Thin film solar cells on low cost glass substrates

The progress obtained so far, and the future trends for the two most successful thin film solar cells, namely CulnGaSe2/CdS and CdTe/CdS, are described in this article. The construction of a solar production plant, located near Varese, northern Italy, expected to produce 15 MW/year, will also be reported. This plant, based on CdTe thin film deposition onto 0,6 x 1.2 square meter glass modules, is being built with the scientific support of Parma University.

The massive use of photovoltaic modules has so far been limited by the high cost when compared to that of electrical energy obtained from conventional energy sources. In order to lower the cost, several materials have been studied and thin film modules have been developed as an alternative to crystalline silicon. Thin films have the advantage that only a few microns of material are needed and that the modules can be monolithic which means that the contacts between the single cells inside the modules are made during the process by using automated laser scribing and material deposition one after each other. This, in prospective, can lower the cost below 0,5 USD/W which is competitive with the cost of electrical energy obtained from conventional sources.