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Near-white emitting QD-LED based on hydrophilic CdS nanocrystals
, Article Journal of Luminescence ; Volume 132, Issue 2 , 2012 , Pages 467-473 ; 00222313 (ISSN) ; Marandi, M ; Saievar Iranizad, E ; Taghavinia, N ; Liu, B ; Sun, H. D ; Sun, X. W ; Sharif University of Technology
Abstract
In this work we report fabrication of a nanocrystal (NC)-based hybrid organicinorganic LED with structure of ITO/PEDOT:PSS/PVK/CdS-NCs/(Al or Mg:Ag). The hydrophilic CdS NCs were synthesized using a novel aqueous thermochemical method at 80 °C and sizes (around 2 nm) were controlled by thioglycolic acid (TGA) as the capping agent. The favorite feature of these NCs is their relatively high emission intensity and broad, near-white emission. The hydrophilic CdS NCs were successfully spin coated using Triton X-100 as the wetting agent. The fabricated LEDs demonstrated a turn on voltage about 7 V for Al metallic contact. The electroluminescence was a broad spectrum at 540 and 170 nm width, which...
Synthesis of CdS nanocrystals by a microwave activated method and investigation of the photoluminescence and electroluminescence properties
, Article Applied Surface Science ; Volume 257, Issue 23 , September , 2011 , Pages 9796-9801 ; 01694332 (ISSN) ; Iranizad, E. S ; Marandi, M ; Taghavinia, N ; Amrollahi, R ; Sharif University of Technology
2011
Abstract
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...
Fast two-step microwave-activated synthesis of Mn doped ZnS nanocrystals: Comparison of the luminescence and doping process with thermochemical approach
, Article Journal of Luminescence ; Volume 131, Issue 4 , April , 2011 , Pages 721-726 ; 00222313 (ISSN) ; Hajisalem, G ; Taghavinia, N ; Houshiar, M ; Sharif University of Technology
2011
Abstract
In this work we report a fast two-step microwave activated synthesis of the ZnS:Mn nanocrystals. Zn(NO3)2 and Na2S 2O3 were used as the precursors and Mn(NO 3)2 was employed as the source of the impurity. The aqueous synthesis was based on the heat sensitivity of Na2S 2O3, which releases some S species on heating. Consequently, the reaction was well activated under microwave irradiation resulting in formation of ZnS:Mn nanocrystals. Thioglycerol (TG) was also used as the capping agent and the catalyst of the reaction. The synthesis process was done in two steps, i.e. 1 min irradiation without TG and then injection of TG and continuation of irradiation. ZnS:Mn nanocrystals were quickly formed...