Project title: Nanowire energy selective contacts for valley photovoltaics
Host Institution: Technical University of Munich (TUM)
Host Supervisor: Prof. Gregor Koblmüller
Co-host Institution: Ècole Polytechnique de Paris (L’X)
Co-host Supervisor: Prof. Jean-François Guillemoles
Summary project: Currently, leading photovoltaic technologies are reaching their upper theoretical efficiency, which is why new approaches to circumvent this ceiling must be developed. Hot carrier solar cells are one type of 3rd generation photovoltaic devices, which aim to boost the power conversion efficiency by applying two main strategies: 1) inhibiting one of the main loss mechanisms in solar cell absorbers, i.e. thermalization loss, and 2) extracting photo-generated hot carriers with energy selective contacts. Nanostructures offer versatile tools to meet both of these strategies. Their strong quantum confinement inhibits the thermalization loss and has proven to allow the formation of hot distributions. In addition, their geometry favors the implementation of energy selective contacts while maintaining high conductivity for selected carriers.
This project aims to produce a proof of concept for ultrathin nanowire-based energy selective contacts for hot carrier solar cells. Due to the unique properties of nanowires, they can address the key requirements for the design of selective contacts suitable for efficient hot carrier extraction. Advancements in this technology bring new insights about hot carriers in semiconductors and open potential avenues for high efficiency solar cells. This study relies on the strong collaboration between the leading experts in the growth of ultrathin nanowires (< 20 nm) and the advanced opto-electrical characterization of hot carriers in nanostructures. The results of the action are thus expected to provide valuable information on electronic and optoelectronic devices in which hot carriers are part of their operations.