Thermally activated delayed fluorescent material, preparation method therefor and application of thermally activated delayed fluorescent material

Abstract

The invention belongs to the technical field of application of photoelectric materials and particularly relates to a thermally activated delayed fluorescent material, a preparation method therefor andan application of the thermally activated delayed fluorescent material. According to the thermally activated delayed fluorescent material, the preparation method therefor and the application of the thermally activated delayed fluorescent material, the thermally activated delayed fluorescent material is formed through introducing a phenyl bridge between a donor fragment and a receptor fragment oronto a donor/receptor fragment, the PI conjugation degree of the thermally activated delayed fluorescent material is extended, the distance of separated electrons is enlarged, the energy loss of a triplet-charge reaction is avoided due to a material delocalization effect design, and device efficiency roll-off is improved through regulating and controlling an exciton transition angle. When the thermally activated delayed fluorescent material is applied to a device as a luminescent layer object material or a light outlet layer material, blue shift of luminescent wavelength will be caused by N substitution on donor/receptor fragments, the electron withdrawing capability of diphenyl sulfide sulfone is weakened, widening of energy gaps is facilitated, and deep blue light is achieved; and object-to-subject triplet energy backflow can be effectively inhibited by a triplet energy level lower than that of a subject material, so that triplet excitons are confined into a luminescent layer, the light withdrawing efficiency is increased, and thus, the thermally activated delayed fluorescent material is an ideal luminescent layer object material or light outlet layer material.

Description

technical field [0001] The invention belongs to the field of photoelectric material application technology, and in particular relates to a thermally induced delayed fluorescent material and its preparation method and application. Background technique [0002] OLED stands for Organic Light-Emitting Diode (Organic Light-Emitting Diode), also known as Organic Electroluminescence Display (OELD). OLED has the characteristics of self-illumination. It uses a very thin organic material coating and glass substrate. When the current passes through, the organic material will emit light, and the OLED display screen has a large viewing angle and can significantly save power. Therefore, OLED is regarded as One of the most promising products of the 21st century. [0003] Although organic electroluminescent materials and devices can achieve an internal quantum efficiency close to 100%, the commonly used transition metal iridium and platinum complexes are too expensive and have limited rese...

AI Technical Summary

Problems solved by technology

However, the reported high-efficiency deep blue thermally induced delayed fluorescent materials and device maximum efficiencies are basically at extremely low current densities (2 ), the performance of deep blue TADF devices is far inferior to other light colors

In addition, all TADF devices, at high current densities, singlet-triplet annihilation (STA), triplet-triplet annihilation (TTA), triplet-polaron annihilation (TPQ), and excited states The non-radiative attenuation caused by molecular vibration relaxation will make the efficiency roll-off very serious, and the roll-off performance is more obvious for deep blue TADF devices. Therefore, the further design and synthesis of TADF materials can improve device efficiency from the perspective of regulating excitonic transitions. Roll-off is a hot spot in the field of OLED research

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