有机电致发光器件中观察到的三重态-三重态湮灭导致的荧光发射

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300mA/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.

Direct Observation of Enhanced Electrofluorescence Emission through Triplet-triplet Annihilation in Organic Light-emitting Devices

With N,N'-dimethyl-quinacridone (DMQA) heavily doped into tris-(8-hydroxyquinoline) aluminum (Alq3) as emission layer, a super-linear luminance enhancement with the increase of current density in organic light-emitting devices was observed. When the concentration of DMQA was 1.6%～5.6%(in mass fraction) and the current density excess 300 mA/cm2, contrary to the roll-off in electroluminescence (EL) efficiency, the EL efficiency ascends with current density. About ～0.22 cd/A enhanced EL efficiency is observed from 300 mA/cm2 to 700 mA/cm2, which is believed to be contributed to the extra regenerated singlet excitons resulted from T*-T* annihilation.