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261.
Bj?rn?T?rngren Simon?Sandén Johan?O.?Nyman Armi?Tiihonen Hua?Jiang Janne?Ruokolainen Janne?Halme Ronald??sterbacka Jan-Henrik?Sm?ttEmail authorView authors OrcID profile 《Journal of nanoparticle research》2017,19(11):365
Plasmonic metal nanoparticles have shown great promise in enhancing the light absorption of organic dyes and thus improving the performance of dye-sensitized solar cells (DSSCs). However, as the plasmon resonance of spherical nanoparticles is limited to a single wavelength maximum (e.g., ~ 520 nm for Au nanoparticles), we have here utilized silica-coated gold nanorods (Au@SiO2 NRs) to improve the performance at higher wavelengths as well. By adjusting the aspect ratio of the Au@SiO2 NRs, we can shift their absorption maxima to better match the absorption spectrum of the utilized dye (here we targeted the 600–800 nm range). The main challenge in utilizing anisotropic nanoparticles in DSSCs is their deformation during the heating step required to sinter the mesoporous TiO2 photoanode and we show that the Au@SiO2 NRs start to deform already at temperatures as low as 200 °C. In order to circumvent this problem, we incorporated the Au@SiO2 NRs in a TiO2 nanoparticle suspension that does not need high sintering temperatures to produce a functional photoanode. With various characterization methods, we observed that adding the plasmonic particles also affected the structure of the produced films. Nonetheless, utilizing this low-temperature processing protocol, we were able to minimize the structural deformation of the gold nanorods and preserve their characteristic plasmon peaks. This allowed us to see a clear redshift of the maximum in the incident photon-to-current efficiency spectra of the plasmonic devices (Δλ ~ 14 nm), which further proves the great potential of utilizing Au@SiO2 NRs in DSSCs. 相似文献
262.
Jozef Saloň Viktor Milata Nadežda Prónayová Ján Leško 《Monatshefte für Chemie / Chemical Monthly》2000,131(3):293-299
Summary. Reaction of 5-aminoquinoxaline with alkoxymethylene derivatives affords the corresponding quinoxalinoaminoethylenes. These
undergo a thermal cyclization to yield angularly annelated 10H-pyrido[2,3-f]quinoxalines. The structures of all products were deduced from their IR, UV, mass, 1H, and 13C NMR spectra.
Received September 24, 1999. Accepted November 18, 1999 相似文献
263.
264.
Kärhä Petri Baumgartner Hans Askola Janne Kylmänen Kasperi Oksanen Benjamin Maham Kinza Huynh Vo Ikonen Erkki 《Optical Review》2020,27(2):195-204
Optical Review - We have developed a setup for measuring differential spectral responsivities of unifacial and bifacial solar cells under bias light conditions. The setup uses 30 high-brightness... 相似文献
265.
Janne I. Kokkala Karen Meagher Reza Naserasr Kari J. Nurmela Patric R. J.
stergrd Brett Stevens 《组合设计杂志》2020,28(1):5-24
A covering array of strength is an array of symbols from an alphabet of size such that in every subarray, every ‐tuple occurs in at least one row. A covering array is optimal if it has the smallest possible for given , , and , and uniform if every symbol occurs or times in every column. Before this paper, the only known optimal covering arrays for were orthogonal arrays, covering arrays with constructed from Sperner's Theorem and the Erd?s‐Ko‐Rado Theorem, and 11 other parameter sets with and . In all these cases, there is a uniform covering array with the optimal size. It has been conjectured that there exists a uniform covering array of optimal size for all parameters. In this paper, a new lower bound as well as structural constraints for small uniform strength‐2 covering arrays is given. Moreover, covering arrays with small parameters are studied computationally. The size of an optimal strength‐2 covering array with and is now known for 21 parameter sets. Our constructive results continue to support the conjecture. 相似文献
266.
Ya Chen Janne Jaakola Yanling Ge Antti Säynätjoki Ari Tervonen Simo-Pekka Hannula Seppo Honkanen 《Journal of Non》2009,355(45-47):2224-2227
We report a study on the properties of silver nanoparticles formed in glass using a masked silver–sodium ion-exchange technique, a process that has been used to fabricate patterned optical waveguides. Characterizations reveal that spherical nanoparticles with a diameter of 5–10 nm are concentrated below the mask edge at a depth of 50–100 nm from the surface. The amount of nanoparticles and the wavelength of the associated localized surface plasmon resonance can be controlled by the spacing between adjacent mask openings. After gentle etching, the surface morphology of the sample shows well-defined nanoparticle patterns. These closely packed nanoparticles embedded in the glass surface have a potential to be used for high-sensitivity surface enhanced spectroscopy, in a glass waveguide device. 相似文献
267.
Janne?Gr?hnEmail author Artur?Nicolau Jouni?R?tty? 《Journal d'Analyse Mathématique》2018,134(2):747-768
The aim of this paper is to consider certain conditions on the coefficient A of the differential equation f″ + Af = 0 in the unit disc which place all normal solutions f in the union of Hardy spaces or result in the zero-sequence of each non-trivial solution being uniformly separated. The conditions on the coefficient are given in terms of Carleson measures. 相似文献
268.
Helga Bettentrup Taneli Laamanen Mika Lastusaari Marja Malkamäki Janne Niittykoski Eugeniusz Zych 《Journal of luminescence》2009,129(12):1661-1663
The Y2O3:Eu3+,Mg2+,TiIV materials (xEu: 0.02, xMg: 0.08, xTi: 0.04) were prepared by solid state reaction. The purity and crystal structure of the material was studied with the X-ray powder diffraction. Luminescence properties were studied in the UV-VUV range with the aid of synchrotron radiation. The emission of Y2O3:Eu3+,Mg2+,TiIV had a maximum at 612 nm (λexc: 250 nm) due to the 5D0→7F2 transition of Eu3+. The excitation spectra (λem: 612 nm) showed a broad band at 233 nm, due to the charge transfer transition between O2− and Eu3+, and at 297 nm due to the Ti→Eu3+ energy transfer. Only very weak persistent luminescence was discovered. In the room and 10 K temperature excitation spectra, the line at 208 nm is due to the formation of a free exciton (FE) and a broad band at 199 nm was related to the valence-to-conduction band absorption of the Y2O3 host lattice. The absorption edge was ca. 205 nm giving 6.1 eV as the energy gap of Y2O3. 相似文献
269.
270.
Degradation and Crystallization of Cellulose in Hydrogen Chloride Vapor for High‐Yield Isolation of Cellulose Nanocrystals 下载免费PDF全文
Prof. Eero Kontturi Anne Meriluoto Dr. Paavo A. Penttilä Dr. Niki Baccile Dr. Jani‐Markus Malho Prof. Antje Potthast Prof. Thomas Rosenau Prof. Janne Ruokolainen Prof. Ritva Serimaa Prof. Janne Laine Prof. Herbert Sixta 《Angewandte Chemie (International ed. in English)》2016,55(46):14455-14458
Despite the structural, load‐bearing role of cellulose in the plant kingdom, countless efforts have been devoted to degrading this recalcitrant polysaccharide, particularly in the context of biofuels and renewable nanomaterials. Herein, we show how the exposure of plant‐based fibers to HCl vapor results in rapid degradation with simultaneous crystallization. Because of the unchanged sample texture and the lack of mass transfer out of the substrate in the gas/solid system, the changes in the crystallinity could be reliably monitored. Furthermore, we describe the preparation of cellulose nanocrystals in high yields and with minimal water consumption. The study serves as a starting point for the solid‐state tuning of the supramolecular properties of morphologically heterogeneous biological materials. 相似文献