King Abdullah University of Science and Technology continues to advance thin solar films with solar inkjet printing.
Printed organic photovoltaic cells achieve an efficiency of 4.73%.
Super light, thin and flexible photovoltaic cells that they can even “float” on the surface of a soap bubble. We can therefore see in the incredible photograph of the team from King Abdullah University (KAUST), which is working on the new generation of solar organic thin films.
The work, directed by Derya Baran, aims to create a new source of energy for electronic devices where the use of traditional batteries is limited, such as medical biosensors and new robotic skins.
Rather than large batteries or connecting to a power grid, we thought about using ultra-thin and lightweight organic solar cells to harvest light energy, indoors and out.
Until yesterday, these units were manufactured with spiral coating or thermal evaporation, technologies which are not scalable and which limit the geometry of the device. This technology involves the use of a transparent, conductive but brittle and rigid material called indium tin oxide (RO) as an electrode. To overcome these limitations, the team used inkjet printing.
We formulate functional inks for every layer of solar cell architecture.
One of the great innovations added by the KAUST team is the replacement of the ITO. To make the new photovoltaic cells ultra light, the team printed a transparent, flexible and conductive polymer called PEDOT: PSS, or polystyrene sulfonate (3,4ethylenedioxyoxythiophene). And again through the printer, he inserted a layer of organic photovoltaic material (P3HT: O-IDTBR) which catches light and a layer of zinc oxide, sealing the unit with parylene, a flexible protective layer , waterproof and biocompatible.
Inkjet printing is a science in itself. Intermolecular forces inside the cartridge and ink must be overcome to eject very fine droplets from an extremely small nozzle. Solvents also play an important role after the ink is cured, as the drying behavior affects the quality of the film.
After optimizing the ink composition for each layer of the device, the ultralight photovoltaic cells were printed on glass to test their performance. They reached a 4.73% conversion efficiency, breaking the previous record of 4.1% for a fully printed organic cell.
Our results mark a step forward for a new generation of versatile, ultralight and printed solar cells for use as a power source or for integration into implantable medical devices.
More information: kaust.edu.sa