Final Results of the European Project Flexcellence Roll to Roll Technology for the Production of High Efficiency Low Cost Thin Film Solar Cells

This paper reports on the final main results of the Flexcellence project. The project was running for 3 years and its goal was the development of equipments and processes for cost-effective roll-to-roll production of high-efficiency flexible thin-film silicon solar cells and modules. All aspects necessary for the successful implementation of the technology could be considered simultaneously and at the end of the project, worldwide level results could be achieved; Indeed, the feasibility of wide web coating of amorphous and microcrystalline layers by roll-to-roll Very High Frequency (VHF) Plasma Enhanced Chemical Vapour Deposition (PECVD) was demonstrated with a new 50cm width VHF PECVD electrode developed during the project, nano-textured substrates with very specific and advantageous optical properties were produced, the three most promising Chemical Vapor Deposition processes for thin film silicon were investigated, solar cells up to 9.8% stabilized efficiency were deposited on low cost plastic substrates and laboratory-scale VHF PECVD reactors, new insulating and conductive inks, new parameters for laser scribing and a better-optimized laser patterning design led to improved series connection process and higher module’s output power. Finally the work made on the encapsulation processes and reliability testing led to significant breakthrough in the field of long-term outdoor stability of flexible modules on plastic foils. Most of these developments were either directly industrially exploited by the partners or subjects of further investigations for commercial use.