Conducting Polymer Ionomer Doping for Moisture Resistance
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Solution Overview
Problem
Conducting polymer-based opto-electronic devices face issues with water uptake and by-product decomposition, leading to reduced efficiency and lifetime, particularly in organic electroluminescent devices due to the use of materials like PEDOT-PSS, which absorbs moisture and decomposes, causing exciton quenching.
Innovation Solution
A composition of a conducting polymer doped with an ionomer that has a low water uptake and can crosslink with the polymer, using a specific ionomer structure represented by Formula (1), which includes different ionic groups for controlled doping and reduced by-product formation, along with physical or chemical crosslinking agents to enhance film properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If PEDOT-PSS is used as a conducting polymer doped with PSS, then the hole injection layer can be easily formed, but PSS absorbs moisture leading to increased water uptake and device degradation
Solution Approach 1:
The patent extracts PSS (poly(4-styrenesulfonate)) from the PEDOT-PSS composite and replaces it with an alternative dopant system. The hole injection layer is formed using PEDOT doped with a different dopant that does not exhibit high moisture absorption, thereby removing the harmful moisture uptake property while retaining the conducting polymer's functionality.
Solution Approach 2:
The patent creates a new composite material system by combining PEDOT with an alternative dopant (such as polyacrylic acid or other carboxylic acid dopants) instead of PSS. This composite maintains the desirable properties of PEDOT while introducing a dopant with lower moisture absorption characteristics, thus resolving the water uptake issue.
2Ease of manufacture
If PSS is used as a dopant for PEDOT, then the conducting polymer can be easily doped, but PSS decomposes by reaction with electrons releasing by-products that diffuse to adjacent organic film causing exciton quenching
Solution Approach 1:
The patent removes PSS from the doping system and replaces it with alternative dopants that do not decompose to release harmful by-products. The alternative dopants maintain the doping functionality without the side effect of electron-induced decomposition and sulfate release, thereby preventing exciton quenching in adjacent organic films.
Solution Approach 2:
The patent addresses the harmful decomposition of PSS by selecting dopants whose decomposition products are benign or less harmful. The alternative dopants may decompose into less reactive species or stabilize under device operating conditions, converting the potential harm of decomposition into a beneficial or neutral outcome.
3Ease of manufacture
If conventional conducting polymer compositions are used, then the device can be manufactured with standard materials, but the device efficiency and lifetime are reduced due to moisture absorption and by-product decomposition
Solution Approach 1:
The patent develops improved composite material formulations by combining conducting polymers with alternative dopants and potentially crosslinking agents. These composite materials maintain ease of manufacture through established processing techniques while achieving enhanced device efficiency and lifetime by eliminating moisture absorption and by-product decomposition issues.
Solution Approach 2:
The patent modifies the chemical composition parameters of the conducting polymer system by changing the dopant identity, concentration, and molecular weight. These parameter changes result in materials that retain processability while exhibiting improved stability, lower moisture uptake, and reduced decomposition, thereby enhancing device performance.
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 composition results in improved device efficiency and extended lifetime for opto-electronic devices by minimizing water absorption and by-product decomposition, leading to enhanced performance in organic electroluminescent devices and other applications.
Implementation Method 1
can physically crosslink with the conducting polymer
Implementation Method 2
has a low water uptake
Implementation Method 3
undergo either p-and/or n-redox doping by chemical and/or electrochemical processes
Data Source
AI summary
A composition including a conducting polymer and an ionomer, and an opto-electronic device including the composition are provided. The composition is prepared by doping a conducting polymer with an ionomer which has stabilized association with the conducting polymer backbone, has a low water uptake, has a low content of by-products decomposed by a reaction with electrons, and can physically crosslink with the conducting polymer. Thus, the opto-electronic device including the composition has improved device performance such as device efficiency and lifetime.