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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.

Chemical defects that fluoresce in the shortwave infrared open exciting opportunities in deep-penetration bioimaging, chemically specific sensing, and quantum technologies. However, the atomic size of defects and the high noise of infrared detectors have posed significant challenges to the studies of these unique emitters. Here we demonstrate high throughput single-defect spectroscopy in the shortwave infrared capable of quantitatively and spectrally resolving chemical defects at the single defect level. By cooling an InGaAs detector array down to −190 °C and implementing a nondestructive readout scheme, we are able to capture low light fluorescent events in the shortwave infrared with a signal-to-noise ratio improved by more than three orders-of-magnitude. As a demonstration, we show it is possible to resolve individual chemical defects in carbon nanotube semiconductors, simultaneously collecting a full spectrum for each defect within the entire field of view at the single defect limit.

Organic color‐centers (OCCs) have emerged as promising single‐photon emitters for solid‐state quantum technologies, chemically specific sensing, and near‐infrared bioimaging. However, these quantum light sources are currently synthesized in bulk solution, lacking the spatial control required for on‐chip integration. The ability to pattern OCCs on solid substrates with high spatial precision and molecularly defined structure is essential to interface electronics and advance their quantum applications. Herein, a lithographic generation of OCCs on solid‐state semiconducting single‐walled carbon nanotube films at spatially defined locations is presented. By using light‐driven diazoether chemistry, it is possible to directly patternp‐nitroaryl OCCs, which demonstrate chemically specific spectral signatures at programmed positions as confirmed by Raman mapping and hyperspectral photoluminescence imaging. This light‐driven technique enables the fabrication of OCC arrays on solid films that fluoresce in the shortwave infrared and presents an important step toward the direct writing of quantum emitters and other functionalities at the molecular level.

Strategically introduced defects can be used to modify carbon nanotubes for new properties and functions. For example, chemical defects can act as atomic traps for electrons, holes, electron-hole pairs, and even molecules and ions ( 1 ). The ability to control the placement of these defects on carbon nanotubes could enable a plethora of fundamental studies and potential applications in imaging, sensing, disease diagnostics, and quantum information science ( 2 – 4 ). However, there is yet no effective way to do this with atomic precision ( 5 – 7 ). On page 535 of this issue, Lin et al. ( 8 ) report the creation of ordered defect arrays by programming DNA strands to wrap around and traverse the entire length of a single-walled carbon nanotube.