Spectroelectrochemical Signatures of Surface Trap Passivation on CdTe Nanocrystals.

ABSTRACT: The photoluminescence (PL) quantum yield of semiconductor nanocrystals (NCs) is hampered by in-gap trap states due to dangling orbitals on the surface of the nanocrystals. While crucial for the rational design of nanocrystals, the understanding of the exact origin of trap states remains limited. Here, we treat CdTe nanocrystal films with different metal chloride salts and we study the effect on their optical properties with in situ spectroelectrochemistry, recording both changes in absorption and photoluminescence. For untreated CdTe NC films we observe a strong increase in the PL intensity as the Fermi-level is raised electrochemically and trap states in the bandgap become occupied with electrons. Upon passivation of these in-gap states we observe an increase in the steady state PL

SUBMITTER: van der Stam W 

PROVIDER: S-EPMC6251563 | biostudies-literature | 2018 Nov

REPOSITORIES: biostudies-literature