One-Pot, Large-Scale Synthesis of Organic Color Center-Tailored Semiconducting Carbon Nanotubes

Abstract

Organic color center-tailored semiconducting single-walled carbon nanotubes are a rising family of synthetic quantum emitters that display bright defect photoluminescence molecularly tunable for imaging, sensing, and quantum information processing. A major advance in this area would be the development of a high-yield synthetic route that is capable of producing these materials well exceeding the current μg/mL scale. Here, we demonstrate that adding a chlorosulfonic acid solution of raw carbon nanotubes, sodium nitrite, and an aniline derivative into water readily leads to the synthesis of organic color center-tailored nanotubes. This unexpectedly simple one-pot reaction is highly scalable (yielding hundreds of milligrams of materials in a single run), efficient (reaction completes in seconds), and versatile (achieved the synthesis of organic color centers previously unattainable). The implanted organic color centers can be easily tailored by choosing from the more than 40 aniline derivatives that are commercially available, including many fluoroaniline and aminobenzoic acid derivatives, and that are difficult to convert into diazonium salts. We found this chemistry works for all the nanotube chiralities investigated. The synthesized materials are neat solids that can be directly dispersed in either water or an organic solvent by a surfactant or polymer depending on the specific application. The nanotube products can also be further sorted into single chirality-enriched fractions with defect-specific photoluminescence that is tunable over ∼1100 to ∼1550 nm. This one-pot chemistry thus provides a highly scalable synthesis of organic color centers for many potential applications that require large quantities of materials.

Luminescent Defects in Single‐Walled Carbon Nanotubes for Applications

“…[84,85] In addition, a one-pot process in which the diazonium compound is generated in situ from an aromatic amine is possible and has been demonstrated. [86] Overall, a large variety of functional moieties have been attached to sp 3 defects through diazonium chemistry and thus enabled their various applications, for example, as optical sensors (see Section 6). Some functional groups are not compatible with diazonium chemistry or the resulting compounds have a limited shelf life.…”

Brightening of Long, Polymer-Wrapped Carbon Nanotubes by sp3 Functionalization in Organic Solvents

“…However, despite the substantial progress in terms of purification and processing, light-emitting devices based on carbon nanotubes are still limited by their low absolute PLQYs (~1 % in dispersion and ~0.1 % in films) resulting from the presence of low-lying dark exciton states 13 and the fast diffusion of mobile excitons to nonradiative quenching sites. 14,15 The most promising approach to enhance the PLQY of SWNTs is their functionalization with a limited number of oxygen 16,17 or sp 3 defects [18][19][20] that act as luminescent exciton traps with depths on the order of 100 meV. Excitons trapped at these defect sites are not subject to otherwise dominant diffusion-limited contact-quenching, 14 and the modification of the local electronic structure by the defects enables radiative relaxation and red-shifted emission (labelled as E11*, or E11*for different binding configurations).…”

Beyond Color: The New Carbon Ink

“…The sidewalls of CNTs can be covalently functionalized, such as by reacting them with diazonium salts in water or chlorosulfonic acid. [ 76,94 ] Such functionalization has been used to tailor the physical and chemical properties of CNTs, including solubility. Lately, work from our groups and many others have shown a small number of controlled functional groups can have a drastic positive impact on their optical and electronic properties.…”