Publication date: 3rd July 2020
PbS nanocrystals are among the most-studied infrared-active QD materials, with potential applications ranging from solar cells to IR LEDs to photon up/down conversion systems and thermoelectrics. Despite their rich history we continue to learn new things about PbS QD chemistry, photophysics, and self-organization into ordered solids. In this talk, I will highlight recent work from my lab at MIT on the structure of PbS QD surfaces. In particular, I will demonstrate neutron scattering as a powerful emerging tool for the characterization of colloidal QDs and the detailed information that small-angle neutron scattering (SANS) can provide about the ligand layers surrounding QDs. Additionally, I will demonstrate the underappreciated role of unbound – or “free” – ligand in mediating the structure of self-assembled QD superlattices.