Search results for "fabrication"
showing 10 items of 460 documents
Dynamic preparation of TiO2 films for fabrication of dye-sensitized solar cells
2006
Preparation of nanocrystalline porous titanium dioxide (TiO2) films with roll-to-roll compatible methods was studied. Gravure printing was used for spreading TiO2 paste and paper calendering for pressing TiO2 nanoparticle films. Influence of different preparation methods on performance of fabricated dye-sensitized solar cells (DSSCs) was investigated. The attained light into electricity conversion efficiency was compared with DSSCs fabricated on conductive plastic substrates by doctor-blading spreading with subsequent static pressing. The latter method achieved a light conversion efficiency as high as 5.1%. The efficiency of the cells with a gravure printed TiO2 film was found to be rather …
Supercontinuum generation with 532 nm quasi-continuum pulses in photonic crystal fibre tapers
2007
We report experimental results on supercontinuum generation in PCF tapers using quasi-continuous pump pulses of 7 ns duration at 532 nm. SC generation in normal and anomalous dispersion regimes are presented. Introduction Supercontinuum generation (SC) in photonic crystal fibres (PCF), fibre tapers, and PCF tapers has been demonstrated in the past with pump pulses of fs, ps, and tenths of ns duration [1-2]. Here, we present experimental results on SC generation in PCF tapers using quasi-continuous pump pulses of 7 ns duration at 532 nm. Fabrication of the PCF tapers The PCF from which the tapers were made, was a large-air-hole PCF ("cobweb" PCF) with two rings of air holes around a solid si…
Frequency conversion of propagating surface plasmon polaritons by organic molecules
2008
We demonstrate frequency conversion of surface plasmon polaritons (SPP) by utilizing the coupling between organic dye molecules and SPP. Launching of SPPs into a plasmonic waveguide is done in two ways: by optically excited molecules and by quantum dots (QDs). QDs are demonstrated to overcome the major problem of bleaching occurring with molecules. The SPP propagates tens of micrometers and clear frequency conversion is observed in the SPP spectrum after passing an area of converter molecules. The use of molecules and QDs as elements of all-plasmonic devices has the potential for high integration and use of self-assembly in fabrication. Peer reviewed
Monitoring the Etching Process in LPFGs towards Development of Highly Sensitive Sensors
2017
Trabajo presentado en la Eurosensors 2017 Conference. París, 3–6 de septiembre de 2017. In this work, the monitoring of the etching process up to a diameter of 30 µm of two LPFG structures has been compared, one of them had initially 125 µm, whereas the second one had 80 µm. By tracking the wavelength shift of the resonance bands during the etching process it is possible to check the quality of etching process (the 80 µm fibre performs better than de 125 µm fibre), and to stop for a specific cladding mode coupling, which permits to obtain an improved sensitivity compared to the initial structure. This work was supported by the Spanish Agencia Estatal de Investigación (AEI) and Fondo Europeo…
Aluminum Plasmonics: Fabrication and Characterization of Broadly Tunable Plasmonic Surfaces for Plasmon Molecule Strong-Coupling and Fluorescence Enh…
2018
Our work based on previous studies [1, 2] confirms, that simple aluminum nanostructures can be utilized as effective plasmonic resonators over a broad range of frequencies and wavelengths. The nanostructured surfaces, fabricated by electron-beam lithography demonstrated relatively narrow-band resonances and are suitable for various plasmonic applications ranging from metal enhanced fluorescence to strong-coupling [1, 2, 3, 4, 5] experiments. We represent data for molecule-plasmon coupling near the strong coupling limit and demonstrate that these aluminum structures do act as fluorescence increasing substrates. In this work, we used two different types of dyes. We studied the narrow band j-a…
Nanostructure Formation on ZnSe Crystal Surface by Electrochemical Etching
2021
The article describes a simple method for nanostructuring the surface of monocrystalline zinc selenide. It is shown that the traditional electrochemical etching of n-ZnSe (111) samples in a concentrated solution of nitric acid leads to the appearance of massive etching pits and small pores on the surface. The dynamics of the process and stages of crystal dissolution has been studied. It is assumed that the porous zinc selenide obtained in this way can be used in optoelectronic structures, as well as as buffer layers for growing zinc oxide.
Deposition of Cu Nanoparticles on the Surface of Metallic Aluminum
2012
Deposition of Cu particles by electrolysis at constant electrode potential and by internal electrolysis methods was investigated. The composition of deposited material was confirmed by optical and scanning electron microscope methods. Combination of electrolysis at constant electrode potential with internal electrolysis method was found most effective for fabrication of nanoparticle arrays. Single crystalline Cu particles are fabricated by internal electrolysis, while polycrystalline ones obtained by combined chronopotentiometric and internal electrolysis methods. The formation mechanism of Cu nanoparticles is described.
Classification et chronologie de bas fourneaux de réduction du fer à usage unique au sud-ouest du Niger
2016
In southwestern Niger, near Niamey, several thousand single-use bloomery furnaces have been mapped and identified. The archaeological study of approximately 30 furnaces and their slag reveals the existence of four methods for iron smelting: three types of pit furnace and one slag-tapping type. The slag pit furnaces are clearly differentiated by the form and volume of their pits. All slag-tapping furnaces drain off slag through small openings. The slag is tapped either vertically or laterally. According to radiocarbon dates, the smelting activity developed in the 2 nd century AD and intensified through to the 14 th century. It continued to evolve until the middle of the 20 th century. The lo…
Transfer of plasmid DNA into cells with microelectroporation arrays on a chip
2000
The possibility to transfer pure DNA into bacterial cells forms the basis for the genetic engineering of the cell. Electroporation is a powerful and easy technique to introduce plasmid DNA into cells. Its drawback for use with high-throughput approaches is that with standard electroporation chambers the reactions have to carried out one after the other and the electroporation cuvettes are expensive. To obtain the possibility of high-throughput electroporation reactions Escherichia coli cells were electroinjected in parallel with different plasmids in reactions as small as 100 nl on a microstructured array of electrodes, forming hundred separate electroporation units on a chip of a square in…
Biofabrication of biosilica-glass by living organisms
2008
Biosilicification is an evolutionarily old and widespread type of biomineralization both in unicellular and multicellular organisms, including sponges, diatoms, radiolarians, choanoflagellates, and higher plants. In the last few years combined efforts in molecular biology, cell biology, and inorganic and analytical chemistry have allowed the first insight into the molecular mechanisms by which these organisms form an astonishing variety of siliceous structures that cannot be achieved by chemical methods. Here we report about the present stage of knowledge on structure, biochemical composition, and mechanisms of biosilica formation, focusing our attention particularly on sponges because of t…