Elements of Solar Panels

When sunlight hits a photovoltaic cell, the semiconductors in the cell absorb some of the light and transfer the energy into electrons which generate an electric current. This current is extracted via conductive metals, and can be used to charge appliances or put energy into a grid.


Silica, Copper, Cadmium, Gallium, Germanium, Indium, Selenium and Tellurium are elements and components of semiconductors that are used in photovoltaic cells, as they feature high levels of light absorption and conversion to electricity. Semiconductors are materials that possess electrical properties, and are crucial for the functioning of electrical appliances.


Silica is the second most abundant material on earth- found in sand, quartz and many living organisms. Silica can be used to manufacture products ranging from glass to computer chips. Solar cells made from silica are cheap and feature high reliability, lasting about 25 years- they are known to retain around 80% of their efficiency even after this time span. Around 95% of panels sold today utilize silica as a semiconductor.



Abundant in the earth’s crust and usually found via mining, copper has very high thermal and electric conductivity, thus it is most often used in wiring. Copper can be incorporated into solar cells as copper indium gallium diselenide (CIGS). Commercial CIGS have efficiencies of 12-14%.



Cadmium is found in smaller deposits around the globe, and is commonly used as corrosion protection in batteries or in coatings and alloys. It can be used to develop cadmium telluride solar cells, which are the second most common type of photovoltaics on the market (5% of systems sold) with a lab-tested efficiency of 22.1%.



Found from the mining and processing of bauxite ore or aluminum, gallium is used in semiconductors or in light-emitting equipment. Gallium can be used in photovoltaic cells as gallium arsenide, which garners a higher efficiency rating of 28.8%- this is largely because electrons can move through GaAs much faster than they can through silicon cells.



Mined from sphalerite, germanium is used as a semiconductor and transistor in electronic devices. Germanium-incorporated photovoltaics can reach 40% efficiency, though these cells are more expensive and fragile.



Indium is a byproduct of mining other metals, and is used in solar cells because it can conduct electricity, bond to glass, and is transparent. Indium is used in the CIGS cells mentioned previously with a 12-14% efficiency rating.


Found in metal sulfide ores, selenium is used in photovoltaics due to its conductivity, and has been shown to boost the efficiency of thin-film solar panels to 22%.



One of the least common minerals on earth (there are about 3 parts per billion of tellurium in most rocks), tellurium is a byproduct of copper refining. It can be alloyed with cadmium to have a high electrical conductivity and can be used in a thin film to enhance conversion of sunlight into electricity. Photovoltaic and thermoelectric activity encompass 2/3 of global tellurium usage.