OLED Multi-Layer Structure Enhancing Electron-Hole Recoupling
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Solution Overview
Problem
The existing organic light emitting diodes (OLEDs) face inefficiencies in electron and hole re-coupling due to energy level differences and simple membrane structures, leading to poor emitting efficiency and shorter device lifetime.
Innovation Solution
The OLED employs a complex multi-layer structure comprising specific layers such as a first and second hole-transporting layer, a light-emitting layer with a lower unoccupied molecular orbital energy level, an electron-transporting layer, and an electron injection layer, with precise thicknesses and materials like PEDOT:PSS, TAPC, and MDP3FL, to enhance electron confinement and re-coupling opportunities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple membrane structure is used in OLED, then the device complexity is reduced, but the electron-hole re-coupling efficiency deteriorates
Solution Approach 1:
The membrane structure is divided into multiple functional layers including hole-transporting layer, light-emitting layer, and electron-transporting layer. Each layer is segmented with specific thicknesses (hole-transporting layer: 5-20 nm, light-emitting layer: 30-50 nm, electron-transporting layer: 10-30 nm) to independently control charge carrier transport and re-coupling processes, thereby improving re-coupling efficiency while maintaining manageable device complexity
Solution Approach 2:
Different regions of the membrane structure are assigned different material properties and thicknesses to optimize local functions. The hole-transporting layer uses materials with specific hole mobility, the light-emitting layer is positioned at the interface with specific thickness to maximize re-coupling, and the electron-transporting layer has tailored electron mobility characteristics, creating local quality variations that enhance overall device performance
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 significantly improves the emitting efficiency and brightness of OLEDs, extending their lifetime by effectively confining electrons and preventing electrode destruction.
Implementation Method 1
the electrons and electronic holes, produced by the first electrode and the second electrode, propagate and re-couple inside the organic light-emitting layer as a result of external electrical field, so as to release energies to ignite the emitting molecules of the organic light-emitting layer lighting
Data Source
AI summary
The present invention discloses an organic light emitting diode and a manufacturing method thereof. The OLED comprises a first electrode, a first hole-transporting layer disposed on the first electrode, a second hole-transporting layer disposed on the first hole-transporting layer, a first light-emitting layer disposed on the second hole-transporting layer, an electron-transporting layer disposed on the first light-emitting layer, an electron injection layer disposed on the electron-transporting layer and a second electrode disposed on the electron injection layer. The energy level of the first light-emitting layer in the lowest unoccupied molecular orbital is lower than that of the second hole-transporting layer, and the thickness of the first hole-transporting layer is larger than that of the second hole-transporting layer.