Metal Alkoxide Inks for High Resolution Electrohydrodynamic Inkjet Printing with Applications in Meta-Optics, Photonics, and Plasmonics

Abstract

Additive manufacturing at the micron and sub-micron scale is a rapidly expanding field with electrohydrodynamic inkjet (EHD) printing proving to be a critical fabrication technique that will enable continued advancement. Increasing the range of materials compatible with EHD printing to create micron and sub-micron scale features is critical to increasing the variety of devices that can be fabricated with this method. Ceramic, semiconducting, and hybrid organic-inorganic materials are essential for meta-optics and micro-electromechanical systems devices and yet these materials are vastly underexplored for applications in EHD printing. A range of novel printing formulations with varying material properties, all containing a titanium alkoxide precursor that is compatible with EHD, are investigated in search of a material capable of achieving high resolution EHD printing objectives. Methods for more efficiently developing novel printing formulations are presented along with optimized TiO2 printing solutions that can consistently produce final printed features on the order of 500 nm; the highest resolution features ever reported for this family of materials and this method. These solutions are used to fabricate functional and representative meta-optical device components. The first additively manufactured, EHD printed and functional mid-infrared meta-optical lens, capable of focusing 5 µm light is presented along with optical device components for hybrid plasmonic bullseye antennae, designed to focus 1530 nm light.