Chemistry - An Asian Journal,
Год журнала:
2024,
Номер
19(21)
Опубликована: Июль 29, 2024
Abstract
Despite
the
rapid
development
of
thermally
activated
delayed
fluorescent
(TADF)
materials,
developing
organic
light‐emitting
diodes
(OLEDs)
with
small
efficiency
roll‐off
remains
a
formidable
challenge.
Herein,
we
have
designed
TADF
molecule
(mClSFO)
based
on
spiro
fluorene
skeleton.
The
highly
twisted
structure
and
multiple
charge‐transfer
channels
effectively
suppress
aggregation‐caused
quenching
(ACQ)
endow
mClSFO
excellent
exciton
dynamic
properties
to
reduce
roll‐off.
Fast
radiative
rate
(k
r
)
reverse
intersystem
crossing
(RISC)
RISC
1.6×10
7
s
−1
1.07×10
6
,
respectively,
are
obtained
in
mClSFO.
As
result,
OLEDs
obtain
impressive
maximum
external
quantum
(EQE
max
exceeding
20
%
across
wide
doping
concentration
range
10–60
wt
%.
30
doped
OLED
exhibits
an
EQE
23.1
roll‐off,
maintaining
18.6
at
1000
cd
m
−2
.
low
dependence
observed
emitter
underscore
its
significant
potential.
National Science Review,
Год журнала:
2024,
Номер
11(6)
Опубликована: Март 23, 2024
ABSTRACT
Multi-boron-embedded
multiple
resonance
thermally
activated
delayed
fluorescence
(MR-TADF)
emitters
show
promise
for
achieving
both
high
color-purity
emission
and
exciton
utilization
efficiency.
However,
their
development
is
often
impeded
by
a
limited
synthetic
scope
excessive
molecular
weights,
which
challenge
material
acquisition
organic
light-emitting
diode
(OLED)
fabrication
vacuum
deposition.
Herein,
we
put
forward
B‒N
covalent
bond-involved
π-extension
strategy
via
post-functionalization
of
MR
frameworks,
leading
to
the
generation
high-order
B/N-based
motifs.
The
structurally
electronically
extended
π-system
not
only
enhances
rigidity
narrow
linewidth
but
also
promotes
reverse
intersystem
crossing
mitigate
efficiency
roll-off.
As
illustrated
examples,
ultra-narrowband
sky-blue
(full-width
at
half-maximum
as
small
8
nm
in
n-hexane)
have
been
developed
with
multi-dimensional
improvement
photophysical
properties
compared
precursor
emitters,
enables
narrowband
OLEDs
external
quantum
efficiencies
(EQEmax)
up
42.6%,
company
alleviated
decline
brightness,
representing
best
reported
single-host
OLEDs.
success
these
highlights
effectiveness
our
design
advanced
MR-TADF
confirms
extensive
potential
high-performance
optoelectronic
devices.
Advanced Optical Materials,
Год журнала:
2025,
Номер
unknown
Опубликована: Фев. 21, 2025
Abstract
The
preparation
of
narrow
emission
bandwidth
materials
is
crucial
for
the
development
advanced
organic
light‐emitting
diodes
(OLEDs).
In
this
review
article,
state‐of‐the‐art
methodologies
used
emitters
with
high
color
purity
are
summarized,
and
favorable
design
strategies
rationally
organized.
Currently
OLEDs
have
some
issues,
such
as
device
stabilization
that
must
be
resolved,
should
also
considered.
Given
recent
exponential
growth
in
number
types
narrowband
emissive
organometallic
complexes
exhibiting
multiple‐resonance
thermally
activated
delayed
fluorescence
metal‐to‐ligand
charge
transfer
characteristics,
there
an
urgent
need
to
establish
key
technology
descriptors
purity.
review,
developments
boron,
fused
indolocarbazole,
carbonyl,
phosphine
oxide,
exhibit
spectra
described,
future
directions
advance
performance
devices
suggested.
Angewandte Chemie International Edition,
Год журнала:
2024,
Номер
63(38)
Опубликована: Июль 6, 2024
Herein,
we
propose
a
regional
functionalization
molecular
design
strategy
that
enables
independent
control
of
distinct
pivotal
parameters
through
different
molecule
segments.
Three
novel
multiple
resonances
thermally
activated
delayed
fluorescence
(MR-TADF)
emitters
A-BN,
DA-BN,
and
A-DBN,
have
been
successfully
synthesized
by
integrating
highly
rigid
three-dimensional
adamantane-containing
spirofluorene
units
into
the
MR
framework.
These
molecules
form
two
distinctive
functional
parts:
part
1
comprises
boron-nitrogen
(BN)-MR
framework
with
adjacent
benzene
fluorene
forming
central
luminescent
core
characterized
an
exceptionally
planar
geometry,
allowing
for
narrow
FWHM
values;
2
includes
peripheral
mesitylene,
benzene,
adamantyl
groups,
creating
unique
"umbrella-like"
conformation
to
mitigate
intermolecular
interactions
suppress
exciton
annihilation.
