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What are Solar Panels Made Of?
A solar panel is essentially a series of interconnected solar cells that have been joined together in order to create an electrical circuit. A solar panel comprises of two interconnected materials and this is known as a semiconductor. Solar cells are what convert photons emitted by sunlight into electricity through the photovoltaic effect. Solar cells have electrical features such as resistance, current, and voltage and all these features vary based on the amount of light received. Solar panels have gotten more efficient as time has progressed but very few panels are more than 20% efficient. Making individual solar cells more efficient is one of the biggest challenges the industry is facing now.
Solar cells have seen three stages of development
Silicon by far is the most popular semiconductor material used in most solar panels due to a wide variety of reasons. Solar cells are typically classified into first, second, and third generation cells. Conventional or first generation cells are made of crystalline silicon which is the dominant form of silicon used in PV panels. Most PV modules comprise of crystalline silicon cells that are made of monocrystalline silicon and multicrystalline. In 2013 alone, crystalline silicon-based cells accounted for over 90% of global PV production.
What about second generation cells?
Second generation solar cells are made of materials such as cadmium telluride, amorphous silicon, and copper indium gallium selenide. They are essentially thin film solar cells, and thin film cells are more efficient as they have fewer active material in individual cells. Nearly every type of thin film cell places the necessary active materials between two pieces of glass, metal or plastic, and they are heavier than first generation panels as they use more than one piece of substrate. Thin films have always been cheaper than first generation cells, but only in recent times have they become more efficient.
Third generation solar cells
Third generation PV cells are the latest generation of solar cells and most of these types are under development. Some of the common types of third gen photovoltaics being developed or sold right now include polymer cells, copper zinc tin sulfide cells, and perovskite cells among others. These solar cells are attempting to break the barriers in place with regards to power efficiency. According to the Shockley-Queisser limit, a single cell cannot be more than 31-41% efficient. Third generation cells are