Modified Graphene Doped Silver Paste for Solar Cells
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Solution Overview
Problem
Current solar cell front side silver pastes face limitations in reducing contact resistance and series resistance, which hampers the photoelectric conversion efficiency, and there is a lack of research on additives to improve printability and ohmic contact with silicon substrates.
Innovation Solution
A solar cell front side silver paste doped with modified graphene, comprising specific ratios of silver powder, organic binder, glass powder, and surface-modified graphene, which reduces contact resistance and series resistance, enhancing the photoelectric conversion efficiency by forming a good ohmic contact with silicon substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional silver paste is used, then the basic electrode function is achieved, but the contact resistance and series resistance remain high, limiting photoelectric conversion efficiency
Solution Approach 1:
The patent applies composite materials by combining silver powder with modified graphene to create a hybrid conductive paste. The modified graphene forms a conductive network that works synergistically with the silver particles to reduce both contact resistance at the silicon interface and series resistance along the gate lines, thereby improving photoelectric conversion efficiency without compromising electrode functionality
Solution Approach 2:
The patent employs parameter changes by modifying the chemical and physical properties of graphene through surface treatment with coupling agents. This modification changes the interfacial parameters between the conductive paste and silicon substrate, enabling better wetting and adhesion, which directly reduces contact resistance and enhances electrical contact quality
2Reliability
If conventional silver paste is used, then the electrode structure is formed, but the ohmic contact with silicon substrate is insufficient, hampering efficiency improvement
Solution Approach 1:
The patent uses modified graphene as an intermediary material between the silver paste and silicon substrate. The graphene layer with modified surface properties acts as a mediator that improves interfacial bonding and promotes ohmic contact formation during the sintering process, bridging the gap between the conductive paste and the silicon surface more effectively than conventional materials
3Reliability
If gate line width is reduced and height to width ratio is increased, then shading area is reduced and efficiency is improved, but the printability and formation of good contact become more difficult
Solution Approach 1:
The patent applies parameter changes by modifying the rheological and adhesive parameters of the silver paste through the addition of modified graphene. This enables the paste to maintain good printability and form accurate fine gate line patterns while simultaneously achieving low contact resistance and high-quality ohmic contact, thus resolving the contradiction between manufacturing precision and contact quality
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 modified graphene doped silver paste significantly reduces contact resistance to 0.0018 Ω, improving the photoelectric conversion efficiency and market prospects by forming effective ohmic contact with silicon substrates.
Implementation Method 1
the ohmic contact performance between the paste and the silicon substrate is improved, the series resistance of the paste is reduced
Implementation Method 2
by the use of graphene which has a two-dimensional planar structure, high electrical conductivity and thermal conductivity
Data Source
AI summary
A solar cell front side silver paste doped with modified graphene and its preparation method are disclosed. The solar cell front side silver paste doped with modified graphene comprises by weight 0.1-5 parts of modified graphene, 88-91 parts of silver powder, 5-15 parts of organic binder, 1-5 parts of organic solvent, 1-3 parts of glass powder, wherein the modified graphene is a surface modified graphene. A solar cell front side silver paste is developed, which is screen printed on a crystalline silicon wafer, sintered at a high temperature, penetrates the SiNx passivation layer in the crystalline silicon wafer, and thus forms a good ohmic contact.