Until recently, the only known answer was silicon cells in a rigid frame. Today, most solar panels are made of silicon. Although silicon-based panels still dominate the global market, the use of other materials has increased.
A brief history of modification: three generations of solar cells
Experts divide all photovoltaic devices capable of absorbing light photons and converting them into electric current into three generations.
What solar panels of the first generation consist of
Structurally, such modules consist of the following elements:
- a metal base sheet – the base contact;
- The lower filler layer of silicon semiconductor with a predominance of n-type electrons – due to the addition of phosphorus;
- Top crystalline layer, saturated with p-type electrons – usually by doping with boron;
- anti-reflective coating – to maximize radiation absorption;
- a thin, metallized grid-type contact with a wire to short-circuit the network;
- Thick protective glass – usually heavy duty tempered glass;
- a framing frame.
Wafers with a thickness of about 200-300 m are known as polycrystalline Poli-Si. They have a lifetime of about 25 years and an average performance drop of about 1%.
The next generation of batteries are based on the same physical principle as the previous generations, but with different rare earth elements. These elements are usually combined with anti-reflective film and metal base.
Thin-film refers to the film with a smaller working layer than silicon. Due to its thinness, it is usually considered more advantageous than traditional silicon panels when used under ideal conditions.
What a 3rd generation solar panel consists of
The 3rd generation panels are mainly composed of organic materials and are not used with semiconductor materials.
Their main advantage is their cheapness of production. They have the widest possible transparency and geometry.
The main drawback today is low efficiency, ranging from 0.1 to 7%.
Semiconductor materials – what solar panels are made of today
The main semiconductor materials used to produce 99% of the photovoltaic cells on the global market today are:
- Monocrystalline silicon – Cultivated as large crystals by Professor Czochralski’s method. Next, silicon cylindrical “powders” are cut into very thin discs, 0.2-0.4 mm thick, and subjected to specialized chemical processing. Almost finished cells are ground, polished, coated with protective coatings and metallized. If you want to make a solar battery with your own hands, such photovoltaic cells are bought in a store, and the other parts of the monoblock are made on their own from improvised materials.
- Polycrystalline silicon – Produced in metallurgical crucibles by the cheaper method of directional crystallization (block-cast). Once the silicon raw material is melted, it is slowly cooled which results in “needle-like” multi-directional crystals. In operation, such a surface is slightly worse than a monocrystal in perfect light, but more efficient in other cases. For this reason, when installing a set of batteries on roofs, Mono-Si is often mounted on the south slopes and Poli-Si on the southwest and southeast slopes.
- Amorphous silicon – what solar panels of this type are made of The basis of this type of battery is hydrogenated silicon with a large coefficient of radiant absorption. Modern models combine several layers enriched with germanium and carbon. This eliminates the main disadvantage of a-Si panels – rapid cell degradation.
What CdTe thin-film solar cells are made of
Cadmium telluride is the best single-transition material for high-performance electronic components. It has a wide range of properties that make it highly efficient.
The film substrate can be made of glass or metal, and the cells can be flexible. CdTe is a highly efficient and stable type of solar cell.
Peculiarity of the structure of CIGS-type solar panels
The basis of these batteries is a mix of copper, indium, and gallium. Due to their high efficiency and durability, they are very expensive.
Despite the potential applications of solar panels, their commercial viability is still limited by the amount of indium and gallium that can be produced annually. In addition, making batteries requires a massive amount of capacity.
What are GaAs and InP solar cells made of?
The basic elements of this group are InPb in phosphide and GaAs in gallium arsenide. The unique feature of these components is their complete retention at extremely hot temperatures.
Almost all of the space station’s components are built on their basis. This method is very efficient and can reach a theoretical efficiency of 85%.
What are organic solar cells made of?
Despite the low efficiency of organic-based panels, their various advantages have been widely explored. Currently, organic-based panels are being studied for their 3rd generation.
Advantages of the technology:
- easy and cheap to create;
- no disposal problems;
- unlimited fields of application;
- possibility of manufacturing in a transparent form.
These panels are lightweight and can be built into windows to regulate transparency.
What are solar panels made of?
They are made up of a thin glass substrate and an applied conductive paint. This material is easy to use due to its versatility and the possibility of obtaining any desired color shades.
Features of solar cells with quantum dots
Physical quantum dots are the last generation batteries that will be able to absorb and convert light. They have the properties of microscopic inclusions of semiconductors.
A huge advantage of such panels is the ability to operate even at night, generating about 40% of the maximum daytime power.