Optical studies on some dyes for liquid solar concentrators
TL;DR: In this paper, the spectral properties of some luminescent dyes, derivatives of xanthene and benzoxazinone groups, in a liquid polymer matrix, Triton x-100, have been studied.
About: This article is published in Solar Energy Materials.The article was published on 1990-03-01. It has received 17 citations till now. The article focuses on the topics: Matrix (mathematics) & Xanthene.
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TL;DR: In this paper, the effect of the sample preparation and perylene dye concentration on the glass transition temperature and dielectric relaxation of poly(methyl methacrylate) doped with fluo- rescent perylene (FRE) dye was investigated.
Abstract: Poly(methyl methacrylate) doped with fluo- rescent perylene dye was prepared by both radical polymer- ization of methyl methacrylate and solvent casting from polymer solutions. The samples were characterized by dif- ferential scanning calorimetry, Fourier transform infrared spectroscopy, electrical conductivity, and dielectric proper- ties. Both conductivity and dielectric properties were mea- sured in the temperature range 303- 433 K and the frequency range 10 3 to 5 10 6 Hz. The results show that the direct- current electrical conductivity increased by increasing dye content in solvent-cast samples, whereas it decreased radi- cally polymerized samples. The results of alternating-cur- rent conductivity suggest electron hopping between filled and empty localized states. The study of dielectric properties showed two relaxation peaks corresponding to the dipole segmental and dipole group losses. Explanations based on the polymer free volume and acid- base interactions were proposed to examine the influence of the sample prepara- tion and perylene dye concentration on the glass-transition temperature and dielectric relaxation of the samples. The obtained results recommend the thermal and molecular sta- bility of luminescent solar concentrator (LSC) matrices pre- pared by radical polymerization over those prepared by solvent casting. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 793- 805, 2003
28 citations
01 Mar 2019
TL;DR: In this paper, a planar LSC with a hollow-core plastic optical fiber filled with aqueous solutions of R-phycoerythrin (R-PE), extracted from Gracilaria sp. algae is presented.
Abstract: DOI: 10.1002/adsu.201800134 manufacture.[1] The first reported examples are planar devices[2–5] (p-LSCs) containing optical active centres able to complement the absorption of the PV cell and emission in the PV cell absorption spectral range. Given the refractive index contrast between the LSC surface and the air, the emitted radiation is guided in the LSC by total internal reflection to PV cells located at its edges.[2,6] Other relevant aspect of the LSC operation is that analogous performance is expected under direct or diffuse light incidence,[7–9] permitting to prospect the use of PV panels under cloudy conditions, which is a significant advantage for integration of PV cells in urban buildings. As an illustrative example of the real-world applicability of these devices, we highlight the implementation of large scale LSCbased panels in a noise barrier configuration as outdoors alongside a roadway in the Netherlands.[10–12] Other applications are envisaged in PV urban integration, as LSCs are attractive to contribute to zero-energy buildings in which the LSCs are embedded in façades, or windows.[13–15] Furthermore, LSCs are candidates to contribute in mobile energy, as they may be integrated in wearable fabrics and outdoor furniture.[16] In particular, target delivered power values up to 10 W may be feasible with the actual figures of merit for LSCs, allowing to charge low-voltage devices, e.g., mobile Luminescent solar concentrators (LSCs) are photovoltaic (PV) complementary devices to overcome the mismatch between the Si-based PV cells, response and the solar spectrum, allowing PV urban integration. Challenges for the luminescent layer include the use of abundant and sustainable natural organic molecules. Here, LSCs composed of a glass container and based on bundles of cylindrical hollow-core plastic optical fibers filled with aqueous solutions of R-phycoerythrin (R-PE), extracted from Gracilaria sp. algae are presented. The R-PE solutions absorb in the UV/visible spectral range (300–550 nm) and convert this radiation into red-emission (550–700 nm) with a maximum absolute quantum yield of ≈0.39. In this work, LSCs with distinct geometries are reported, in which the R-PE emission yields optical conversion efficiency values up to ≈6.88% and ≈4.74% for a planar device and for a bundle of cylindrical LSCs, respectively, which are the largest values known for liquid-based LCSs using sustainable emitting centres. Moreover, the coupling of the LSCs to commercial Si-based PV devices yields power conversion efficiency values of ≈0.27% (planar) and ≈23.03 × 10−3%, (bundle). These values illustrate the potential of this approach for the development of natural-based LSCs meeting the requirements of reliable, sustainable, and competitive energy systems. Sustainable and Liquid Photovoltaics
26 citations
TL;DR: In this article, solid samples of polymethyl methacrylate (PMMA) free and mixed with coumarin-6 or fluorescein sodium organic laser dyes have been prepared by a casting method.
