Light trapping leads to higher-efficient thin-film, flexible solar cells
The EU-funded project DIELECTRIC PV (Advanced light trapping with dielectric micro-particle self-assembled arrays for low-cost and high-performance thin film solar cells) developed a new technique for improving the trapping of light in thin-film Si solar cells based on periodic arrangements of resonant dielectric microparticles (DMPs). The initiative’s main goal was to construct prototype cells that possess enhanced sunlight-to-electricity conversion efficiency due to the action of DMP arrays incorporated on their transparent top contact. Researchers carried out computational modelling using numerical finite difference time-domain software to determine optimal conditions for the best-performing dielectric-based photonic elements. They also analysed in detail the physical mechanisms caused by such elements, which enable substantial light absorption enhancement in thin-film photovoltaic (PV) devices. Additional photonic structures based on plasmonic metal nanoparticles were also explored and shown to lead to light-trapping action for longer wavelengths (near-infrared range). DIELECTRIC PV demonstrated highly promising, low-cost and industrially compatible light-trapping strategies. These have the potential to significantly boost optical absorption in any type of thin solar cell material, allowing greater efficiency and enabling the cells’ thickness to be reduced. Optically thicker but physically thinner PV devices also mean cheaper and faster fabrication as well as improved flexibility, which is crucial for roll-to-roll manufacturing and application to bendable substrates, such as paper and polymers. This can lead to consumer-oriented products like sun-powered intelligent packaging, wearable PVs, portable electronics, building-integrated PVs and light-powered internet of things. The technological breakthrough for thin-film solar cells represented by DIELECTRIC PV will help the EU PV industry to recover its leadership position with new affordable products for the global market, while promoting investment and job creation in Europe.
Keywords
Light trapping, photonic-enhanced solar cells, thin-film, silicon, dielectric microparticles, DIELECTRIC PV
