Quasi-two-dimensional
(quasi-2D)
mixed-halide
perovskites
are
a
requisite
for
their
applications
in
highly
efficient
blue
perovskite
light-emitting
diodes
(PeLEDs)
owing
to
strong
quantum
confinement
effect
and
high
exciton
binding
energy.
The
pace
of
quasi-2D
PeLEDs
is
hindered
primarily
by
two
factors:
challenges
precisely
managing
the
phase
distribution
defect-mediated
nonradiative
recombination
losses.
Herein,
we
utilize
2,2-diphenylethylamine
(DPEA+)
with
bulky
steric
hindrance
disturb
assembly
process
slender
spacer
host
cation,
4-fluorophenylethylammonium
(p-F-PEA+),
enhancing
management
PeLEDs.
DPEA+
not
only
inhibits
small-n
but
also
strengthens
carrier
transport
alleviates
quenching.
In
addition,
dual
additives─formamidine
acetate
(FAoAc)
guanidine
thiocyanate
(GASCN)─were
incorporated
assist
tailoring
passivation
remaining
defects
films.
C═O
SCN-
groups
can
coordinate
Pb2+
suppress
charge
trap
density
recombination.
As
result
employing
synergetic
strategy
comprehensive
regulation
defect
passivation,
optimized
device
achieves
emission
at
479
nm
5×
improvement
external
efficiency
(EQE)
13×
increase
operating
stability.
This
paves
simple
route
toward
high-performance
blue-emission
Angewandte Chemie International Edition,
Journal Year:
2024,
Volume and Issue:
63(22)
Published: April 3, 2024
Deep-blue
perovskite
light-emitting
diodes
(PeLEDs)
based
on
quasi-two-dimensional
(quasi-2D)
systems
exist
heightened
sensitivity
to
the
domain
distribution.
The
top-down
crystallization
mode
will
lead
a
vertical
gradient
distribution
of
quantum
well
(QW)
structure,
which
is
unfavorable
for
deep-blue
emission.
Herein,
thermal
annealing
treatment
proposed
address
polydispersity
issue
QWs
in
quasi-2D
perovskites.
formation
large-n
domains
at
upper
interface
film
can
be
effectively
inhibited
by
introducing
low-temperature
source
process.
Combined
with
utilization
NaBr
inhibit
undesirable
n=1
domain,
vertically
concentrated
QW
structure
ultimately
attained.
As
result,
fabricated
device
delivers
narrow
and
stable
emission
458
nm
an
impressive
external
efficiency
(EQE)
5.82
%.
Green
sky-blue
PeLEDs
remarkable
EQE
21.83
%
17.51
are
also
successfully
achieved,
respectively,
using
same
strategy.
findings
provide
universal
strategy
across
entire
perovskites,
paving
way
future
practical
application
PeLEDs.
Science Advances,
Journal Year:
2024,
Volume and Issue:
10(20)
Published: May 17, 2024
Deep-blue
perovskite
light-emitting
diodes
(PeLEDs)
of
high
purity
are
highly
sought
after
for
next-generation
displays
complying
with
the
Rec.
2020
standard.
However,
mixed-halide
materials
designed
deep-blue
emitters
prone
to
halide
vacancies,
which
readily
occur
because
low
formation
energy
chloride
vacancies.
This
degrades
bandgap
instability
and
performance.
Here,
we
propose
a
vacancy–targeting
passivation
strategy
using
sulfonate
ligands
different
chain
lengths.
The
groups
have
strong
affinity
lead(II)
ions,
effectively
neutralizing
Our
successfully
suppressed
phase
segregation,
yielding
color-stable
PeLEDs
an
emission
peak
at
461
nanometers
maximum
luminance
(
L
max
)
2707
candela
per
square
meter
external
quantum
efficiency
(EQE)
3.05%,
one
highest
standard–compliant
PeLEDs.
We
also
observed
notable
increase
in
EQE
up
5.68%
1978
by
changing
carbon
length.
Advanced Functional Materials,
Journal Year:
2023,
Volume and Issue:
33(35)
Published: May 8, 2023
Abstract
Quasi‐2D
perovskites,
as
one
of
the
promising
materials
applied
in
perovskite
light‐emitting
diodes
(PeLEDs),
have
attracted
great
attention
for
their
superior
semiconductor
properties.
The
inherent
multiquantum
well
structure
can
induce
a
strong
confinement
effect,
which
is
especially
suitable
blue
emission.
However,
compared
to
green
counterparts,
emitters
constructed
from
quasi‐2D
perovskites
are
more
sensitive
n
domain
distribution
(where
represents
number
PbX
6
inorganic
layers).
Suffering
inefficient
management,
PeLEDs
now
face
variety
negative
issues,
including
color
instability,
multipeak
emission,
and
poor
fluorescence
yield.
