(Invited) 3D Conformal Additive Printing of Semiconducting Nanocrystals for Energy Harvesting and Biosensing

Abstract

Semiconducting nanocrystals have been widely studied in the past two decades with unique and superior energy conversion and sensing properties compared to their bulk form. However, there is still a prominent need to transform the nanocrystals into functional devices in a scalable and low-cost manufacturing process and translate their unique properties from nanoscale to meso- or macro- scale. This work explores a novel 3D conformal aerosol jet printing approach to convert a wide range of nanocrystals into flexible and functional devices for energy harvesting and biosensing. Solution-processed chalcogenide nanoplate inks have been synthesized and printed into flexible thermoelectric energy harvesters, which yield competitive figure of merit ZT values comparable with their rigid bulk counterparts fabricated by conventional method. A flexible thermoelectric device is demonstrated with high power density of 19 mW/cm2 and 1 mW/cm2 with 80 K and 20 K temperature difference respectively. In addition, we have utilized biocompatible 2D nanomaterial inks and printed complex device patterns on 3D curved substrates and soft materials (e.g. hydrogel) for biosensing. The printed sensors can be used as bioelectrodes, temperature sensing, strain sensing, etc. The printed energy harvester and bio-sensors can be integrated into a self-powered wireless sensor system, which can completely eliminate the need of external power supply and greatly facilitate the implementation of these sensors. The 3D conformal aerosol jet printing of colloidal nanoparticle inks demonstrated here opens up exciting opportunities to transform semiconducting nanocrystals into functional and flexible devices for broad energy harvesting and sensing applications.