• Mattila, Tomi
• Kemppainen, Antti
• Alastalo, Ari
• Seppä, Heikki
• Allen, Mark
• Leppäniemi, Jaakko
• Suhonen, Mika

Abstract

Metallic nanoparticle inks and pastes are recognized asan enablingtechnology for printing high-quality conductors onlow-cost, flexiblesubstrates. Conductor grids in optoelectronic devices areexampleapplications, where low metal fill factor and highconductivity aredesired. High conductivity is obtained through sinteringof thenanoparticles, which is typically accomplished by heatingtheprinted structure. However, sintering by oven curing isoftenproblematic due to e.g. shrinking of the printingsubstrate and isgenerally considered an inconvenient process stageespecially in theroll-to-roll (R2R) printing environment, where therequired ovenlengths may exceed tens of meters. As a solution to thistechnological drawback, the rapid electrical sintering(RES) methodhas recently been introduced. In this work, wedemonstrate RESover a constantly moving substrate emulating a R2Rprintingenvironment. The sintering power is focused betweensinteringelectrodes having a lateral spacing of less than 1 mm anda verticalworking distance of 25 ?m from the ink layer on thesubstrate. Gridwiring inkjet printed on a temperature sensitive flexiblesubstrate isefficiently sintered with a sintering power of 6.5 Wacross a 5 mmwide strip. We provide a power budget and relevant systemtolerance limits when upscaling and applying the methodin anindustrial-scale R2R production line. The providedanalysis appliesto a number of large-area electronic applicationsutilizing narrow and highly conducting wiring such asorganic light emitting diode(OLED) lighting panels, photovoltaics (PV), touch screensandbackplane electrodes for displays.

Topics

• nanoparticle
• impedance spectroscopy
• laser emission spectroscopy
• sintering
• curing