concentrations, these nanoparticles induce multiple scattering events, increasing photon absorption probability and concentrating the light within a small spatial domain, leading to localized, intense heating that inactivates microorganisms in close proximity...
December 14, 2017: Environmental Science & Technology
Navendu Mondal, Apurba De, Anunay Samanta
Excitation of semiconductor quantum dots (QDs) by photons possessing energy higher than the band-gap creates a hot electron-hole pair, which releases its excess energy as waste heat or under certain conditions (when hν > 2Eg) produces multiple excitons. Extraction of these hot carriers and multiple excitons is one of the key strategies for enhancing the efficiency of QD-based photovoltaic devices. However, this is a difficult task as competing carrier cooling and relaxation of multiple excitons (through Auger recombination) are ultrafast processes...
December 13, 2017: Nanoscale
Her Shuang Toh, Roxanne Line Faure, Liyana Bte Mohd Amin, Crystal Yu Fang Hay, Saji George
This article presents a simple, one-step, in situ generation of silver nanoparticle-functionalized fabrics with antibacterial properties, circumventing the conventional, multistep, time-consuming methods. Silver nanoparticle formation was studied with a library of capping agents (branched polyethylenimine [BPEI] of molecular weight [Mw] 10,000 and 25,000, polyvinylpyrrolidone, polyethylene glycol, polyvinylalcohol and citrate) mixed with silver nitrate. The mixture was then exposed to an assortment of light wavelengths (ultraviolet, infrared and simulated solar light) for studying the light-assisted synthesis of nanoparticles...
2017: Nanotechnology, Science and Applications
Marco A Allodi, John P Otto, Sara H Sohail, Rafael G Saer, Ryan E Wood, Brian S Rolczynski, Sara C Massey, Po-Chieh Ting, Robert E Blankenship, Gregory S Engel
Pigment-protein complexes in photosynthetic antennae can suffer oxidative damage from reactive oxygen species generated during solar light harvesting. How the redox environment of a pigment-protein complex affects energy transport on the ultrafast light-harvesting timescale remains poorly understood. Using two-dimensional electronic spectroscopy, we observe differences in femtosecond energy-transfer processes in the Fenna-Matthews-Olson (FMO) antenna complex under different redox conditions. We attribute these differences in the ultrafast dynamics to changes to the system-bath coupling around specific chromophores, and we identify a highly-conserved tyrosine/tryptophan chain near the chromophores showing the largest changes...
December 13, 2017: Journal of Physical Chemistry Letters
Martin Schwarze, Benjamin D Naab, Max L Tietze, Reinhard Scholz, Paul Pahner, Fabio Bussolotti, Satoshi Kera, Daniel Kasemann, Zhenan Bao, Karl Leo
Efficient n-doping of organic semiconductors requires electron donating molecules with small ionization energies, making such n-dopants usually sensitive to degradation under air exposure. A workaround consists in the usage of air stable precursor molecules containing the actual n-doping species. Here, we systematically analyze the doping mechanism of the small molecule precursor o-MeO-DMBI-Cl, which releases a highly reducing o-MeO-DMBI radical upon thermal evaporation. n-Doping of bis-HFl-NTCDI yields air stable and highly conductive films suitable for application as electron transport layer in organic solar cells...
December 13, 2017: ACS Applied Materials & Interfaces
Qunping Fan, Yan Wang, Maojie Zhang, Bo Wu, Xia Guo, Yufeng Jiang, Wanbin Li, Bing Guo, Chennan Ye, Wenyan Su, Jin Fang, Xuemei Ou, Feng Liu, Zhixiang Wei, Tze Chien Sum, Thomas P Russell, Yongfang Li
In this work, a nonfullerene polymer solar cell (PSC) based on a wide bandgap polymer donor PM6 containing fluorinated thienyl benzodithiophene (BDT-2F) unit and a narrow bandgap small molecule acceptor 2,2'-((2Z,2'Z)-((4,4,9,9-tetrahexyl-4,9-dihydro-s-indaceno[1,2-b:5,6-b']dithiophene-2,7-diyl)bis(methanylylidene))bis(3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile (IDIC) is developed. In addition to matched energy levels and complementary absorption spectrum with IDIC, PM6 possesses high crystallinity and strong π-π stacking alignment, which are favorable to charge carrier transport and hence suppress recombination in devices...
