Enhancement of the photovoltaic performance in PbS nanocrystal:P3HT hybrid composite devices by post-treatment-driven ligand exchange.

A methodology for achieving versatile and facile ligand exchange by post-fabrication chemical treatment in PbS nanocrystal:poly(3-hexylthiophene) (P3HT) hybrid composite photovoltaic devices is demonstrated. We report a considerable improvement of the photovoltaic performance after post-fabrication chemical treatment using acetic acid to produce PbS nanocrystals surrounded by short-length ligands. Annealing induced morphological and photovoltaic performance changes in the resulting composite devices were investigated as a function of the annealing time.