Multiple exciton generation solar cells: Effects of nanocrystal shape on quantum efficiency

Semiconductor nanocrystals (NCs) have the ability to perform a process, termed multiple exciton generation (or MEG), which produces two electrons for every absorbed photon. This has been experimentally confirmed using ultrafast spectroscopic techniques for many semiconductor NC families. The shape of the NCs has been found to play an important role in the efficiency of MEG. Spherical PbSe NCs have been used to fabricate devices that exhibit greater than 100% quantum efficiencies, here we report on the use of NC morphologies and hybrid NC assemblies that can increase the power conversion efficiency in a device.