Single-walled carbon nanotubes shell decorating porous silicate materials: A general platform for studying the interaction of carbon nanotubes with photoactive molecules

Abstract

Single-walled carbon nanotubes (SWCNTs) have been deposited onto the external surface of porous silicate materials by deposition from a solution of individualized, protonated SWCNTs in chlorosulfonic acid. It is demonstrated that the deposited SWCNTs can be deprotonated on the silicate surface, yielding a microporous or mesoporous material with individual or small bundles of SWCNTs. These carbon nanotubes present all the spectral characteristics of pristine SWCNTs, including van Hove transitions, Raman and NIR photoluminescence. Furthermore, it is shown that these materials can be used as scaffolds to study the interaction of SWCNTs with photoactive molecules loaded in the cavities of the porous silicate materials. As a proof-of-concept, we showed that the photoluminescence of tris(2,2 0 -bipyridine)ruthenium(II) can be quenched by protonated SWCNTs in the nearby surface decreasing its lifetime by nearly two orders of magnitude. This represents a novel application for these materials, especially considering the large amount of different molecules that can be immobilized in the internal cavities of these porous silicates.

Films of Bare Single-Walled Carbon Nanotubes from Superacids with Tailored Electronic and Photoluminescence Properties

“…In a previous publication we showed that SWCNTs protonated by chlorosulfonic acid (CSA) adhere efficiently to silicon oxide microporous and mesoporous particle surfaces. 25 We hypothesized that a similar behavior could be obtained for such protonated nanotubes (p-SWCNTs) on flat silicon oxide surfaces. Here we report the photophysical and electronic properties of films made by SWCNT deposition from CSA onto flat fused silica windows (Figure 1).…”

“…26,27 In a previous article, we reported that the bulk NIRphotoluminescence of p-SWCNTs can be regenerated by deprotonating the SWCNT surface. 25 To determine whether this process also occurs for CNTs deposited on fused silica, a film was made from a dilute SWCNT CSA solution and then treated with diethyl ether. Figure 2 shows the fluorescence image of such a film.…”

Increased Solubility, Liquid-Crystalline Phase, and Selective Functionalization of Single-Walled Carbon Nanotube Polyelectrolyte Dispersions

“…To exploit the outstanding properties of individualized SWCNTs, one has to overcome the formidable van der Waals attractions among tubes (0.5 eV/nm), which is the main obstacle to make uniform and stable dispersions. Over the past few years, many effective dispersion technologies have been developed, including covalent sidewall functionalization, − noncovalent interaction-assisted dispersion, − and superacid dissolution. ,− Another intriguing way to disperse SWCNTs is by forming SWCNT polyelectrolytes, where nanotubes are negatively charged by reduction by alkali metals. Upon adding polar aprotic solvents, the negatively charged sidewalls of the nanotubes induce Coulombic repulsion between tubes, resulting in their spontaneous dissolution. − Early work in this field showed that SWCNT polyelectrolytes can be synthesized by metallic lithium reduction. , Later, Pénicaud reported the use of other alkali metals and showed that SWCNT salts [A(THF)] n CNT (A = Li, Na, K) could spontaneously dissolve in a series of aprotic organic solvent, such as dimethyl sulfoxide (DMSO) and sulfolane. − However, the reported solubility of HiPco SWCNT polyelectrolytes was relatively low (0.4 mg/g in DMSO), which prevents the formation of a liquid crystal and limits its further processing into macroscopic assembly such as SWCNT fibers or sheets …”

Carbon/metal nanotubes with tailored order and configuration by direct carbonization of inverse block copolymer micelles inside nanoporous alumina

“…[1][2][3][4][5] Among the numerous carbonaceous hybrid materials reported to date, carbon nanotubes (CNTs) containing metal or metal oxide nanoparticles (NPs) have been intensively studied owing to their high electrical conductivity, their large surface area and their porosity. [5][6][7][8][9][10] Hybrid CNTs have been synthesized by established methods including chemical vapor deposition (CVD), 11 electrospinning 12 and hard template wetting. 13 Block copolymers (BCPs) mixed with carbon precursors like phenolic resins were used as structure-directing soft templates in the preparation of mesoporous carbonaceous thin films or monoliths with well-defined long-range periodicity, 14,15 as well as in the synthesis of mesoporous carbon nanorods inside shape-defining nanoporous hard templates such as anodic aluminium oxide.…”