A solar energy device comprising: a substrate; a photovoltaic layer on said substrate; a back conductor in contact with said substrate; a grid conductor in contact with said substrate; said photovoltaic layer being of a material selected from the class consisting of: monoclinic zinc diphosphide (also...http://www.google.com/patents/US20020062858?utm_source=gb-gplus-sharePatent US20020062858 - High efficiency solar photovoltaic cells produced with inexpensive materials by processes suitable for large volume production
