Surface modification effects on defect-related photoluminescence in colloidal CdS quantum dots. Issue 17 (19th April 2018)

• Record Type: Journal Article
• Authors: Lee, TaeGi; Shimura, Kunio; Kim, DaeGwi
• Is Part Of: Physical chemistry chemical physics. Volume 20:Issue 17(2018)
• Page Start: 11954
• Page End: 11958
• Publication Date: 2018-04-19
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c7cp07812a
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : We investigated the effects of surface modification on the defect-related PL in colloidal CdS QDs. Abstract : We investigated the effects of surface modification on the defect-related photoluminescence (PL) band in colloidal CdS quantum dots (QDs). A size-selective photoetching process and a surface modification technique with a Cd(OH)2 layer enabled the preparation of size-controlled CdS QDs with high PL efficiency. The Stokes shift of the defect-related PL band before and after the surface modification was ∼1.0 eV and ∼0.63 eV, respectively. This difference in the Stokes shifts suggests that the origin of the defect-related PL band was changed by the surface modification. Analysis by X-ray photoelectron spectroscopy revealed that the surface of the CdS QDs before and after the surface modification was S rich and Cd rich, respectively. These results suggest that Cd-vacancy acceptors and S-vacancy donors affect PL processes in CdS QDs before and after the surface modification, respectively.