Advanced Multijunction Solar Cell & Concentrator System Development for DOD Terrestrial and Space Applications

The objective of this Phase I effort is to investigate the feasibility of using quaternary alloys based on the established II-VI compounds HgTe, CdTe and ZnTe to generate crystals with the desired bandgaps for solar cells and the use of additional down-converting glass plates to allow for enhanced absorption. A number of theoretical calculations predict efficiencies that are significantly higher than current state-of-the-art results. Monolithic two-terminal cells that offer advantages in terms of weight and interconnect simplicity will be investigated. We will develop this system, first by modeling photon absorption and electrical carrier transport in the proposed 2-junction structure. Subsequently, we will fabricate a single-junction II-VI HgCdZnTe solar cell. In parallel, we will develop and test transparent, rare-earth doped fluorozirconate-based glass ceramics for UV photon down-conversion. Finally, we will work on fusion techniques of the two systems. Previous experience in developing HgCdTe for infrared detection and glass-ceramic plates for radiation detection has given us the experience to develop the proposed system.