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在高浓度DMQA掺杂于Alq3作为发射层的器件中直接观察到了超线性的发射增强现象。当DMQA的浓度在1.6% ~5.6%之间时,电流密度大于300 mA/cm2,电致发光效率随电流密度的增大而增加。这是由于在重掺杂器件中,较多的染料有效的转移了Alq3中的激子,降低了器件中的非辐射损失,同时,三重态-三重态湮灭过程产生了新的单重态激子,贡献了额外发光的结果。当后者的贡献大于器件中的非辐射损失时,器件的发光效率将随电流的增大而上升。
Superlinear emission enhancement was directly observed in devices doped with high concentrations of DMQA in Alq3 as the emissive layer. When the concentration of DMQA is between 1.6% and 5.6%, the current density is greater than 300 mA / cm2. The electroluminescence efficiency increases with the increase of current density. This is due to the fact that in heavily doped devices, more dye efficiently shifts the excitons in Alq3 and reduces non-radiative losses in the device, while triplet-triplet annihilation processes produce new singlet-level excitations Son, contributed to the extra glow of the result. When the latter contributes more than non-radiative losses in the device, the device’s luminous efficiency will increase with increasing current.