User:Judomonster/Luminescent Solar Concentrator

The luminescent solar concentrator (LSC) is a planar, non-imaging concentrator for photovoltaic cells. It can make photovoltaic energy more cost-effective through concentration and spectral conversion of sunlight. The LSC is based on absorption, subsequent re-radiation and trapping of incident light. This concept was originally proposed in the 1976 and attracted much interest in the years to follow. However, material shortcomings limited the performance of the LSC causing the research to decline. The past few years have seen a renewed interest in this type of concentrator due to the availability of novel materials such as inorganic nanostructures.

Functional Principle
A typical LSC consists of a transparent plate, either doped with luminescent centres or coated with a thin, index-matched film containing more concentrated luminescent centres. Light incident on the large face of the concentrator is collected by the luminescent centres in accordance with their absorption spectra and subsequently re-radiated, depending on their luminescence quantum efficiency (LQE). Ideally, a large fraction of the re-emission is trapped within the plate by total internal reflection and ultimately guided to the concentrator edges, where it can be coupled into PV cells. The geometrical ratio between LSC face area and edge area allows for the concentration, while the emission spectrum of the luminescent centres can be spectrally matched to the absorption of the PV cells.

Luminescent centres
Originally, organic dyes were used as the luminescent centres. Novel, inorganic nanostructures, such as quantum dots (QDs) and nanorods (NRs) are advantageous due to their broad absorption and narrow emission spectra, their photo-stability and an appropriate degree of control over their spectral properties during preparation [3]. NRs, in particular, have been found to exhibit less self-absorption and the related losses compared to QDs [4].

Advantages
can enhance the efficiency of photovoltaic (PV) cells in three ways, through concentration of light, spectral shifting and reduced cell heating. LSCs are flat non-tracking devices that concentrate direct as well as diffuse irradiation. This makes them suitable for urban, building integrated applications, where they could substitute conventional building materials, thereby offsetting some of the costs.

Application
The LSC is suitible for building integrated photovoltaics.

Thin-film LSC
The thin-film LSC is a variant.

Stack
A LSC stack can use sunlight more efficiently.