Affordable electricity by thin-film solar cells
Researchers around the world have long been trying to develop low-cost solar cells in a bid to make solar power affordable on a large scale. Such solar cells ought to be both highly efficient and easy to manufacture with high throughput. An EU team within the INDUCIS (Development and industrial implementation of cost effective advanced CIGS photovoltaic technologies) project exploited the potential of CIGS-based solar cells for achieving high-efficiency photovoltaic devices together with that of electrodeposition for low-cost manufacturing on a commercial scale. Intense competition among different photovoltaic technologies is evident on the market, and EU researchers need to figure out how to secure a competitive edge in thin-film technologies, which are currently mainstream. Detailed characterisation of the electrodeposition process and identification of the main efficiency loss mechanisms in such cells performed by the INDUCIS team can help towards achieving this aim. Researchers demonstrated new and simple methodologies suitable for online chemical assessment of CIGS absorber layers. The gallium to indium and sulfur to selenium content ratios on the absorber surface determine the bandgap of the CIGS layer, the open-circuit voltage and, last, the conversion efficiency of the solar module. Newly developed monitoring methodologies based on the combined use of multiwavelength Raman and photoluminescence spectroscopies enabled the team to assess selective deposition of materials on different device layers: window, buffer and absorber. Lastly, researchers introduced new light scattering methodologies for in-situ monitoring of the electrodeposition process in real time. These included Raman scattering analysis of the electrolytic baths and techniques for controlling the growth of the electrodeposited layer. High efficiency and low cost of photovoltaic devices are vital to accelerate the development and deployment of low-carbon technologies. CIGS electrodeposition improves efficiency and material utilisation. It can decrease manufacturing costs of solar modules and make solar electricity affordable to all as it has the potential to be fabricated in a continuous roll-to-roll process.
Keywords
Electricity, thin film, solar cells, CIGS, electrodeposition, INDUCIS, photovoltaic