Surface-Textured Conductive Glass via Nanoparticle Masking
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Solution Overview
Problem
Current methods for producing surface-textured conductive glass for solar cells, such as AZO conductive glass made by hydrochloric acid wet etching and BZO conductive glass by LPCVD, face challenges like uneven products, low yield, and high costs due to the difficulty in controlling wet etching and long plasma etching times, making it hard to achieve U-shaped surface textures necessary for microcrystalline silicon and cadmium telluride thin film solar cells efficiently and cost-effectively.
Innovation Solution
A method involving magnetron sputtering of a transparent conductive film on glass, followed by immersion coating with nano/micro-spheres as a mask, and subsequent removal using ultrasonic vibration to create uniformly distributed U-shaped nano/microscopic pits, allowing for low-cost production of surface-textured conductive glass with high transmittance and low sheet resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If wet etching is used to create surface texture on conductive glass, then U-shaped surface texture can be achieved, but the process suffers from uneven products, low yield, and high costs due to difficult control
Solution Approach 1:
The patent introduces a self-assembled monolayer of nanoparticles as an intermediary masking layer during sputtering. This nanoparticle layer mediates the deposition process, causing the conductive material to deposit preferentially in the gaps between particles, thereby forming uniform U-shaped pits without requiring wet etching. This resolves the contradiction by achieving the desired shape through a different mechanism that provides better control and uniformity.
Solution Approach 2:
The patent replaces the chemical wet etching process with a physical sputtering process using nanoparticle masks. Instead of using chemical reactions to create the texture, the method uses physical deposition controlled by nanoparticle positioning, followed by removal of the particles to reveal the U-shaped structure. This substitution eliminates the control issues inherent in wet etching while achieving the same morphological result.
2Shape
If LPCVD is used to produce BZO or AZO conductive glass with U-shaped texture, then the surface texture requirement is met, but long plasma etching time increases production cost
Solution Approach 1:
The patent performs preliminary action by self-assembling a monolayer of nanoparticles on the conductive film surface before the main texturing process. This pre-positioned mask layer guides the subsequent sputtering process to automatically form U-shaped pits in the correct locations and shapes, eliminating the need for time-consuming plasma etching steps required by LPCVD methods.
Solution Approach 2:
The patent changes the fundamental parameters of the texturing approach by transitioning from plasma-based etching (LPCVD) to sputtering-based deposition with nanoparticle masking. This parameter change in the physical-chemical process enables faster texturing formation without the prolonged etching times characteristic of LPCVD methods.
3Ease of manufacture
If planar FTO conductive glass is used for cadmium telluride solar cells, then production cost is reduced, but light absorption performance deteriorates due to lack of surface texture
Solution Approach 1:
The patent segments the texturing process from the conductive film deposition by using a separate nanoparticle masking layer. This allows the conductive FTO film to be deposited planarly (maintaining low cost and simplicity), while the surface texture is subsequently created through controlled sputtering in the presence of the nanoparticle mask. The segmentation enables independent optimization of each function: low-cost planar deposition and effective light trapping texture.
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 enhances industrial production efficiency, yield, and cost-effectiveness by producing high-quality, low-cost surface-textured conductive glass suitable for solar cells with U-shaped surface textures, improving the performance and affordability of solar cells.
Implementation Method 1
coating a transparent conductive film (ITO, AZO, etc.) by magnetron sputtering
Implementation Method 2
absorbing nano/micro-spheres onto the surface of the transparent conductive film as a mask by using an immersion coating method
Implementation Method 3
removing the nano/micro-spheres by mechanical or chemical means such as the ultrasonic vibration method
Data Source
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AI summary
A surface-textured conductive glass for solar cells, characterized by a transparent conductive film coated on a glass substrate, the upper surface of which is of a surface texture with nano/micro-scopic U-shaped pits.