Describe i. mono-crystalline, ii. poly-crystalline as used in PV module solar cell construction

Mono-crystalline solar cells are made from a single crystal of silicon, which is known for its high efficiency. The cells are cut from the crystal in a way that maximizes their ability to convert sunlight into electricity. Because of the high quality of the silicon used and the precise cutting process, mono-crystalline solar cells are typically more efficient than other types of solar cells.

Poly-crystalline solar cells, on the other hand, are made from multiple silicon crystals that are melted together to form a block, which is then cut into individual cells. Because the crystals are not arranged as perfectly as in mono-crystalline cells, poly-crystalline cells are not as efficient. However, they are generally less expensive to produce, which makes them a popular choice for many solar installations.