Tandem OLED Sublayer Triplet Lifetime and Efficiency Trade-off
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Solution Overview
Problem
Existing tandem light-emitting devices have low luminous efficiency and short lifetime, failing to meet brightness and performance requirements.
Innovation Solution
A light-emitting device structure with a first light-emitting sublayer having a longer triplet lifetime and lower luminous efficiency, and a second light-emitting sublayer with higher luminous efficiency, where the first sublayer includes an iridium (III) complex and the second sublayer includes a platinum (II) complex, both with specific organic ligands, is used in a tandem configuration to improve both lifetime and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a tandem light-emitting device with double-layer light-emitting unit is used to improve brightness and lifetime, then the display quality and lifetime are improved, but the luminous efficiency remains not high enough
Solution Approach 1:
The patent applies local quality by creating asymmetric light-emitting sublayers with different triplet lifetimes and luminous efficiencies. The first light-emitting sublayer has a longer triplet lifetime but lower luminous efficiency, while the second light-emitting sublayer has a shorter triplet lifetime but higher luminous efficiency. This localized differentiation of material properties within the tandem structure enables each sublayer to contribute differently to the overall performance, resolving the contradiction between lifetime and luminous efficiency at the system level.
2Illumination intensity
If existing tandem light-emitting device structure is used, then the device can operate with double light-emitting units, but the brightness fails to meet use requirement
Solution Approach 1:
The patent employs parameter changes by systematically adjusting the triplet lifetime and luminous efficiency parameters of the light-emitting materials in each sublayer. By selecting materials with specific parameter combinations (longer triplet lifetime for first sublayer, higher luminous efficiency for second sublayer), the patent optimizes the overall brightness output and performance reliability of the tandem device, meeting the use requirements that existing structures fail to achieve.
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 device achieves enhanced luminous efficiency and extended lifetime, significantly improving the performance of the light-emitting device and display panel by leveraging the complementary properties of the first and second light-emitting sublayers.
Implementation Method 1
the first doping material includes a first phosphorescent light-emitting material; and the second doping material includes a second phosphorescent light-emitting material
Implementation Method 2
a light-emitting functional layer disposed on a side of the first electrode away from the substrate, the light-emitting functional layer including a first light-emitting layer, a charge-generating layer, and a second light-emitting layer sequentially disposed on the first electrode
Data Source
AI summary
Disclosed are a light-emitting device and a display panel. A light-emitting functional layer includes a first light-emitting layer, a charge-generating layer, and a second light-emitting layer sequentially disposed on a first electrode. The first light-emitting layer includes a first light-emitting sublayer, and the second light-emitting layer includes a second light-emitting sublayer. A triplet lifetime of a material of the first light-emitting sublayer is longer than that of a material of the second light-emitting sublayer, and luminous efficiency of the material of the first light-emitting sublayer is less than that of the material of the second light-emitting sublayer.