Beyond Color: The New Carbon Ink

Abstract

For thousands of years, carbon ink has been used as a black color pigment for writing and painting purposes. However, recent discoveries of nanocarbon materials, including fullerenes, carbon nanotubes, graphene, and their various derivative forms, together with the advances in large‐scale synthesis, are enabling a whole new generation of carbon inks that can serve as an intrinsically programmable materials platform for developing advanced functionalities far beyond color. The marriage between these multifunctional nanocarbon inks with modern printing technologies is facilitating and even transforming many applications, including flexible electronics, wearable and implantable sensors, actuators, and autonomous robotics. This review examines recent progress in the reborn field of carbon inks, highlighting their programmability and multifunctionality for applications in flexible electronics and stimuli‐responsive devices. Current challenges and opportunities will also be discussed from a materials science perspective towards the advancement of carbon ink for new applications beyond color.

Cleanly Removable Surfactant for Carbon Nanotubes

“…This strategy works even for nanotubes of small diameters (∼0.78 nm), which are susceptible to thermal oxidation at elevated temperatures. This work provides new insights for the choice or design of surfactants in applications such as electrical sensors, , printable electronics, , and optoelectronics where the clean removal of the surfactant after solution processing is key to enhanced device performance.…”

“…Single-walled carbon nanotubes (SWCNTs) are a family of cylindrical carbon allotropes that exhibit extraordinary electrical, optical, and mechanical properties. 1−3 Because these carbon nanomaterials are synthesized as a heterogeneous mixture of different structures that bundle strongly, polymers 4−8 and surfactants, 9−11 such as sodium dodecyl sulfate (SDS) and sodium deoxycholate (DOC), are widely used to disperse SWCNTs in solution for subsequent purification, 12 fiber spinning, 13 ink formulation, 14 and the fabrication of highperformance nanoelectronic devices. 10 However, after solution processing, surfactants become unwanted contaminants.…”

Self-Powered Carbon Ink/Filter Paper Flexible Humidity Sensor Based on Moisture-Induced Voltage Generation

“…Due to many advantages such as good electrical conductivity, high chemical and thermal stability, and light weight, many carbon materials, including graphene, graphene oxide (GO), and carbon nanotubes (CNTs), are widely used as humidity-sensitive materials. − Xiaoyu Li et al reported a novel high-performance humidity sensor based on graphene oxide/multiwalled carbon nanotubes, and the synergistic effect of this GO/MWCNTs composite resulted in greatly improved performance of the sensor in all aspects . However, humidity sensors based on carbon materials still face a few problems in practical applications, such as the ease in agglomeration of graphene and carbon nanotubes, high cost, toxicity, and environmental pollution.…”

Noncovalent Functionalization of Single-Walled Carbon Nanotubes with a Photocleavable Polythiophene Derivative

“…Conjugated polymers are good candidates for use as functional dispersants [ 13 ] because extended π-structures bearing solubilizing units (e.g., alkyl chains) can bind noncovalently through π-π interactions to SWCNTs, allowing the formation of SWCNT suspensions. Subsequently, such suspensions can be used to make solution-processed SWCNT films using coating and printing techniques [ 14 ]. However, the solubilizing conjugated polymer remains attached to the surface of the SWCNTs, meaning that the resulting film can be damaged upon exposure to the solvent in which it was made.…”