Roll-to-roll manufacturing of organic photovoltaic modules

Organic photovoltaics are being explored for powering electronic devices by harvesting the sun's energy or indoor lighting. Such solar cells have shown promise as they can be deposited on thin flexible foils that enable flexibility of integration within products while keeping the weight light. Several R&D efforts are underway in creating improved organic solar cells in terms of their efficiency and other performance metrics. One such is the FACESS project (ldquoFlexible Autonomous Cost Efficient Energy Source and Storagerdquo), funded under the 7th Framework Programme of the European Commission. The main goal is to develop economically viable solar cells on large scale for mass production to achieve the power conversion efficiency (PCE) up to 2.5% thus producing 250 mW under AM1.5 illumination. This requires selection, modification and up-scaling of suitable solar cell materials, effective patterning technologies, development of the printing processes and improved encapsulation technologies. This development will be done keeping all the time the application, the potential and the required performance in mind. The development and experimental results of roll-to-roll techniques such as wet chemical etching of an anode electrode, gravure printing of PEDOT:PSS and the P3HT:PCBM photoactive layer and gas barrier lamination of the printed modules will be presented in detail. The performance status for lab-scale printed solar cells is currently 2.4% of PCE under AM1.5 illumination. In addition the major technological challenges and solutions for roll-to-roll manufacturing will be summarised.