The three main types of thin film technologies use cadmium-telluride, copper-indium-gallium-selenide and amorphous-silicon to convert sunlight into electricity.
The trade exists so that the exporters can avoid the costs of properly managing the hazards (lead and cadmium) and simply reap the profits from the valuable material (copper).
The ink will work on silicon solar panels as well as those using alternative materials such as cadmium telluride (used by First Solar in the U.S.) or copper indium gallium selenide (used by Solar Frontier in Japan).
Among the technologies are new ways of making already-commercialized formulations, like amorphous silicon and cadmium telluride, and newer formulations like CIGS, named for the elements it is made out of, copper, indium, gallium and selenium, and CIS, which leaves out the gallium.