Stacked organic light emitting device and preparation method thereof

Abstract

The invention discloses a stacked organic light emitting device and a preparation method thereof. The stacked organic light emitting device comprises an anode, a hole injection layer, a first hole transport layer, a first light emitting layer, a first electron transport layer, a charge generation layer, a second hole transport layer, a second light emitting layer, a second electron transport layer, an electron injection layer and a cathode which are sequentially stacked. The charge generation layer comprises a metal oxide layer, an n-type doped layer and a metal oxide doped layer which are sequentially stacked. The metal oxide layer can improve the electron transport rate. The n-type doped layer can provide electrons and holes at the same time, and improves the stability and light scattering effect of the charge generation layer. The metal oxide doped layer improves the hole transport rate, and meanwhile, the metal oxide is of an amorphous structure which can inhibit crystallization of polycrystalline hole transport materials and avoid the presence of electron traps. The invention further provides a preparation method of the stacked organic light emitting device.

Description

technical field [0001] The invention relates to the field of organic electroluminescence, in particular to a stacked organic electroluminescence device and a preparation method thereof. Background technique [0002] In 1987, C.W.Tang and Van Slyke of Eastman Kodak Company in the United States reported a breakthrough in the research of organic electroluminescence. A high-brightness, high-efficiency double-layer organic electroluminescent device (OLED) has been prepared using ultra-thin film technology. Brightness up to 1000cd / m at 10V 2 , its luminous efficiency is 1.51lm / W, and its lifespan is more than 100 hours. [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 t...

AI Technical Summary

Problems solved by technology

At present, in order to improve luminous brightness and luminous efficiency, more and more researches are based on stacked devices. This structure usually uses the charge generation layer as a connecting layer to connect several light-emitting units in series. Compared with unit devices, Stacked structure devices often have doubled current efficiency and luminous brightness. At present, most of the research is to use two or more materials with hole injection or electron injection as the charge generation layer (such as Cs:BCP / V 2 o 5 ), or n-type and p-type doped layers as charge generation layers (such as n-type (Alq 3 :Li) and p-type (NPB:FeCl 3 )), or Al-WO 3 - Au, etc. are connected in sequence with multiple light-emitting units, but the light transmittance and luminous efficiency of this device are low, which is not conducive to the further application of stacked organic electroluminescent devices

At the same time, the preparation of this charge generation layer requires at least two procedures, which brings certain complexity to the preparation.

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