Angewandte Chemie,
Год журнала:
2024,
Номер
unknown
Опубликована: Дек. 3, 2024
Abstract
Achieving
high
efficiency
narrowband
near‐ultraviolet
(NUV)
emitters
in
organic
light
emitting
diode
(OLED)
is
still
a
formidable
challenge.
Herein,
proof‐of‐concept
hybridized
local
and
charge
transfer
(HLCT)
molecule,
named
ICz‐BO,
prepared
characterized,
which
both
multiresonant
(MR)
skeletons
are
integrated
via
conjugation
connection.
A
slightly
distorted
structure
weak
intramolecular
(CT)
interaction
between
two
MR
subunits
lead
to
high‐lying
reverse
intersystem
crossing
(h‐RISC)
channel
of
T
6
→
S
1
,
also
evidenced
by
experimental
calculated
results.
Impressively,
the
ICz‐BO
emitter
exhibits
outstanding
NUV
emission
at
404
nm
with
full‐width
half
maximum
28
toluene
solution.
The
solution
processable
OLED
shows
an
excellent
device
performance
recorded
external
quantum
12.01
%,
concomitant
extremely
low
y‐axis
Commission
Internationale
de
l’Éclairage
(CIE
y
)
value
0.031.
To
best
our
knowledge,
this
highest
reported
for
HLCT‐based
NUV‐OLEDs
date.
This
research
proves
that
skeleton
plays
positive
effect
on
hot
exciton
emitter,
provides
alternative
paradigm
developing
high‐efficiency
emitters.
ACS Applied Materials & Interfaces,
Год журнала:
2024,
Номер
16(38), С. 51201 - 51211
Опубликована: Сен. 16, 2024
Organic
light-emitting
diodes
(OLEDs)
have
been
extensively
investigated
in
full-color
displays
and
energy-saving
lighting
owing
to
their
unique
advantages.
However,
deep-blue
OLEDs
based
on
nondoped
emitting
layers
with
a
satisfactory
external
quantum
efficiency
(EQE)
are
still
rare
for
applications.
In
this
work,
six
hot
exciton
materials,
PPIM-12F,
PPIM-22F,
PPIM-13F,
PPIM-23F,
PPIM-1CN,
PPIM-2CN,
designed
synthesized
via
an
isomer
engineering
design
strategy
photophysical
properties
OLED
performance
systematically
investigated.
These
emitters
all
possess
wide
band
gaps
(3.53-3.69
eV),
hybrid
local
charge
transfer
(HLCT)
characteristics,
good
thermal
stabilities.
The
C2
series
compounds,
show
redder
emission
peaks
than
the
N1
counterparts
of
PPIM-1CN.
addition,
LUMO
energy
levels
decrease
consecutively
sequence
PPIM-22F
<
PPIM-23F
PPIM-2CN
lower
respective
position
isomers
CV
measurements
indicate
that
such
renders
fine-tuning
levels,
incorporation
electron
acceptors
at
extended
PI
unit
is
better
choice
improve
injection
ability.
Theoretical
simulations
they
may
harvest
triplet
through
upper-level
reverse
intersystem
crossing
process,
which
decreases
gathering
excitons
allows
be
fabricated
by
nondoping
technology.
Among
them,
difluorobenzene
substituent
manifests
best
OLEDs,
exhibits
maximum
EQE
7.87%
Commission
Internationale
de
ĺEclairage
(CIE)
coordinates
(0.16,
0.10).
This
work
demonstrates
effective
considerable
improvement
device
subtle
change
molecular
structure
engineering.
Chemical Science,
Год журнала:
2024,
Номер
unknown
Опубликована: Янв. 1, 2024
Spiro-acridine
modified
N/B/O
type
MR-TADF
emitters
realized
deep
blue
fluorescence
with
an
EQE
max
of
20.5%
and
CIE
(0.147,
0.048),
which
is
state-of-the-art
efficiency
for
deep-blue
MR
y
approaching
the
BT.2020
standard.
Advanced Optical Materials,
Год журнала:
2024,
Номер
unknown
Опубликована: Ноя. 18, 2024
Abstract
Highly
efficient
blue
organic
light‐emitting
diodes
(OLEDs)
generally
exhibit
inferior
color
purity
or
large
full
width
at
half
maximum
(FWHM).
Therefore,
emitting
materials
with
simultaneously
high
efficiency
and
small
FWHM
in
the
deep‐blue
region
are
challenging
to
construct.
To
address
this,
hybrid
multi‐resonance
thermally
activated
delayed
fluorescence
(MR‐TADF)
emitters
designed
by
combining
boron‐based
MR‐TADF
materials,
which
efficiency,
indolo[3,2,1‐jk]carbazole
(ICz)‐based
purity.
Two
synthesized
hybridizing
ICz
a
core
prepare
OLEDs
The
emitter
exhibits
external
quantum
of
28.7%
emission
454
nm
an
25
nm,
CIE
y
0.053,
nearly
satisfying
BT
2020
standard.
device
achieved
this
work
is
one
highest
values
reported
for
close
0.05.
