OLED P-Doped Layer Reduces Turn-On Voltage
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Solution Overview
Problem
Organic electroluminescent displays (OLEDs) are prone to color cast due to inconsistent turn-on voltages between blue, red, and green sub-pixels, leading to unwanted activation of adjacent sub-pixels and poor display quality.
Innovation Solution
Incorporating a P-doped layer between the first carrier functional layer and the light-emitting layer in the organic electroluminescent device, which reduces the hole injection potential barrier and modifies energy level bending, thereby decreasing the turn-on voltage and preventing unwanted activation of adjacent sub-pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional OLED structure without doped layers is used, then the device structure is simple, but the turn-on voltage is inconsistent across different colored sub-pixels causing color cast
Solution Approach 1:
The patent introduces P-doped layers specifically in the blue sub-pixel and N-doped layers in the red sub-pixel, creating localized doping regions rather than uniform doping across all pixels. This local quality approach allows selective modification of turn-on voltages in specific sub-pixels that need adjustment, thereby eliminating color cast while maintaining simplicity in green sub-pixels and avoiding complete restructuring of the entire device
Solution Approach 2:
The patent modifies the turn-on voltage parameter of specific sub-pixels by introducing doped layers with different doping concentrations (e.g., 0.1-10 wt% for P-dopant, 0.01-5 wt% for N-dopant). By changing the doping concentration parameter in the doped layers, the turn-on voltage can be precisely tuned to achieve consistency across blue, red, and green sub-pixels, eliminating color cast without requiring complete device redesign
2Reliability
If the turn-on voltage of blue sub-pixel is reduced to match red and green sub-pixels, then color cast is eliminated, but the hole injection potential barrier must be reduced
Solution Approach 1:
The patent introduces a P-doped layer as an intermediary between the hole injection layer and the blue light-emitting layer. This intermediary layer with modified energy levels facilitates hole injection into the blue sub-pixel by creating a smoother energy gradient, thereby reducing the hole injection potential barrier and lowering the turn-on voltage to match red and green sub-pixels, eliminating color cast
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 reduces turn-on voltage differences between sub-pixels, preventing color cast and enhancing display quality by ensuring that only the intended sub-pixel is activated, even when carriers migrate to adjacent pixels.
Implementation Method 1
a P-doped layer is arranged between the first carrier functional layer and the light-emitting layer
Implementation Method 2
Organic Electroluminescent Display, such as Organic Light Emitting Diode (OLED)
Data Source
AI summary
An organic electroluminescent device and an organic electroluminescent apparatus are disclosed. The organic electroluminescent device includes a first electrode layer, a first carrier functional layer, a light-emitting layer and a second electrode layer stacked in sequence, wherein a P-doped layer is arranged between the first carrier functional layer and the light-emitting layer. Thus the energy level bending of an interface between the first carrier functional layer and the light-emitting layer is modified, and the hole injection potential barrier at the interface between the two is reduced, thereby effectively reducing the turn-on voltage of the organic electroluminescent device.