The ups and downs of photovoltaics

When applied to solar cells, up-conversion (UC) and down-conversion (DC) layers enable a single-junction photovoltaic (PV) device to overcome the Shockley-Queisser efficiency limit and are thus referred to as a third generation PV technology.  UC layers absorb sub-bandgap photons and for every 2-3 incident photons a single higher-energy above-bandgap photon can be emitted.  On the other hand, a DC layer placed on top of a solar cell can ideally absorb one high-energy photon and emit two lower-energy (but still above-bandgap) photons, thus enabling quantum efficiencies of up to 200%.   This talk will explore advances made in the area of UC and DC and the potential of these passive luminescent conversion layers to PV in general.



Bryce studied physics in New Zealand before completing a Masters and PhD in electrical engineering at University of New South Wales (UNSW, Australia).  He worked at both UNSW and the Australian National University (ANU) before joining Heriot-Watt University (HWU) in the Edinburgh, UK, in 2006.  In 2008 he was promoted to full professor.  Since April 2014 he is co-director of the institutes Institute of Microstructure Technology (IMT) and the Light Technology Institute (LTI) at the Karlsruhe Institute of Technology (KIT).  His primary research area is nanophotnics for energy, with a particular interest in 3rd generation PV, spectral conversion and nanophotonics.  His ambitions to make a difference in the real world are reflected in one very different area of systems research –  batteryless PV-powered water treatment systems for developing country applications – and before joining KIT he lived in Tanzania for 1.5 years pursuing this goal.