Optical Efficiency of Luminescent Solar Concentrator Based on Oxyfluoride Glass with Molecular Silver Clusters
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CAL MATERIALS
Optical Efficiency of Luminescent Solar Concentrator Based on Oxyfluoride Glass with Molecular Silver Clusters D. S. Agafonovaa, A. I. Sidorova, b, *, and S. A. Tarasovb a St.
Petersburg Electrotechnical University “LETI,” St. Petersburg, 197376 Russia b ITMO University, St. Petersburg, 197101 Russia *e-mail: [email protected] Received December 2, 2019; revised April 1, 2020; accepted June 3, 2020
Abstract—Oxyfluoride glass with luminescent molecular clusters of silver is shown to be promising as a luminescent solar concentrator (LSC) for the conversion of the solar UV radiation into visible radiation or as the first cascade of a multilayer LSC. Experimental data on the absorption and luminescence of the given glass are used for the numerical simulation. The spectral optical efficiency of LSC reaches 17.7% for a wavelength range of 310–475 nm, and the integral intensity reaches 12%. A mirror reflector on the side faces increases the efficiency of LSC. Decreasing the LSC thickness and increasing its surface enhance the degree of photon concentration. Keywords: luminescence, silver molecular cluster, luminescent solar concentrator, spectral conversion, optical efficiency DOI: 10.1134/S0030400X20100021
INTRODUCTION The use of solar energy is promising due to its environmental friendliness and availability. The Sun creates an average irradiance of 1361 W/m2 in the upper layers of the Earth’s atmosphere [1] which can completely cover the needs of humanity in energy. However, the economic characteristics of solar elements, including photovoltaic converters (PVC), prevent their mainstream use. Therefore, increasing the efficiency and decreasing the cost of solar elements is a relevant task. Firstly, the efficiency of the conversion of the solar radiation can be increased at the use of spectral conversion of short-wavelength radiation into the longwavelength region of the spectrum corresponding to the spectral sensitivity of PVC (down conversion) [2]. Secondly, the efficiency of conversion can be enhanced due to the concentration of radiation on a PVC having a small area. The concentrators of the second type are built on the basis of mirror and lens elements. As a rule, they have a complex construction, require cooling and the Sun tracking systems due to low efficiency at diffuse lighting [3]. The luminescent solar concentrators (LSC) make the combination of both approaches possible. In terms of geometry, the solar concentrators can be rectangular, cylindrical, and also in the form of optical fibers [4–9]. In the simplest case, the LSC is a luminescent plate of arbitrary shape with a PVC attached to one of its ends. The solar radiation excites
luminescence in the plate which, at the same time, is an optical waveguide. When the conditions of total internal reflection are met, the luminescence emission is directed as waveguide modes to the ends where it can be converted into PVC electrical signal. The luminescence mechanism provides the spectral conversion and the LSC shape provides the concentration of the
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