Although photovoltaic industry rapidly grows, photovoltaic-module and related manufacturers face severe economic situation because of surprising price reduction mainly due to too much supply over demand. However, steady technological development is most important even in such situation for future continuous prosperity in photovoltaic industries. Thinner wafer is one of the key technologies for cost reduction of crystalline silicon solar cells. Various methods have been developed for improved properties of thinner wafer crystalline silicon solar cells. Mass production starts for compound thin-film solar cells including cadmium telluride and copper-indium-gallium-selenide. Various types of polymer materials and interconnector ribbons are used in module-manufacturing processes and those materials determine the reliability of modules. Such technological issues will be discussed in this article for crystalline silicon, compound thin-film solar cells and modules after short overview of photovoltaic markets.