Lefteris’s research focuses on photovoltaics and solar energy conversion, with emphasis on light-harvesting and photon management structures for enhanced performance. He investigates ultra-thin film organic architectures to improve light absorption and solar energy utilisation. His work involves time-resolved spectroscopy to study photophysical processes, as well as silicon surface chemistry to engineer interfaces for enhanced device performance. He develops spectral management techniques to tailor the solar spectrum, integrated into existing photovoltaic technologies. These strategies aim to enhance the performance and reduce the cost of solar electricity, contributing to the development of sustainable and affordable energy solutions.

Recent Publications

• Photosensitised silicon solar cell: Progress and challenges. Chem. Commun. DOI: 10.1039/D5CC02567B. (2025)
• 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).

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.

Light-Harvesting 

The term light-harvesting refers to the photosynthetic process that enhances the absorption cross-section of the reaction centre via excitation energy transfer, often described as resonance energy transfer. This research aims to develop a light-harvesting framework for efficient solar energy collection, with a focus on the photosensitisation of silicon solar cells. Previous experiments have shown similar energy transfer mechanisms between molecules and semiconductors, as evidenced by fluorescence quenching near silicon surfaces in Langmuir-Blodgett (LB) films. We use time-resolved fluorescence spectroscopy and fluorescence lifetime imaging microscopy to assess energy transfer dynamics and photon collection efficiencies in these structures.

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 onto the silicon surface enables the combination of efficient optical absorption by dye molecules with the excellent electronic properties of thin silicon converters. This strategy separates photovoltaic conversion into two functions: a light-harvesting unit with a high absorption cross-section, and a silicon converter that efficiently separates photo-generated charges and produces electricity. The resulting organic–inorganic architecture represents a paradigm shift in 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 focuses on the development of Luminescent Solar Concentrators (LSCs) and Luminescence Down Shifting (LDS) structures for efficient spectral management and light trapping in solar cells, applicable to both indoor and outdoor environments. An LSC typically consists of a flat plate doped with a luminescent species that absorbs incident sunlight, whether direct or diffuse. A significant portion of the re-emitted light is trapped within the plate by total internal reflection (TIR) and guided toward solar cells positioned along all edges of the collector, maximising the capture and conversion of the guided photons.

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).