Multilayer Front Electrode for Photovoltaic Devices
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Solution Overview
Problem
Conventional photovoltaic devices with single-layer transparent conductive oxide (TCO) front electrodes suffer from high sheet resistance, significant infrared radiation transmission, reduced light transmission, increased fabrication costs, and a narrow process window, leading to reduced photovoltaic module output power and efficiency.
Innovation Solution
A multilayer front electrode structure comprising a transparent conductive coating with alternating layers of conductive metallic IR reflecting layers and TCO layers, including silver and indium tin oxide, is applied to a glass substrate, enhancing conductivity, reducing infrared radiation absorption, and optimizing light transmission and reflection spectra.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-layer TCO front electrode is used, then the structure is simple and fabrication is easier, but sheet resistance is high and conductivity is poor
Solution Approach 1:
The patent applies composite materials by combining TCO layers with metallic IR-reflecting layers to create a multilayer front electrode. This composite structure achieves low sheet resistance (high conductivity) through the metallic layers while maintaining transparency through the TCO layers, resolving the contradiction between structural simplicity and electrical performance.
Solution Approach 2:
The patent segments the single-layer electrode into multiple functional layers: TCO layers for transparency and conductivity, and metallic layers for IR reflection and additional conductivity. This segmentation allows each layer to contribute its specific property, achieving overall superior performance compared to a single-layer structure.
2Ease of manufacture
If a single-layer TCO front electrode is used, then fabrication is simpler, but infrared radiation transmission is significant causing increased operating temperature
Solution Approach 1:
The patent incorporates metallic layers with high IR reflectivity into the front electrode composite structure. These metallic layers selectively reflect infrared radiation while allowing visible light transmission, thereby reducing heat accumulation and operating temperature without complicating the fabrication process significantly.
Solution Approach 2:
The patent applies local quality by designing the multilayer electrode to have different optical properties at different wavelengths: TCO layers provide transparency in the visible range, while metallic layers provide IR reflection. This wavelength-selective property allows the electrode to maintain visibility transmission while blocking harmful infrared heat.
3Reliability
If TCO layer thickness is increased to reduce sheet resistance, then conductivity improves, but light transmission in the visible spectrum decreases
Solution Approach 1:
The patent segments the conductivity function between TCO layers and metallic layers. The TCO layers can be kept thin to maintain visibility transmission, while the metallic layers provide the necessary conductivity and IR reflection. This functional segmentation resolves the trade-off between thickness, conductivity, and optical transmission.
Solution Approach 2:
The composite multilayer structure allows thin TCO layers to be combined with metallic layers, achieving low sheet resistance through the metallic conductivity while maintaining high visible light transmission through the thin transparent layers. The composite provides both electrical and optical performance simultaneously.
4Ease of manufacture
If conventional single-layer TCO electrode is used, then fabrication costs are lower, but process window is narrow making manufacturing difficult
Solution Approach 1:
The patent segments the electrode into multiple layers that can be deposited independently, allowing each layer to be optimized separately. This segmentation expands the process window by enabling independent control of TCO and metallic layer parameters, making the manufacturing process more flexible and adaptable to different conditions.
Solution Approach 2:
The composite multilayer structure provides process flexibility by allowing independent optimization of each layer's deposition parameters. The TCO and metallic layers can be processed with different conditions, expanding the overall process window and making manufacturing more robust despite increased structural complexity.
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 multilayer front electrode structure achieves lower sheet resistance, increased photovoltaic module output power, reduced operating temperature, and cost-effective fabrication while expanding the process window, thereby enhancing the overall efficiency and reliability of photovoltaic devices.
Implementation Method 1
at least one infrared (IR) reflecting and conductive substantially metallic layer of or including silver, gold, or the like
Implementation Method 2
conductive substantially metallic layer of or including silver, gold, or the like
Implementation Method 3
at least one transparent conductive oxide (TCO) layer (e.g., of or including a material such as tin oxide, zinc oxide, or the like)
Implementation Method 4
transparent conductive oxide (TCO) layer
Implementation Method 5
reduced sheet resistance and thus increased conductivity and improved overall photovoltaic module output power
Implementation Method 6
increased reflection of infrared (IR) radiation thereby reducing the operating temperature of the photovoltaic module
Implementation Method 7
reflection of infrared (IR) radiation
Data Source
AI summary
This invention relates to a front electrode/contact for use in an electronic device such as a photovoltaic device. In certain example embodiments, the front electrode of a photovoltaic device or the like includes a multilayer coating including at least one transparent conductive oxide (TCO) layer (e.g., of or including a material such as tin oxide, ITO, zinc oxide, or the like) and/or at least one conductive substantially metallic IR reflecting layer (e.g., based on silver, gold, or the like). In certain example instances, the multilayer front electrode coating may include one or more conductive metal(s) oxide layer(s) and/or one or more conductive substantially metallic IR reflecting layer(s) in order to provide for reduced visible light reflection, increased conductivity, cheaper manufacturability, and/or increased infrared (IR) reflection capability.