The first part of the talk will discuss our recent research in applying photonics to luminescent solar concentrators. Luminescent solar concentrators downshift and concentrate incident sunlight onto edge-mounted solar cells, and the tunability and high quantum yield of semiconductor nanocrystals make them natural candidates as the luminescent material. Our work focuses on the integration of photonic mirrors with LSCs, which reduce losses to the escape cone and redirect the angle of light propagation through the concentrator. We will discuss how the design of the mirrors changes for different luminophores and LSC geometries, and on experimental LSCs that use both Cd-based and Si nanocrystals as the luminescent material.
The second part of the talk will discuss spectrally-selective structures used for light management in photovoltaic modules. These structures are designed to enhance transmission of sunlight above the bandgap of Si to improve photocurrent, and enhance reflection of light below the bandgap to reduce module operating temperature. We will show how the structures change at different interfaces within the module, the importance of designing mirrors that operate under diffuse illumination, and the effect of geographical location on mirror performance. Finally, we show how the mirror performance evolves as a function of number of layers, and that significant energy yield improvements can be realized with less than 10 layers.