Nanocrystal solar cell A third-generation solar cell, developed in 2005 at the US Department of Energy’s Lawrence Berkeley National Laboratory in conjunction with University of California at Berkeley. It is the ﬁrst ultra-thin solar cell comprised entirely of inorganic nanocrystals, and spin-cast from solution. The cost and manufacture are comparable with solar cells made from organic polymers. They are more stable in air because they contain no organic materials. They combine the properties of organics with the ability to retain the broadband absorption and superior transport properties of traditional photovoltaic semiconductors. They have the cost-reduction potential that has made organic cells a viable alternative to conventional semiconductor counterparts. Rodshaped nanometer-sized crystals of two semiconductors, cadmium-selenide (CdSe) and cadmium-telluride (CdTe), are synthesized separately and then dissolved in solution and spincast onto a conductive glass substrate. The resulting ﬁlms, which are about 1000 times thinner than a human hair, have comparable conversion efﬁciencies as the best organic solar cells. It is still substantially lower than conventional silicon solar cell thin ﬁlm.