nl9b04491_si_001.pdf (1.67 MB)
Hot Carrier Dynamics in Perovskite Nanocrystal Solids: Role of the Cold Carriers, Nanoconfinement, and the Surface
journal contribution
posted on 2020-03-12, 12:07 authored by Thomas
R. Hopper, Andrei Gorodetsky, Ahhyun Jeong, Franziska Krieg, Maryna I. Bodnarchuk, Marios Maimaris, Marine Chaplain, Thomas J. Macdonald, Xiaokun Huang, Robert Lovrincic, Maksym V. Kovalenko, Artem A. BakulinCarrier
cooling is of widespread interest in the field of semiconductor
science. It is linked to carrier–carrier and carrier–phonon
coupling and has profound implications for the photovoltaic performance
of materials. Recent transient optical studies have shown that a high
carrier density in lead-halide perovskites (LHPs) can reduce the cooling
rate through a “phonon bottleneck”. However, the role
of carrier–carrier interactions, and the material properties
that control cooling in LHPs, is still disputed. To address these
factors, we utilize ultrafast “pump–push–probe”
spectroscopy on LHP nanocrystal (NC) films. We find that the addition
of cold carriers to LHP NCs increases the cooling rate, competing
with the phonon bottleneck. By comparing different NCs and bulk samples,
we deduce that the cooling behavior is intrinsic to the LHP composition
and independent of the NC size or surface. This can be contrasted
with other colloidal nanomaterials, where confinement and trapping
considerably influence the cooling dynamics.