Comparison of Doping Levels of Single‐Walled Carbon Nanotubes Synthesized by Arc‐Discharge and Chemical Vapor Deposition Methods by Encapsulated Silver Chloride

Abstract

In this paper, we have performed the filling of single‐walled carbon nanotubes (SWCNTs) with mean diameters of 1.4 and 1.9 nm synthesized by the arc‐discharge and chemical vapor deposition (CVD) methods, respectively, with silver chloride. The doping effect of the encapsulated compound on SWCNTs is studied by Raman spectroscopy and X‐ray photoelectron spectroscopy. It is shown that the filling of nanotubes with silver chloride leads to p‐doping of SWCNTs accompanied by charge transfer from the SWCNTs to the salt and downshift of their Fermi level. It is found that the filling of SWCNTs synthesized by different methods results in different doping levels of nanotubes. The arc‐discharge 1.4 nm‐diameter SWCNTs have larger doping level than CVD 1.9 nm‐diameter nanotubes. The obtained information about the influence of the filler on the electronic properties of SWCNTs synthesized by different methods is elemental for applications of nanotubes in nanoelectronic devices.

Unconventional Thermoelectric Materials for Energy Harvesting and Sensing Applications

“…The most typical strategy for noncovalent doping of SWCNTs is molecular redox doping, which involves exposing CNTs to organic molecules with strong electron donor or acceptor character to promote spontaneous electron transfer to/from the SWCNTs. Molecules can be adsorbed onto the surfaces of SWCNTs (Figure a) ,− and/or may be encapsulated within the endohedral volume of the SWCNTs (Figure b). − Donor molecules with HOMO values closer to vacuum than the first SWCNT conduction level ( c 1 ) values serve as reductants, injecting electrons into the SWCNTs that can contribute to electrical conductance in a coupled SWCNT network. In contrast, acceptor molecules with LUMO values farther from vacuum then the first SWCNT valence level ( v 1 ) serve as oxidants, removing electrons from SWCNTs to produce mobile holes in SWCNT networks.…”

Applications of Pristine and Functionalized Carbon Nanotubes, Graphene, and Graphene Nanoribbons in Biomedicine

“…If the chemical functionalization of CNTs is performed endohedrally, the functional molecules are encapsulated inside the channels of nanotubes [28][29][30][31][32][33][34][35][36][37][38][39][40][41]. This technique has two advantages.…”

Applications of Filled Single-Walled Carbon Nanotubes: Progress, Challenges, and Perspectives

“…Acceptor doping was observed for SWCNTs filled with many different substances that can be grouped as (1) molecules-organic molecules (tetracyano-p-quinodimethane (TCNQ) and tetrafluorocyano-p-quinodimethane (F 4 TCNQ) [6,7]), fullerenes (C 60 [8][9][10][11][12][13][14][15], C 70 , C 78 , C 82 [12][13][14]) and endohedral fullerenes (Gd@C 82 [16,17], La@C 82 , K@C 60 , Ca@C 60 , Y@C 60 [10,12]); (2) simple substances-non-metals (sulfur, selenium, and tellurium [18]); and (3) chemical compounds-metal oxides (chromium (VI) oxide [19]), metal halogenides (tin (II) fluoride [20], silver chloride [21][22][23], silver halogenides [24], iron halogenides [25], cobalt bromide [26], nickel halogenides [27], iron bromide, cobalt bromide, nickel bromide [28], manganese halogenides [29,30], zinc halogenides [31], terbium chloride, zinc chloride, cadmium chloride [32], thulium chloride [33], erbium chloride [34], praseodymium chloride [35], terbium chloride, thulium chloride, praseodymium chloride [36], copper halogenides [37], copper iodide [38,39], copper chloride [40], cadmium halogenides…”