An anonymous reader quotes a report from Phys.Org: Solar cells can now be made so thin, light and flexible that they can rest on a soap bubble. The new cells, which efficiently capture energy from light, could offer an alternative way to power novel electronic devices, such as medical skin patches, where conventional energy sources are unsuitable. Until now, ultrathin organic solar cells were typically made by spin-coating or thermal evaporation, which are not scalable and which limit device geometry. This technique involved using a transparent and conductive, but brittle and inflexible, material called indium tin oxide (ITO) as an electrode. To overcome these limitations, the team applied inkjet printing. “We formulated functional inks for each the layer of the solar cell architecture,” says Daniel Corzo, a Ph.D. student in Baran’s team.
Instead of ITO, the team printed a transparent, flexible, conductive polymer called PEDOT:PSS, or poly(3,4-ethylenedioxythiophene) polystyrene sulfonate. The electrode layers sandwiched a light-capturing organic photovoltaic material. The whole device could be sealed within parylene, a flexible, waterproof, biocompatible protective coating. […] After optimizing the ink composition for each layer of the device, the solar cells were printed onto glass to test their performance. They achieved a power conversion efficiency (PCE) of 4.73 percent, beating the previous record of 4.1 percent for a fully printed cell. For the first time, the team also showed that they could print a cell onto an ultrathin flexible substrate, reaching a PCE of 3.6 percent. The research has been published in the journal Advanced Materials Technologies.
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