Low-cost and Flexible Transparent Electrodes Based on Ag–ZTOF (Zn–Sn–O–F) Amorphous Composites Through Ink-jet Printing

Sn-doped In2O3 (ITO) is the industry standard and most widely used transparent conducting electrode (TCE) because of its good electrical and optical properties. However, ITO has a number of disadvantages: ITO is not a suitable TCE for next-generation, high-efficiency, flexible OLEDs, because of its inappropriate work function, difficulty in creating desired patterns, low stability, delaminantion due to fracturing on flexible substrates, high cost, and the need to process at high temperatures, which limits the high speed manufacture of integrated ITO substrates. Therefore, there is a critical need to develop low-cost TCE as an alternative to ITO for next-generation OLEDs. The US Department of Energy’s (DOE) TCE 2020 cost-target is <$8/m2, with a sheet resistance of <10 ohms/sq, and a transmittance of >90% at 550 nm. Currently, ITO used as the conventional TCE costs >$20/m2. Hazen, in collaboration with NREL, proposes to demonstrate low-cost (indium free) TCE based on silver metal–zinc tin oxyfluoride (Ag–ZTOF) amorphous composites using novel metal–organic (MO) precursors through inkjet printing (IJP) and low-temperature processing. IJP is a contactless, direct patterning process ideal for depositing TCE as a roll-to-roll (R2R) process. Our proposal combines innovations in materials, chemistry, and deposition methods to develop low-cost TCE applicable to many advanced technologies. The Hazen–NREL team will perform the following tasks: (1) Develop and demonstrate Metal-Organic (MO) precursors for Ag–ZTOF composite films; (2) Demonstrate spin-coated Ag–ZTOF composite films processed at <325°C with a sheet of resistance of <10 ohms/sq, and a transmittance of >90% at 550 nm; and (3) Demonstrate IJP of Ag–ZTOF composite films on flexible substrates with the same electrical and optical properties, and perform cost–modeling to show viabilityfor<$10/m2 production.