COLL 21

This history provides a backdrop for an overview of the present status of the field of solar photoconversion and its goals and challenges. The presentation will illustrate the present use of molecular constructs and heterogeneous interfaces to effect the fundamental steps in charge separation requisite for efficient energy transduction. These research efforts will be explored within the perspective of the long term applications in fuel production and electric power generation, showing that most chemical systems presently under study have promise in either application.

Several problems in this field have surfaced that provide challenges to the research community. Of great difficulty is the understanding and construction of homogeneous catalytic systems for photoproduction of oxygen and hydrogen. Also, no semiconductor photoelectrodes presently known can split water when illuminated with visible light. When molecular dyads, triads, or other constructs for separation of photogenerated charge are assembled in densely packed arrays, second order electrostatic interactions and feedback loops are created that dissipate energy. Such effects form a fundamental part of the systematic overview needed to predict the behavior of organic and mixed organic/inorganic photogalvanic solar cells.