Solar Photovoltaic Modules.

September 17, 2021 amorphous, cells, concentrators, lenses, module, modules, monocrystalline, multicrystalline, polycrystalline, power, PV, thin-film No Comments

A PV module consists of many PV cells wired in parallel to increase current and in series to produce a higher voltage. 36 cell modules are the industry standard for large power production.

The module is encapsulated with tempered glass (or some other transparent material) on the front surface, and with a protective and waterproof material on the back surface. The edges are sealed for weatherproofing, and there is often an aluminum frame holding everything together in a mountable unit. In the back of the module there is a junction box, or wire leads, providing electrical connections.

Conventionally, PV modules are designed and manufactured for outdoor applications. Thus, they can operate under the sun, rain, and other climate impacts, which make possible the use of PV modules as potential components for external enclosures of buildings.

With the development in the past few decades, various types of PV module technologies are now available in the PV market, but not all these technologies are suitable for the integration or incorporation in building envelopes, since PV modules are traditionally designed mainly for power generation, and their functionalities as envelope elements are generally overlooked.

There are currently four commercial production technologies for PV Modules:

• Single Crystalline. This is the oldest and more expensive production technique, but it's also the most efficient sunlight conversion technology available. Module efficiency averages about 10% to 12%^[*].
• Polycrystalline or Multicrystalline. This has a slightly lower conversion efficiency compared to single crystalline but manufacturing costs are also lower. Module efficiency averages about 10% to 11%^[*].
• String Ribbon. This is a refinement of polycrystalline production, there is less work in production so costs are even lower. Module efficiency averages 7% to 8%^[*].
• Amorphous or Thin Film. Silicon material is vaporized and deposited on glass or stainless steel. The cost is lower than any other method. Module efficiency averages 5% to 7%^[*]

Module electrical connections are made in series to achieve a desired output voltage or in parallel to provide a desired current capability (amperes) of the solar panel or the PV system. The conducting wires that take the current off the modules are sized according to the current rating and may contain silver, copper or other non-magnetic conductive transition metals. Bypass diodes may be incorporated or used externally, in case of partial module shading, to maximize the output of module sections still illuminated.^{[citation needed]}

Some special solar PV modules include concentrators in which light is focused by lenses or mirrors onto smaller cells. This enables the use of cells with a high cost per unit area (such as gallium arsenide) in a cost-effective way.

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Newer Semiconductor Materials.

September 16, 2021 bandgap, cell, cells, DSSC, dye, inorganic, nanoparticles, OPV, organic, perovskite, polymer, PPV, PV, quantum dots, solar, thin-film, titanium dioxide No Comments

Newer Materials.

1. Dye-Sensitized.

Another type of solar cell material is a small molecule dye, such as a ruthenium metalorganic dye, that can absorb a broad range of the visible region of sunlight. An inorganic mesoporous nanoparticle layer, usually titanium dioxide, increases the area for light absorption. Solar cells using these materials can be made using solution processing, making them inexpensive to fabricate.

Dye-sensitized solar cells (DSSCs) belong to the group of thin-film solar cells which have been under extensive research for more than two decades due to their low cost, simple preparation methodology, low toxicity and ease of production.

Still, there is lot of scope for the replacement of current DSSC materials due to their high cost, less abundance, and long-term stability.

2. Organic/Polymer.

Semiconducting polymers such as polyphenylene vinylene (PPV) and small organic small molecules such as phthalocyanines, polyacenes, and squarenes are also used in solar cells. These highly conjugated organic molecules have a broad absorption in the visible and near infrared region. These materials are deposited as thin films either by vacuum deposition methods or solution processing, and solar cells using these materials are usually thin and flexible. However, the efficiency of these cells is still low, just a little more than 10%, hence they have not been commercialized yet.

OPV cells are currently only about half as efficient as crystalline silicon cells and have shorter operating lifetimes, but could be less expensive to manufacture in high volumes.

They can also be applied to a variety of supporting materials, such as flexible plastic, making OPV able to serve a wide variety of uses.

3. Perovskite.

Perovskite cells are generally hybrid organic-inorganic lead or tin-halide materials, such as methylammonium lead halide. The cells are built with layers of materials that are printed, coated, or vacuum-deposited onto an underlying support layer, known as the substrate.

These materials can be solution-processed, hence enable inexpensive and simple fabrication. They are typically easy to assemble and can reach efficiencies similar to crystalline silicon.In the lab, perovskite solar cell efficiencies have improved faster than any other PV material, from 3% in 2009 to over 25% in 2020.

One of the key advantages of these materials is their ability to absorb sunlight across the entire visible spectrum.

To be commercially viable, perovskite PV cells have to become stable enough to survive 20 years outdoors, so researchers are working on making them more durable and developing large-scale, low-cost manufacturing techniques.

4. Quantum dots.

Nanoparticles, a few nm in size, called quantum dots are another type of emerging materials used in solar cells that conduct electricity through tiny particles of different semiconductor materials just a few nanometers wide. They are low bandgap semiconductor materials such as CdS, CdSe, and PbS. Their bandgaps can be tuned over a wide range by changing the size of the particles.

Quantum dots provide a new way to process semiconductor materials, but it is difficult to create an electrical connection between them, so they’re currently not very efficient. However, they are easy to make into solar cells. They can be deposited onto a substrate using a spin-coat method, a spray, or roll-to-roll printers like the ones used to print newspapers.

Many common materials used for fabricating quantum dots such as Cd and Pb are considered toxic, hence other alternative materials such as copper indium selenide are being developed.

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Thin-Film Solar Cell.

September 16, 2021 a-Si, amorphous, Cadmium Telluride, CdTe, cell, cells, CIGS, Copper Indium Gallium Selenide, GaAs, Gallium Arsenide, PV, silicon, solar, thin-film No Comments

Thin-Film.

Thin-film are cells that have light-absorbing layers about 350 times smaller than the standard silicon. Because of their narrow design and the efficient semiconductor built into their cells, thin-film solar cells are the lightest PV cell you can find while still maintaining strong durability.

The cell is made by depositing one or more thin layers of PV material on a supporting material such as glass, plastic, or metal.

Thin-film solar panels are typically made with one of the following four technologies:

• Cadmium Telluride (CdTe) – The most widely used thin-film technology, CdTe holds roughly 50% of the market share for thin-film solar panels. CdTe contains significant amounts of Cadmium – an element with relative toxicity – so this is a factor of consideration. First Solar is the top innovator and seller in this space.

• Amorphous Silicon (a-Si) – The second most popular thin-film option after CdTe, a-Si is the most similar technology to that of a standard silicon wafer panel. a-Si is a much better option than its counterparts (CdTe, CIGS) in terms of toxicity and durability, but it is less efficient and is typically used for small load requirements like consumer electronics. The quest for scale is always a hindrance for a-Si.

• Copper Indium Gallium Selenide (CIGS) – Laboratory CIGS cells have reached efficiency highs of 22.4%. However, these performance metrics are not yet possible at scale. The primary manufacturer of CIGS cells was Solyndra (which went bankrupt in 2011). Today, the leader is Solar Frontier. MiaSolé also manufactures CIGS panels in the U.S. and China.

• Gallium Arsenide (GaAs) – A very expensive technology, GaAs holds a world record 28.9% efficiency for all single-junction solar cells. GaAs is primarily used on spacecrafts and is meant for versatile, mass-scale installments of PV energy in unusual environments.

It is used in building-integrated photovoltaics and as semi-transparent, photovoltaic glazing material that can be laminated onto windows.

Thin film solar panels are the cheapest, but have the lowest efficiency rating and require a lot of space to meet your energy needs

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