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Ultra-high-resolution quantum dot LEDs come out The research results of the team of Professor Li Fushan of Fuzhou University are published

 Last Update: 2022-05-01
 Source: Internet
 Author: User

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[ Hot Focus on Chemical Machinery and Equipment Network ] Recently, the team of Professor Li Fushan of Fuzhou University and researcher Qian Lei of Ningbo Institute of Materials, Chinese Academy of Sciences have proposed a method to suppress leakage of high-resolution devices by combining ordered molecular self-assembly technology and transfer printing technology.
A new strategy of current to fabricate high-performance ultra-high-resolution quantum dot light-emitting diodes (LEDs)
.

Chemical machinery and equipment network hotspots focus on chemical machinery and equipment

Quantum dot light-emitting diode (QLED) is a self-luminous technology that does not require additional light sources and is still in the research and development stage, and has broad application prospects in the field of lighting displays due to its excellent optoelectronic properties, such as high color purity and high luminous efficiency.

.
As early as a few years ago, there were teams working on the QLED project.
If the synthesis of quantum dots meets the requirements of LED optoelectronic performance, then quantum dot LEDs are expected to combine the advantages of both gallium nitride LEDs and OLEDs
.

Quantum dots are a class of particulate materials with a size of less than 20nm.
Due to their small size, their quantum confinement effect is significant.
Therefore, quantum dots can emit pure color light with a narrow spectral width, and the color of light emission is determined by the physical properties of quantum dots.
Covers visible light
.
Quantum dots have a unique property, that is, whenever they are stimulated by light or electricity, they will emit colored light.
The color of the light is determined by the material, size and shape of the quantum dots.
This property allows the quantum dots to change.
The color of the light emitted by the light source
.
Quantum dots can completely convert the blue light emitted by the LED light source into white light, instead of only absorbing part of it like YAG phosphors.
Naturally less electricity is required
.
The white light of QLED can be completely consistent with the ideal lighting source in principle, which is closer to natural light, and the heat generation is greatly reduced.
The more efficient performance makes it better in terms of energy saving and emission reduction
.

　　In recent years, driven by emerging concepts such as "metaverse" and smart medical care, next-generation displays have set higher standards for pixel resolution to meet the ever-escalating needs of applications such as massive information and near-eye displays
.
The development of extremely high-resolution displays with thousands or even 10,000-level PPI (the number of pixels per inch) that can output massive information in a tiny space is a development trend and a condition
.

　　However, QLED's quantum dots cannot achieve the same evaporation method as self-luminous OLEDs due to their shortcomings that they are easily affected by heat and moisture.
Only inkjet printing processes can be developed
.
How to achieve high-resolution pixelation of quantum dot light-emitting diodes is still a key bottleneck
.

　　In this study, the researchers used ordered molecular self-assembly technology to achieve dense and defect-free quantum dot monolayers, and combined with transfer printing technology to achieve ultra-high-resolution quantum dot display of sub-micron pixels, the highest resolution It can reach 9072-25000PPI (the limit resolution of the human eye is about 300PPI), realize the uniform pickup and release of the quantum dot patterned film, and can easily prepare ultra-high-resolution quantum dot light-emitting diodes with sub-micron pixels
.
Importantly, this is one of the highest pixel densities for a display device reported to date
.

　　Meanwhile, in order to suppress the leakage current of the device, this work proposed for the first time to embed a honeycomb-patterned wide-bandgap non-luminescent quantum dot layer as a charge blocking layer between the luminescent quantum dot pixels, thereby achieving a brightness as high as 262400 cd m-2, and the external A red QLED with a quantum efficiency of 14.
72%
.
This uniform and dense barrier layer effectively reduces the leakage current of the device and greatly improves the efficiency of the device
.
Compared with previous research, this achievement has better performance in high-resolution quantum dot display, which opens up a new route for realizing ultra-high-resolution luminescence display with high performance
.

　　According to reports, this new high-resolution patterning method can further realize full-color display in the future
.
The promise of ultra-high-resolution quantum dot light-emitting diodes can be applied to next-generation "near-eye" devices such as head-mounted displays and smart glasses for virtual reality (VR) and augmented reality (AR) applications
.
Relevant research papers were recently published online in the top international journal "Nature-Photonics"
.

　　Original title: Ultra-high-resolution quantum dot LEDs come out, and the research results of the team of Professor Li Fushan of Fuzhou University are published

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