Elucidating the effect of precursor decomposition time on the structural and optical properties of copper() nitride nanocubes

• Published in: RSC advances 2020-09, Vol.1 (56), p.34231-34246
• Main Authors: Kadzutu-Sithole, Rudo, Machogo-Phao, Lerato F. E, Kolokoto, Tshwarela, Zimuwandeyi, Memory, Gqoba, Siziwe S, Mubiayi, Kalenga P, Moloto, Makwena J, Van Wyk, Juanita, Moloto, Nosipho
• Format: Article
• Language: English
• Subjects: Absorption spectra; Chemistry; Copper; Copper compounds; Cubes; Decomposition; Disintegration; Excitons; Nanoparticles; NMR; Nuclear magnetic resonance; Nucleation; Nuclei; Optical properties; Photoluminescence; Reaction mechanisms; Ripening; Thermal decomposition
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/c9ra09546b

To study the effect of time on the colloidal synthesis of Cu 3 N nanoparticles, copper( ii ) nitrate was thermally decomposed at 260 °C for up to 60 min in octadecylamine as a stabilizing ligand. Thermolysis of the nitrate followed four steps which included; nucleation, growth, ripening and decomposition. At 5 min, partially developed nanocubes were found in a dense population of Cu 3 N nuclei. Well-defined Cu 3 N nanocubes were obtained at 15 min with no presence of the nuclei. TEM images showed disintegration of the cubes at 20 min and as time progressed, all the Cu 3 N decomposed to Cu by 60 min. The formation of the Cu 3 N nanocubes was confirmed by XRD and XPS. FTIR suggested the formation of a nitrile (RCN) as a result of the thermal decomposition in octadecylamine (ODA) and this was confirmed using NMR and hence, a reaction mechanism was then proposed. The optical properties of the as-synthesized Cu 3 N were studied using UV-vis and photoluminescence spectroscopies. The absorption spectra for particles synthesized from 5 min to 15 min showed a singular exciton peak while from 20 min to 60 min two peaks were observed. The two peaks may both be associated with the two direct transitions observed in Cu 3 N or the more red-shifted peak could be a result of localized surface plasmon resonance due to the Cu nanoparticles. Nevertheless, similar to other studies, it is clear that the optical properties of Cu 3 N are complex. To study the effect of time on the colloidal synthesis of Cu 3 N nanoparticles, copper( ii ) nitrate was thermally decomposed at 260 °C for up to 60 min in octadecylamine as a stabilizing ligand.