As we know, sunlight contains energy. When light hits your skin, or the sidewalk, or ice cream, atoms vibrate to produce heat. However, not all materials act the same way when exposed to light. When light is absorbed by a group of materials called semiconductors (silicon, for example), electrons are knocked loose from their atoms. (Semiconductors are special because their electrons get up and move when exposed to light, instead of just jiggling in place and producing heat like other materials.) The movement of electrons creates current flow; the electricity created can be captured. If we have enough electrons running around, we can harness them for power.
Solar cells are made from large silicon crystals that are sliced into wafers (think salami), then printed with electrodes. In order to make enough power to be useful, solar cells are electrically connected and made into modules. The cells are sandwiched between a backing material and an acrylic front and sealed with silicon glue to create a solar module.
A typical module will have 60, 72, or 96 solar cells, depending on the design. Solar cells are electrically connected in series so that the voltage of one cell adds to the other.
Solar modules (also called solar photovoltaic (PV) panels) are rated in watts (W). The power produced by solar panels is direct current (DC), which can be used to charge batteries but not for your home. A device called an inverter converts DC power to AC power, which is suitable to be fed to your utility company (aka, the grid) or your home.