Synthesis and Study of Fluorescent Forest-like Carbon Nanotubes Doped with Oxides of Rare-earth Elements

Abstract

Background: Methods for obtaining the hybrids of multi-wall carbon nanotubes (MWCNTs) and rare earths are in progress. Such composites may possess luminescent properties, which could be of interest for various areas, in particular, medicine (imaging), engineering (fluorescent polymers, LED and relative materials), among other applications. Lanthanide oxides, additionally, can serve as catalysts for MWCNTs formation and catalysts of several organic reactions. Objective: The goal of this work is to obtain the composites of MWCNTs with strontium aluminate, doped with several lanthanides (Eu, Ce, La, Nd, and Sm), via the spray pyrolysis method and to study the properties of the formed hybrids. Methods: The spray pyrolysis method in the temperature range from 780 to 850oC, starting from toluene as a carbon source and ferrocene as a catalyst precursor. SrAl12O19 doped with rare-earths were added to carbon matter in the ultrasonic field. Methods: Among various structures, the forest-like nanostructures have been observed in some cases. The formed coated carbon nanotubes possess fluorescent properties due to the attachment of lanthanide- doped ceramic compound (SrAl12O19) to their surface, allowing the emission control for each dopant: yellow (Nd2O3), blue (Eu2O3 and Sm2O3), intense orange (La2O3), light orange (Ce2O3). Conclusion: MWCNTs decorated with strontium aluminate (SrAl12O19), doped with a series of lanthanide oxides (Nd2O3, Eu2O3, La2O3, Ce2O3, Sm2O3), were obtained by the spray pyrolysis technique on the surface of optical fibers. Lanthanum- and cerium-containing coatings were found to show a better deposition on the MWCNTs surface, exhibiting uniform coating. MWCNTs, coated with Nd-, Ce-, and Eu-doped SrAl12O19 were shown to reveal the best conductive properties.

Structural study of the rare earth compounds: Sm(OH)3, NdOHCO3, CeO2, and Ho2O3, prepared by Chemical Bath Deposition, and its correlation with crystal growth mechanism

“…A recently proposed mechanism of grain boundary migration known as the "mixed control mechanism" and the associated principles of microstructural evolution represent the basis of the solidstate single crystal growth technique [10]. Various ER synthesis techniques, both chemical and physical; have been reported in the last decades: hydrothermal synthesis [11], spray pyrolysis technique [12], thermal decomposition [13], Chemical Bath Deposition (CBD) technique [7,8,]. CBD technique has been applied in the preparation of various nanocrystals; Semiconductors [16], ER oxides [7,8,14,15].…”