What are the advantages and disadvantages of single monocrystals and polycrystals?

Monocrystals and polycrystalline silicon differ in the manufacturing process, power generation efficiency, cost, and more, depending on the material selected for the solar panel. Additionally, the physical appearances of monocrystals and polycrystalline silicon also vary, despite being composed of the same silicon element, resulting in certain differences:

1. Manufacturing Process Differences :

Monocrystals are made by processing silica to enhance its purity, whereas polycrystalline silicon is produced by recycling silicon particles generated during the production process of single crystals. Essentially, a single crystal is a veneer and polycrystal is a plywood.

2. Crystal Arrangement Differences :

Monocrystals and polycrystals contain unit cells with distinct arrangements. Specifically, monocrystals are arranged in a regular pattern, whereas polycrystals are arranged in an irregular pattern. As a result, the conversion rate of monocrystals in high light is higher and the natural power generation is greater. However, in low light, polycrystals are more efficient.

3. Physical Appearance Differences :

Monocrystals have glossy panel surfaces with colors that do not blend due to the regularly arranged crystals. In contrast, monocrystals are darker in color, mostly appearing as dark blue or black, whereas polycrystalline silicon appears mostly light blue. The scientific conclusion that darker colors absorb photons better suggests that the color of monocrystals plays an important role in absorbing solar energy. Conversely, polycrystals with irregularly arranged crystals have a slightly variegated pattern. Looking at the residential PV system, if the monocrystal panel and the polycrystalline panel are compared under the same power, the size of the polycrystalline panel is larger, resulting in a larger installation area. If the appearance and coverage area costs are important factors, monocrystal panels will be an ideal choice.

4. Power Generation Efficiency Differences :

Solar panels yield varying power generation efficiencies and their ability to transform solar energy into electricity depends on the selected materials. Single crystals have higher power generation efficiency and can generate elevated performance electricity than other materials. The power generation efficiency is denoted by the term "conversion efficiency" and solar panels with conversion efficiency above 20% are considered to have high performance. The high density of single-crystal crystal results in small power generation losses and an efficiency of approximately 20%. Conversely, polycrystals have a lower crystal density and generate more power losses than monocrystals, resulting in an efficiency of about 15%.

5. Cost Differences :

Monocrystals have a rounded shape that is expensive to manufacture, and monocrystals with exceptional power generation efficiency tend to be more costly. Polycrystalline products are sold at a relatively lower price as they have a rectangular shape that requires no polishing, resulting in comparatively lower manufacturing costs than monocrystals.