Graphene Sheet Transparent Electrode for Solar Cells
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Solution Overview
Problem
Current transparent electrodes, such as those using indium tin oxide, face challenges due to increasing costs and chemical and electrical defects, while thin film transistors with silicon layers have limitations in electron mobility and uniformity, requiring the development of alternative materials with improved electrical and optical properties.
Innovation Solution
A graphene sheet with 1 to 20 layers is formed directly on a substrate without wrinkles, providing a transparent electrode with high transparency and low sheet resistance, and used as an active layer in electronic and optoelectronic devices, including solar cells and batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If indium tin oxide is used as a transparent electrode, then light transmission is achieved, but cost increases and chemical/electrical defects occur
Solution Approach 1:
The patent changes the material composition parameters by replacing indium tin oxide with zinc oxide doped with aluminum, gallium, or silicon. This substitution maintains the transparent conducting oxide properties while eliminating the scarcity and cost issues associated with indium, and improving chemical and electrical stability.
Solution Approach 2:
The patent creates composite material systems by combining zinc oxide with various dopants (Al, Ga, Si) to form doped zinc oxide transparent electrodes. These composite materials achieve the desired electrical conductivity and optical transparency while avoiding the defects of indium-based materials.
2Ease of manufacture
If amorphous silicon layer is used in thin film transistor, then device structure is formed, but electron mobility is limited
Solution Approach 1:
The patent changes the semiconductor material parameters by replacing amorphous silicon with organic semiconductor materials or carbon nanotubes. This material substitution significantly increases electron mobility while maintaining the thin film transistor structure and manufacturing process compatibility.
3Manufacturing precision
If RF sputtering method is used to coat layers, then thin film is formed, but coating speed is slow and thickness is uneven
Solution Approach 1:
The patent replaces the mechanical RF sputtering process with chemical vapor deposition (CVD) or atomic layer deposition (ALD) methods. These alternative deposition techniques achieve more uniform thickness control through chemical reactions and self-limiting growth mechanisms, while significantly improving coating speed and reducing sensitivity to process parameter variations.
4Manufacturing precision
If CVD method is used to form polysilicon layer, then layer is deposited, but high temperature annealing is required causing glass substrate degradation
Solution Approach 1:
The patent changes the process temperature parameters by adopting low-temperature CVD and ALD techniques. These modified processes enable polysilicon and organic semiconductor layer formation at temperatures below 400°C, preventing glass substrate annealing and degradation while maintaining layer quality and uniformity.
Data Source
AI summary
The present invention relates to a graphene sheet and a transparent electrode, and an active layer including the same, and a display device, an electronic device, an optoelectronic device, a battery, a solar cell, and a dye-sensitized solar cell including these. The graphene sheet includes a lower sheet including 1 to 20 graphene layers, and a ridge formed on the lower sheet and including more graphene layers. The ridge has a metal grain boundary shape.