Research Interests

Light-Harvesting

The term ”light-harvesting” describes the process occurring in photosynthesis which enhances the absorption cross-section of the photosynthetic reaction complex by excitation energy transfer, often called resonance energy transfer. The proposed research aims to develop a light-harvesting framework as a means of sunlight energy collection with application towards the photosensitisation of silicon solar cells. Previous experimental results have revealed the existence of a similar energy transfer mechanism between a molecule and a semiconductor, as demonstrated by the quenching of molecular fluorescence in proximity to silicon for Langmuir-Blodgett (LB) films. We use Time-Resolved Fluorescence Spectroscopy and Fluorescence Lifetime Imaging Microscopy on the light-harvesting structures to determine energy transfer and photon collection efficiencies.

Relevant publications

• Efficient triplet exciton phosphorescence quenching from a rhenium monolayer on silicon. Journal of Materials Chemistry C (2024)
• Silicon photosensitisation using molecular layers. Faraday Discuss. 222, 405–423 (2020).
• Light harvesting in silicon(111) surfaces using covalently attached protoporphyrin IX dyes. Chem. Commun. 53, 12120–12123 (2017).

Silicon Surface Chemistry

Silicon photosensitisation using light-harvesting structures represents an attractive solution for reducing the amount of semiconductor material needed by up to two orders of magnitude in the manufacture of solar cells. The direct covalent attachment of alkyl layers and chromophores on the silicon surface offers exciting chemistry that combines the efficient optical absorption of dye molecules with the excellent electronic properties of thin silicon converters. The above approach divides the photovoltaic conversion process into two processes: an energy collector (light-harvesting), which absorbs light with a high optical absorption cross-section and transfers energy to a semiconductor converter (silicon) that efficiently separates the photo-generated charges and produces electricity. The resulting organic-inorganic structure presents a step-change in thinking about photovoltaic energy conversion.

Relevant publications

• Danos, L. et al. Silicon photosensitisation using molecular layers. Faraday Discuss. 222, 405–423 (2020).

Luminescent Solar Concentrators

This area of research involves the development of Luminescent Solar Concentrators (LSC) and Luminescence Down Shifting (LDS) structures for efficient spectral management and light trapping in solar cells for indoor and outdoor applications. An LSC usually consists of a flat plate, doped with a luminescent species, which absorbs the incident sunlight (direct or diffuse). A large fraction of the emitted light is then trapped within the collector by total internal reflection (TIR) and is directed to a solar cell at the edge of the collector where the remaining edges of the collector can be covered by mirrors.

Relevant publications

• Parel, T. S. et al. Modelling and experimental analysis of the angular distribution of the emitted light from the edge of luminescent solar concentrators. Opt. Mater. (Amst). 42, 532–537 (2015).
• Parel, T. S. et al. Modeling photon transport in fluorescent solar concentrators. Prog. Photovoltaics Res. Appl. 23, 1357–1366 (2014).
• Danos, L. et al. Chapter 9. Photon Frequency Management Materials for Efficient Solar Energy Collection. in RSC Energy and Environment Series No. 12 Materials Challenges: Inorganic Photovoltaic Solar Energy (ed. Irvine, S. J. C.) 297–331 (Royal Society of Chemistry, 2014). doi:10.1039/9781849733465-00297.
• Danos, L. et al. Increased efficiencies on CdTe solar cells via luminescence down-shifting with excitation energy transfer between dyes. Sol. Energy Mater. Sol. Cells 98, 486–490 (2012).

PhD Supervision Interests

A range of projects are available and we welcome applications from self-funded students or from students seeking external funding. • Development of Light-Harvesting Structures for Efficient Solar Energy Collection. • Photonic Luminescent Solar Concentrator. • Photophysics of Energy Materials. • Silicon Photosenistisation.