Luminescent Solar Concentrators (LSCs) are a versatile device that shows potential for a simple and diverse solution for aesthetically pleasing photovoltaic integration. The device is comprised of polymer sheets, doped with fluorophores such a fluorescent dye, quantum dots or rare earth materials. Incident light is absorbed by the fluorophores and reemitted at a longer wavelength. Some of this reemitted light is then trapped within the polymer, and wave guided towards the edges, where it is collected at the edges by attached photovoltaic panels.

Applications range from large scale; Building Integrated Photovoltaics (BIPV) such as windows, walls or roadside barriers, mid-scale; such as window blinds, tent or boat sails, through to small scale applications such as wearable technologies, watch straps or furniture.

Theory

We have explored the fundamental limits in performance of LSCs (Papakonstantinou and Tummeltshammer, 2015), alignment of fluorophores and energy transfer (Tummeltshammer et al., 2014, 2016), to pursue a better understanding of the possibilities for highly-efficient LSCs.

Simulation

The group has developed a Monte-Carlo Raytracing model allowing for accurate and efficient modelling of the device. Simulation allows for easy optimisation of devices saving resources and time, as well as exploring possibilities for the technologies expansion. The model outputs the devices efficiency as well as showing expected losses. This has been further combined with FDTD to create a hybrid model that can model from nano to macro scale devices, allowing us to explore the use of plasmonic LSCs (Tummeltshammer et al., 2013).

Fabrication

Our group has facilities for in house fabrication of LSCs, both rigid and flexible (Clemens Tummeltshammer et al., 2016). With the help of collaborators from both within and outside UCL we aim to develop LSCs with highly efficient state-of-the-art fluorophores.

 

Characterisation

We have the expertise and facilities for effectively characterising the efficiencies of LSCs. Our published methods (C. Tummeltshammer et al., 2016) allow for us to determine how much each loss mechanism is affecting the efficiency, allowing for us to build innovative solutions to reduce these losses in the future.

Publications

• Portnoi, M., Sol, C., Tummeltshammer, C., & Papakonstantinou, I. (2017). Impact of curvature on the optimal configuration of flexible luminescent solar concentrators. Optics Letters, 42(14), 2695–2698. https://doi.org/10.1364/OL.42.002695

• Tummeltshammer, C. et al. On the Ability of Förster Resonance Energy Transfer to Enhance Luminescent Solar Concentrator Efficiency. Nano Energy (2016). doi:10.1016/j.nanoen.2016.11.058

• Tummeltshammer, C., Taylor, A., Kenyon, A. J. & Papakonstantinou, I. Flexible and fluorophore-doped luminescent solar concentrators based on polydimethylsiloxane. Opt. Lett. 41, 713–716 (2016).
• Papakonstantinou, I. & Tummeltshammer, C. Fundamental limits of concentration in luminescent solar concentrators revised: the effect of reabsorption and nonunity quantum yield. Optica 2, 841–849 (2015).
• Tummeltshammer, C., Taylor, A., Kenyon, A. J. & Papakonstantinou, I. Losses in luminescent solar concentrators unveiled. Sol. Energy Mater. Sol. Cells 144, 40–47 (2015).
• Tummeltshammer, C., Taylor, A., Kenyon, a J. & Papakonstantinou, I. Homeotropic alignment and FRET : the way to a brighter luminescent solar concentrator. J. Appl. Phys. 173103, 1–7 (2014).
• Tummeltshammer, C., Brown, M. S., Taylor, A., Kenyon, A. J. & Papakonstantinou, I. Efficiency and loss mechanisms of plasmonic Luminescent Solar Concentrators. Opt. Express 21, A735--A749 (2013).

Funding

• EPSRC Doctoral Training Award. (2015-2018)
  
• UCL BEAMS School PhD Impact Award. (2012-2015)
  
• EU FP7 programme, Marie-Curie Career Integration Grant, No. 293567. “SOLAR-PLUS, Maximizing the efficiency of Luminescent Solar Concentrators by implanting resonant plasmonic nanostructures”. (2011-2015)