Photoluminescence Properties of Single‐Walled Carbon Nanotubes Influenced by the Tether Length of Reagents with Two Reactive Sites

Abstract

The functionalization of single‐walled carbon nanotubes (SWNTs) is an effective method for controlling a local band gap, resulting in photoluminescence (PL) in the near‐infrared region. Herein, SWNTs were functionalized using a series of bromoalkanes and dibromoalkanes to evaluate the effects of their length on the nanotube PL properties. When bromoalkanes (CnH2n+1Br) or dibromoalkanes (CnH2nBr2) with tether lengths of six or more were utilized for six different semiconducting SWNTs, the obtained SWNT adducts exhibited two new PL peaks, whereas dibromoalkanes with tether lengths of 3–5 (CnH2nBr2: n=3–5) produced single peaks. Combined with theoretical calculations, the results suggested that the tether length of reagents changes the formation mechanism of functionalized adducts, that is, CnH2nBr2 (n=3–5) tends to result in kinetic products.

Control of functionalized single-walled carbon nanotube photoluminescence via competition between thermal rearrangement and elimination

“…19,34 The wavelength shift after the thermal treatment may be attributed to the formation of 1,2-L ++ (6,5) SWNTs-C 3 H 4 Me 2 as a kinetically preferred isomer during the functionalization reaction, while the 1,2-L + (6,5) SWNTs-C 3 H 4 Me 2 is formed as the thermodynamically favored product after the thermal treatment. 31 The higher spin density at 1,2-L ++ carbon atom in the butylated SWNTs radical supported the hypothesis that the 1,2-L ++ adduct is the kinetically preferred product. 31…”

“…31 The higher spin density at 1,2-L ++ carbon atom in the butylated SWNTs radical supported the hypothesis that the 1,2-L ++ adduct is the kinetically preferred product. 31…”

Stepwise Functionalization of Single‐Walled Carbon Nanotubes with Subsequent Molecular Conversion to Control Photoluminescence Properties

“…Thus, 1,3-dibromopropane derivatives exhibited high stability under sonication and heating conditions. [9,28] Corresponding to the changes in the absorption and Raman spectra, the PL spectral change after the deprotection reaction of SWCNTs-G1NHBoc was significant, whereas that of SWCNTs-G2NHBoc and SWCNTs-NHBoc was slight. In contrast to those of SWCNTs-G1NHBoc, both the E 11 * and E 11 ** PL intensities and the PL intensity ratio (E 11 * PL/E 11 ** PL) of SWCNTs-G1NH 2 increased.…”

Recent progress in controlling the photoluminescence properties of single-walled carbon nanotubes by oxidation and alkylation

“…Using arylation reactions, the PL wavelength of (6,5) SWCNTs can be extensively tuned by electronic effects, 24,34,42 steric effects of substituents, 43–48 and the number of reactive sites. 26,34,42,47,49–52 These findings offer deep insights into the factors governing the PL attributes. This feature article highlights seminal and recent advancements in controlling the NIR PL wavelength of SWCNTs through oxidation and alkylation reactions.…”

“…Furthermore, the optical resolution of the functionalized SWCNTs has been achieved for (6,5) chirality. 42,48,52,80 The functionalization of (6,5) SWCNTs using 2,4dibromopentane to produce SWCNTs-C 3 H 4 Me 2 led to a new PL peak at 1216 nm. The subsequent thermal treatment produced a new PL peak at 1268 nm, SWCNTs-C 3 H 4 Me 2 (300 1C, 6 h), while the intensity of the PL peak at 1216 nm decreased (Fig.…”