Anion Permeability Evaluation for Graphene Membranes
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Solution Overview
Problem
Current methods for evaluating anion permeability in graphene-containing membranes used in electrochemical devices are inadequate, particularly for assessing their performance in flexible and durable solar cells and organic EL devices, where high-temperature processing can damage organic materials and metal ions can impair device activity.
Innovation Solution
A method involving a measuring apparatus with an aqueous solution, a silver-metal working electrode, a counter electrode, and a reference electrode, where the reaction current is measured with and without the graphene-containing membrane, allowing for the evaluation of anion permeability through cyclic voltammetry by comparing the currents generated with and without the membrane's presence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ITO films are formed by sputtering at high temperature and annealed, then electroconductivity is improved, but organic materials cannot be subjected to those procedures and metal ions may intrude into active elements to impair device activity
Solution Approach 1:
A graphene-containing membrane is introduced as an intermediary layer between the ITO electrode and the organic photoelectric conversion layer. This membrane acts as a protective barrier that prevents metal ions (indium and halogen) from the ITO film from migrating into the organic active elements, while maintaining electrical conductivity and transparency. The membrane resolves the contradiction by enabling the use of high-performance ITO electrodes without their harmful side effects on organic materials.
2Reliability
If silver is used in low-resistant and high-transparent ITO/Ag/ITO or silver nanowires, then transparency and conductivity are improved, but silver is deteriorated by acids or halogens and causes migration that lowers transparency and impairs device activity
Solution Approach 1:
The graphene-containing membrane serves as a protective intermediary layer that shields the silver component from contact with acids and halogens in the aqueous electrolyte. This prevents silver deterioration and migration, maintaining both the transparency and conductivity benefits of silver-based electrodes while eliminating their stability problems.
3Reliability
If graphene-containing membranes are used as transparent electrode material, then electroconductivity and stability are improved, but anion permeability evaluation methods are inadequate for assessing performance in flexible and durable solar cells
Solution Approach 1:
The patent replaces conventional, inadequate mechanical or chemical evaluation methods with an electrochemical measurement approach. By using cyclic voltammetry to measure reaction current between silver-metal and anions, the system provides a precise, quantitative method for evaluating anion permeability that directly reflects the membrane's performance in actual electrochemical device operation.
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
This method effectively assesses anion permeability, enabling the evaluation of graphene-containing membranes' performance and aiding in the development of more durable and flexible electrochemical devices by identifying suitable membrane properties for improved stability and conductivity.
Implementation Method 1
measuring the reaction current I0 between the silver-metal and the anions while the electrode potential of said working electrode to said counter electrode is being periodically changed
Implementation Method 2
measuring the reaction current I0 between the silver-metal and the anions while the electrode potential of said working electrode to said counter electrode is being periodically changed
Implementation Method 3
evaluating anion-permeability of said graphene-containing membrane
Implementation Method 4
evaluating anion-permeability of said graphene-containing membrane
Data Source
Figure 1
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Figure 5~6
AI summary
[Problem] To provide a method for easily evaluating anion permeability of a graphene-containing membrane and also to provide a photoelectric conversion device employing a graphene-containing membrane having controlled anion permeability. [means to solve the problem] A method for evaluating anion-permeability of a graphene-containing membrane comprising the steps of: (i) preparing a measuring apparatus comprising an aqueous solution containing anions, a working electrode containing silver-metal, a counter electrode and a reference electrode; (ii) measuring the reaction current I0 between the silver-metal and the anions while the electrode potential of the working electrode to the counter electrode is being periodically changed and driven under the condition that the electrodes are in contact with the aqueous solution; (iii) measuring the reaction current I1 under the condition that, instead of the working electrode, the graphene-containing membrane electrically connecting to the working electrode is in contact with the aqueous solution; and (iv) comparing the currents I0 and I1 to evaluate anion-permeability of the graphene-containing membrane; and a photoelectric conversion device comprising a graphene-containing membrane. When this membrane is evaluated by the above method, the reaction current I1 has a peak on the positive potential side and the integrated charge amount Q1 on the positive potential side is 20% or less based on the integrated charge amount Q0 on the positive potential side in the absence of the graphene-containing membrane.