Inks and pastes based on colloidal metal dispersions can be used to print conductive structures. The metal particles often carry an insulating, organic ligand that stabilizes their suspension and must be removed after printing to reduce the resistance^[1]. High-temperature sintering limits the choice of substrates (PET foil, paper) and makes it harder to create flexible devices. Hybrid nanoparticles overcome this problem by combining a metal core with a conductive organic ligand that remains in the material^[2,3]. This yields particle-based inks that can be processed by inkjet printing and become conductive directly upon drying as they form a hybrid film.
Pure hybrid particle films are mechanically soft and prone to scratching. Here, we increase scratch resistance and improve adhesion through the addition of insulating polymers such as poly vinyl alcohol (PVA) to create composites that retain the sinter-free processing of the hybrid and gain the film-forming and adhesive properties of PVA to protect the material. We present data on the properties of composite films inkjet-printed onto PET foil and glass, including scratch resistance tests and adhesion tests using scotch tape and a steel wool tests. The resistivities of the individual structures were determined by a 4-point measurement in combination with confocal microscopy.
We found that small fractions of the additive PVA (5 vol% PVA of a dried line) improve the mechanical properties. For example, a scotch tape test increased the resistances of a pure hybrid structure by the factor 2.5, while that of the composite hardly changed. A PVA content of 5 vol% only slightly influence the resistivity.
References:
[1] K. Ryu, Y.-J. Moon, K. Park, J.-Y. Hwang, S.-J. Moon, J. Electron. Mater. 2016, 45, 312-321.
[2] B. Reiser, L. González-García, I. Kanelidis, J. H. M. Maurer, T. Kraus, Chem. Sci. 2016, 7, 4190.
[3] A. Escudero, L. González-García, R. Strahl, D.J. Kang, J. Drzic, T. Kraus, Inorg. Chem. 2021, 60, 22, 17103-17113.