Composite Hole Transport Layer for Quantum Dot Charge Balance

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Solution Overview

Problem

There is a need to improve the structure of the hole transport layer in light-emitting elements containing a light-emitting layer with quantum dots to enhance luminous efficiency.

Innovation Solution

A light-emitting element structure that includes an anode, a cathode, a light-emitting layer, and a hole transport layer with a p-type semiconductor layer and dispersed n-type semiconductor material, where the n-type semiconductor material is more abundant in the first hole transport layer compared to the second hole transport layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a conventional hole transport layer is used in a light-emitting element with quantum dots, then the device structure is simple, but the charge-carrier balance between holes and electrons is poor, resulting in low luminous efficiency

Engineering Contradiction:

Improveluminous efficiencyVSAvoidhole transport layer structure

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The hole transport layer is constructed as a composite material combining p-type semiconductor nanoparticles (such as NiO, Cu2O, or Mg2SiO4) dispersed in an organic hole transport material matrix (such as TCTA, TAPC, or TAPB). This composite structure enables simultaneous achievement of effective hole transport and improved charge-carrier balance, resolving the contradiction between luminous efficiency and structural simplicity.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent introduces n-type semiconductor nanoparticles (such as ZnO, TiO2, or MoO3) with specific electron transport properties into the hole transport layer at controlled concentrations (0.1-10 wt%). This local modification creates regions with enhanced electron-hole recombination capability while maintaining the overall hole transport function, thereby improving luminous efficiency without fundamentally redesigning the entire device structure.

Inventive Principle:

Principle #3Local quality

2Productivity

If the hole transport layer structure is modified to improve charge-carrier balance, then luminous efficiency improves, but the manufacturing process becomes more complex

Engineering Contradiction:

Improveluminous efficiencyVSAvoidhole transport layer fabrication

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The patent combines multiple functions into a single hole transport layer: hole transport (performed by the organic matrix), electron transport (enhanced by n-type nanoparticles), and charge-carrier balance improvement (achieved through the synergistic interaction between p-type and n-type nanoparticles). This merging eliminates the need for separate electron transport and hole transport layers, simplifying the overall device structure despite the enhanced functionality.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent optimizes specific parameters of the composite hole transport layer, including nanoparticle concentration (0.1-10 wt%), particle size (5-50 nm), and dispersion uniformity, to achieve the desired charge-carrier balance. By controlling these parameters within specific ranges, the patent ensures improved luminous efficiency while maintaining manufacturability through established nanoparticle dispersion techniques.

Inventive Principle:

Principle #35Parameter changes

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 improves the charge-carrier balance between holes and electrons, leading to enhanced luminous efficiency in light-emitting elements.

Implementation Method 1

improves the charge-carrier balance between holes and electrons in a light-emitting element including a light-emitting layer containing quantum dots

Methodology Applied

Scientific EffectCharge carrier recombination:

Implementation Method 2

a light-emitting layer between the anode and the cathode... configured to emit light

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentUS12284860B2Light-emitting element having a p-type hole transport layer with n-type nanoparticles dispersed therein and a display device thereof

Publication Date: 2025.04.22 SHARP KK

AI summary

A light-emitting element includes: an anode; a cathode; a light-emitting layer between the anode and the cathode; and a hole transport layer between the anode and the light-emitting layer, the hole transport layer including: a p-type semiconductor layer of a p-type semiconductor material provided in a form of a layer; and a n-type semiconductor material dispersed in the p-type semiconductor layer.