Growing large, oriented
grains of perovskite often leads to efficient
devices, but it is unclear if properties of the grains are responsible
for the efficiency. Domains observed in SEM are commonly misidentified
with crystallographic grains, but SEM images do not provide diffraction
information. We study methylammoinium lead iodide (MAPbI3) films fabricated via flash infrared annealing (FIRA) and the
conventional antisolvent (AS) method by measuring grain size
and orientation using electron back-scattered diffraction (EBSD) and
studying how these affect optoelectronic properties such as local
photoluminescence (PL), charge carrier lifetimes, and mobilities.
We observe a local enhancement and shift of the PL emission at different
regions of the FIRA clusters, but we observe no effect of crystal
orientation on the optoelectronic properties. Additionally, despite
substantial differences in grain size between the two systems, we
find similar optoelectronic properties. These findings show that optoelectronic
quality is not necessarily related to the orientation and size of
crystalline domains.
Localizing light
to nanoscale volumes through nanoscale resonators
that are low loss and precisely tailored in spectrum to properties
of matter is crucial for classical and quantum light sources, cavity
QED, molecular spectroscopy, and many other applications. To date,
two opposite strategies have been identified: to use either plasmonics
with deep subwavelength confinement yet high loss and very poor spectral
control or instead microcavities with exquisite quality factors yet
poor confinement. In this work we realize hybrid plasmonic–photonic
resonators that enhance the emission of single quantum dots, profiting
from both plasmonic confinement and microcavity quality factors. Our
experiments directly demonstrate how cavity and antenna jointly realize
large cooperative Purcell enhancements through interferences. These
can be controlled to engineer arbitrary Fano lineshapes in the local
density of optical states.
A general, one-step patterning technique for colloidal quantum dots by direct optical or e-beam lithography. Photons (5.5–91.9 eV) and electrons (3 eV–50 kV) crosslink and immobilize QDs down to tens of nm while preserving the luminescent properties.
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