Dependence of the Performance of Vacuum Deposited Organic Light Emitting Diodes on Layer Thickness and Composition

Efficient green electroluminescence from an organic double-layer device between two electrodes was first reported by Tang and Van Slyke [1,2]. Subsequently, there has been considerable interest in using various fluorescent organic molecules in similar structures to produce electroluminescence in different spectral regions. Also, more complex, triple layer "double heterostructure" devices have been reported[3]. However, although devices emitting throughout the visible spectrum have been successfully fabricated [1,4,5], there is a lack of quantitative information relating the organic layer thickness and heterojunction properties to device performance.