An organic electroluminescent device

Abstract

The present invention involves a kind of mechanical and electrical lighting device. The main material of the luminous layer is the composition of the material of the cavity transmission and the electronic transmission ability. 1 H Single -level Smart Smart Smart Smart S 1 F ; The three -line state energy level T in the at least one material in the main material of the material 1 H Single -line energy level S, which is higher than N‑π excited state 1 H , And t 1 H Crickets 1 H ≤0.3EV; or, at least one material in the main material CT excited state of the three -line state energy level T 1 H Three -line state energy level S, higher than N‑π excited state 1 H , And T 1 H Crickets 1 H ≥1EV, and the difference between the second and third -line state -level energy level and CT stimulation of the main material of the main material is ‑0.1 ~ 0.1EV; the organic functions adjacent to the light layer areThe three -line state T of the layer of the material 1 Both are higher than the single -line SNE SIO 1 H EssenceThe thermal activation delayed fluorescent materials used by the present invention limits the compound of the luminous area as the main material, which effectively suppresss the efficiency rolling phenomenon. The efficiency of the device is improved to 13 % to 18 %.

Description

technical field [0001] The invention relates to the technical field of organic electroluminescent devices, and specifically designs an organic electroluminescent device using a heat-activated delayed fluorescent material as a main material. Background technique [0002] The light-emitting layer of the organic electroluminescent device OLED is mainly made of all fluorescent materials, all phosphorescent materials or a mixture of fluorescent materials and phosphorescent materials. Among them, the light-emitting layer generally adopts a high triplet T 1 , a host material with a wide energy gap. The organic light-emitting material system includes a fluorescent system and a phosphorescent light-emitting system. A doped system is used, and the fluorescent system only uses the singlet exciton energy. The ideal internal quantum efficiency is only 25%. Low, while the phosphorescent system can utilize singlet and triplet exciton energy at the same time, and the internal quantum effic...

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Problems solved by technology

[0006] For this reason, the technical problem to be solved by the present invention is that the light-emitting host material in the prior art has a lower triplet T 1 And the smaller energy gap Eg (the energy level difference between HOMO and LUMO) leads to the problem of low efficiency of exciton recombination, and then provides an organic electroluminescent device, using thermally activated delayed fluorescent material as the host material limit The recombination of excitons in the light-emitting region effectively suppresses the efficiency roll-off phenomenon, and the device efficiency is increased to 13% to 18%.

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