Intermediate Band Materials (MIB) have been proposed in previous works as a new kind of photovoltaic materials. These materials are principally characterized by an intermediate partially occupied band, isolated from the valence and conduction bands of the host semiconductor. These materials have a theoretical efficiency greater than that of conventional solar cells because they can absorb photons with a lower energy than the bandgap of the original host semiconductor. However, although the operation of these solar cells has been described, it is necessary to use a method to be able to propose the material which has these properties. In this work, a theoretical study of the electronic and optoelectronic properties using quantum-mechanics calculations is presented. The results confirm that MIB are able to absorb photons of lower energy than the host semiconductor. (c) 2004 Elsevier B.V. All rights reserved.