Investigation of carrier multiplication in van der Waals heterostructures for highly efficient solar cells

Presently, the two-dimensional (2-D) crystals and their van der Waals heterostructures (vdWHs) are attracting a lot of attention from the scientific community due to the unique features that they offer such as the possibility to widely tune their band gap, study strong light-matter interactions at the ultimate thickness limit.

These features are of great relevance for the light harvesting applications as in photodiodes and photovoltaic cells. In this project, we propose to optimise the (opto-)electrical and photovoltaic behaviours of these components.

The state-of-the-art ab-initio quantum transport solver relying on the density-functional theory and the Non-Equilibrium Green’s Function formalism will be employed to simulate the I-V characteristics of single- and multiple-junction vdWHs as well as their optoelectronic and photoresponse properties.

Electron interactions with phonons and photons will be taken into account to ensure very accurate performance predictions.

The validity of our models will be tested by comparing our results for vdWH-based devices with experimental data from our collaborators. These results will advance our understanding of the light-matter interaction in the atomistic scale vdWH junctions.

We will then investigate whether the innovative idea of using the inter-layer carrier multiplication will lead to significant improvement of the light conversion efficiency of the photovoltaic cells.

Novel vdWH-based superlattice photovoltaic cells will be designed and optimised with the precisely calibrated atomistic simulator.

The most promising device configuration will serve as reliable design guidelines for our experimental collaborators so that the designed devices can be manufactured and characterised.

This project aims to significantly increase the light conversion efficiency of vdWH-based solar cells by enabling the cascade inter-layer carrier multiplication.