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Title: Near-white emitting QD-LED based on hydrophilic CdS nanocrystals
Authors: Sun, Xiaowei
Molaei, M.
Marandi, M.
Saievar-Iranizad, E.
Taghavinia, N.
Liu, B.
Sun, H. D.
Issue Date: 2011
Source: Molaei, M., Marandi, M., Saievar-Iranizad, E., Taghavinia, N., Liu, B., Sun, H., et al. (2012). Near-white emitting QD-LED based on hydrophilic CdS nanocrystals. Journal of luminescence, 132(2), 467-473.
Series/Report no.: Journal of luminescence
Abstract: In this work we report fabrication of a nanocrystal (NC)-based hybrid organic–inorganic 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 was about 50 nm red shifted compared to photoluminescence spectra. The CIE color coordinates of the LED at (0.33, 0.43) demonstrated a near white light LED with an emission on green–yellow boundary of white. Annealing of the device up to 190 °C had a positive effect on the performance, possibly due to better contacts between layers. Replacing Al contacts with Mg:Ag reduced the turn-on voltage to 6 V and changed CIE color coordinate to (0.32, 0.41). The EL peak was also shifted to 525 nm, with a brightness of 15 Cd/m2 at working voltage of 15 V. The current efficiency and external quantum efficiency of device were 0.08 Cd/A and 0.03% at current densities higher than 10 mA/cm2.
ISSN: 0022-2313
DOI: 10.1016/j.jlumin.2011.08.038
Rights: © 2011 Elsevier B.V.
Fulltext Permission: none
Fulltext Availability: No Fulltext
Appears in Collections:SPMS Journal Articles

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