Abstract: Solar photovoltaics (PV) is now a >$100B/year industry, with ~45 GW of PV installed in 2014 and more planned for 2015. While the US generates ~1% of its electricity with PV, countries such as Spain, Germany, and Italy now have 3-7% of their electricity demand met by PV. Estimates made by the Department of Energy indicate that the US may in time increase to ~10% of electricity from PV, but further growth will be greatly slowed without low-cost energy storage. In the first part of the talk, I will discuss prospects for hybridizing concentrator photovoltaics (CPV) with concentrating solar power (CSP) to produce electricity efficiently while simultaneously generating dispatchable heat energy stored in thermal fluids at ~400°C. In the second part of the talk, I will present my group’s efforts to realize low-cost, high-efficiency III-V on Si tandem cells as another means to increase PV adoption. I will show that single-crystal III-Vs are the only known materials that have shown higher cell efficiency than Si, and are thus the most suitable candidates for integration on Si. Historically, materials mismatch between III-Vs and Si have led to very high defect densities and low solar cell efficiencies. By carefully balancing defect nucleation and growth, we have recently reduced defect densities by ~20x, enabling dramatic increases in efficiency. In both projects, I will show that our efforts are tied together by expertise with growth, characterization, and device applications of novel electronic materials.

Speaker(s): Minjoo Larry Lee,

Location:
Room: MC603
Bldg: McConnell Engineering Building
3480 University Street
Montreal, Quebec
H3A209