Fabrication of flexible all-inorganic nanocrystal solar cells by room-temperature processing

Abstract

We demonstrate the fabrication of all-inorganic heterostructured n–p junction devices made of colloidal PbS quantum dots (QDs) and TiO₂ nanorods (NRs). The entire device fabrication procedure relies on room-temperature processing, which is compatible with flexible plastic substrates and low-cost production. Through Kelvin Probe Force Microscopy and femtosecond pump and probe spectroscopy we decipher the electron transfer process occurring at the interface between the colloidal PbS QDs and TiO₂ anatase NRs. Overall we demonstrate a high power conversion efficiency of ∼3.6% on glass and ∼1.8% on flexible substrates, which is among the highest reported for entirely inorganic-nanocrystal based solar cells on plastic supports.