ABSTRACT
Solar cells can be divided into three different generations. The rst-generation solar cells are made from crystalline semiconductor wafers (200-300 μm), and 90% of the solar cell market is based on these rst-generation solar cells. Approximately 40% of the cost of a solar module is due to thick silicon wafers. Second-generation solar cells are based on thin-lm (1-2 μm) technology. This lm is deposited on low-cost substrates such as glass, plastic, or stainless steel. The main focus of these solar cells is lowering the amount of material used. They contain a variety of semiconductors like cadmium telluride, copper indium diselenide, and so on, as well as amorphous and polycrystalline silicon. A major limitation of thin-lm solar cells is their ineffective absorbance near bandgap, in particular, for the indirect bandgap semiconductor silicon. Therefore, it is important to trap light inside the solar cell in order to increase the absorbance. Third-generation solar cells are presently investigated with the goal to increase the efciency using second-generation SCs.
