University of Louisville,
Keywords: intense pulsed light, roll to roll, thin film
Summary:The Intense Pulsed Light (IPL) technology is well suited to continuous manufacturing platforms such as roll-to-roll due to its very large processing area and rapid processing time scales. The IPL technique delivers high energy pulses of broad spectrum light (UV-Vis-NIR) in a very short duration (ms) over a large processing area (cm2). Photosensitive materials within depositied thin films absorb the light and this energy is immediately released and can both initiate chemical reactions and thermal processes. The deposition of the thin films can simply be accomplished using traditional solution phase depositions of inks, which is aided by the use of nanomaterials. The nanomaterials are convenient for the formation of thin films of varying morphologies and are amenable to several solution phase deposition processes spanning a range of viscosities. The nanomaterials are also important as they can reduce the energy required to initiate sintering of inorganic materials. The absorption of the light is limited within the thin film and as such the high temperatures are not transferred to the underlying substrate. In the past few years, the method has found a number of applications within the flexible electronics industry as printed structures for wire traces, transparent conductors and RFID. Our group has extended the IPL process beyond the traditional use of single metal conductors into more functional multi-metal structures, metal oxides, mixed metal oxides and complex materials containing components with low sublimation temperatures. Applications for these materials include optically transparent conductors, absorbers for electricity generation, 3-D printed ceramics and other electronic materials critical to the renewable energy devices. In this talk, the IPL technique will be described and results of the densification by IPL of nanomaterials deposited using traditional solution phase deposition techniques will be presented. The results include models of the chemical and thermal response within the film/substrate as well as morphology changes observed by XRD, SEM, TEM UV-Vis and TGA. Finally these films will be demonstrated in functional devices. The talk concludes with the discussion of how the IPL process fits into a roll-to-roll manufacturing scheme. Dharmadasa, R., B. Lavery, I. M. Dharmadasa and T. Druffel, Intense pulsed light treatment of cadmium telluride nanoparticle-based thin films. ACS Appl Mater Interfaces, 2014. 6(7): p. 5034-40. Draper, G. L., R. Dharmadasa, M. E. Staats, B. W. Lavery and T. Druffel, Fabrication of Elemental Copper by Intense Pulsed Light Processing of a Copper Nitrate Hydroxide Ink. ACS Appl Mater Interfaces, 2015. 7(30): p. 16478-85.