Controlled Growth of Well-Defined Conjugated Polymers from the Surfaces of Multiwalled Carbon Nanotubes: Photoresponse Enhancement via Charge Separation

Abstract

The installation of heterojunctions on the surfaces of carbon nanotubes (CNTs) is an effective method for promoting the charge separation processes needed for CNT-based electronics and optoelectronics applications. Conjugated polymers are proven state-of-the-art candidates for modifying the surfaces of CNTs. However, all previous attempts to incorporate conjugated polymers to CNTs resulted in unordered interfaces. Herein we show that well-defined chains of regioregular poly(3-hexylthiophene) (P3HT) were successfully grown from the surfaces of multiwalled CNTs (MWNTs) using surface-initiated Kumada catalyst-transfer polycondensation. The polymerization was found to proceed in a controlled manner as chains of tunable lengths were prepared through variation of the initial monomer-to-initiator ratio. Moreover, it was determined that large-diameter MWNTs afforded highly ordered P3HT aggregates, which exhibited a markedly bathochromically shifted optical absorption due to a high grafting density induced planarization of the polymer chains. Using ultrafast spectroscopy, the heterojunctions formed between the MWNTs and P3HT were shown to effectively overcome the binding energy of excitons, leading to photoinduced electron transfer from P3HT to MWNTs. Finally, when used as prototype devices, the individual MWNT-g-P3HT core-shell structures exhibited excellent photoresponses under a low illumination density.

A multifunctional platform with single-NIR-laser-triggered photothermal and NO release for synergistic therapy against multidrug-resistant Gram-negative bacteria and their biofilms

“…2c, TG, TG-NO, TG-B and TG-NO-B exhibited an absorption over a broad range in the Vis-NIR region with the absorbances of 0.604, 0.528, 0.977 and 0.928 at 808 nm, respectively. Both TG-B and TG-NO-B showed a higher absorption at 808 nm, probably because of the enhanced electron transfer by grafting BA moieties onto the graphene sheets [41,42]. Next, the photothermal effect of TG-NO-B was investigated by measuring the temperature evolution profile of its suspensions (0-200 μg/mL) under 808 nm laser irradiation (0.25-1.0 W/cm 2 , 600 s).…”

Polythiophene Grafted onto Single‐Wall Carbon Nanotubes through Oligo(ethylene oxide) Linkages for Supercapacitor Devices with Enhanced Electrochemical Performance

“…The obtained results are consistent with the findings of Geng's work. [39] XPS spectra analysis of the SWCNTs-COOH, PD2ET and PD2ET-g-SWCNTs samples was applied to investigate the interaction between the components of the prepared hybrid. The full XPS survey spectral curves of SWCNTs-COOH, PD2ET and PD2ET-g-SWCNTs hybrid are presented in Figure 3a.…”

Grafting of trifluoromethylated poly(phenylene oxide)s on a single‐walled carbon nanotube via surface‐initiated chain‐growth condensation polymerization

“…However, due to the poor miscibility of SWNTs with solvents and polymers, the preparation and solution processing of carbon nanotube (CNT)‐containing composites remains a challenge. Considerable efforts have been made to achieve homogeneous dispersion of CNTs in various matrices via physical methods aided by sonication and strong non‐covalent interactions or via covalent bonding such as carboxylate, small molecules (i.e., diazonium salts and carbenes), and polymers . Functionalization of CNTs with well‐defined polymers has been achieved with surface‐initiated polymerization methods such as anionic, atom transfer radical, reversible addition‐fragmentation chain transfer, nitroxide‐mediated, ring‐opening, ring‐opening metathesis, and coordination polymerization …”