Directive dielectric designs for high efficiency photovoltaics

Solar energy is, together with wind, one of the main sources of renewable energy for the future, mostly coming from of solar cells based on photovoltaics. The technique has rapidly developed over the past decades, resulting in large efficiency increases and tremendous price reduction. But further improvement is needed to meet the demands for the energy transition. In this thesis we present several concepts and designs to achieve this, all based on directive light emission from dielectric nanophotonic structures. In chapter 2 we explain why not only light absorption, but also light emission in an important parameter for efficient photovoltaics. In the following chapters we present different designs that can lead to the described efficiency increases. In chapter 3 and 4 we work with a highly optimized nanophotonic microlens. We first show how this structure can give record directivity, and subsequently combine it with the new wonder material for photovoltaics, mixed halide perovskite, to create a self-optimizing system with even higher directivity. This self-optimization is exploited further in chapter 5 to make solar concentrator that exhibits self-tracking and diffuse light utilization. In the final two chapters we investigate luminescent solar concentrators that make use of directional light emitters and show a great potential for efficiency increase. Overall we show a variety of directive dielectric designs that each can lead to novel device applications.