Any solar panel is an assembly of photovoltaic cells which are actually double silicon wafers converting sunlight into electricity. Photons, constituting the light, knock out electrons in a semiconductor, thus driving them from one silicon wafer to another. If you connect wires to these wafers, the current will flow through them. The brighter the light falling on the wafer the bigger the wafer area and the more electricity it will produce. Therefore such cells are often combined into larger modules including 36, 60 or 72 wafers.
Currently there are around a dozen semiconductors available with similar properties. Some of them are able to convert up to 40% of light energy into electricity, but, unfortunately, they are still too expensive for commercial production. Solar cells based on crystalline silicon are the best value for money with an efficiency at around 14-18% and at a very reasonable price.