Conductive Polymer Aqueous Paste for Low-Resistivity Printing
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Solution Overview
Problem
Existing printable inks and pastes for electrically conductive organic layers in photovoltaic cells and other applications often result in high surface resistivity values, leading to reduced electrical conductivity and efficiency, and require energy-intensive evaporation processes to maintain conductivity.
Innovation Solution
An aqueous composition comprising a conductive polymer, such as PEDOT:PSS, combined with cellulose ether in specific weight ratios, is used to create a printable ink or paste with low surface resistivity values, suitable for various printing techniques, including screen printing, without the need for evaporation-based volume reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional printable inks and pastes are used for electrically conductive organic layers, then the manufacturing process is simpler, but the surface resistivity values are high leading to reduced electrical conductivity
Solution Approach 1:
The patent uses a composite aqueous composition combining conductive polymer (PEDOT:PSS) with cellulose ether (hydroxypropylmethylcellulose) and additional conductive polymer particles. This composite approach achieves low surface resistivity (≤500 Ω/sq) while maintaining printability and eliminating the need for evaporation processes, thus improving electrical conductivity without significantly complicating manufacturing.
Solution Approach 2:
The patent modifies the compositional parameters of the printable ink by incorporating specific ratios of conductive polymer (0.5-5% wt), cellulose ether (1-100% wt relative to conductive polymer), and additional conductive polymer particles (5-50% wt). These parameter changes enable the formulation to achieve both low surface resistivity and good printability without requiring energy-intensive evaporation steps.
2Reliability
If evaporation processes are used to maintain conductivity in printable inks, then electrical conductivity is improved, but energy consumption increases
Solution Approach 1:
The patent extracts and eliminates the evaporation step from the conventional manufacturing process. By formulating an aqueous composition with optimized conductive polymer and cellulose ether ratios, the ink achieves low surface resistivity directly after printing and drying, removing the need for energy-intensive evaporation processes while maintaining electrical conductivity ≤500 Ω/sq.
Solution Approach 2:
The aqueous composition is formulated to self-optimize its conductivity properties through the synergistic interaction between conductive polymer, cellulose ether, and additional conductive polymer particles. The composition maintains stability and achieves desired electrical properties through simple drying, making the system self-sufficient without requiring external evaporation energy input.
3Reliability
If the volume of printable ink is reduced through evaporation to improve conductivity, then electrical performance is improved, but the manufacturing time and energy increase
Solution Approach 1:
The patent performs preliminary action by pre-formulating the ink with optimized concentrations of conductive polymer (0.5-5% wt) and cellulose ether (1-100% wt relative to conductive polymer) along with additional conductive polymer particles (5-50% wt). This preliminary optimization ensures that the ink achieves desired electrical conductivity after simple drying, eliminating the need for time-consuming post-printing evaporation volume reduction steps.
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 achieves low surface resistivity values (less than or equal to 500 Ω/sq) and good electrical conductivity, improving the performance of electrically conductive layers in photovoltaic cells and other applications while simplifying the manufacturing process.
Implementation Method 1
aqueous composition comprising at least one conductive polymer and at least one cellulose ether
Data Source
AI summary
Aqueous composition comprising:from 0.5% by weight to 5% by weight, preferably from 1% by weight to 4% by weight, with respect to the total weight of said aqueous composition, of at least one conductive polymer;from 1% by weight to 100% by weight, preferably from 2% by weight to 10% by weight, more preferably from 15% by weight to 50% by weight, with respect to the total weight of said at least one conductive polymer, of at least one cellulose ether.Said aqueous composition may advantageously be used as a printable ink or printable paste in various techniques such as, for example, screen printing, gravure printing, flexographic printing, spray coating, slot die coating, spin-coating, ink-jet printing. Preferably, said aqueous composition may advantageously be used as a printable paste for screen printing. More particularly, said aqueous composition may be used for the preparation of electrically organic conductive layers, even more particularly for the preparation of electrically organic conductive layers used in photovoltaic cells (or solar cells), in printable electronics, in organic light-emitting diodes (OLEDs), in touch screens, in antistatic coatings.