Absorption luminescent solar concentrator

Efficiency yields of re-absorption and re-emission processes have been studied as part of an attempt to understand the problem of photon transport in luminescent solar concentrators. The results suggest that the mean photon transport length is proportional to the square root of the surface area of the concentrator for all geometries. 

Fig. 2. Flat-plate luminescent solar concentrator with photovoltaic ribbon on the edge. Qualitative typical emission and absorption spectra are also given...

Many issues must be adequately addressed for successful inqilementation of in-line solar spectrum alteration using organic dyes. Many of these issues for inline spectrum alteration are shared widi the luminescent solar concentrator. Therefore, the wealth of literature that exists for the luminescent solar concentrator is a very useful information source. Among these issues are dye stability, re-absorpdon, isotropic emission, quantum yield, and matrix absorption. In the following paragrtq)hs, each of these issues will be discussed. 

Another issue regarding the use of spectrum shifting dyes is re-absorption of emitted photons before they enter the photovoltaic device (5,13,14). This occurs due to an overlap in the absorption and emission bands of a dye. While this is an enormous problem for luminescent solar concentrators, it should not be as significant for the in-line spectrum alteration concept. This is because tiie optical... 

Nonmetallic inorganic materials are widely used for optical purposes lenses, pigments, interference filters, laser hosts, luminescent coatings, displays, solar cells, fiber optics, lamp bulbs, and tubes. For optical applications use is made of the refractory index, light absorption, luminescence, and nonlinear optical behavior of materials. These are intrinsic but may depend on the concentration of impurities. Refraction index and optical absorptivity in insulators are atomic properties and are only indirectly related to the structure, but the structure affects the selection rules and the term splitting in the atomic chromophores. The coordination number determines the intensity and wavelength of absorption and... 

It is realized today that in order for a LSC device to be efficient, one of the major requirements is that a great part of the solar spectrum (Fig. 1) should be absorbed, and that a large Stokes shift is needed between the absorption and the emission in order to prevent appreciable self-absorption of the luminescence. Another requirement involves a thermodynamical limitation of flux concentration which may be expressed31 by the inequality... 

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