The present energy crisis has forced scientists and governments to expand energy research in non-conventional energy resources. Among the various non-conventional energy sources suggested, the solar energy offers the best solutions particularly, the conversion of sunlight directly into electricity without causing changes in ecology and the environment. Many attempts were made and are being made to make advances in the theoretical and technological aspects of the conversion of solar energy into utilizable form. The photovoltaic technologies, especially photoelectrochemical route is still in its infancy, but have potential to play an important role in meeting the demands of electric power in this 21st century, provided that such systems can be made competitive with conventional power generation and others. These cells are easy and simple to fabricate, more convenient and require almost no sophistication while processing. This book which is based on a research study gives a information about synthesis of cadmium lead selenide thin films and their characterization and applications particularly in the solar energy harvesting. This book is essential for researcher working in this field.