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Synthesis of CdS nanocrystals by a microwave activated method and investigation of the photoluminescence and electroluminescence properties

Molaei, M ; Sharif University of Technology | 2011

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  1. Type of Document: Article
  2. DOI: 10.1016/j.apsusc.2011.06.020
  3. Publisher: 2011
  4. Abstract:
  5. We have synthesized CdS nanocrystals (NCs) by a microwave activated method. CdSO4 and Na2S2O3 were used as the precursors and thioglycolic acid (TGA) was used as capping agent molecule. The aqueous synthesis was based on the heat sensitivity of Na2S 2O3. In this method, microwave irradiation creates the activation energy for dissociation of Na2S2O3 and leads to the CdS NCs formation. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses demonstrated hexagonal phase CdS NCs with an average size around 3 nm for sample prepared at 5 min irradiation time. A band gap range of 3.38-2.89 eV was possible only by increasing the microwave irradiation time, corresponding to a 2.7-3.7 nm size. Photoluminescence (PL) spectra showed a white emission between 400 and 750 nm. The best attained PL quantum yield (QY) of the NCs was about 10%. Synthesized NCs were used as emissive layer in a light emitting device (LED) with ITO/PEDOT:PSS/PVK/CdS-NCs/ AL structure. Turn on voltage of fabricated device was about 7 V. The CIE color coordinate of the LED at (0.34, 0.43) demonstrated a near white light LED with an emission on green-yellow boundary of white
  6. Keywords:
  7. Synthesis ; Aqueous synthesis ; Average size ; Capping agent ; CdS ; CdS nanocrystals ; CdS nanostructures ; Color coordinates ; Electroluminescence properties ; Emissive layers ; Fabricated device ; Heat sensitivity ; Hexagonal phase ; Irradiation time ; Light emitting devices ; Photoluminescence spectrum ; PL quantum yield ; Thioglycolic acid ; White emissions ; White light ; Activation energy ; Cadmium compounds ; Cadmium sulfide ; Irradiation ; Light ; Light emission ; Nanocrystals ; Photoluminescence ; Quantum yield ; Sodium ; Transmission electron microscopy ; X ray diffraction ; X ray diffraction analysis ; Microwave irradiation
  8. Source: Applied Surface Science ; Volume 257, Issue 23 , September , 2011 , Pages 9796-9801 ; 01694332 (ISSN)
  9. URL: http://www.sciencedirect.com/science/article/pii/S0169433211008828