By manipulating light inside solar cells, it is possible to increase their absorption capacity – and thus their efficiency. Various techniques can be used to achieve this, such as employing mirrors that scatter light, forcing it to travel a longer path within the solar cell. The same techniques that help solar cells with absorption actually help LEDs to emit light. This thesis therefore examines the effect of various ‘light management’ techniques on both solar cells and a new class of LEDs that cool themselves by emitting light. These so-called thermophotonic LEDs can theoretically achieve very high efficiencies and could therefore offer future opportunities for more efficient cooling and better recovery of residual heat from, for example, industrial processes. Using numerical models, the thesis identifies the current bottlenecks hindering the realisation of thermophotonic LEDs and outlines a realistic path for both thermophotonic LEDs and ultra-efficient solar cells towards the highest achievable efficiency and power output in practice.
Jasper van Gastel graduated for Master’s degree in physics, focusing on solid state physics and the interaction of light and matter. He graduated cum Laude in 2020 with a Master’s thesis titled: Quasi-ray-tracing Photovoltaic Modelling, in which he studied photon recycling and light trapping in the presence of various absorption-modulating effects around the band edge. During his PhD, supervised by John Schermer, Jasper continued his efforts numerically studying III-V PV cells, and additionally studied LEDs and thermophotonic devices. Lastly, he built measurement equipment for absolute electroluminescence measurements and supervised internship projects aimed at the simulation and development of scattering mirrors based on TPM colloidal particles, as well as characterization of PV cells for monochromatic power conversion. He is currently employed at CoolSem Technologies, where he is working on thermo-mechanical simulations of chip dies and packaging.