Browsing by Subject "Polymer solar cells"

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    A life cycle analysis of polymer solar cell modules prepared using roll-to-roll methods under ambient conditions
    (Elsevier, ) Espinosa, Nieves; García-Valverde, Rafael; Urbina, Antonio; Krebs, Frederik C.; Física
    A life cycle analysis was performed on a full roll-to-roll coating procedure used for the manufacture of flexible polymer solar cell modules. The process known as ProcessOne employs a polyester substrate with a sputtered layer of the transparent conductor indium-tin-oxide (ITO). The ITO film was processed into the required pattern using a full roll-to-roll process, employing screen printing of an etch resist and then applying etching, stripping, washing and drying procedures. The three subsequent layers; ZnO, P3HT:PCBM and PEDOT:PSS were slot-die coated and the silver back electrode was screen printed. Finally the polymer solar modules were encapsulated, using a polyester barrier material. All operations except the application of ITO were carried out under ambient conditions. The life cycle analysis delivered a material inventory of the full process for a module production, and an accountability of the energy embedded both in the input materials and in the production processes. Finally, upon assumption of power conversion efficiencies and lifetime for the modules, a calculation of energy pay-back time allowed us to compare this roll-to-roll manufacturing with other organic and hybrid photovoltaic technologies. The results showed that an Energy Pay-Back Time (EPBT) of 2.02 years can be achieved for an organic solar module of 2% efficiency, which could be reduced to 1.35 years, if the efficiency was 3%.
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    Life cycle assessment of ITO-free flexible polymer solar cells prepared by roll-to-roll coating and printing
    (Elsevier, ) Espinosa, Nieves; García-Valverde, Rafael; Urbina, Antonio; Lenzmann, Frank; Manceau, Matthieu; Angmo, Dechan; Krebs, Frederik C; Física
    Indium is a scarce and expensive material that has been identified as a bottleneck for future organic electronics deployment in large scale. Indium is the main constituent of Indium Tin Oxide (ITO), which is the most successful transparent electrode in organic photovoltaics (OPV) so far. A new process, termed Hiflex, allows for manufacture of flexible OPV modules where the ITO electrode has been replaced by a sputtered Al/Cr electrode in an inverted device architecture with front illumination. This work presents a life cycle assessment of the Hiflex process, in order to compare the environmental impact of avoiding ITO as electrode. The new ITO-free process reduces some of the processing steps, leading to important reductions of the energy input during OPV module manufacturing in comparison to ITO-based modules. The environmental analysis reveals an Energy Pay-Back time (EPBT) of 10 years due to the high-energy consumption of Al/Cr roll-to-roll sputtering and to the relatively low efficiency of the Hiflex OPV modules (E1%). An optimization of the active area fraction could easily reduce the EPBT to E5 years. A further enhancement of the efficiency to 5% would give rise to a promising EPBT of only 1 year. Our work highlights that vacuum processing steps should be avoided.