In
this
review,
development
optical
properties
overviewed.
Then,
classification
summary
strategies
management
proposed.
Finally,
challenges
potential
directions
summarized.
This
review
expected
provide
comprehensive
perspective
reference
on
toward
efficient
PeLEDs.
Film
uniformity
of
solution-processed
layers
is
the
cornerstone
large-area
perovskite
light-emitting
diodes,
which
often
determined
by
'coffee-ring
effect'.
Here
we
demonstrate
a
second
factor
that
cannot
be
ignored
solid-liquid
interface
interaction
between
substrate
and
precursor
can
optimized
to
eliminate
rings.
A
film
with
rings
formed
when
cations
dominate
interaction;
whereas
smooth
homogeneous
emitting
are
generated
anions
anion
groups
interaction.
This
due
fact
type
ions
anchored
determine
how
subsequent
grows.
interfacial
adjusted
using
carbonized
polymer
dots,
who
also
orient
crystals
passivate
their
buried
traps,
enabling
225
mm2
diode
high
efficiency
20.2%.
Advanced Functional Materials,
Journal Year:
2023,
Volume and Issue:
33(41)
Published: June 20, 2023
Abstract
Producing
efficient
blue
and
deep
perovskite
LEDs
(PeLEDs)
still
represents
a
significant
challenge
in
optoelectronics.
Blue
PeLEDs
have
problems
relating
to
color,
luminance,
structural
electrical
stability
so
new
materials
are
needed
achieve
better
performance.
Recent
reports
suggest
using
low
n
states
(
=
1,
2,
3)
electroluminescence
Ruddlesden–Popper
(RP)
films.
However,
there
fewer
on
the
other
quasi‐2D
structure,
Dion–Jacobson
(DJ)
perovksites,
despite
their
highly
desirable
optical
properties,
due
difficulty
achieving
charge
injection.
To
resolve
this
issue,
herein,
w
e
mixed
DJ
phase
precursors,
propane‐1,3‐diammonium
(PDA)
bromide
into
RP
perovskites
fabricated
low‐dimensional
PeLEDs.
It
is
found
that
these
specific
precursors
aid
suppressing
both
1)
high
≥
4)
phases
an
effective
strategy
blue‐shifting
sky‐blue
sub‐470
nm
region.
With
optimization
of
PDA
concentration
device
layers,
it
achieved
external
quantum
efficiency
1.5%
at
469
stable
for
first
PeLED
be
reported
perovskites.
Advanced Functional Materials,
Journal Year:
2024,
Volume and Issue:
34(27)
Published: March 3, 2024
Abstract
Structuring
metal
halide
perovskites
with
mixed
anions
is
a
promising
strategy
for
attaining
the
desired
bandgap
and
emission
color
technological
applications
such
as
electroluminescent
(EL)
light‐emitting
diodes
(LEDs)
ultrahigh‐definition
displays.
However,
these
suffer
from
severe
EL
spectral
stability
issues.
During
device
operation,
homogeneously
perovskite
phases
are
prone
to
form
halide‐segregated
domain
spatially
inhomogeneous
color,
which
hinders
practical
use
of
LEDs
(PeLEDs).
In
this
review,
comprehensive
survey
performed
about
underlying
driving
forces
phase
segregation,
representative
strategies
discussed
development
color/spectral
stable
PeLEDs.
Finally,
future
directions
prospects
outlined
regarding
further
enhancement
Advanced Optical Materials,
Journal Year:
2025,
Volume and Issue:
unknown
Published: Jan. 28, 2025
Abstract
Perovskite
light‐emitting
diodes
(PeLEDs)
have
demonstrated
significant
potential
in
the
display
sector,
attributed
to
their
wide
color
gamut,
narrow
emission
spectra,
and
cost‐effectiveness.
Despite
rapid
advancements
red
green
PeLEDs,
attainment
of
high
brightness
external
quantum
efficiency
(EQE)
for
blue
PeLEDs
remains
a
considerable
challenge,
which
substantially
limits
practical
applications
white
lighting
optical
communication.
In
this
study,
method
passivation
quasi‐2D
perovskites
using
hydrazide
derivatives
with
varying
alkyl
chain
lengths
is
presented.
Density
functional
theory
analysis
indicates
that
can
effectively
adsorb
onto
halogen
vacancies,
thereby
reducing
charge
trapping
states
associated
undercoordinated
Pb
2+
.
Experimental
results
demonstrate
optimal
derivative
better
eliminate
non‐radiative
recombination
loss,
suppress
ions
migration,
regulate
phase
distribution,
facilitating
smoother
energy
transfer.
Through
approach,
stable
sky‐blue
are
achieved
an
EQE
14.5%
maximum
luminance
2659
cd
m
−2
This
work
offers
systematic
understanding
additive
design,
will
further
enhance
performance
stability
PeLEDs.
