Photon frequency management can benefit from recent advances in photonics and this section provides a brief outline of different ways to increase the efficiency of collectors beyond the TIR efficiency limit. Spectrally selective filters have been proposed for application to lumines­cent solar collectors in order to reduce the light losses through the TIR escape cone. […]

Typical external quantum efficiency (EQE) curves for thin film solar cells fabricated in the PV21 consortium are shown in Figure 9.17 for three different platforms—amorphous silicon (a-Si), CdTe and CIGS—together with the AM1.5G solar spectrum photon flux. The short wavelength region (300-500 nm), which is of interest in the down-shifting process, shows a reduced spectral […]

9.5.1 Introduction Luminescence down-shifting (LDS) of the incident solar spectrum was orig­inally proposed by Hovel et al.58 in order to overcome the low spectral response in the blue region of the solar spectrum in some types of solar cells. Figure 9.16 (a) A typical down-shifting structure for a CdTe solar cell. (b) A similar structure […]

The characterisation techniques and principal results can be conveniently illustrated on the example of single-dye collectors. Studies carried out so far on the effect of mirrors on the fluorescent collectors indicate that a small air gap between the mirror and the edge of the collector is needed for better collector efficiency39 and any attempt on […]

In this section we introduce a simple characterisation technique based on the absorption and emission spectra of fluorescent collectors used for a spectral-based analysis of the performance of the collectors using the two – flux model outlined in Section 9.2.3. The analysis is based on careful measurements of the edge fluorescence of the collector and […]

9.4.1 Introduction Luminescence solar collectors (LSCs) or concentrators were first introduced in the late 1970s (see, for example ref. 16-20). Following intense research activity in the 1980s, the area has received renewed interest in the past decade or so due to the availability of new materials and the advent of photonics, leading to more optimistic […]

The good overlap of the absorption and emission spectra of the BASF dyes shown in Figure 9.5 forecasts efficient energy transfer in a mixture of these dyes. This will lead to an increase of the absorption efficiency in the dye layer and, at the same time, the emission wavelength can be shifted towards the red […]

The fluorescence spectra and intensities of fluorescent samples are depen­dent on the optical density of the samples and the geometry of fluorescence detection.34 Of particular importance is fluorescence quenching at high dye concentrations, and the fluorescence emitted by the collectors provides a good vehicle how this quenching can be quantified. A simple method is to […]