Nanocrystal photovoltaics: a review of recent progress

Crystalline inorganic light-absorbing photovoltaic (PV) device layers can be deposited from solution using semiconductor nanocrystal inks to alleviate the problems due to high-temperature and vacuum processing. Inks can be formulated using various semiconductor nanocrystals, so that it is possible to tune band gap energy and target specific compositions of the absorber layers. Nanocrystal PV devices have exhibited efficiencies of up to 7%, and higher efficiencies of 12% have been achieved by sintering the nanocrystals. Recently, nanocrystal quantum dot PV devices have exhibited external quantum efficiencies (EQEs) above 100% due to multiple exciton generation (MEG) and extraction.