Light-Emitting Material LUMO Alignment for Low Turn-On Voltage

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Solution Overview

Problem

Current light-emitting devices have a relatively high turn-on voltage due to the high LUMO energy level difference between N-type and P-type materials, which hinders electron mobility and efficiency.

Innovation Solution

A light-emitting material comprising a host material with N-type and P-type compounds, specifically designed to reduce the LUMO energy level difference through structural modifications, and a light-emitting device structure that includes a hole blocking layer with a compound to further enhance electron migration, thereby lowering the turn-on voltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If conventional N-type and P-type materials are used in light-emitting devices, then the device structure is stable and materials are readily available, but the LUMO energy level difference is high which hinders electron mobility and increases turn-on voltage

Engineering Contradiction:

Improveelectron mobilityVSAvoidturn-on voltage stability

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The patent modifies the chemical structure of the N-type material by introducing specific substituent groups (M1 and M2 groups with electron-withdrawing or electron-donating characteristics) to adjust the LUMO energy level. This parameter change in the molecular structure directly reduces the LUMO energy level difference between N-type and P-type materials, thereby improving electron mobility while maintaining device stability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality modification by specifically designing the substituent groups at particular positions (R1, R2, R3) on the N-type material molecule. By controlling the electronic properties at these local positions through selective substituent placement, the overall LUMO energy level is optimized to reduce the energy level difference with P-type materials, enhancing electron transport without compromising overall device reliability

Inventive Principle:

Principle #3Local quality

2Ease of manufacture

If the LUMO energy level difference between N-type material and doping material is large, then material selection is easier and manufacturing is simpler, but electron mobility is reduced and working voltage increases

Engineering Contradiction:

Improvematerial selection simplicityVSAvoidworking voltage

Core Design Contradiction:

Ease of manufactureVSPower

Solution Approach 1:

The patent systematically adjusts the LUMO energy level parameter of the N-type material through controlled modification of substituent groups. By changing the electronic properties of these groups, the LUMO energy level is precisely tuned to reduce the energy level difference with the doping material, thereby lowering the working voltage while maintaining a structured approach to material selection

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If the LUMO energy level difference between N-type material and hole blocking layer is large, then device structure is simpler and manufacturing is easier, but electron migration from hole blocking layer to N-type material is difficult and turn-on voltage increases

Engineering Contradiction:

Improvedevice structure simplicityVSAvoidturn-on voltage

Core Design Contradiction:

Device complexityVSEase of operation

Solution Approach 1:

The patent modifies the LUMO energy level parameter of the N-type material to create better energy level alignment with the hole blocking layer. This parameter adjustment facilitates electron migration from the hole blocking layer to the N-type material, reducing the turn-on voltage while maintaining a relatively simple device structure without requiring additional complex layers

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

The solution improves electron mobility and reduces the turn-on voltage in light-emitting devices by minimizing the LUMO energy level differences, leading to more efficient and cost-effective light-emitting performance.

Implementation Method 1

a LUMO (lowest unoccupied molecular orbital) energy level difference between an N-type material and a doping material can be reduced. Therefore, mobility of electrons in the light-emitting material can be improved

Methodology Applied

Scientific EffectElectron mobility enhancement through LUMO energy level alignment:

Implementation Method 2

a LUMO energy level difference between the N-type material and a hole blocking layer can also be reduced, so that electrons can be easily migrated from the hole blocking layer to the N-type material

Methodology Applied

Scientific EffectElectron migration through energy level alignment:

Implementation Method 3

the doping material is a phosphorescent material

Methodology Applied

Scientific EffectPhosphorescence: Phosphorescence

Data Source

PatentUS20240373747A1Light-emitting materials and light-emitting devices

Publication Date: 2024.11.07 CHENGDU BOE OPTOELECTRONICS TECH CO LTD

AI summary

The present disclosure provides a light-emitting material and a light-emitting device. The light-emitting material includes a host material and a doping material, where the host material includes an N-type material and a P-type material, and the N-type material includes a compound with a structural formula shown in Formula 1 or Formula 2. In the present disclosure, a turn-on voltage of the light emitting device can be reduced.