Advanced Functional Materials,
Год журнала:
2025,
Номер
unknown
Опубликована: Янв. 28, 2025
Abstract
Quasiplanar
donor–acceptor
(D–A)
thermally
activated
delayed
fluorescence
(TADF)
molecules
are
appealing
candidates
for
efficient
red/near‐infrared
(NIR)
emitters
but
have
not
been
realized.
Herein,
the
first
time,
a
stepwise
approach
to
achieve
this
goal
via
spiro‐locked
C─C
covalent
bond
linking
strategy
combined
with
subtle
management
of
intermolecular
C─H···CN
noncovalent
bonds
in
condensed
states
is
presented.
This
synergetic
effect
enables
newly
developed
molecule,
DCN‐SAC
,
only
attain
nearly
unity
photoluminescence
quantum
yield,
horizontal
dipole
ratio
up
89%
at
5
wt%
doped
conditions
also
quasiplanar
configuration
high‐exciton‐harvesting
J‐aggregates
under
neat
conditions.
The
optimized
organic
light‐emitting
diode
(OLED)
using
as
dopant
furnishes
topmost
external
efficiency
(EQE)
38.7%
631
nm
among
all
red
OLEDs
based
on
TADF
materials.
More
importantly,
‐based
nondoped
OLED
affords
remarkable
EQE
12.6%
an
emission
peak
730
nm,
which
sets
record‐breaking
value
previously
reported
devices
similar
region.
These
findings
reveal
effectiveness
and
great
potential
planarity,
presenting
new
paradigm
developing
high‐efficiency
red/NIR
OLEDs.
Advanced Optical Materials,
Год журнала:
2025,
Номер
unknown
Опубликована: Март 17, 2025
Abstract
As
a
classic
deep‐blue
light‐emitting
fluorophore,
fluorene
has
constructed
kinds
of
star
blue
emitters
featuring
tuning
optical
performances,
but
their
derivatives
with
narrow‐band
emission
characteristic
are
still
relatively
lacking
for
the
requirement
high‐resolution
display.
Here,
feasible
strategy
is
proposed
and
implemented
improving
traditional
luminescent
building‐block,
an
indolo[3,2,1‐
jk
]carbazole
(ICz)
fragment
fused
to
framework
via
one‐pot
double‐halide
cyclized
coupling
(DHCC)
reaction.
Three
ICz‐based
fusing‐strategy
all
inherit
narrowed
performance,
show
better
lighting
behavior
stable
electrical
thermal
properties.
By
inserting
large
phenyl
spirofluorene,
intermolecular
interactions
in
DPtIDCz
SFtIDCz
tuned
significantly
more
saturated
non‐doped
OLEDs.
Especially,
electroluminescence
spectrum
peaked
at
402
nm
narrow
full‐width
half‐maximum
(FWHM)
28
nm,
its
CIE
coordinate
removed
(0.166,
0.033)
from
(0.162,
0.051)
tIDCz,
implying
importance
adjustment
side
chain
structure.
These
results
demonstrate
that
using
DHCC
reaction
achieve
modification
highly
feasible,
derived
materials
can
maintain
commonly
characteristics
both,
which
have
reference
significance
design
narrow‐emission
building‐blocks
future.
Materials,
Год журнала:
2025,
Номер
18(9), С. 2043 - 2043
Опубликована: Апрель 29, 2025
Organic
violet-blue
fluorescent
materials
have
garnered
significant
interest
for
a
broad
spectrum
of
applications.
A
series
triazine-based
molecules,
that
is,
2,4,6-tri(9H-carbazol-9-yl)-1,3,5-triazine
(TCZT),
2,4,6-tri(1H-indol-1-yl)-1,3,5-triazine
(TIDT),
and
2,4,6-tris(3,6-di-tert-butyl-9H-carbazol-9-yl)-1,3,5-triazine
(TDBCZT),
exhibiting
emission
were
synthesized
via
catalyst-free
aromatic
nucleophilic
substitution
reaction.
These
compounds
possess
non-planar
twisted
structure
with
favorable
charge-transfer
characteristics,
demonstrating
excellent
thermal
stability
(decomposition
temperatures
370
°C,
384
230
respectively).
Cyclic
voltammetry
analysis,
combined
time-dependent
density
functional
theory
(TD-DFT)
calculations
at
the
B3LYP/6-31G(d)
level,
offered
detailed
insights
into
their
electronic
structures
electrochemical
properties.
Optical
properties
systematically
characterized
using
Ultraviolet-visible
(UV-Vis)
absorption
photoluminescence
(PL)
spectroscopy.
The
exhibited
luminescence
peaks
located
397
nm,
383
402
nm
in
toluene,
respectively.
In
respective
films,
varying
degrees
spectral
shifts,
408
381
369
nm.
Moreover,
CIE
(Commission
Internationale
de
l'Éclairage)
coordinates
TIDT
toluene
(0.155,
0.067),
indicative
violet
purity.
demonstrated
two-photon
(TPA)
properties,
cross-sections
4.6
GM,
15.3
7.4
Notably,
they
large
molar
absorptivities
substantial
quantum
yields
(PLQYs),
suggesting
potential
practical
applications
as
materials.
