Laser-induced forward transfer: a digital approach for printing devices on regular paper

Abstract

Inkjet printing (IJP) is the most widespread direct-write technique in paper electronics. However, its use is limited, since its low-viscosity nano-inks leak through the cellulose fibers. Thus, a planarization coating is frequently used as barrier, despite that this makes substrates more expensive and less ecofriendly. Alternatively, high solid content screen printing (SP) inks could allow printing on regular paper due to their high viscosity and their large particle size; however, they cannot be printed through IJP. Another digital technique is required: laser-induced forward transfer (LIFT). The aim of this work is to prove the feasibility of LIFT for printing devices on regular paper. The main transfer parameters are systematically varied to obtain uniform Ag-SP interconnects, which performance is improved by a multiple-printing approach, resulting in low resistances with a much better performance than those typical of IJP. After optimizing the printed lines functionality, a proof-of-concept consisting on a radio-frequency inductor is provided. The characterization of the device shows a substantially higher performance than that of the same device printed with IJP ink in similar conditions, which proves the potential of LIFT for digitally fabricating devices on regular paper.