Novel 7-Membered Ring Compound for OLED Electron Transport
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Solution Overview
Problem
Conventional electron transport materials with hole blocking functionality in OLEDs suffer from limited luminous efficiency and device lifetime, despite efforts to enhance their performance.
Innovation Solution
A novel compound comprising a 7-membered ring segment formed by a cis-stilbene segment and a bridge atom with a fluorene segment connecting via a double bond, exhibiting hole-blocking, reversible electron transport, and balanced charge mobility properties, is developed for use in OLEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electron transport materials with hole blocking functionality are used in OLEDs, then the device can operate with basic functionality, but the luminous efficiency and device lifetime are limited
Solution Approach 1:
The patent changes the chemical structure parameters of electron transport materials by introducing specific molecular frameworks (e.g., TmPyPb, TPBi, 3TPYMB, BmPyPb, DPyPA) with optimized electron affinity and HOMO/LUMO energy levels. These parameter changes enable simultaneous improvement of hole blocking capability, electron transport efficiency, and device stability, resolving the contradiction between luminous efficiency and device lifetime
Solution Approach 2:
The patent develops composite electron transport materials that combine hole blocking functionality with electron transport capability in a single material system. By designing molecules with specific structural features (such as carbazole, triphenylene, and pyridine moieties), the material achieves multiple functions simultaneously, improving both luminous efficiency and device lifetime without relying on separate functional layers
2Productivity
If conventional fluorescent materials are used as the light-emitting layer, then the device structure is simple, but only 25% of excitons are used for light emission due to triplet excited state loss
Solution Approach 1:
The patent converts the harmful triplet excited states that were previously lost into useful light emission by introducing phosphorescent materials or thermally activated delayed fluorescence (TADF) materials. These materials enable triplet excitons to emit photons through phosphorescence or reverse intersystem crossing, transforming the 75% loss into a beneficial contribution to quantum yield while maintaining relatively simple device structures
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 novel compound improves external quantum efficiency, current efficiency, power efficiency, maximum luminance, and device lifetime of OLEDs compared to phosphorescent OLEDs using conventional materials, demonstrating superior performance.
Implementation Method 1
exhibiting hole-blocking, reversible electron transport, and balanced charge mobility properties
Implementation Method 2
exhibiting hole-blocking, reversible electron transport, and balanced charge mobility properties
Implementation Method 3
a novel compound as hole-blocking type electron-transporters and/or emitters for OLEDs
Data Source
AI summary
A novel compound is disclosed, which comprises: a 7-membered ring segment, which is formed by a cis-stilbene segment and a bridge atom with four bonds; and a fluorene segment connecting to the bridge atom with a double bond. In addition, an organic electronic device is also disclosed, and an organic layer therein comprises the novel compound of the present invention.