CFN Colloquium

In my talk I will describe some of the ongoing research in three different areas of photovoltaics at IBM. Concentrator photovoltaics, which has not yet benefitted from the economies of scale that silicon photovoltaics has, can offer significant advantages over flatpanels in regions with high direct normal incidence, and also has the potential to be mass manufactured cheaply using readily available materials and components. I will describe some of the work at IBM in building high concentration photovoltaic systems. In the second area, earth abundant thin film PV, I will describe our research on fabricating solar cells using the material copper-zinc-tin-sulfide (CZTS), a compound with readily available, cheap and non toxic components that may turn out to be a viable alternative to CIGS and CdTe without the toxicity and availability issues that are associated with them. This is a less mature material compared to CdTe or CIGS however, and the challenge currently is to demonstrate cells with high efficiencies. I will describe results from vacuum deposited materials that now have achieved efficiencies of 8.4% and higher. Finally, if time permits, I will describe some of our work on silicon nanowire solar cells, which while demonstrating higher light absorption and even slightly higher efficiencies compared to their planar counterparts, have so far not demonstrated any significant advantage with respect to their potential—I will present data and discuss the reasons behind this.