Sensitivity enhancement of flexible gas sensors via conversion of inkjet-printed silver electrodes into porous gold counterparts

Abstract

This work describes a facile, mild and general wet chemical method to change the material and the geometry of inkjet-printed interdigitated electrodes (IDEs) thus drastically enhancing the sensitivity of chemiresistive sensors. A novel layer-by-layer chemical method was developed and used to uniformly deposit semiconducting single-wall carbon nanotube (SWCNT)-based sensing elements on a Kapton® substrate. Flexible chemiresistive sensors were then fabricated by inkjet-printing fine-featured silver IDEs on top of the sensing elements. A mild and facile two-step process was employed to convert the inkjet-printed dense silver IDEs into their highly porous gold counterparts under ambient conditions without losing the IDE-substrate adhesion. A proof-of-concept gas sensor equipped with the resulting porous gold IDEs featured a sensitivity to diethyl ethylphosphonate (DEEP, a simulant of the nerve agent sarin) of at least 5 times higher than a similar sensor equipped with the original dense silver IDEs, which suggested that the electrode material and/or the Schottky contacts between the electrodes and the SWCNTs might have played an important role in the gas sensing process.

Inkjet-Printing of Nanoparticle Gold and Silver Ink on Cyclic Olefin Copolymer for DNA-Sensing Applications

“…Analysis of the effective surface revealed that the resulting structures are porous. Even though the porosity of the electrodes had no enhancing effect on DNA sensing in this work, other applications (e.g., glucose sensing [45]) may benefit from the relatively simple production process, which can be an attractive alternative to common fabrication methods like dealloying, template based synthesis [45] or chemical conversion of inkjet-printed Ag structures, which leads to only weakly cohesive porous gold [46].…”

Fully Inkjet‐Printed VO2‐Based Radio‐Frequency Switches for Flexible Reconfigurable Components

“…In contrast to the above‐mentioned subtractive technologies, additive manufacturing techniques (inkjet, screen, and 3D printing) offer extremely low cost, completely digital, and highly scalable manufacturing processes . Due to these advantages, additive manufacturing techniques have been used to realize sensors, transistors, RF inductors, RF capacitors, RF filters, RF identification (RFID) tags, and so on. There have only been a few reports on printed RF switches .…”

Organic Flexible Electronics

“…As a result, the NO 2 gas sensors showed good performance with a high sensitivity of ≈96% and recovery time of 30 s when exposed to 60 ppm NO 2 at room temperature. To enhance their sensitivity, the CNTs could be functionalized with conducting polymers that can interact with the target molecules or metal nanoparticles to change the contact resistance between the electrode material and the CNT channel …”