What are the technical routes available for photovoltaic cells?

The main technical routes for photovoltaic cells include the following options:

Crystalline silicon solar cells

Monocrystalline silicon solar cells

Structure and principle: Monocrystalline silicon solar cells are based on monocrystalline silicon as the basic material, with a complete crystal structure and regular atomic arrangement. Its working principle is to utilize the photoelectric effect of silicon materials. When photons strike the solar cell, the electrons in the silicon atoms absorb the energy of the photons and transition into free electrons, thereby generating an electric current.

Efficiency and advantages: The conversion efficiency is relatively high, with the laboratory maximum efficiency exceeding 25%, and the mass production efficiency is also constantly improving. It has good stability and a long service life, and its performance is relatively stable under conditions such as light and temperature changes.

Application scenarios: Widely used in distributed photovoltaic power generation systems, large-scale ground-mounted power stations and other fields, it has obvious advantages especially in scenarios with high requirements for power generation efficiency and stability.

Polycrystalline silicon solar cells

Structure and principle: Polycrystalline silicon solar cells are composed of multiple small grains, and their crystal structure is not as regular as that of monocrystalline silicon. The working principle is also based on the photoelectric effect. However, due to some defects at the grain boundaries, it has a certain impact on the transport of photogenerated carriers.

Efficiency and advantages: The manufacturing cost is relatively low and the production process is relatively mature. Although the conversion efficiency is slightly lower than that of monocrystalline silicon solar cells, it still has a relatively high cost performance in large-scale applications.

Application scenarios: It is widely used in large-scale ground-mounted photovoltaic power stations and can reduce the construction cost of the power stations to a certain extent.

Thin-film solar cell

Amorphous silicon thin-film solar cells

Structure and principle: Amorphous silicon thin-film solar cells deposit a layer of amorphous silicon thin film on substrates such as glass and stainless steel as a photoelectric conversion layer. Amorphous silicon has the structural characteristics of short-range ordered and long-range disordered. Its photoelectric conversion principle is similar to that of crystalline silicon, but due to the structural differences, the migration and recombination mechanisms of photogenerated carriers are different.

Efficiency and advantages: The preparation process is simple, the cost is relatively low, and it can be prepared on flexible substrates, featuring good flexibility and lightness. It is suitable for application in fields such as building-integrated photovoltaics (BIPV) and small portable photovoltaic equipment.

Application scenarios: It is commonly used in scenarios such as building curtain walls and roof photovoltaic tiles that are integrated with buildings, as well as in some special application fields with high requirements for weight and space.

Cadmium telluride (CdTe) thin-film solar cells

Structure and principle: Cadmium telluride is used as the light absorption layer, and it is usually prepared by methods such as chemical bath deposition and physical vapor deposition. Cadmium telluride has an appropriate bandgap width and can effectively absorb the visible light part of sunlight, thereby generating the photoelectric effect.

Efficiency and advantages: It has a relatively high conversion efficiency and a cost advantage in large-scale production. It has good weak light performance and can still maintain a certain power generation efficiency on cloudy days or under low light conditions.

Application scenarios: Suitable for large-scale ground-mounted power stations and some areas with relatively poor lighting conditions.

Copper indium gallium selenide (CIGS) thin-film solar cells

Structure and Principle: The light-absorbing layer of CIGS solar cells is composed of elements such as copper, indium, gallium, and selenium. By adjusting the proportion of each element, the performance of the battery can be optimized. Its crystal structure has a relatively high light absorption coefficient and can fully absorb light of different wavelengths in sunlight.

Efficiency and advantages: It has a relatively high conversion efficiency and can theoretically achieve a relatively high ultimate efficiency. Meanwhile, it has good stability and radiation resistance, and performs exceptionally well under different environmental conditions.

Application scenarios: It can be applied in distributed generation, BIPV and other fields, especially in some building photovoltaic projects with high requirements for battery performance and appearance, it has unique advantages.

New type of battery cell

Perovskite solar cells

Structure and Principle: Perovskite solar cells use organic-inorganic hybrid perovskite materials as the light-absorbing layer, featuring a unique crystal structure and excellent photoelectric performance. Its photoelectric conversion process includes links such as light absorption, carrier generation, transport and collection. Perovskite materials exhibit a high light absorption coefficient, a long carrier diffusion length and a low carrier recombination rate in it.

Efficiency and advantages: The conversion efficiency has improved rapidly, with laboratory efficiency exceeding 25%, and it has the potential for a simple preparation process and low cost. Its materials have strong designability, and the performance of the battery can be optimized by adjusting the composition and structure.

Application scenarios: Currently in the research and development and pilot application stage, it is expected to be widely applied in distributed photovoltaic power generation, flexible photovoltaic devices and other fields.

Heterojunction solar cell (HJT

Structure and principle: Heterojunction solar cells deposit amorphous silicon films and microcrystalline silicon films respectively on a crystalline silicon substrate to form a P-N junction. This structure combines the advantages of crystalline silicon and amorphous silicon, featuring a relatively high open-circuit voltage and short-circuit current.

Efficiency and advantages: High conversion efficiency, mass production efficiency has reached a relatively high level, and it also has excellent low-temperature performance and weak light response characteristics. Meanwhile, its process is relatively simple and suitable for large-scale production.

Application scenarios: It has broad application prospects in both distributed photovoltaic and large-scale ground-mounted power stations, especially in some projects with high requirements for power generation efficiency and cost per kilowatt-hour, where it is more competitive.

Back contact with the battery cells

Structure and principle: Back-contact solar cells place both the positive and negative electrodes on the back of the battery, with no electrodes blocking the front, thereby enhancing the light absorption efficiency. It achieves efficient collection and transmission of photogenerated carriers by fabricating complex electrode structures and passivation layers on the back of the battery.

Efficiency and advantages: It features a high conversion efficiency and an attractive appearance, making it suitable for application scenarios with high requirements for power generation efficiency and appearance. As there are no electrodes on the front, the reflection and occlusion of light by the electrodes are reduced, thereby improving the optical performance of the battery.

Application scenarios: Photovoltaic cells are often used in distributed photovoltaic power generation systems such as rooftop photovoltaic and building-integrated photovoltaic, which can not only meet the power generation demands but also enhance the aesthetic appeal of buildings