Investigating thallium-based materials for use in multijunction photovoltaics

The optimum band placement for both multijunction photovoltaics, where layers of semiconductor materials are connected in series, and split junction photovoltaic systems, consisting of a number of physically separated solar cells, are investigated. Possible implementations of these designs are suggested, based on design constraints such as lattice matching, use of possible substrates, and ease of material growth. In order to realize these implementations, Tl-bearing semiconductor materials were required in the structures; this is a class of materials that has not been extensively studied, particularly for use in photovoltaics. Simulations of the most promising structures were performed, with efficiencies promising to outperform current high-efficiency cells.