Electromagnetic and microwave absorbing properties of amorphous carbon nanotube–cadmium selenide quantum dot hybrids

Amorphous carbon nanotubes (α-CNTs) have been synthesized by heating a mixture of ferrocene and ammonium chloride at a low temperature of 200 °C. Surface morphological studies reveal that the as-prepared nanotubes are straight tubular structures with open ends. The Raman spectra reveal the presence of defects in the nanotubes. Both chemical oxidation and hybridization treatments result in hybridization between α-CNTs and cadmium selenide quantum dots (CdSe QDs), giving an increase in the average outer diameter, surface roughness and the number of defects for the α-CNTs. The decreasing outer diameter size of nanotubes reduces the permittivity contribution in overall due to size quantization effect. Chemical functionalization initiated by the oxidation and attachment of CdSe QDs due to hybridization improve the dispersion stability and permittivity of α-CNTs. The α-CNTs–CdSe QD hybrids have the potential for electromagnetic and microwave absorption applications as they exhibit a high imaginary component of permittivity (dielectric loss).

► α-CNT–CdSe QD hybrids are successfully synthesized.
► Size quantization effect reduces the permittivity of α-CNT.
► Oxidation and hybridization improve permittivity of α-CNT.
► α-CNTs–CdSe QD hybrids with high dielectric loss have potential as microwave absorber.