Eray Aydil, the Alstadt Lord Mark Professor at NYU Tandon School of Engineering's Department of Chemical and Biomolecular Engineering, will deliver a seminar entitled, "Reviving “Fool’s Gold” as a Photovoltaic Material." Hosted by Michael D. Ward.
For more information on Eray Aydil, click here.
Abstract: Pyrite FeS2, (fool’s gold) has long be en considered an ideal semiconductor for low-cost, sustainable solar cells because it is composed of earth-abundant, non-toxic, inexpensive elements and it absorbs light so strongly that a 100 nm thick film can absorb >90 % of incoming sunlight. Pyrite was pursued vigorously in the 1980’s for thin film solar cells but all attempts failed, with disappointing efficiencies, less than 3 %. With the rise of other high efficiency thin film solar cells, such as CdTe and CuInGaSe2 (CIGS), enthusiasm for pyrite vanished. Fool’s gold was dead as a solar cell material. Interest in FeS2 reemerged around 2009 motivated in part by the sustainability, cost, and toxicity concerns with CdTe and CIGS. This time, however, a few groups, including ours, are pursuing the fundamental origins of the disappointing performance of FeS2 rather than attempting to produce efficient cells via the trial-and-error approach that previously failed. For three decades, electronic transport data from thin FeS2 films were interpreted as p-type, while single crystals have been unambiguously established as n-type. This unexpected difference came to be known as the “Doping Puzzle”. Recently, we resolved this puzzle and showed that FeS2 films are not p-type but in fact n-type. In thin films with low mobility hopping conduction artificially inverts Hall coefficient, incorrectly indicating p-type conduction. For three decades, FeS2 based solar cells might in fact have been designed based on a mistaken presumption. In this talk I will summarize our recent efforts in reviving FeS2 as a photovoltaic material. I will also summarize our new efforts, at Tandon, in developing materials for quantum cutting to boost the efficiencies of commercial Si, CIGS, CdTe and other types of solar cells.