The
resulting
A-DBN
exhibit
remarkably
values
ranging
from
18
14
nm
near-unity
photoluminescence
quantum
yields.
Particularly,
OLEDs
based
on
DA-BN
demonstrate
outstanding
efficiencies
35.0
%
34.3
%,
as
low
22
25
nm,
respectively,
effectively
accomplishing
integration
high
color
purity
device
performance.
Advanced Materials,
Год журнала:
2025,
Номер
unknown
Опубликована: Янв. 23, 2025
Abstract
Herein,
a
parallel
“bifunctional
group”
modulation
method
is
proposed
to
achieve
controlled
of
the
emission
wavelength
and
full‐width
at
half‐maximum
(FWHM)
values.
As
result,
three
proof‐of‐concept
emitters,
namely
DBNDS‐TPh,
DBNDS‐DFPh,
DBNDS‐CNPh,
are
designed
synthesized,
with
first
functional
dibenzo[
b,d
]thiophene
unit
concurrently
reducing
bandgap
elevate
their
triplet
state
energy.
A
second
group
1
,
′:
3
′,
″‐
triphenyl
electron
acceptors
1,3‐difluorobenzene
benzonitrile
respectively,
deepen
HOMO
LUMO
levels.
Accordingly,
CIE
coordinates
DBNDS‐CNPh
(0.13,
0.77),
(0.14,
0.76)
in
dilute
toluene
solution.
This
marks
instance
achieving
y
value
0.77
solutions.
Significantly,
non‐sensitized
pure‐green
OLEDs
based
on
DBNDS‐TPh
DBNDS‐DFPh
demonstrate
peak
EQE
35.0%
34.5%,
corresponding
(0.18,
0.75),
(0.17,
doping
concentration
wt.%,
representing
green
OLED
reaching
0.76
bottom‐emitting
device
structure
as
reported
literature.
Angewandte Chemie International Edition,
Год журнала:
2024,
Номер
unknown
Опубликована: Июль 12, 2024
Benzophenone
skeletons
containing
a
carbonyl
unit
(O=C)
have
been
widely
used
as
electron
acceptors
in
the
thermally
activated
delayed
fluorescence
(TADF)
materials.
Herein,
we
present
novel
molecular
design
concept
for
TADF
materials
by
transitioning
from
to
an
amide
(O=C-N)
skeleton
acceptor.
The
unit,
compared
its
counterpart,
offers
more
stable
electronic
configuration.
Leveraging
this
insight,
developed
series
of
high-performance
molecules
based
on
benzoyl
carbazole
and
carbazoline
acceptors.
These
exhibit
exceptionally
small
singlet-triplet
energy
gaps
pronounced
aggregation-enhanced
emission
properties,
achieving
photoluminescence
quantum
yields
neat
films
high
99
%.
Consequently,
these
serve
efficient
emitters
non-doped
organic
light-eimtting
diodes
(OLEDs),
reaching
maximum
efficiency
(EQE
FlexMat.,
Год журнала:
2024,
Номер
1(1), С. 46 - 53
Опубликована: Апрель 1, 2024
Abstract
Recently,
a
novel
paradigm
of
boron‐
and
nitrogen‐embedded
polycyclic
nanographites
featuring
multiple
resonance
thermally
activated
delayed
fluorescence
(MR‐TADF)
has
garnered
substantial
interest
due
to
their
extraordinary
attributes
efficient
narrowband
emissions
with
small
full
width
at
half
maxima
(FWHMs).
Despite
an
array
diverse
color
tuning
strategies,
it
remains
elusive
how
effectively
manipulate
device
efficiencies
without
altering
the
materials'
intrinsic
MR‐TADF
characteristics.
Here,
advanced
‘non‐conjugate
fusion’
design
methodology
was
proposed,
aimed
dramatically
amplifying
horizontal
orientations
emitters
while
preserving
short‐range
charge‐transfer
properties.
As
envisioned,
when
compared
classical
BCz‐BN
mother
core,
proof‐of‐concept
emitter
mICz‐BN
achieved
impressively
enhanced
dipole
ratio
(
83%
vs.
75%)
analogous
emission
wavelengths
(∼486
nm),
FWHMs
(∼26
nm)
photoluminescence
quantum
yields
(∼93%).
Consequently,
external
efficiency
optimized
yielded
performance
enhancement
1.2‐fold
30.5%
25.3%)
whilst
keeping
spectrum
almost
unchanged.
Materials Horizons,
Год журнала:
2024,
Номер
11(19), С. 4674 - 4680
Опубликована: Янв. 1, 2024
The
spiroannulation
of
multiple
resonance
core
skeleton
gives
rise
to
pure-green
emitters
and
superior
electroluminescence
performance
with
low
efficiency
roll-off.
