A method of printing both decorative graphics and functional components onto flexible organic solar panels is aiming to bring solar energy into the realm of interior design. VTT Technical Centre of Finland is behind the new process which allows energy to be collected from interior lighting as well as sunlight to power small devices and sensors.

The process sees organic solar panels mass produced using the roll-to-roll method at a rate of up to 100 meters of layered film per minute. VTT's Research Team Leader Tapio Ritvonen says the process uses one rotary screen printing layer and two gravure printing layers on plastic substrate. Functional layers are printed between plastic foils, with a final step of encapsulation with barrier films.

The organic solar panels are just 0.2 mm thick including the electrodes and polymer layers where the light is collected. They can be placed on interior or exterior surfaces such as windows and walls, as well as on machines or devices, opening up possibilities for solar panels to be not only functional but also works of art.

The researchers tested the process by printing leaf-shaped photovoltaic cells, two hundred of which create one square meter of active solar panel surface. This was shown to generate 3.2 amps of electricity with 10.4 watts of power at Mediterranean latitudes.

Although they are cost-effective to produce, have low material consumption and are flexible, light and recyclable, organic solar panels have much lower efficiency than conventional, rigid silicon-based solar panels. To improve efficiency the researchers are also working on roll-to-roll manufacturing methods for perovskite solar panels with promising results: the first solar cells manufactured in their laboratory have roughly five times better performance than organic photovoltaic cells.

Source: VTT

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