Luminescent solar concentrators are planar concentrators based on trapping light and wave-guiding it to attached PV cells. They are well suited for building integration, viable in locations with significant indirect sunlight and can be complementary to geometric high-concentration systems. Nanorods have been proposed as novel luminescent centres with promising properties, such as reduced self-absorption. Several nanorod doped concentrators have been fabricated and characterised in order to investigate the dependence of LSC performance on size and dopant concentration. The experimental results illustrate the effect of re-absorption and the associated losses with increasing size and concentration. Computational results using a raytrace model are in good agreement with the experiments. Furthermore, the raytrace model was employed to make realistic projections and extend the parameter range of the experiment.

Optisches Modul, umfassend ein Substrat und eine auf dem Substrat aufgebrachte Polymerschicht, wobei Substrat und Polymerschicht im Spektralbereich von 250 bis 700 nm transparent sind und in der Polymerschicht (a) fluoreszierende Additive (A), die zumindest im Spektralbereich von 250 bis 400 nm (UV-Bereich) absorbieren und ausgewahlt sind aus der Gruppe bestehend aus Gruppe der Fluoreszenzfarbstoffe, Quantenpunkte, Nanophosphoren und deren Mischungen, worin (i) die Fluoreszenzfarbstoffe ausgewahlt sind aus der Gruppe bestehend aus Naphtylimiden, Naphthyldiimiden, Styrylen, und Stilbenen, und (ii) die Quantenpunkte ausgewahlt sind aus der Gruppe bestehend aus InAs, InP, GaAs, GaP, GaN, InGaAs, GaInP/InP, ZnS, ZnSe, ZnO, ZnTe, PbS, PbSe, PbTe, ZnO:M, ZnS:M, ZnSe:M mit M = Ag, Cu, Al, Mn, Lanthanid, (b) fluoreszierende Additive (B), die zumindest im Spektralbereich von 400 bis 700 nm (sichtbarer-Bereich) absorbieren und ausgewahlt sind...

The electrical and spectral output from luminescent solar concentrator (LSC) devices is predicted using thermodynamic modelling and ray-trace modelling techniques. Predicted output from four LSCs of varying dimensions, containing different luminescent dyes, are found to be in good agreement with measured output taken from fabricated LSCs. Despite the many different processes involved in the two modelling approach, predicted short circuit current densities from both approaches are found to be in excellent agreement.

The fabrication and performance of sensors utilizing the piezoelectric properties of P(VDF/TrFE) copolymer thin films are described. The IR spectra of porous PTFE films, and electron micrographs showing their structure, are presented. Finally the fabrication and performance of a sensor utilizing the piezoelectric properties of a porous PTFE film in contact with a compact or normal PTFE film are described.

Ferroelectric copolymers of vinylidene fluoride and trifluoroethylene [P(VDF/TrFE)] have a strong piezoelectric and pyroelectric effect with a high potential for sensor and transducer applications. Porous polytetrafluoroethylene (PTFE) exhibits excellent electret properties and is suitable for transducer applications based on its macroscopic piezoelectricity. In this work the preparation of piezoelectric P(VDF/TrFE) films onto flexible as well as on any shaped printed circuits achieved through a spray technique from the polymer solution is reported. Results on array sensors, measuring dynamic pressure in air flow field monitoring as well as dynamic force measurements, are presented. Electret transducers made by porous PTFE are prepared and their sensor properties are described.

Electron beam poling was developed and applied to thin polymer layers by use of a scanning electron microscope. Molecular manipulations of orientation of the molecules were induced by focused electron beams, and detected by means of infrared spectroscopy as well as by nonlinear optical methods. Using electron beam microlithography microscopic polarization structures have been written into thin fluoropolymer layers by means of a direct, computer-controlled writing process; they were read out through potential contrast images as well as by studies concerning second harmonic generation (SHG)

Electron beam radiation was used to store information into thin fluoropolymer layers. The data storage processes and mechanisms were investigated by second harmonic generation (SHG) and Fourier-Transform Infrared Spectroscopy.

Based on theoretical considerations, an i.r.-technique is presented which allows the mean CF2 dipole orientation to be determined in uniaxially drawn poly(vinylidene fluoride) (PVDF) in dependence on an external electric field applied to the sample during spectra registration. The method includes measurements at different angles of incidence. Information about dipole orientation in trans-sequences of different lengths or in crystallites and in non-crystalline regions may, in principle, be obtained.

On the basis of a mechanical model of a vibrating CF/sub 2/-group under the influence of an electric field it is shown that the evaluation of band frequencies makes it possible to discriminate between dipole orientation angles theta and theta + pi . The field-induced frequency changes experimentally found can be explained by the model in connection with dipole reorientation caused by the field.< >

During thermooxidative treatment of PAN fibres at temperatures between 180 and 320-degrees-C several chemical reactions take place. As a result of cyclization by means of N-bridges and dehydrogenation, connected with the formation of conjugated double bonds, aromatic rings are formed. Furthermore, carbonyl groups occur due to oxidation. The resulting product is insoluble and nonmeltable. Therefore the mentioned reactions as well as the composition of the final product may be investigated by means of only a limited number of methods, among which high-resolution C-13-solid state-NMR and infrared spectroscopy proved to be particularly suitable. The reaction starts at about 180-degrees-C, the first being dehydrogenation. Cyclization and oxidation follow as temperature further increases.

In carbon fibre processing, poly(acrylonitrile) filaments are stabilized by heat treatment giving rise to complex physical and chemical structure transitions of the precursor material. The combined application of DSC and shrinkage force measurements, IR and 13 C-CP/MAS-NMR spectroscopy, as well as wide and small angle X-ray scattering is useful to elucidate the various structural transitions and therefore to optimize the stabilization process.

Acta PolymericaVolume 39, Issue 4 p. 209-210 New Book Electron energy-loss spectroscopy in the electron microscope. Von R. F. EGERTON. ISBN 0-306-42158-5. New/London: Plenum Press 1986. XII, 410 S., geb., $ 59.50 A. Büchtemann, A. BüchtemannSearch for more papers by this author A. Büchtemann, A. BüchtemannSearch for more papers by this author First published: April 1988 https://doi.org/10.1002/actp.1988.010390418AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume39, Issue4April 1988Pages 209-210 RelatedInformation

Acta PolymericaVolume 37, Issue 3 p. 192-192 New Book Einführung in die Physikalische Chemie. Von H. LABHART. Teil V: Molekülspektroskopie. 2., neubearb. Aufl. von E. HASEL-BACH. ISBN 3-540-12983-9. Berlin/Heidelberg/New York/Tokyo: Springer-Verlag 1984. XI., 156 S., 58 Abb., geheftet DM 24,80 A. Büchtemann, A. BüchtemannSearch for more papers by this author A. Büchtemann, A. BüchtemannSearch for more papers by this author First published: March 1986 https://doi.org/10.1002/actp.1986.010370326AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume37, Issue3March 1986Pages 192-192 RelatedInformation

PVC(E) latex samples of polymers obtained by standard and seed polymerisation were subjected to glow discharge etching under mild conditions at two different temperatures. Depending on the experimental conditions the etched particles reveal more or less distinctly differentiate dstructural units extending from less than 10 nm to about 20 nm in size. These subunits are considered as regions of higher order within the particles observed.

An algorithm for the parameter determination of broad particle size distributions from optical diffraction patterns of electronmicrographs is experimentally tested using some model objects. Experimentally obtained parameters fit theoretical ones with good accuracy. Possible error sources are thoroughly discussed.