Solar panels are made up of photovoltaic cells

Solar panels are made up of photovoltaic cells. A photovoltaic cell converts light energy into electricity. At the heart of a photovoltaic cell is an NP junction where negative and positive plates made of silicon and other materials are placed close together. Electrons want to jump across from the Negative to the Positive side. This force is known as voltage but energy is still needed to make electrons jump across. Energy in the form of photons from sunlight enables electrons to jump across which creates the flow of electricity which is known as current. Even the best solar cells only achieve around 40% efficiency. There are several things than can improve the efficiency of solar cells: Silicon is very shiny so most of the sunlight is reflected which is a waste of energy. This is why solar panels have a dark non-reflective coating so that more light flows into the cell. Light can have different amounts of energy just like it can have different colours. Most solar cells are designed to create electricity with only a small amount of light but this means that only a low voltage is produced. The strength of the voltage known as “Band gap energy” depends on how much energy is required for electrons to jump across the NP junction. In strong sunlight you get extra current but the voltage doesn’t really increase. New research involves multi-junction cells which have more than one electric field. This allows the panel to operate in low light and also take advantage of stronger light with increased current and voltage. Another issue is that the electricity generated by a photovoltaic cell needs to travel through a semiconductor and semiconductors aren‘t great at conducting electricity. Wires are good conductors but they block out light so new transparent conductors are being developed to improve solar cell efficiency.