Although the market for thin-film photovoltaic panels has incredible potential, it currently represents a small fraction of the solar panel market. However, this may change in the near future, and some PV industry experts expect thin-film solar panels to have a large market share in the near future.
The Cadmium Telluride Accelerator Consortium (CATC) is a 3-year initiative to accelerate the development of CdTe solar technologies. Its goal is to make thin-film CdTe photovoltaic cells more efficient and economical, and to create new markets for thin-film solar panels.
What are thin-film photovoltaic panels?
Unlike traditional photovoltaic panels, which are made of crystalline silicon, thin-film photovoltaic panels consist of several layers of light-absorbing materials, such as amorphous silicon, CdTe or copper indium gallium selenide. These materials are deposited on a substrate, often glass, metal or plastic.
Researchers at MIT have developed ultrathin fabric photovoltaic cells that can be easily applied to any surface, making them a portable and versatile power source. These thin and flexible photovoltaic cells, which are thinner than a human hair, can be integrated into a variety of objects such as sails, tents and even drone wings. The photovoltaic cells are highly efficient, generating 18 times more energy per kilogram compared to conventional solar panels, and are made using scalable printing processes.
Thin-film photovoltaic modules can be lightweight, flexible and even transparent, enabling integration into a variety of surfaces and applications. While thin-film solar panels have advantages in terms of aesthetics, cost and versatility, they generally have lower energy conversion efficiency than crystalline silicon panels, but this may change as thin-film solar panel technology advances.
What are thin-film photovoltaic panels made of?
Thin-film photovoltaic panels consist of thin layers of various photovoltaic materials deposited on a substrate, such as glass, plastic or metal. These layers are typically a few nanometers to a few microns thick, which is much thinner than the wafers used in traditional solar panels.
There are different types of materials used in thin-film photovoltaic panels, some of which include:
Amorphous silicon (a-Si).
These photovoltaic cells use non-crystalline silicon as the semiconductor material. They are flexible, lightweight and can be produced at low cost, but are less efficient than other thin-film modules.
Cadmium Telluride (CdTe).
CdTe photovoltaic cells consist of a thin layer of cadmium telluride semiconductor. They have high absorption coefficients and can achieve high conversion efficiencies. CdTe cells are cost-effective and have been widely deployed in utility-scale photovoltaic installations, but cadmium is toxic, so it is of environmental concern.
Copper-indium gallium selenide (CIGS).
CIGS panels are made from a combination of copper, indium, gallium and selenium and can be deposited on flexible substrates. Thin-film CIGS panels offer advantages such as high absorption coefficients, better low-light performance and excellent temperature coefficients (so they work well in hot weather). However, they are more expensive than other thin-film photovoltaic technologies.
Organic photovoltaics (OPV).
These photovoltaic cells are made of organic semiconductor materials. OPV cells are lightweight, flexible and can be fabricated using low-cost printing techniques. Although these cells have lower efficiency compared to other thin-film technologies, they have the potential to be integrated into various applications due to their flexibility, such as building-integrated photovoltaics.
Advantages and disadvantages of current thin-film photovoltaic panels.
There are many different types of thin-film photovoltaic panels, and their advantages and disadvantages vary somewhat. Here are some general advantages and disadvantages.
Advantages of thin-film photovoltaic panels over conventional photovoltaic panels.
Because thin-film photovoltaics have so many positive features, they have great potential.
- Easier thin film manufacturing process. Although it varies somewhat depending on the technology and substrate, thin-film photovoltaics are generally easier to manufacture. In fact, increasing domestic production of thin-film photovoltaic cells could have a positive impact on the move toward energy independence.
- Lower cost. Thin-film photovoltaic cells require less semiconductor material compared to crystalline photovoltaic panels and are easier to manufacture. As a result, they have lower production costs than crystalline photovoltaic panels.
- Greater versatility. Thin-film cells can be manufactured on flexible substrates, allowing for more versatile applications. They can be integrated into curved surfaces and even clothing, expanding the possibilities for solar energy production.
- Resource consumption. Conventional silicon photovoltaic panels require more resources than thin-film solar panels. Silicon panels require high-purity silicon, the production of which is energy-intensive and requires complex manufacturing processes. Thin-film solar panels, on the other hand, can be manufactured using less material, reducing the need for limited resources.
- Low-light performance. Thin-film solar cells typically perform better in low-light conditions, such as cloudy weather or shaded areas. This makes them more suitable for locations with less favorable weather conditions or shaded by trees and buildings.
- Better performance in hot weather. Photovoltaic panels tend to produce less electricity when temperatures rise above 77° F or 25° C. However, thin-film photovoltaic cells are usually not as susceptible to a drop in energy production during hot weather.
