Triarylamine Fluorene Polymers for OLED Lifetime
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Solution Overview
Problem
Existing semiconductive polymers used in displays, particularly those driven by pulsed conditions, have inadequate lifetimes, especially for blue light-emitting polymers, and existing solutions do not effectively address the specific challenges of pulsed driving conditions.
Innovation Solution
A semiconductive polymer comprising a triarylamine repeat unit with specific structural features, such as phenyl or naphthyl groups and branched alkyl or alkoxy substituents, is developed to enhance the lifetime in pulsed driven displays, which can also function as a hole transport or emission material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing semiconductive polymers are used in pulsed driven displays, then the device can operate with simple substrate structure and low cost, but the lifetime of the display is inadequate
Solution Approach 1:
The patent changes the chemical parameters of the polymer by introducing specific triarylamine repeat units with controlled substituents (Ar1, Ar2, R groups) to improve lifetime performance under pulsed driving conditions while maintaining structural manageability
Solution Approach 2:
The patent creates composite polymer structures by combining triarylamine repeat units with specific aromatic substituents (phenyl, naphthyl groups) and solubilising groups to achieve both improved reliability and processability
2Reliability
If blue light-emitting polymers are used to achieve desired emission color, then the display can provide full color capability, but the lifetime is particularly inadequate
Solution Approach 1:
The patent modifies the chemical structure parameters of blue light-emitting polymers by incorporating specific triarylamine repeat units with electron-donating groups to enhance both lifetime and emission performance simultaneously
Solution Approach 2:
The patent introduces specific functional groups (Ar1, Ar2, R substituents) at localized positions within the polymer repeat unit to improve blue emission lifetime without compromising overall emission intensity
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 semiconductive polymer exhibits superior lifetime performance in pulsed driven displays compared to polymers with other repeat units, such as DPF or PFB, under both DC and pulsed driving conditions, effectively addressing the limitations of existing polymers.
Implementation Method 1
Each pixel is a light-emitting diode (LED), such as a polymer LED (PLED)... An electroluminescent layer 3 is provided between anode 2 and cathode 4
Data Source
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AI summary
A pulsed driven display comprising an organic light-emitting device, said device comprising an organic layer comprising a semiconductive polymer, said polymer comprising a fluorene or triarylamine repeat unit, the fluorene or triarylamine repeat unit having a group R pendent from the polymer backbone, wherein R has general formula (I) where Ar1 represents phenyl or a group comprising napthyl; Ar2 represents phenyl or a group comprising napthyl; R' represents a substituent group; R" = H or a substituent; n=0, 1, 2 or 3; m=0 or 1; and n'=1 or 2, with the proviso that m=0 if n=0.