Low-voltage organic electroluminescent blue light emitting device and preparation method thereof

Abstract

The invention discloses a low-voltage organic electroluminescent blue light emitting device. The low-voltage organic electroluminescent blue light emitting device is composed of an ITO transparent substrate, a p-type doping injection layer, a hole transport layer, a luminescent layer with the hole transport characteristic, a hole diffusion layer, an electronic transport layer, an electronic buffer layer and a metal back electrode in a stacked mode. The luminescent layer with the hole transport characteristic is made of blue light emitting materials. The hole diffusion layer is made of organic semiconductor materials with the bipolar transport characteristic. The HOMO energy level of the hole diffusion layer is between the HOMO energy level of the luminescent layer and the HOMO energy level of the electronic transport layer. A photoluminescent spectrum of the hole diffusion layer and an absorption spectrum of the luminescent layer overlap. The low-voltage organic electroluminescent blue light emitting device has the advantages that the p-type doping injection layer and the hole diffusion layer are arranged in the device, so that the injection capability of holes is improved; meanwhile, cancellation, caused by accumulation of a large number of holes, of excitons in the luminescent layer is avoided, and efficient luminescence of the device at a low voltage is realized; the device has the advantages of low driving voltage, high brightness, high efficiency, good stability and simple preparation processes.

Description

technical field [0001] The invention belongs to the technical field of organic electroluminescence, and in particular relates to a low-voltage organic electroluminescent blue light emitting device and a preparation method thereof. Background technique [0002] With its outstanding advantages, organic electroluminescent devices (OLEDs) are gradually becoming a very popular emerging flat-panel display product. It has high brightness, wide viewing angle, low power consumption, fast response, 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 known as a new generation of flat panel displays and have bright application prospects. High-efficiency monochrome 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 rese...

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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 bandgap width of the blue light material ( eg ) is usually large, and the driving voltage required by the light-emitting device is relatively high, while organic light-emitting materials will generate excessive Joule heat at high current densities, thereby reducing the light-emitting performance of the device

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