Electrospray as a Fabrication Tool in Organic Photovoltaics

摘要

Organic photovoltaics (OPV) will play a critical role in achieving ultra-low cost solar cells below the 1 $/W production cost goal. Electrospray is uniquely suited for manufacturing OPVs since it exhibits many desired characteristics of an ideal fabrication process including controllable and monodisperse droplet size, the ability of operating at atmospheric pressure, compatibility with roll-to-roli production processes, and added benefits from the material interaction with the electrical field such as less material loss and self-organized nano structures. In this review, we set the stage with a brief introduction, first describing the fundamental concepts of electrospray, leading into an explanation of its unique properties We then review the effort of applying electrospray in making Polymer Solar Cells (PSC) as well as Dye Sensitized Solar Cells (DSSC). Many results showed the simplicity implementing electrospray for fabrication of PSC which eliminated slow vacuum processes, expensive high purity environments, and the widely used technique of spin coating. So far, the electrospray has been found to improve active layer morphology, and demonstrated the ability to create very high efficiency devices. Finally we discuss the barriers currently limiting electrospray from becoming a feasible technique for large scale industrial production, including challenges related to fabrication a massively multiplexed electrospray device and understanding of the fundamental physics regarding the role of droplet electrical charge upon impact to the substrate and transport phenomenon of aerosols and thin films at the micron level and below.