Printing solar cells by electrospray
Recent advances in solution processible thin film solar cells are amazingly fast, with records of power conversion efficiencies constantly being refreshed. These high performance solar cells rekindled researchers’ dream of printing solar cells in a continuous roll-to-roll fashion like printing newspapers. However, conventional spray and inkjet printing technology produces droplets of at least ten microns in diameter, which are too large for the 100 nm film thickness required for modern photovoltaics. Electrospray is a unique atomizing technology that can generate uniform sub-micrometer size droplets. In fact, the superior capability of generating charged droplets in the nanometer range helped Prof. John B. Fenn at Yale University to pioneer the electrospray ionization mass spectroscopy (ESI-MS) that eventually brought him the Nobel Prize in Chemistry in 2002. The breakthrough of multiplexed electrospray eliminates the doubt of scalability of this emerging printing/deposition technology. Therefore, electrospray has caught researchers’ attention as a superior printer head for creating the films of nanometer range in the most advanced solar cells.
Electrospray is a promising tool for making thin film solar cells owning to
its ability of generating scalable, tunable sub-micrometer droplets
Prof. Xinyan Zhao and Prof. Weiwei Deng from Southern University of Science and Technology (SUSTech) reviewed the recent progress in electrospray printing solution processible photovoltaics (PV). Electrospray is uniquely suited for fabricating PVs due to its several desirable characteristics of an ideal manufacturing process such as compatibility with roll-to-roll production processes, tunability and uniformity of droplet size, capability of operating at atmospheric pressure, and negligible material waste. The review begins with an introduction of the fundamentals and unique properties of electrospray. The evaporation time and residence time are emphasized because they jointly affect the deposition outcome. Efforts of electrospray printing polymer solar cells, perovskite solar cells, and dye sensitized solar cells are subsequently reviewed. Collectively, these results demonstrate the advantages of electrospray for solution processed photovoltaics. Electrospray also exhibits the capability of producing uniform films as well as nanostructured and even multiscale films. So far, the electrospray has been found to improve active layer morphology, and create devices with efficiencies comparable with that of spin-coating. The authors also discussed challenges and research opportunities that enable electrospray to become a mainstream technique for industrial scale production.
About The Group
The research group of Prof. Weiwei Deng focuses on the fluid dynamics of low-dimensional liquid subjects (droplets, jets, and films) and their applications in additive manufacturing, especially the printing and deposition of advanced materials. Dr. Weiwei Deng is a Professor in the Department of Mechanics and Aerospace Engineering at the Southern University of Science and Technology (SUSTech). Prior to joining SUSTech, he was a tenured associate professor at Virginia Tech (2015-2017) and an assistant professor at the University of Central Florida (2010-2015). He received his Ph.D. in Mechanical Engineering from Yale University in 2008 and B.S. from Tsinghua University in China. His group’s work has been featured as the cover article of Physical Review Letters and Soft Matter. He is the recipient of National Science Foundation CAREER Award.
Zhao X Y, Deng W W. Printing photovoltaics by electrospray. Opto-Electron Adv 3, 190038 (2020).