Electroluminescence from Single PVK Layer Organic Light Emitting Diode Using Different Dyes at Different Concentrations

In this work, organic light emitting diodes are fabricated using a single PVK layer doped with a dye. Three different dyes are used: crystal violet, fluorescein, and bromophenol blue. The structure of the single layer device is doped PVK sandwiched between indium tin oxide (ITO) and Indium-Gallium alloy (InGa) layers as anode and cathode, respectively. The I-V characteristic curves and electroluminescence emitted from the devices have been investigated in details with the concentration of the dyes. It is found that the threshold voltage after which the device begins to emit can be reduced by increasing the dye concentration up to 5%. It is found that devices fabricated using crystal violet and bromophenol blue dyes are more efficient than those fabricated using fluorescein dye. There is some preference of bromophenol blue dye over the crystal violet dye due to the smaller values of threshold voltages.