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Interstitial sulfur photoluminescence in thermochemically synthesized CdS nanocrystals (NCs)

Molaei, M ; Sharif University of Technology | 2011

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  1. Type of Document: Article
  2. DOI: 10.1051/epjap/2011100518
  3. Publisher: 2011
  4. Abstract:
  5. We have synthesized CdS NCs (NCs) by a thermochemical approach. CdSO 4 and Na2S2O3 were used as the precursors and thioglycolic acid (TGA) was used as capping agent molecule. The structure and optical property of the NCs were characterized by means of XRD, TEM, UV-visible optical spectroscopy and photoluminescence (PL). XRD and TEM analyses demonstrated hexagonal phase CdS NCs with an average size of around 2 nm. Synthesized NCs exhibited a band gap of about 3.21 eV and showed a broad band emission from 400 to 750 nm centered at 503 nm. This broad band emission is related to surface states of CdS and our results showed that the emission peak can be attributed to the interstitial sulfur. The best attained photoluminescence quantum yield of the NCs was about 11%. At the same conditions the PL quantum yield of TGA capped NCs was about 20 times higher than that of TG capped NCs
  6. Keywords:
  7. Average size ; Broadband emission ; Capping agent ; CdS ; CdS nanocrystals ; Emission peaks ; Hexagonal phase ; Photoluminescence quantum yields ; PL quantum yield ; Surface state ; TEM analysis ; Thioglycolic acid ; UV-visible optical spectroscopy ; XRD ; XRD , TEM ; Cadmium sulfide ; Optical properties ; Photoluminescence ; Quantum yield ; Sodium ; Sulfur ; Cadmium compounds
  8. Source: EPJ Applied Physics ; Volume 56, Issue 1 , 2011 ; 12860042 (ISSN)
  9. URL: http://www.epjap.org/articles/epjap/abs/2011/10/ap100518/ap100518.html