Quantum Dot Top-Emission Display Layering for Carrier Balance
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Solution Overview
Problem
The layered structure of top emission light emitting devices using quantum dots and display devices incorporating such devices have not been established, limiting the development of efficient and optimized display devices.
Innovation Solution
A display device with a layered structure comprising a first electrode, an emitting layer made of inorganic quantum dots, and a second electrode, with optional thin film transistors using In-Ga-Zn-O-based semiconductors, and layers formed via inkjet or coating processes, allowing for top emission and flexible designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If quantum dots are used in light emitting devices, then light emission efficiency is improved, but the layered structure is not yet established
Solution Approach 1:
The device is divided into distinct functional layers: first electrode, first intermediate layer, quantum dot layer, second intermediate layer, and second electrode. This segmentation allows optimization of each layer's properties while maintaining overall device functionality and establishing a reproducible layered structure.
Solution Approach 2:
The patent employs composite material structures including inorganic quantum dots dispersed in the emitting layer, and combines different material systems (oxide semiconductors, organic compounds, inorganic materials) in intermediate layers to achieve both high light emission efficiency and structural stability.
2Device complexity
If organic compounds are used in light emitting devices, then device structure is established, but device thickness increases
Solution Approach 1:
The patent utilizes thin film intermediate layers (first and second intermediate layers) with controlled thickness to maintain device structure integrity while minimizing overall device thickness. These thin inorganic layers provide necessary functional properties without adding excessive thickness.
3Productivity
If all layers are formed of inorganic materials, then manufacturing efficiency is improved, but carrier balance becomes difficult to control
Solution Approach 1:
Different intermediate layers are designed with distinct local properties: the first intermediate layer uses oxide semiconductor with specific carrier concentration for electron transport, while the second intermediate layer uses different inorganic materials optimized for hole transport. This local differentiation achieves carrier balance control within the all-inorganic structure.
Solution Approach 2:
The patent controls carrier balance by adjusting parameters such as carrier concentration, layer thickness, and material composition in each intermediate layer. By varying these parameters, optimal charge transport and recombination are achieved in the all-inorganic quantum dot light emitting device.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The layered structure optimizes the display device, enabling efficient carrier balance and improved light emission efficiency, with all inorganic layers facilitating production and reducing shadowing and power consumption.
Implementation Method 1
The emitting layer is formed of an inorganic layer containing quantum dots, and the light emitting device is a top emission device
Implementation Method 2
at least one of the layer between the first electrode and the emitting layer, the emitting layer, and the layer between the emitting layer and the second electrode is formed by an inkjet process
Data Source
AI summary
Provided is a display device containing quantum dots. A display device includes a display area. The display area has a light emitting device in which a first electrode, a layer between the first electrode and an emitting layer, the emitting layer, a layer between the emitting layer and a second electrode, and the second electrode are stacked in this order on a substrate. The emitting layer is formed of an inorganic layer containing quantum dots, and the light emitting device is a top emission device. A thin film transistor connected to the light emitting device is preferably an n-ch TFT.