Strong quantum confinement effects in polymer-based PbS nanostructures prepared by ion-exchange method

Nanostructures of narrow band-gap semiconductiors such as PbS provide a large scope for band-gap engineering as strong quantum confinement effects can alter the bulk band-gap value all the way from 0.41 to 2.3 eV, rendering the material transparent in most of the visible range of the electromagnetic spectrum. This paper discusses the preparation and characterization of polymer-based PbS nanostructures showing large characteristic blue shift in optical absorption. Enhancement in electrical resistivity is observed as a result of quantum confinement. This material is found to exhibit strong thermal lens effects, which is utilized to achieve optical limiting at low laser power levels.