Quantum Dot Emission Layer Charge Blocking for Thickness Control
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Solution Overview
Problem
The insulation layer in existing light-emitting elements needs to be thin to prevent charge tunneling and reduce resistance, but this makes it difficult to control the thickness, leading to decreased yield and efficiency.
Innovation Solution
Incorporating a charge blocking layer with transition metal elements like Ni, Cu, Cr, La, Zn, Ti, V, Mo, and W, and oxide semiconductor components between the light-emitting layer and transport layers to effectively block charges and improve control over layer thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the insulation layer is made thin to prevent charge tunneling and reduce resistance, then charge blocking performance improves, but thickness control becomes difficult leading to decreased yield
Solution Approach 1:
The patent uses a composite charge blocking layer containing both an oxide insulator and an oxide semiconductor. The oxide insulator provides charge blocking capability while the oxide semiconductor contributes to thickness controllability and film formation properties, resolving the contradiction between thin-layer performance and manufacturing precision
Solution Approach 2:
The patent specifies precise compositional parameters for the charge blocking layer: the oxide semiconductor content is controlled at 1-50 atomic percent relative to the oxide insulator. This parameter control enables simultaneous achievement of effective charge blocking and controllable thickness
2Loss of energy
If the insulation layer is made thin to reduce overall resistance, then electrical performance improves, but charge leakage increases
Solution Approach 1:
The composite structure combining oxide insulator and oxide semiconductor creates a layered material system where the insulator component blocks charges effectively while the semiconductor component maintains lower resistance, simultaneously addressing both energy loss and charge leakage concerns
Solution Approach 2:
The charge blocking layer exhibits local quality differentiation through its composite composition, with the oxide insulator providing localized charge blocking zones and the oxide semiconductor providing conductive pathways, achieving both low resistance and charge leakage prevention
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 configuration enhances the yield and efficiency of light-emitting elements by reducing charge leakage and allowing better control over layer thickness, thereby improving overall performance.
Implementation Method 1
The insulation layer in the light-emitting element of Patent Literature 1 needs to be so thin that the charges injected from one of the electrodes can tunnel through the insulation layer
Data Source
AI summary
A light-emitting element (2) includes: an anode (4); a hole transport layer (6); a light-emitting layer (8) containing quantum dots (16); an electron transport layer (10); and a cathode (12), arranged in this order, the light-emitting element further including a charge blocking layer (14) either between the light-emitting layer and the hole transport layer or between the light-emitting layer and the electron transport layer or both, wherein the charge blocking layer contains, as an element: a transition metal element that is a component of an oxide semiconductor; at least one selected from Al, Mg, and Si; and O.