Optimisation of Luminescent Downshifting Layers for Large-scale PV Systems Integration

Abstract

This research project aims to enhance Photovoltaic (PV) technology's power conversion efficiency by adding a Luminescent Downshifting Layer (LDS). An LDS increases the solar spectrum absorption range of a PV cell, enabling better integration into residential and commercial buildings. The LDS layer enhances photon interaction with the PV cell, which increases power conversion efficiency. The project focused on fabricating an LDS layer for silicon PV cells to boost their interaction with the solar spectrum. Subsequently, these LDS-PV cells were integrated into different systems, thus improving overall efficiency. The aesthetic appeal of LDS layers, available in various colours, can increase their desirability for building façades without compromising building functions. Luminescent dyes of different concentrations and thicknesses were tested and optimised in LDS layers, transparent polymers doped with luminescent dye applied to solar cells using a spin coating technique. These optimised LDS layers increased the solar cell power conversion efficiency. As part of the larger EU project IDEAS, these LDS-layered PV cells were integrated into a Compound Parabolic Concentrator (CPC) system and tested under actual weather conditions in Ferrara, Italy, and County Mayo, Ireland. The LDS layer, integrated into a CPC system, produced over 100 W during peak exposure compared to 60 W from a commercial PV panel. These LDS-layered systems demonstrated integration into a completely renewable energy system, including heat pump-powered underfloor heating and AI-controlled operation unit. Simulations identified optimal luminescent dyes and their concentrations for the LDS layer tailored to specific PV cells. Lumogen Violet was most suitable for enhancing silicon solar cell efficiency. Due to supply issues, methyl orange from Sigma Aldrich was used, showing potential efficiency enhancement as a 20 μm thick LDS layer. This layer expanded the wavelength range for PV system interaction with the light spectrum. The LDS's viability was also assessed for different PV devices, including silicon, a-si, and CdTe, showing broad applicability across various PV technologies. After successful LDS applications to PV cells, Plasmonic LDS(pLDS ) layers that is, LDS layers with metal nanoparticle enhancement, were fabricated and tested. The pLDS layers experienced lower power output, prompting further reassessment for development.