Unravelling the Role of Surface Traps on Carrier Relaxation
and Transfer Dynamics in Ultrasmall Semiconductor Nanocrystals
Supriya Ghosh
Dushyant Kushavah
Suman Kalyan Pal
10.1021/acs.jpcc.8b07222.s001
https://acs.figshare.com/articles/journal_contribution/Unravelling_the_Role_of_Surface_Traps_on_Carrier_Relaxation_and_Transfer_Dynamics_in_Ultrasmall_Semiconductor_Nanocrystals/7074755
Charge
carrier trapping by the surface defects of colloidal semiconductor
nanocrystal (NC) is a ubiquitous process which limits the performance
of NC-based photovoltaic and photocatalytic devices. Although several
empirical approaches led to the enhancement of device efficiency via
passivation of trap states, a systematic and unified description of
trapping mechanism remains obscure. In this contribution, we present
a detailed experimental investigation of the carrier dynamics of CdSe
NCs with varying concentration of surface traps by means of time-resolved
photoluminescence (PL) and absorption. Our study reveals that the
rate of carrier cooling becomes faster as trap density increases because
of the increased hot carrier trapping. A comparative dynamical study
is also presented to demonstrate how trap states influence electron
injection process. This enhanced understanding of the role of trap
sates on charge carrier dynamics can provide valuable insight toward
the rational development of more efficient NC-based optoelectronic
devices.
2018-08-27 00:00:00
Carrier Relaxation
trap density increases
carrier cooling
semiconductor nanocrystal
trap sates
CdSe NCs
surface traps
photocatalytic devices
Ultrasmall Semiconductor Nanocrystals Charge carrier
device efficiency
PL
Transfer Dynamics
surface defects
trap states influence electron injection process
carrier dynamics
trap states
time-resolved photoluminescence
NC-based photovoltaic
NC-based optoelectronic devices
Surface Traps
charge carrier dynamics