Among silicon-based solar cells, monocrystalline silicon solar cells have the highest conversion efficiency and the most mature technology. High-performance monocrystalline silicon cells are based on high-quality monocrystalline silicon materials and related thermal processing techniques.
The current electro-grounding process for monocrystalline silicon is nearing maturity. In battery manufacturing, technologies such as surface texturing, emitter passivation, and zoned doping are generally employed. The main types of batteries developed are planar monocrystalline silicon batteries and grooved buried grid electrode monocrystalline silicon batteries.
Improving conversion efficiency mainly relies on the microstructure treatment of single-crystal silicon surface and the partitioned doping process. Photolithography is used to texture the battery surface, creating an inverted pyramid structure. A 13nm thick oxide passivation layer is then combined with two anti-reflection coatings. An improved electroplating process increases the width-to-height ratio of the gate. The resulting battery achieves a conversion efficiency exceeding 23%, with a maximum value reaching 23.3%.
Kyocera's large-area (225cm²) monocrystalline silicon solar cell has a conversion efficiency of 19.44%. The Beijing Solar Energy Research Institute in China is also actively researching and developing high-efficiency crystalline silicon solar cells. The planar high-efficiency monocrystalline silicon cell (2cm x 2cm) has a conversion efficiency of 19.79%, and the grooved buried grid electrode crystalline silicon cell (5cm x 5cm) has a conversion efficiency of 8.6%.
Advantages and disadvantages of monocrystalline silicon
Monocrystalline silicon solar cells undoubtedly boast the highest conversion efficiency and still dominate in large-scale applications and industrial production. However, despite their high efficiency, the production of monocrystalline silicon solar cells requires large quantities of high-purity silicon material, involves complex processes, consumes significant amounts of electricity, and suffers from low planar utilization of solar cell modules, resulting in persistently high costs for monocrystalline silicon. Significantly reducing these costs is extremely difficult.
In order to save high-quality materials and find alternatives to monocrystalline silicon cells, thin-film solar cells have been developed, among which polycrystalline silicon thin-film solar cells and amorphous silicon thin-film solar cells are typical examples.
