Abstract:
Synthesis of CdSe and CdSeS nanorods (NRs) has been carried out by ‘Hot Injection’ method and deposited through ‘Electrophoretic Deposition’ technique for the fabrication of nanocrystals light emitting diode. The surface morphology and element analysis of the deposited thin films and full Light Emitting Diode (LED) structure (ITO/NiO/CdSeS/ZnO structure in this work) were studied by Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS) respectively. The optical and electrical properties were characterized by Steady-state Photoluminescence (PL) Spectroscopy and Current-Voltage (I-V) measurement respectively. It has been observed from TEM that, CdSeS with Hexylphosphonic acid (HPA) surfactant delivered spherical-head shaped NRs with aspect ratio of 4.5 and the SEM characterization showed, the NRs have been aligned vertically. Subsequently, the CdSeS NRs have been exploited for designing LEDs with the following structure of ITO/NiO/CdSeS/ZnO and different layers (NiO, CdSeS, ZnO) of LED have been viewed by TEM likewise. The NiO layer in full LED structure has been analysed by XPS and it showed that, the peaks have been almost at the same position before and after heat treatment. The high emission light intensity with wavelength of 662 nm has been noticed by PL at room temperature. The CdSeS NRs as emissive layer has been given excellent performance for the device fabrication showing the PL peak intensity at ~7000 a.u. Lastly, the electrical characterization has been done by I-V measurement and good current conductivity has been gained with turn-on voltage between 1.7 to 1.9 volts and forward currents ranging from 1-10.5 mA. At the end of this work, CdSe NRs have been synthesized for next LED structure instead of CdSeS. Herein, by comparing, less Se contained CdSe achieved a smooth surface of aligned NRs with the aspect ratio of 3 and higher intensity of emission light along with 641 nm of peak wavelength, could be used for device fabrication in future.