Cross-linked Hole Transport Material for QLED Carrier Balance
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Solution Overview
Problem
In quantum dot light-emitting diodes (QLEDs), the unbalanced injection rate of electrons and holes into the quantum dot luminescence layer leads to a charged state of quantum dots, resulting in non-radiative recombination and low device efficiency.
Innovation Solution
A hole transport material with a modifying group that can be cross-linked with a cross-linking group of a quantum dot material under external stimulus, enhancing the coupling between the quantum dot light-emitting layer and the hole transport layer, thereby improving hole injection and carrier balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional hole transport materials are used without cross-linking modification, then the device structure is simple and manufacturing is easier, but the carrier injection balance is poor leading to low luminous efficiency
Solution Approach 1:
The patent uses composite materials by combining hole transport materials with modifying groups that have cross-linking functionality. This creates a composite material system where the hole transport material is integrated with groups capable of cross-linking to quantum dot ligands, thereby improving carrier injection balance and luminous efficiency while managing the increased structural complexity through targeted functional integration.
Solution Approach 2:
The patent applies parameter changes by modifying the chemical structure of hole transport materials through the introduction of modifying groups with cross-linking capabilities. This structural parameter change enables dynamic interaction with quantum dot ligands, transforming the static material system into one that can actively regulate carrier injection and improve device performance.
2Reliability
If no cross-linking mechanism is introduced, then the manufacturing process is simpler, but carrier aggregation occurs at interfaces reducing device stability
Solution Approach 1:
The modifying groups on hole transport materials serve as intermediaries that facilitate cross-linking with quantum dot ligands. These intermediary functional groups act as chemical bridges between the hole transport layer and quantum dot layer, preventing carrier aggregation at interfaces and improving device stability without requiring complex manufacturing processes.
Solution Approach 2:
The patent applies preliminary action by pre-equipping hole transport materials with modifying groups that have cross-linking functionality before device assembly. This preliminary structural preparation ensures that cross-linking can occur naturally during device operation or fabrication, improving interface stability without adding complex post-processing steps.
3Productivity
If unbalanced electron and hole injection is allowed, then the device operation is simpler, but Auger recombination occurs reducing overall device efficiency
Solution Approach 1:
The patent uses parameter changes by modifying the hole transport material structure to include cross-linking functional groups. This structural parameter change enables dynamic regulation of hole injection rates through cross-linking interactions with quantum dot ligands, balancing carrier injection and preventing Auger recombination without requiring complex external control mechanisms.
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 cross-linking process increases the luminous efficiency and stability of QLED devices by regulating carrier injection balance, improving carrier recombination rates, and reducing carrier aggregation at interfaces.
Implementation Method 1
the modifying group is configured to be cross-linked with a cross-linking group of a quantum dot material under a set external stimulus
Implementation Method 2
it has the advantages of a wide absorption spectrum, a narrow emission spectrum, a high quantum yield and good fluorescence stability
Data Source
AI summary
The present disclosure provides a hole transport material, a quantum dot light-emitting device and a manufacturing method thereof and a display apparatus. A surface of a quantum dot is modified with a ligand capable of being cross-linked with a modifying group of the hole transport material, that is, a cross-linking group in the ligand, so that when the quantum dot light-emitting device is manufactured, the cross-linking group of the quantum dot material is cross-linked with the modifying group of the hole transport material under a set external stimulus, so that the coupling degree between a light-emitting layer and a hole transport layer is increased and an interface structure between the light-emitting layer and the hole transport layer is weakened, thus facilitating carrier transmission. Under the condition of not sacrificing the transmission rate of electrons, hole injection is increased to the greatest extent, so as to regulate the injection balance of carriers, improve the carrier recombination rate of the quantum dot light-emitting device, and further improve the luminous efficiency and other device performances of the quantum dot light-emitting device. Moreover, the increase of hole injection will reduce the aggregation of carriers at an interface, thereby improving the stability of the device.