The application of static high pressure provides a method for precisely controlling and investigating many fundamental
and unique properties of semiconductor nanocrystals (NCs). This study systematically investigates the high-pressure
photoluminescence (PL) and time-resolved carrier dynamics of thiol-capped CdTe NCs of different sizes, at different
concentrations, and in various stress environments. The zincblende-to-rocksalt phase transition in thiol-capped CdTe
NCs is observed at a pressure far in excess of the bulk phase transition pressure. Additionally, the process of
transformation depends strongly on NC size, and the phase transition pressure increases with NC size. These peculiar
phenomena are attributed to the distinctive bonding of thiols to the NC surface. In a nonhydrostatic environment,
considerable flattening of the PL energy of CdTe NCs powder is observed above 3.0 GPa. Furthermore, asymmetric and
double-peak PL emissions are obtained from a concentrated solution of CdTe NCs under hydrostatic pressure, implying
the feasibility of pressure-induced interparticle coupling.
This study explores comprehensively the carrier dynamics in ZnSeO and ZnTeO using photoluminescence (PL) and
time-resolved PL spectroscopy. As the O concentration increases, the PL emissions shift toward lower energies.
Additionally, the PL lifetime increases with increasing O contents and the decay curves exhibit complex behavior. In the
case of ZnSeO, the mechanism of carrier recombination undergoes a complicated change from trapped to free excitons
with the increase in temperature. The incorporation of O in ZnTe generates a wide distribution of electron localization
below the energy of the E- conduction subband, and these cause broad PL emission and serve as another intermediate band. Electrons in both the E+and the E-conduction subbands favor rapid relaxation to low energy states. Moreover, temperature-independent long carrier lifetimes (> 130.0 ns) that are induced by localized electrons increase with O concentration.
The dynamics of Förster resonance energy transfer (FRET) in mixed-size water-soluble CdTe quantum dots (QDs)
are studied by using photoluminescence (PL) and time-resolved PL spectroscopy. When donor concentration is increased,
an enhancement of both the FRET and quantum efficiency in the mixed-size CdTe QDs films can be observed.
Increasing donor concentration significantly quenches the emission intensity and lifetime in donor QDs and enhances
that in acceptor QDs. However, as D/A ratios exceed 6, the emission intensity and the lifetime of acceptor QDs start to
decline, reflecting a decreasing in both quantum and FRET efficiency due to a markedly declining availability of