PV modules have become the standard for solar. They have steadily become more available to the public as pricing has come down and efficiency has increased. Many variations exist:
Polycrystalline: Manufacturing costs of these modules are lower than mono, but are less efficient. This is however a great alternative if space is not an issue for your solar array.
Monocrystalline: These modules are more efficient at come in at a higher price point. Perfect for smaller system designs that are limited by viable roof space. Allowing for more solar production per metre.
Split-cells: This panel design allows for more cells in a panel, this has the added benefit of increasing panel longevity and panel efficiency.