Abinitio Modeling and Performance Study Of Light Emitting Electro Chemical Cells

Abstract

The lighting sources currently in use such as light emitting diode (LED), compact newlinefluorescent lamp (CFL) have replaced traditional incandescent bulbs. The new techniques newlineof light generation are better but not perfect as their cost of production is very high and newlinetheir fabrication methods are intricate. Moreover, the materials used in these light sources newlineare not environment friendly. newlineNowadays electronic devices with organic materials are being used to overcome these newlinedrawbacks. These organic materials behave like inorganic materials and their conductivity newlinecan be enhanced by doping. newlineLight emitting electrochemical cells (LEC) are preferred and have attracted researchers newlinerecently as lighting and display devices as compared to their organic analogue. The reason newlinefor this being their simple structure, ease of fabrication ecofriendly nature and air stable newlineelectrodes. newlineA Polymer light emitting electrochemical cell (PLEC) is a light emitting optoelectronic newlinedevice consisting of a polymer blend (luminescent polymer, ion transport material and a newlinesalt) embedded in between two electrodes with at least one of the two electrodes being newlinetransparent. newlineThe Polymer LEDs (PLED) especially the ones based on wide band gap polymers, are newlinecharacterized by high turn on voltages. This feature is disadvantageous for the successful newlineapplication of conjugated polymers in flat panel displays and low power optoelectronics. newlineLECs overcome this problem due to the presence of the mobile ions in the active layer, newlinewhich strongly facilitate charge injection already at low applied voltages and make it newlinefairly independent of the potential barrier height and of the trap densities at the newlinepolymer/electrode s interfaces. The threshold voltage is practically decided by the energy newlinegap of the conducting polymer and the color of the emitted light. This feature makes the newlineLEC interesting in low power optoelectronic applications. newlineIn this thesis an attempt has been made to study different electrode and electrolyte newlinematerials used in light emitting electrochemical cell. LECs