Spectral conversion for thin film solar cells and luminescent solar concentrators

Full spectrum absorption combined with effective generation and collection of charge carriers is a prerequisite for attaining high efficiency solar cells. Two examples of spectral conversion are treated in this chapter, i.e., up-conversion and down-shifting. Up-conversion is applied to thin film silicon solar cells and efficiency improvements using lanthanides as up-converter material under monochromatic as well as broadband light are presented. Down-shifting is demonstrated in luminescent solar concentrators, and material issues hampering efficiency improvements are discussed, in particular re-absorption of light emitted by luminescent species. A new class of semiconductor hetero-nanocrystals is shown to be an excellent candidate for surpassing the 10% luminescent solar concentrator efficiency barrier