CN-122010785-A - Bipolar carrier injection material and preparation method and application thereof

Abstract

The invention discloses a bipolar carrier injection material, a preparation method and application thereof, and relates to the technical field of semiconductor materials. The material is generated by the hydrothermal reaction of urea and transition metal salt, and can be used for preparing a hole injection layer and/or an electron injection layer of an organic light-emitting diode device. The invention prepares the solution-processable bipolar carrier injection material with good film forming property and stability by a simple hydrothermal method based on the inorganic material with low cost, realizes the purpose that the same material can be used as a hole injection layer and an electron injection layer, reduces the complexity and the production cost of generating equipment, and provides an effective and feasible new thought for researching the efficient ultraviolet OLED bipolar carrier injection material.

Inventors

• ZHANG XIAOWEN
• HUO LINGYU
• LI MUCI
• YI ZIXUAN
• XIAO YINGLIN

Assignees

• 南宁桂电电子科技研究院有限公司
• 广西自贸区睿显科技有限公司
• 桂林电子科技大学

Dates

Publication Date

20260512

Application Date

20260414

Claims (10)

1. 1. A preparation method of a bipolar carrier injection material is characterized by comprising the following steps: the material is formed by carrying out hydrothermal reaction on urea and transition metal salt, wherein the transition metal salt contains at least one of nickel, cobalt and zinc, the hydrothermal reaction temperature is 175-185 ℃ and the hydrothermal reaction time is 8-12h.
2. 2. The method of manufacturing according to claim 1, characterized in that: The transition metal salt is at least one selected from nickel nitrate, cobalt nitrate and zinc nitrate.
3. 3. The method of manufacturing according to claim 1, characterized in that: the molar ratio of the urea to the transition metal salt is 1 (0.8-1.5).
4. 4. The method of manufacturing according to claim 1, characterized in that: The method also comprises the purification process of cooling the solution after the hydrothermal reaction to room temperature and centrifuging to obtain supernatant.
5. 5. The method of manufacturing according to claim 4, wherein: the centrifugation conditions are 10000-15000rpm, 5-10 minutes.
6. 6. The method of manufacturing according to claim 4, wherein: the method also comprises a film coating process, wherein the supernatant is spin-coated on a substrate, and the film is prepared through annealing treatment.
7. 7. The method of manufacturing according to claim 6, wherein: the spin-coating speed is 3000-3500 rpm, the time is 60-80 seconds, the annealing temperature is 130-220 ℃ and the time is 10-20 minutes.
8. 8. A bipolar carrier injection material produced by the production method according to any one of claims 1 to 7.
9. 9. Use of the bipolar carrier injection material according to claim 8 for the manufacture of an organic light emitting diode device.
10. 10. An organic light-emitting diode device comprises an anode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer and a cathode, and is characterized in that the hole injection layer and/or the electron injection layer is formed by coating the bipolar carrier injection material according to claim 8.

Description

Bipolar carrier injection material and preparation method and application thereof Technical Field The invention belongs to the technical field of semiconductor materials, and particularly relates to a bipolar carrier injection material, and a preparation method and application thereof. Background Organic Light Emitting Diodes (OLEDs) have become a research hotspot in the current photovoltaic field as a new generation of flat panel display and solid state lighting technologies, by virtue of their remarkable advantages of self-luminescence, high contrast, wide viewing angle, fast response speed, and flexibility. Among them, ultraviolet (UV-OLED) has been receiving a great deal of attention in academia and industry in recent years due to its unique application value in the fields of lithography exposure, biosensing, high-density information storage, excitation light source, sterilization and disinfection, etc. However, due to the intrinsic properties of the wide forbidden band of uv-luminescent materials, the highest occupied molecular orbital energy level (HOMO) is extremely deep, resulting in carrier injection facing serious challenges. Firstly, the work function of a conventional transparent anode (such as ITO) is obviously mismatched with the HOMO energy level of an ultraviolet luminescent material, so that a huge hole injection barrier is formed, holes are difficult to effectively inject into a luminescent layer, and the serious unbalance of carriers in the device is caused, so that the luminous efficiency is low. Next, in order to overcome the energy level barrier, the prior art generally relies on active metals such as lithium and cesium or compounds thereof as an electron injection material on the electron injection side. The material has extremely unstable chemical properties and is sensitive to water and oxygen, not only increases the packaging difficulty and failure risk of the device, but also has complex evaporation process and difficult precise control, and severely restricts the stability and the large-scale preparation of the device. More critical, because the contradiction between the difficulty of hole injection and electron injection exists at the same time, and the solution strategies of the two are quite different (the anode side needs high hole injection capability and the cathode side needs low work function electron injection capability), so that at present, a single material is rarely available and can simultaneously have high-efficiency hole injection and electron injection performance (namely bipolar injection characteristics). In the existing ultraviolet OLED device manufacturing process, at least two independent evaporation sources are needed in the vacuum thermal evaporation manufacturing process because different materials are needed to be used for respectively preparing the hole injection layer and the electron injection layer. The method not only remarkably improves the complexity and the production cost of equipment configuration, but also reduces the production efficiency, and limits the large-scale application of the ultraviolet OLED in flexible electronic and multifunctional integrated devices. Therefore, a novel bipolar injection material with a proper energy level structure, high thermal stability and excellent film forming property is developed, so that the novel bipolar injection material can not only effectively bridge a hole injection barrier between an ITO anode and a deep-energy-level ultraviolet light-emitting material, but also replace unstable active metals to realize efficient electron injection, thereby realizing that a single material has a bidirectional injection function, reducing equipment complexity and production cost, and being a key technical problem to be solved urgently in the technical field of current ultraviolet OLED. Disclosure of Invention The invention aims to provide a bipolar carrier injection material, a preparation method and application thereof, and aims to at least partially solve the technical problems in the background technology. For this reason, the present disclosure provides the following technical solutions: In a first aspect, the invention provides a preparation method of a bipolar carrier injection material, which is formed by carrying out a hydrothermal reaction on Urea (Urea) and transition metal salt, wherein the transition metal salt contains at least one of nickel (Ni), cobalt (Co) and zinc (Zn), the temperature of the hydrothermal reaction is 175-185 ℃ and the time is 8-12h. In one or more embodiments, the transition metal salt is selected from at least one of nickel nitrate, cobalt nitrate, zinc nitrate. In one or more embodiments, the molar ratio of urea to transition metal salt is 1 (0.8-1.5). In one or more embodiments, the method further comprises purifying by cooling the solution after the hydrothermal reaction to room temperature, and centrifuging to obtain a supernatant. Further, the centrifugation conditions are 100