Silicon (Si)-based photovoltaic (PV) devices can now be seen on rooftops and solar farms across Europe, yet widespread implementation is hindered by costs and limits in efficiency. The EU-funded project 'Nanomaterials and nanotechnology for advanced photovoltaics' (NANOPV) addressed current bottlenecks in production with large-scale processes and equipment for production of PVs from nanomaterials. The consortium studied a large variety of such materials from zero-dimensional quantum dots, nanocrystals and nanoparticles, to 1D nanowires and nanorods and even 2D ultra-thin nanolayers. In addition to materials' development to enhance efficiency, scientists developed cost-effective large-scale processes and equipment for integration into existing pilot and industrial production lines. Nanomaterials can significantly enhance efficiencies by making better use of the electromagnetic spectrum, taking advantage of a broader range of available wavelengths. More than 20 % energy conversion efficiency was targeted for wafer-based Si devices and more than 15 % for epitaxially grown thin-film Si solar cells. Scientists also assessed low-cost solar cells produced entirely from nanomaterials. Of the more than 50 materials tested, 9 were integrated in wafer-based Si devices and 11 in thin-film Si solar cells. Enhanced conversion efficiency was seen in some cases. A database of the most promising candidates has been created and several were chosen for optimisation within the project. For instance, the team optimised fabrication of solar cells with Si nanorod/nanowire structures. This resulted in thin film solar cells of high efficiency (10 %) that can be produced cost effectively at industrial scale. In addition, incorporation of Si-based nanolayers into Si-based solar cell structures resulted in high conversion efficiency for both wafer-based (> 20 %) and epitaxially grown thin-film (~ 15 %) architectures. NANOPV demonstrated the feasibility of high-efficiency, low-cost PV devices using nanomaterials. The project has contributed to development of a safe, cost-effective and sustainable energy supply with technologies that will enhance the competitive position of the EU in a market poised for a major breakthrough.
Solar cells, silicon, photovoltaic, nanomaterials, nanowires, nanorods