Heat-activated delayed fluorescence compound and application thereof containing 9,9'-diphenyl-acridine unit and application thereof

Abstract

The invention relates to a heat-activated delayed fluorescence compound and application thereof containing a 9,9'-diphenyl-acridine unit and application thereof. The compound is characterized in thatthe energy level difference of the singlet state and triplet state of the compound is lower than or equal to 300 meV to facilitate the improvement of reverse clearance crossing probability of a triplet exciton to a singlet exciton; in addition, a lower singlet and triplet energy level difference is maintained by the heat-activated delayed fluorescence compound, higher electron transition array strength from S1 to S0 is achieved, so that the heat-activated delayed fluorescence compound has higher light radiation transition rate to help to improve the illumination efficiency of the heat-activated delayed fluorescence compound when being used as an organic electroluminescence material.

Description

technical field [0001] The invention relates to the technical field of organic electroluminescent devices, in particular to a thermally activated delayed fluorescent compound and its application. Background technique [0002] Organic electroluminescence can be divided into fluorescence and phosphorescence electroluminescence. According to the spin quantum statistical theory, the formation probability ratio of singlet excitons and triplet excitons is 1:3, that is, singlet excitons only account for 25% of the "electron-hole pairs". Therefore, the fluorescence from the radiative transition of singlet excitons only accounts for 25% of the total input energy, while the electroluminescence of phosphorescent materials can utilize the energy of all excitons through the heavy metal effect, thus having a greater superiority. Most of the existing phosphorescent electroluminescent devices adopt the host-guest structure, that is, the phosphorescent material is doped into the host mater...

AI Technical Summary

Problems solved by technology

[0004] However, there are still many deficiencies in such TADF-based materials and their OLED devices, such as the limited types of materials, and the stability of the devices needs to be improved.

For example, to achieve ΔE ST (The energy level difference between singlet state and triplet state) is less than 0.3eV. Many TADF materials need to completely separate the HOMO-LUMO orbitals in the design of molecular structure, which leads to the reduction of the optical radiation transition rate of TADF materials and also affects Material properties

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