Conventional solar cells are made from silicon in a crystalline form known as c-Si. Unlike thin-film panels, conventional panels contain photovoltaic cells cut from monocrystalline (monocrystalline) or polycrystalline (polycrystalline) silicon wafers. Thin-film panels consist of entire layers of photovoltaic material, rather than tiny silicon cells.
You can classify thin film solar panels based on the material. The four main types are:
- Amorphous Silicon (A-Si)
- Cadmium telluride (CdTe)
- Copper Indium Gallium Selenide or Diselenide (CIGS)
- Organic Photovoltaics (OPV)
Amorphous silicone panels
Amorphous silicon (a-Si) panels use the same materials as conventional solar cells. But in thin-film panels, silicon has an amorphous or "amorphous" structure. These panels use less silicon than conventional solar modules and are therefore more affordable. Amorphous silicon panels were the first thin-film photovoltaic technology developed. You can find the technology used in old calculators and other small devices.
Amorphous silicon panels have a typical energy conversion efficiency of 6% to 8%, while the best crystalline silicon panels approach 23% efficiency.
Advantages and disadvantages
+ Easy and affordable
+ Use non-toxic materials
+ Can be rigid or flexible
Low energy efficiency
- Rapid loss of effectiveness after installation
Shorter service life than crystalline silicon panels
Cadmium telluride plates
Cadmium telluride (CdTe) panels are more efficient than amorphous silicon panels, ranging from 9% to 15%. These are the most popular panels in the thin film solar panel industry, accounting for about half of the global market share. First Solar is one of the leading manufacturers of CdTe panels, having invested more than 1.5 billion dollars in the development of this solar technology.
The main disadvantage of CdTe panels is the use of cadmium, which is a very toxic metal. Cadmium is not a hazard when the panels generate electricity. However, it can pose a hazard to plant workers exposed during production, and disposal is problematic.
Advantages and disadvantages
+ Higher performance than amorphous silicon panels
+ Low production and installation costs
+ Shorter recovery time compared to other thin film panels
Cadmium is a toxic metal
Less efficient than crystalline silicon panels.
- Flexible CdTe sheets are hard to find
Gallium diselenide copper plates
Copper-indium-gallium-diselenide (CIGS) wafers use a series of semiconductor materials arranged in layers. CIGS wafers have a typical efficiency of 12% to 14% compared to CdTe wafers. CIGS technology is also compatible with a variety of materials such as steel, aluminum, glass and plastic.
The main disadvantage of CIGS thin-film panels is their higher production cost, which leads to a longer payback period. Some CIGS panels also use cadmium, which causes the same environmental problems as CdTe panels. However, manufacturers are replacing cadmium with zinc oxides, which are safer materials.
Advantages and disadvantages
+ Higher performance than amorphous silicon panels
+ Compatibility with different materials and surfaces
+ Rigid and flexible panels available
More expensive than other thin boards
Many CIGS devices contain cadmium.
- Longer recovery time than other thin panels
Organic photovoltaic panels
Organic photovoltaic (OPV) panels use polymers and other organic materials with photovoltaic properties to generate energy. The efficiency of OPV panels is about 11%, which is higher than that of a-Si panels. However, OPV panels have a lower efficiency rating than CdTe and CIGS panels.
Since organic materials are abundant and cheap, OPV panels are readily available. But organic photovoltaic materials are less durable than the inorganic compounds used in other thin-film technologies.
Advantages and disadvantages
+ Cheap production process
+ Available in different colors thanks to the variety of absorbents
+ Organic photovoltaic materials are common and safe
Lower efficiency than most photovoltaic technologies
The life span is shorter than that of inorganic solar cells
