Quantum Dot Surface Control for LED Light Extraction
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Solution Overview
Problem
Current methods for forming quantum dots on substrates face challenges in achieving uniformity and control over quantum dot size and distribution, leading to reduced light extraction efficiency in photoelectronic elements like LEDs, particularly in micro-LEDs, due to limitations in patterning techniques such as colloidal quantum dots and ink jet printing.
Innovation Solution
A method involving the formation of multiple surface control layers with varying etch resistance on a substrate, allowing for precise control of quantum dot placement through exposure and etching processes to create patterns that enhance light extraction efficiency by forming quantum dots in specific surface control regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If wet etching process is used for surface roughening, then the surface can be roughened to improve light extraction efficiency, but the distribution and shape of the ruggedness become uneven, resulting in reduced light extraction efficiency and difficulty in producing uniform products
Solution Approach 1:
The patent changes the etching parameters by introducing a dual-stage etching process with different etching solutions and conditions. The first etching process creates initial ruggedness, while the second etching process refines the uniformity of the ruggedness distribution, thereby resolving the contradiction between achieving sufficient roughness and maintaining uniformity.
Solution Approach 2:
The patent segments the single etching process into multiple sequential etching stages, each with specific parameters and objectives. This segmentation allows independent optimization of each stage to achieve both sufficient ruggedness and uniform distribution, preventing the trade-off between these two requirements.
2Quantity of substance
If quantum dots are formed using conventional patterning techniques, then quantum dots can be created on the substrate, but the size and distribution control is poor, leading to reduced light extraction efficiency
Solution Approach 1:
The patent introduces a self-assembled monolayer (SAM) as an intermediary between the substrate and quantum dots. This SAM layer provides uniform nucleation sites that guide the formation of quantum dots with consistent size and distribution, eliminating the poor control associated with conventional direct patterning methods.
Solution Approach 2:
The patent employs self-assembly mechanisms where the quantum dots automatically organize themselves into uniform patterns through surface energy minimization and interparticle interactions. This self-service approach eliminates the need for complex external patterning while achieving precise size and distribution control.
3Productivity
If the surface area of photoelectronic element is increased to form nano- or micro-structures, then high efficiency can be achieved, but the control over quantum dot quantity in specific regions becomes difficult
Solution Approach 1:
The patent applies local quality by creating region-specific surface modifications with different properties. Different zones on the substrate have tailored surface energies, roughness, or chemical compositions that selectively attract or repel quantum dots, enabling precise spatial control of quantum dot distribution across the expanded surface area.
Solution Approach 2:
The patent introduces an additional dimension of control through vertical layering of functional layers with different quantum dot affinities. By stacking layers with gradient properties, the patent achieves three-dimensional control over quantum dot placement, enabling precise regional control even on expanded surfaces.
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
This approach enables precise control over quantum dot quantity and distribution, improving light extraction and conversion efficiency in photoelectronic elements by optimizing surface area and refractive index, thereby enhancing the performance of LEDs and other photoelectronic devices.
Implementation Method 1
A photoelectronic element is a device that converts light energy into electrical energy
Implementation Method 2
a quantum dot emits light corresponding to the bandgap energy of the quantum dot when photons excited by external light are stabilized
Data Source
AI summary
A structure including quantum dots formed in a surface control region, a method of forming a structure including quantum dots in a surface control region, a surface-controlled substrate provided with the structure including quantum dots, and a photoelectronic element using the same. The method includes forming multiple surface control layers that differ in etch resistance on a substrate, securing a surface control region on the substrate by forming control patterns having respectively different sizes in the respective surface control layers depending on the etch resistance values through an exposure process, forming the structure including quantum dots in the surface control region by using the plurality of surface control layers as masks, and removing the surface control layers.