December 13, 2017: Advanced Materials
Changsoon Cho, Jung Hoon Song, Changjo Kim, Sohee Jeong, Jung-Yong Lee
Bandgap tunability and broadband absorption make quantum-dot (QD) photovoltaic cells (PVs) a promising candidate for future solar energy conversion systems. Approaches to improving the electrical properties of the active layer increase efficiency in part. The present study focuses on optical room for enhancement in QD PVs over wide spectrum in the near-infrared (NIR) region. We find that ray-optical light trapping schemes rather than the nanophotonics approach may be the best solution for enhancing broadband QD PVs by suppressing the escape probability of internal photons without spectral dependency...
December 12, 2017: Scientific Reports
Jingxiu Yang, Peng Zhang, Su-Huai Wei
Cs2AgBiBr6 was proposed as one of the inorganic, stable, and non-toxic replacement of the methylammonium lead halides (CH3NH3PbI3, which is currently considered as one of the most promising light-harvesting material for solar cells). However, the wide indirect band gap of Cs2AgBiBr6 suggests that its application in photovoltaics is limited. Here, using the first principle calculation, we show that by controlling the ordering parameter at the mixed sublattice, the band gap of Cs2AgBiBr6 can vary continuously from a wide indirect band gap of 1...
December 13, 2017: Journal of Physical Chemistry Letters
Ping She, Kongliang Xu, Shengyan Yin, Yinxing Shang, Qinrong He, Shan Zeng, Hang Sun, Zhenning Liu
A self-standing macroporous noble metal-zinc oxide (ZnO) sponge of robust 3D network has been fabricated through in-situ growth method. The key to the construction of the bioinspired sponge lies in the choice of commercial polyurethane sponge (CPS) with interconnected and junction-free macroporous structure as the skeleton to support Au/ZnO nanorods (Au/ZnONRs). The resultant Au/ZnO/CPS not only exhibits hierarchical structures representing physical features of CPS, but also demonstrates durable superior photocatalytic activity and hydrogen generation capability...
December 5, 2017: Journal of Colloid and Interface Science
Thomas Krieg, Anne Sydow, Sonja Faust, Ina Huth, Dirk Holtmann
Herein, we demonstrate that CO2 can be converted by an engineered "Knallgas" bacterium (Cupriavidus necator) to the terpene α-humulene. Heterologous expression of the mevalonate pathway and α-humulene synthase resulted in a production of approx. 10 mg α-humulene per gram cell dry mass (CDM) under heterotrophic conditions. This first example of chemolithoautotrophic production of a terpene from carbon dioxide, hydrogen and oxygen is a promising starting point for the production of different high value terpene compounds from abundant and simple raw materials...
December 12, 2017: Angewandte Chemie
Jochen Friedl, Maria A Lebedeva, Kyriakos Porfyrakis, Ulrich Stimming, Thomas W Chamberlain
Redox flow batteries have the potential to revolutionize our use of intermittent sustainable energy sources such as solar and wind power by storing the energy in liquid electrolytes. Our concept study utilizes a novel electrolyte system, exploiting derivatised fullerenes as both anolyte and catholyte species in a series of battery cells, including a symmetric, single species system which alleviates the common problem of membrane crossover. The prototype multi electron system, utilizing molecular based charge carriers, made from inexpensive, abundant and sustainable materials, principally, C and Fe, demonstrates remarkable current and energy densities and promising long-term cycling stability...
December 12, 2017: Journal of the American Chemical Society
Gang Tang, Zewen Xiao, Hideo Hosono, Toshio Kamiya, Daining Fang, Jiawang Hong
Over the past few years, the development of lead-free and stabile perovskite absorbers with excellent performance has attracted extensive attention. Much effort has been devoted to screening and synthesizing this type of solar cell absorbers. Here, we present a general design strategy for designing the layered halide double perovskites Cs3+nM(II)nSb2X9+3n (M = Sn, Ge) with desired photovoltaic-relevant properties by inserting [MX6] octahedral layers, based on the principles of increased electronic dimensionality...
December 12, 2017: Journal of Physical Chemistry Letters
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