23 citations
TL;DR: In this paper, the Coulomb well barrier of charge carriers (WM) was calculated for polymethylmethacrylate (PMMA) and mixed with phthalocyanine, Ni-phthalocyanines and hematoporphyrin IX chloride laser dyes.
20 citations
TL;DR: In this article, a neutral zwitterionic NaF with a small percentage of a cationic form of NaF within the polyacrylic acid (PAA) film is reported.
Abstract: Na-fluorescein (NaF), when embedded in thin polyacrylic acid (PAA) films, shows a single absorption band peaking at 444 nm and an emission band peaking at 505 nm. The quantum yield of fluorescence (Qf) of the NaF/PAA film is 0.65. These spectroscopic properties of NaF in PAA films can be attributed to the existence of a neutral zwitterionic form of NaF with a small percentage of a cationic form of NaF within the PAA film.
19 citations
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01 Jan 1973TL;DR: CRC handbook of chemistry and physics, CRC Handbook of Chemistry and Physics, CRC handbook as discussed by the authors, CRC Handbook for Chemistry and Physiology, CRC Handbook for Physics,
Abstract: CRC handbook of chemistry and physics , CRC handbook of chemistry and physics , کتابخانه مرکزی دانشگاه علوم پزشکی تهران
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700 citations
TL;DR: In this article, a new principle for solar energy conversion is proposed and evaluated theoretically, and the optical path length in a triangular collector is computed, which offers the advantage of separating the various fractions of light and converting them with solar cells with different bandgaps.
Abstract: A new principle for solar energy conversion is proposed and evaluated theoretically. Collection and concentration of direct and diffuse radiation is possible by the use of a stack of transparent sheets of material doped with fluorescent dyes. High efficiency of light collection can be achieved by light guiding and special design of collectors. The optical path length in a triangular collector is computed. In combination with solar cells this type of collector offers the advantage of separating the various fractions of light and converting them with solar cells with different bandgaps. Theoretical conversion efficiency under optimum conditions is 32% for a system with four semiconductors. Thermal energy conversion offers several advantages over conventional collectors: High temperature and efficiency even under weak illumination, separation of heat transport and radiation collection, low thermal mass. Thermal efficiency is computed to be between 42% and 60%. Very attractive appear hybrid systems for generation of thermal and electric energy. An estimate of the economics of electricity generation shows that due to the concentration costs can be much lower than possible today. With the use of only silicon cells the breakeven point of $0.5/W is almost reached. Practical difficulties to be solved are: Synthesis of dyes with stringent requirements, identification of plastic materials with high transparency and development of solar cells with higher bandgaps.
638 citations
TL;DR: Three independent techniques for measuring self-absorption rates are developed, time-resolved emission, steady-state polarization anisotropy, and spectral convolution, and simple relationships relating the efficiency and gain of an LSC to key spectroscopic parameters of its constituents are given.
Abstract: Experimental techniques are developed to determine the applicability of a particular luminescing center for use in a luminescent solar concentrator (LSC). The relevant steady-state characteristics of eighteen common organic laser dyes are given. The relative spectral homogeneity of such dyes are shown to depend upon the surrounding material using narrowband laser excitation. We developed three independent techniques for measuring self-absorption rates; these are time-resolved emission, steady-state polarization anisotropy, and spectral convolution. Preliminary dye degradation and prototype efficiency measurements are included. Finally, we give simple relationships relating the efficiency and gain of an LSC to key spectroscopic parameters of its constituents.
264 citations