The selection of light emitters materials is crucial in the preparation and optimization of OLEDs, and their properties are one of the important factors determining the device performance. Among the three primary colors of red, green and blue required for full-color display, green OLED has the best luminous efficiency, blue light is relatively poor, and the performance of red light device is relatively backward. However, with the continuous in-depth research of light-emitting materials and devices, and the addition of dopants to the light-emitting body, the types and quantities of light-emitting bodies have been greatly developed, and the efficiency of light-emitting devices has also been significantly improved.
Coumarin 6 is a laser dye used as a dopant in the main materials of organic light-emitting diode (OLED). The fluorescence emission peak of Coumarin 6 is located at 500 nm (blue-green color), and the fluorescence quantum efficiency is about 100%. More and more coumarin derivatives have been synthesized and used in green light dyes with the development of organic light-emitting diode green light materials (OLED). Quinacridone (QA) is also an important green fluorescent dye. Its fluorescence is not visible in the solid, but when it is dispersed into the main luminescent material of ALq3, the fluorescence efficiency is very high, the emission wavelength is 540 nm.
Anthracene compound is a typical blue light emitting material, and is one of the blue light emitting materials widely used in OLED devices. Two isomers of 9,10-disubstituted anthracene derivatives (MNBPA and MBPNA) have blue luminescent properties. Using the two isomers as the main materials and Bubd-1 as the sky-blue Dopant, a series of highly efficient and stable blue devices were prepared. The thermal stability and morphological stability of anthracene nucleus were improved by introducing biphenyl to replace naphthalene. Asymmetric high-twist ortho-substituted anthracene derivative MNAN as host and P-NAPPN as dopant can greatly improve the luminescence efficiency of OLED.
4-(dicyanomethyl)-2-methyl-6-[p-(dimethylamino) Styryl]4H-pyran (DCM) is the first red dye used, which has high photoluminescence efficiency, but the concentration quenching of this molecule is more serious. In order to solve the concentration quenching problem, “Auxiliary doping” method can be used to prepare red organic light-emitting diode, that is, in the production process of red organic light-emitting diode, red Rubber (5,6,11,12-tetraphenyltetraene) was added into DCM red material as a synergistic dopants.