Enhancing stimulated emission in organic light emitting diodes

Light emitted by organic light emitting diodes (OLED) is due to recombination of electrically injected electrons and holes providing conditions for exciton formation and photon emission. Enhancing photon emission would lead to possible stimulated emission similar to the conditions achieved in solid state semiconductor laser devices. We present experimental study on the properties of thin films of Alq(3) combined with color converting oxasene Nile Blue thin films in order to enhance stimulated laser emission. Absorption and luminescence efficiencies of single and combined thin films of Alq(3) and NB were measured. The effect of Nile Blue concentration in mixtures with Alq(3) on the optical properties were studied for different thin film thickness. The efficiency of prominent luminescence band due to electro and opto-excitations are determined. Absorption coefficients and energy gaps for the solid films were determined. Formation of crystalline structure for Alq(3) during the preparation process was observed. An attempt to design microcavity configuration that enables enhancement of the stimulated emission are speculated.