Luminescent solar concentrators: the road to low-cost energy from the sun

摘要: Photovoltaics (PVs) enable conversion of solar light into electricity without detrimentally affecting the environment. Unfortunately, cells require high-cost semiconductors, which makes them expensive. Concentrator systems help to minimize coverage needed, but normal concentrators only work for a narrow angular range radiation. Moreover, they need tracking devices and are poorly suited capturing diffuse Luminescent (LSCs) avoid these disadvantages.1, 2 An LSC consists glass or plastic plate containing coated with luminophores (dyes phosphors) that absorb sunlight emit at longer wavelengths (see Figure 1). A substantial part longer-wavelength is trapped by total internal reflection guided edges plate, where it absorbed small-area PV cells. The idea using LSCs already dates back 30 years,3, 4 much research has been carried out in this area.5–8 However, up now, technology not delivered on its promise. Although theoretically concentration could be huge,1, 9 best LSC-based system date10 efficiency 7.1% saves factor 2.5 PV-cell area. reason low numbers primarily losses various kinds. For example, luminophore, no luminescent emitted because limited quantum (QE), i.e., ratio number photons. Another important means loss escaping from concentrator angles larger than critical angle One effective way prevent applying wavelength-selective filter top guide,1, 11, 12 keeps inside. 1. (left) (dots) absorbing (dashed) emitting (solid line) photovoltaic (PV) cell. (right) plates towards edges. (Photo courtesy P. C. Verbunt.)