Hybrid Transparent Electrode Using Shellac Pyrolysis
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Solution Overview
Problem
Existing technologies face challenges in developing transparent conducting electrodes that are cost-effective and durable, particularly with the use of Indium Tin Oxide (ITO) and alternative materials like metal wire meshes and reduced graphene oxide on textured glass, due to high growth temperatures, long processing times, and the need for catalytic nanoparticles and combustible gases.
Innovation Solution
A hybrid transparent conducting electrode is created using a reduced graphene oxide film, metal mesh, and textured glass, where the glass is textured and then coated with the reduced graphene oxide film, either before or after embedding the metal mesh, using a process that eliminates the need for catalytic nanoparticles and reduces processing temperature and time, employing an eco-friendly carbon source like shellac.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional CVD process is used for graphene growth at high temperature (900-1050°C), then graphene quality is improved, but processing time increases (2-6 hours) and energy consumption increases
Solution Approach 1:
The patent changes the temperature parameter from conventional 900-1050°C to a reduced range of 750-850°C, and modifies the atmospheric conditions by using vacuum (10^-3 to 10^-2 mbar) instead of conventional CVD atmosphere. These parameter changes enable high-quality graphene growth in significantly reduced time (1-15 minutes) while maintaining graphene integrity and electrical properties
Solution Approach 2:
The patent applies preliminary oxidation to convert shellac into graphene oxide before the final reduction step. This preliminary action prepares the carbon source in advance, allowing the subsequent high-temperature treatment to directly produce high-quality graphene without requiring extended growth time, thus resolving the time-quality contradiction
2Productivity
If conventional CVD process with catalytic nanoparticles (Nickel, Copper) is used, then graphene growth is promoted, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts and eliminates the catalytic nanoparticle step from the conventional CVD process. By using vacuum thermal decomposition of shellac, the process directly converts the carbon source to graphene without requiring Nickel or Copper catalysts, thereby reducing device complexity and manufacturing steps while maintaining high productivity
Solution Approach 2:
The patent replaces expensive catalytic nanoparticles with shellac, a cheap and readily available organic material. The shellac serves as a disposable carbon source that decomposes completely during the vacuum treatment to form graphene, eliminating the need for costly catalyst materials and simplifying the overall process
3Productivity
If combustible gases (methane, methanol) are used as precursor in CVD process, then graphene growth is achieved, but safety hazards and environmental concerns increase
Solution Approach 1:
The patent replaces hazardous combustible gases with shellac, a solid organic material that serves as a safe and effective carbon precursor. The shellac decomposes under vacuum to provide carbon for graphene formation, eliminating the need for flammable gases and associated safety hazards while maintaining productive graphene synthesis
Solution Approach 2:
The patent substitutes the gas-phase chemical reaction mechanism with a solid-phase thermal decomposition mechanism under vacuum. This substitution replaces the need for combustible gas precursors with a solid carbon source (shellac) that decomposes to form graphene, thereby eliminating safety hazards associated with gas handling while preserving graphene production capability
4Reliability
If metal wire mesh or reduced graphene oxide is applied on textured glass, then transparent conducting electrode is formed, but the texturing process becomes incompatible with subsequent coating processes
Solution Approach 1:
The patent applies preliminary texturing to the glass substrate before any coating processes. This preliminary action creates the desired surface morphology in advance, and subsequent vacuum thermal decomposition and coating steps are designed to be compatible with this pre-textured surface, ensuring both electrode performance and manufacturing ease
Solution Approach 2:
The patent uses vacuum thermal decomposition at controlled temperatures (750-850°C) that are compatible with textured glass surfaces. The vacuum environment and temperature parameters are optimized to deposit graphene without damaging the glass texturing or requiring removal of metal mesh, thereby maintaining manufacturing compatibility while achieving reliable electrode 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 hybrid electrode achieves transparency ranging from 70% to 85% and sheet resistance from 5 Ω/sq to 100 Ω/sq, with improved corrosion resistance and stability under extreme conditions, including high humidity and temperature, while being cost-effective and environmentally friendly.
Implementation Method 1
heating the shellac coated feeder in a furnace/chamber under vacuum to a temperature ranging from about 750° C. to 850° C. for a period ranging from about 1 minute to 15 minutes
Implementation Method 2
heating the shellac coated feeder in a furnace/chamber under vacuum to a temperature ranging from about 750° C. to 850° C.
Implementation Method 3
the vapor of the shellac gets condensed on the textured glass embedded with the metal mesh to form a coating of the reduced graphene oxide
Data Source
AI summary
The present invention relates to hybrid transparent conducting electrode comprising reduced graphene oxide film, metal mesh and textured glass, wherein the reduced graphene oxide film is coated on the textured glass embedded with the metal mesh or the reduced graphene oxide film is sandwiched between the textured glass and the metal mesh. The present invention also relates to a process of preparing the hybrid conducting transparent conducting electrode. The said transparent conducting electrode exhibits transparency ranging from about 70% to 85% with sheet resistance ranging from about 5 Ω/sq to 100 Ω/sq.