A low-voltage organic electroluminescent blue light-emitting device and its preparation method

Abstract

A low-voltage organic electroluminescent blue light-emitting device, consisting of an ITO transparent substrate, a p-type doped injection layer, a hole transport layer, a light-emitting layer with hole transport properties, a hole diffusion layer, an electron transport layer, and an electron buffer layer and a metal back electrode superimposed, wherein the light-emitting layer with hole transport properties uses a blue light-emitting material; the hole diffusion layer is an organic semiconductor material with bipolar transport properties, and the HOMO energy level of the hole diffusion layer is between the light-emitting layer and the Between the HOMO levels of the electron transport layer, the photoluminescence spectrum overlaps with the absorption spectrum of the light emitting layer. The advantages of the present invention are: the organic electroluminescent blue light emitting device contains a p-type doped injection layer and a hole diffusion layer, which improves the hole injection ability and avoids the excitons in the light-emitting layer due to the accumulation of a large number of holes. Quenching solves the problem of high-efficiency light emission of the device under low voltage; it has the characteristics of low driving voltage, high brightness, high efficiency, good stability and simple preparation process.

Description

Technical field [0001] The invention belongs to the technical field of organic electroluminescence, and particularly relates to a low-voltage organic electroluminescence blue light emitting device and a preparation method thereof. Background technique [0002] Organic electroluminescent device (OLED) is gradually becoming a very popular emerging flat panel display product with its outstanding advantages. It has high brightness, wide viewing angle, low power consumption, fast response speed, simple preparation process and low cost. In particular, the advantages of high-quality images, portability, and flexibility are unmatched by other displays (such as CRT, LCD, PDP, etc.). Organic electroluminescent devices are hailed as a new generation of flat panel displays and have bright application prospects. High-efficiency monochromatic display of the three primary colors of red, green and blue is an indispensable part of realizing full-color display. After more than 20 years of resear...

AI Technical Summary

Problems solved by technology

However, the increase in device thickness will increase the voltage drop of the device; in addition, there is generally a problem of energy level mismatch between the electrode and the organic active material, which will hinder the carrier injection, thereby deteriorating the luminescent characteristics of the device; if the light-emitting layer It is a kind of hole-transporting material, so a large number of holes will accumulate at the interface between the electron transport layer and the light-emitting layer with strong hole blocking ability, and the accumulated holes will cause the quenching of excitons, affecting the radiation of excitons. shine

In addition, the band gap (Eg) of blue light-emitting materials is usually large, and the driving voltage required for light-emitting devices is high, while organic light-emitting materials will generate excessive Joule heat at high current densities, which will reduce the light-emitting performance of the device

Images