Abstract-Influence of high-pressure treatment on charge carrier transport in PbS colloidal quantum dot solids

Seung Jin Heo, Seokhyun Yoon, Sang Hoon Oh, Doo Hyun Yoon and Hyun Jae Kim

Nanoscale, 2013, Accepted Manuscript

DOI: 10.1039/C3NR03641C
Received 16 Jul 2013, Accepted 29 Oct 2013
First published online 01 Nov 2013 
http://pubs.rsc.org/en/content/articlelanding/2013/nr/c3nr03641c#divAbstract                                          

We investigated the effects of high-pressure treatment on charge carrier transport in PbS colloidal quantum dot (CQD) solids. We applied high pressure to PbS CQD solids using nitrogen gas to reduce the inter-dot distance. Using this simple process, we obtained conductive PbS CQD solids. Terahertz time-domain spectroscopy was used to study charge carrier transport as a function of pressure. We found that the minimum pressure needed to increase the dielectric constant, conductivity, and carrier mobility was 4 MPa. All properties dramatically improved at 5 MPa; for example, mobility increased from 0.13 cm2 V-1 s-1 at 0.1 MPa to 0.91 cm2 V-1 s-1 at 5 MPa. We propose this simple process as a nondestructive approach for making conductive PbS CQD solids that are free of chemical and physical defects.