Tom Veeken

I am currently a Ph.D. student in the Photonic Materials group, led by Prof. Albert Polman, in the Center for Nanophotonics at AMOLF (Amsterdam, The Netherlands). My work focuses on the theory, fabrication and characterization of photonic nano- and microstructures for spectrum-splitting in novel photovoltaic architectures. The goal of my work is to surpass the Shockley-Queisser efficiency limit by integrating a photonic spectrum-splitting structure into a multi-junction solar cell system.

In my research, I investigate different approaches to photonic spectrum-splitting from a theoretical and numerical simulation perspective. A tapered asymmetric thin-film waveguide proved to be the most versatile approach, which I then fabricated and characterized.I am now working on the demonstration of spectrum-splitting by this tapered waveguide geometry – a confocal microscope and optical transmission spectroscopy are used to quantify the spatial separation of the outcoupled spectrum. Subsequently, the tapered waveguide is integrated into a parallel-stacked multi-junction system.

In parallel, I investigate the directional emission of quantum dots in singlet fission solar cells developed in Bruno Ehrler’s group at AMOLF. Excitons created in the singlet fission top layer are transferred to quantum dots, where they decay radiatively. In this project, I model the dipolar-like emission of the quantum dots as a function of their near-field environment by means of Green’s function calculations and numerical simulations. I then design (resonant) optical nanoantennas to carefully design the LDOS surrounding the quantum dots, therewith steering the emission towards the underlying silicon solar cell.

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