Improvement of the luminescent properties of cadmium sulfide quantum dots by a post-synthesis modification

• Published in: Physica. B, Condensed matter Vol. 453; pp. 81 - 85
• Main Authors: LOPEZ, Israel, GOMEZ, Idalia
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Kidlington Elsevier B.V 15.11.2014; Elsevier
• Subjects: Cadmium sulfide; Cadmium sulfides; Citrates; Condensed matter; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Emission; Exact sciences and technology; Hydroxides; Luminescence; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures; Physics; Precipitation; Quantum dot; Quantum dots; Sulfides; Cadmium sulfide; Quantum dot; Luminescence; Microwave radiation; Quantum dots; Photoluminescence; pH effect; Fabrication property relation; Line intensity; Precipitation; Aqueous solutions; Nanomaterial synthesis; Deep level
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2014.05.002

Here the improvement of the luminescent properties of CdS quantum dots by a post-synthesis modification with aqueous solutions of NaOH at different concentrations is presented. The CdS quantum dots were synthesized by a microwave-assisted method using citrate ions as stabilizer. The addition of the hydroxide ions increased the intensity of the orange-red emission by about 80%. Besides, a violet-blue emission was achieved by means of this post-synthesis modification. The hydroxide ions control the precipitation equilibria of the CdS and Cd(OH)2, dissolving and precipitating the surface of the quantum dots. The NaOH treatment increases the number of traps, which produces less band-edge and more deep-trap emission, which explains the decrease and increase in the intensity of the violet-blue and orange-red emissions, respectively.