Functionalization of Printed Metal-Particle Suspensions by Millisecond Thermal Processing.

The global quest towards novel, flexible and low-cost electronic products with functionality far beyond that offered by conventional size-restricted and rigid semiconductor devices, demands a rapid development of advanced material and deposition technology concepts. One of the most promising pathways to realize this ambitious goal is printed flexible electronics (PFE). Over the past years, printing has successfully demonstrated its potential for manufacture of manifold electronic products such as flexible displays, thin-film solar cells, large-area sensors etc. Importantly, by employing bendable, inexpensive media (e.g.: polymer foils, paper-like substrates) and high-throughput roll-to-roll (R2R) processing, a significant reduction of the overall costs associated with electronic device fabrication has been achieved.
Herein, we report on a successful application of ultra-fast millisecond flash lamp annealing (FLA) as a highly-attractive technique for the functionalization of Ag- and Cu-layers screen printed on low-thermal budget PET and paper-like media for e.g. antenna applications. The effect of the FLA parameters (i.e. pulse duration and energy density), on the substrate behavior as well as on the microstructure and electrical response of the as-flashed films was studied. A significant drop of the sheet resistance of the FL-treated layers as compared to the as-printed films was observed for the selected samples. As ms-FLA permits selective, near-surface heating, a damage of the sensitive substrates was avoided. Being highly-efficient (ultra-short), “non-destructive” (suitable for low-thermal tolerance flexible media) and compatible with R2R processing, FLA offers the realization of advanced PFE products.