Organic light emission diode and preparation method thereof

Abstract

The invention discloses an organic light emission diode and a preparation method thereof. The organic light emission diode comprises a substrate, an anode layer, an organic function layer and a cathode layer which are in stack combination in sequence. The organic function layer comprises a hole transfer layer, a light-emitting layer, an organometallic complex barrier layer, an n-dopant-doped organometallic complex barrier layer and an electron transfer layer which are in stack combination in sequence. A preparation method comprises the steps of providing the substrate, preparing the anode layer, preparing the organic function layer comprising the n-dopant-doped barrier layer, and preparing the cathode layer and the like. The organic light emission diode has excellent use stability, long service life, and excellent luminous efficiency; the process is simple and easy to control the condition; the qualified rate of the finished product is high; the production efficiency is improved effectively; the production cost is reduced; and the organic light emission diode and the preparation method are suitable for industrialized production.

Description

technical field [0001] The invention belongs to the technical field of electric light sources, and in particular relates to an organic electroluminescent device and a preparation method thereof. Background technique [0002] Organic Light Emission Diode (hereinafter referred to as OLED) is a current-mode semiconductor light-emitting device based on organic materials. Its typical structure is to make a layer of tens of nanometers thick organic light-emitting material on the ITO glass as the light-emitting layer, and there is a metal electrode with a low work function above the light-emitting layer. [0003] The principle of OLED light emission is based on the action of an external electric field, electrons are injected from the cathode to the lowest unoccupied molecular orbital (LUMO) of organic matter, and holes are injected from the anode to the highest occupied orbital (HOMO) of organic matter. Electrons and holes meet, recombine, and form excitons in the light-emitting l...

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Problems solved by technology

For example, the use of PN-doped transport layer technology can reduce the start-up voltage of OLED devices to improve light efficiency, and is conducive to the extension of life, but there are also problems: the thermal stability of P dopants such as F4-TCNQ is relatively poor, During the use of OLED devices, the doping structure itself is unstable, especially for the N doping of the electron transport layer, which is usually doped with alkali metal compounds, but due to the small volume of alkali metal ions, the diffusion ability Strong, the diffusion distance in the organic layer is long, the alkali metal ions will not only diffuse in the transport layer, but also diffuse into the light-emitting layer, directly leading to the quenching of excitons, affecting the light efficiency and life of the device

[0006] In order to prevent the diffusion of dopants, some researchers currently use organic materials such as Bphen and PBD to make barrier layers. However, due to the poor film quality and thermal stability of organic materials such as Bphen and PBD, their barrier effects are very limited.

And in the process of electron transport, when electrons are injected from the doped transport layer into the barrier layer, due to the large difference in conductivity of the two materials, there is an electron injection barrier, which is for the carrier in the light-emitting layer. The recombination is unfavorable and hinders the improvement of the light efficiency of OLED devices

In addition, as the driving voltage changes, this blocking performance will also change, resulting in the instability of the light effect

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