Solar cells have a long history, but they are still in the development stage for a long time. When sunlight hits the solar cell, it will generate electric charge, and the photovoltaic effect will appear. The amount of charge depends on multiple factors: battery material (silicon, thin film, etc.), battery area (a larger battery area means more individual batteries can be converted into more voltage or current), and the quality of the light source. The most efficient and attractive light source is the sun that is easily available and cost-free.
The difference between thin film and crystalline silicon solar panels:
Even if waste silicon wafers are used in thin-film solar panels, silicon wafers are not necessarily low-cost considering its efficiency level. Thin-film solar cells are cheaper than traditional solar panels, but the efficiency is also lower, and the photovoltaic conversion rate is between 20%-30%.
According to the different materials used, typical thin-film solar cells can be divided into the following four categories: amorphous silicon (a-Si) and thin-film silicon (TF-Si); cadmium telluride (CdTe); copper indium gallium selenium (CIS or CIGS) and dye-sensitized solar cells (DSC) plus other natural materials.
The structure of thin-film solar cells and silicon crystal solar cells is not much different, it contains a six-layer structure. In this structure, the transparent coating is covered with the anti-reflection layer, underneath is the PN junction, and then the contact plate and the substrate. Obviously, the operating principle (photovoltaic) and crystalline silicon cells are the same.
Silicon VS thin film
Crystalline silicon technology has been around for some time and has proven to be valuable. Thin film technology is still in its infancy, but it has the potential to achieve lower costs under the same efficiency and reliability. In that case, how should I choose?
The advantages of crystalline silicon are high conversion efficiency, reaching 12%-24.2%, high stability, easy manufacturing, and high reliability. Time is another advantage: crystalline silicon modules have been in production in the 1970s, and monocrystalline silicon panels can withstand harsh environments and can be used for space flight.
Other advantages include heat resistance and low installation costs. And considering the time of disposal/recycling, silicon is more environmentally friendly.
The disadvantage is that in terms of initial cost, crystalline silicon is the most expensive solar module. Moreover, the solar energy absorption factor is very low, and the material is brittle and fragile.
Thin-film solar cells are cheaper than old-fashioned crystalline silicon solar cells, can be prepared on thin silicon wafers, and are more flexible and easier to handle. And compared with crystalline silicon, it is not easily damaged by external shocks.
The main disadvantage of thin-film solar cell modules is low efficiency, which can offset its price advantage in some applications. Its structure is also more complex, and flexible thin-film batteries require special installation skills, so at least they cannot be used in aerospace at present.
Crystalline silicon and thin-film solar panels can be used in many applications. According to their advantages and disadvantages, crystalline silicon cells are used more in occasions that require high efficiency, while thin-film cells are often used in low-cost and more flexible occasions.
It may be felt that in the current market, thin-film batteries are not only catching up with crystalline silicon battery modules, but will surpass crystalline silicon in all aspects, including price and efficiency. One way to reduce the cost of thin-film solar cells is to use non-environmentally friendly materials such as cadmium. The manufacturer claims that it is safe as long as it is well enclosed and in use. But for now, there is no recycling plan for such components.