Solar panels are devices that absorb sunlight and convert solar radiation energy directly or indirectly into electrical energy through the photoelectric effect or photochemical effect. The main material of most solar panels is silicon, but due to the high manufacturing cost, its widespread use is still somewhat limited.
Currently, crystalline silicon materials (including polycrystalline silicon and monocrystalline silicon) are the most important photovoltaic materials, with a market share of over 90%, and will remain the mainstream material for solar cells for a considerable period of time to come.
Monocrystalline silicon
Monocrystalline silicon solar cells have an average photoelectric conversion efficiency of around 18%, with a maximum of around 25%, which is the highest among all types of solar cells. However, their manufacturing cost is very high, preventing their widespread use. Because monocrystalline silicon is typically encapsulated with tempered glass and waterproof resin, it is robust and durable, with a lifespan of up to 25 years.
Polycrystalline silicon
The manufacturing process of polycrystalline silicon solar cells is similar to that of monocrystalline silicon solar cells, but the photoelectric conversion efficiency of polycrystalline silicon solar cells is significantly lower, around 16%. In terms of manufacturing cost, they are cheaper than monocrystalline silicon solar cells due to simpler material manufacturing, lower energy consumption, and lower overall production costs, thus leading to their widespread adoption. However, polycrystalline silicon solar cells also have a shorter lifespan than monocrystalline silicon solar cells. In terms of performance-price ratio, monocrystalline silicon solar cells are slightly better.
amorphous silicon
Amorphous silicon solar cells, a new type of thin-film solar cell that emerged in 1976, are manufactured using methods completely different from those of monocrystalline and polycrystalline silicon solar cells. The process is greatly simplified, requiring very little silicon material and resulting in lower power consumption. Its main advantage is its ability to generate electricity even in low-light conditions. However, the main problem with amorphous silicon solar cells is their relatively low photoelectric conversion efficiency, which is around 10% at the international advanced level, and it is also not very stable, with its conversion efficiency decreasing over time.
Multi-component compounds
Multi-component compound solar cells refer to solar cells that are not made of a single-element semiconductor material. Many varieties are being researched in various countries, but most have not yet been industrialized. The main types include: a) Cadmium sulfide solar cells; b) Gallium arsenide solar cells; c) Copper indium selenide solar cells (a novel multi-component bandgap gradient Cu(In, Ga)Se2 thin-film solar cell).
Cu(In, Ga)Se2 is a high-performance solar energy absorption material. It is a multi-element semiconductor material with a gradient band gap (the energy difference between the conduction band and valence band), which can broaden the solar energy absorption spectrum and thus improve photoelectric conversion efficiency. Based on it, thin-film solar cells with significantly higher photoelectric conversion efficiencies than silicon thin-film solar cells can be designed. A photoelectric conversion efficiency of 18% can be achieved, and no solar radiation-induced performance degradation (SWE) has been observed in these thin-film solar cells. Their photoelectric conversion efficiency is about 50-75% higher than that of commercial thin-film solar panels, representing the highest level of photoelectric conversion efficiency in the world for thin-film solar cells.
