PbS nanocrystal photodetectors with inorganic ligands

Full text: While the functionality of colloidal nanocrystals for opto-electronic applications has been demonstrated, such devices suffer usually from unsufficient charge transport. This problem was recently solved by replacement of the nanocrystals organic, insulating ligands, by inorganic ones. Here we apply AsS33 - inorganic ligands to PbS nanocrystals to fabricate photoconducting detectors. These are obtained by multi-dip-casting of glass substrates patterned by interdigitate gold electrodes into nanocrytal solutions. Photoconductivity with a responsivity in the order of 500 A/W is measured, representing the second highest value ever reported for PbS nanocrystal based devices. The detectivity is sufficiently high to allow for photodetector miniaturization to sizes of a few micrometers in square. (author)