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(英文)

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

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/cm^2,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。

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 lightemitting devices was observed. When the concentration of DMQA was 1. 6% - 5.6% （in mass fraction） and the current density excess 300 mA/cm^2, 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/cm^2 to 700 mA/cm^2, which is believed to be contributed to the extra regenerated singlet excitons resulted from T ^＊ -T ^＊ annihilation.