OLED Mixed Electron Transport Layer for Voltage and Efficiency
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Solution Overview
Problem
Conventional light-emitting devices, particularly those using organic light-emitting diodes (OLEDs), face issues with device deterioration due to the electron transport layer containing 8-hydroxyquinolinolato-lithium (Liq), which affects efficiency and lifespan, and require high driving voltages.
Innovation Solution
Incorporating a mixed layer with specific compounds having a concentration gradient in the electron transport layer, along with a metal halide and lanthanum-based metal in the electron injection layer, to control electron migration and hole leakage, thereby reducing driving voltage and enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If electron transport efficiency is improved, then device performance increases, but charge balance is disrupted and hole leakage occurs
Solution Approach 1:
The patent implements electron transport layers with concentration gradients where the composition varies spatially. This allows different regions to perform different functions: one region optimizes electron transport while another region maintains charge balance, preventing hole leakage through localized material distribution.
Solution Approach 2:
The patent uses composite structures combining multiple organic compounds with complementary properties. These composite electron transport layers work synergistically to achieve both high electron transport efficiency and proper charge balance, with each component contributing specific functionality to prevent hole leakage.
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 effectively prevents device deterioration, achieves low driving voltages, and improves the efficiency and reliability of light-emitting devices by optimizing charge balance and exciton formation.
Implementation Method 1
a mixed layer made of different compounds having a concentration gradient that effectively controls the electron migration rate
Implementation Method 2
the electron injection layer includes a metal halide and a lanthanum-based metal
Implementation Method 3
Carriers, such as holes and electrons, recombine in the emission layer to produce excitons. These excitons transit from an excited state to a ground state, thereby generating light
Data Source
AI summary
The present application provides a light-emitting device and an electronic apparatus including the light-emitting device. The light-emitting device includes: a first electrode; a second electrode facing the first electrode; an interlayer between the first electrode and the second electrode and including an emission layer; and an electron transport layer and an electron injection layer between the emission layer and the second electrode, wherein the electron transport layer includes a mixed layer including a first compound and a second compound, the first compound includes a C14-C60 carbocyclic group, and a triplet energy of the first compound is about 2.0 electron volts or lower, the second compound includes a π electron-depleted nitrogen-containing C1-C60 cyclic group, and a triplet energy of the second compound is about 2.5 electron volts or greater, and the electron injection layer includes a metal halide and a lanthanum-based metal.