- Shorter energy payback period. Thin-film photovoltaic panels have a shorter payback period compared to silicon panels. The payback period refers to the period of time required for a solar panel to generate the same amount of energy that was used in its production process.
Disadvantages of thin-film solar panels compared to conventional photovoltaic panels.
Although thin-film photovoltaics have many advantages, they also have some disadvantages. However, scientists are working to overcome some of these disadvantages, so innovations can mitigate them in the future.
- Shorter lifespan than crystalline photovoltaic panels. Some thin-film technologies are more susceptible to degradation over time due to degradation caused by light or moisture absorption. This degradation can reduce performance and shorten overall life by about 10 to 20 years. In particular, OPV panels have a shorter lifespan than crystalline panels and other thin-film technologies.
- Lower efficiency of photovoltaic panels. Today, thin-film photovoltaic cells tend to have lower conversion efficiencies than crystalline photovoltaic panels. This means that they generate less renewable energy from a given area, requiring larger installations to generate the same amount of solar energy. This is most disadvantageous when space is limited.
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Applications of thin-film photovoltaic panels.
The properties of thin-film photovoltaic panels are ideal for a wide range of applications, which is why this technology has such great potential.
Building-integrated photovoltaics (BIPV).
Thin-film photovoltaic panels can be seamlessly integrated into building materials such as windows, facades, roofs and even flexible surfaces such as curtains or awnings. Such integration allows buildings to generate electricity while maintaining aesthetics, enabling wider use of solar energy in the construction industry.
Portable and wearable devices.
The flexibility and lightness of thin-film photovoltaic cells make them ideal for portable and wearable applications. They can be incorporated into backpacks, tents, camping equipment and even clothing to provide power.
Transportation.
Thin-film photovoltaic panels can be used on the surfaces of vehicles, including cars, buses, trains and bicycles. They can generate electricity to power on-board systems such as air conditioning, lighting and entertainment, reducing dependence on fossil fuel energy sources and increasing the use of clean energy.
Consumer electronics.
Their thin and flexible nature makes them suitable for integration into consumer electronics devices such as smartphones, tablets, e-book readers and smartwatches. By incorporating thin-film photovoltaic panels into the design of these electronic devices, battery life can be extended or additional power can be provided for charging, reducing the need for external power sources.
Agricultural applications.
Thin-film photovoltaic panels can power irrigation systems in agriculture, helping to reduce dependence on polluting fossil fuels. They can also be integrated into greenhouses, providing electricity for lighting, ventilation and other equipment.
Thin-film photovoltaic cells can provide a solution for agrivoltaic projects that are currently limited by traditional rigid photovoltaic panels. Due to the difficulty of positioning and the heavy weight of rigid solar panels, farmers implementing an agrivoltaic solution may have to abandon the project altogether. Thin-film photovoltaics can solve such problems because they are lightweight, flexible and adaptable, while generating greater energy and water savings and healthier crops.
Military and defense.
Because thin-film photovoltaic cells can be used to power remote surveillance systems, communications equipment and other devices in the field, they have potential applications in military and defense. Their lightweight and flexible design makes them easy to deploy and integrate into various military structures and equipment.
Disaster relief in developing countries.
Thin-film photovoltaic panels can play a key role in providing energy in developing countries with limited access to reliable electricity. They can be used to create small photovoltaic systems for community electrification, lighting and charging stations. In natural disaster situations, thin-film photovoltaic panels can quickly power shelters and critical infrastructure when the grid is down.
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Which is better, thin-film or monocrystalline photovoltaic panels?
Monocrystalline photovoltaic panels are generally considered better than thin-film panels due to their higher efficiency and more compact design. Monocrystalline panels have a higher energy conversion rate, so they take up less space, especially on small roofs. Although thin-film panels are lighter and can be flexible, monocrystalline panels offer higher efficiency and are more commonly used in residential and commercial photovoltaic installations.
Can I walk on thin-film photovoltaic panels?
In general, walking on thin-film photovoltaic panels is not a good idea, as they tend to be more fragile and less durable than traditional crystalline silicon panels. Walking or putting weight on thin-film panels can lead to damage, affecting their energy performance and potentially causing electrical problems. To ensure the long life and performance of thin-film photovoltaic panels, it is imperative to follow the manufacturer’s operation and maintenance guidelines and recommendations.
Thin-film photovoltaic panels may gain market share in the decades to come.
Although thin-film photovoltaic panels currently have a small market share, it is likely to increase in the future. While it has a number of very attractive features, there are some drawbacks that researchers will hopefully be able to overcome quickly. Improving the technology to increase efficiency and lifetime would enable the widespread use of thin-film solar cells in many applications.