OLED Charge Generation Layer for Lower-Voltage Emission
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Solution Overview
Problem
Current organic light emitting devices face challenges in efficiency and require higher driving voltages, which limit their application and commercialization.
Innovation Solution
Incorporating a charge generation layer with a p-type charge injection or generation layer having electric conductivity of 1×10−6 S/cm or more between the anode and light emitting units, enabling efficient charge transfer and balancing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional organic light emitting device structure is used, then device simplicity is maintained, but efficiency is low and driving voltage is high
Solution Approach 1:
The device is segmented into multiple functional layers including a charge generation layer and charge injection layer positioned between the anode and light emitting unit. This segmentation allows optimized charge injection and transport pathways, improving efficiency while reducing the voltage required for operation.
Solution Approach 2:
A charge generation layer and charge injection layer are introduced as intermediary layers between the anode and light emitting unit. These intermediary layers facilitate efficient charge transfer and reduce energy barriers, thereby lowering driving voltage while enhancing overall device efficiency.
2Productivity
If charge generation layer with high electric conductivity is introduced, then charge transfer efficiency is improved, but device structure complexity increases
Solution Approach 1:
The electric conductivity parameter of the charge injection layer is optimized to be 1×10^-6 S/cm or more. By controlling this specific parameter, the layer achieves efficient charge transfer functionality while maintaining a relatively simple structural configuration.
Solution Approach 2:
The charge injection layer is designed to perform multiple functions simultaneously: charge generation, charge injection, and charge transport. This multi-functionality reduces the need for additional separate layers, thereby improving charge transfer efficiency without proportionally increasing structural complexity.
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 efficiency, reduces driving voltage, and enhances the lifetime of the organic light emitting device by facilitating effective charge injection and transfer.
Implementation Method 1
the p-type charge injection layer, the p-type charge generation layer, or the layer which simultaneously injects and generates p-type charges has electric conductivity of 1×10−6 S/cm or more
Implementation Method 2
when a voltage is applied between the two electrodes, holes from the anode and electrons from the cathode each flow into the organic material layer. The holes and the electron are bonded to form excitons. The excitons emit photons that correspond to the energy difference while falling back to the ground state.
Data Source
AI summary
Provided is an organic light emitting device that includes an anode, a cathode provided to face the anode, and one or more light emitting units provided between the anode and the cathode, wherein the organic light emitting device includes a charge generation layer provided between the anode and the one light emitting unit, or between the two light emitting units adjacent to each other among the light emitting units, the charge generation layer comprises a p-type charge injection layer, a p-type charge generation layer, or a layer which simultaneously injects and generates p-type charges, and the p-type charge injection layer, the p-type charge generation layer, or the layer which simultaneously injects and generates p-type charges has electric conductivity of 1×10−6 S/cm or more.