High‐Performance Solution Processable Red TADF‐OLED with External Quantum Efficiency Exceeding 28% Using a Multi‐Resonance Emitter Host
Advanced Materials,
Год журнала:
2025,
Номер
unknown
Опубликована: Апрель 7, 2025
Abstract
Achieving
high‐efficiency
soluble
red
thermally
activated
delayed
fluorescence
(TADF)
emitters
remains
a
substantial
challenge
owing
to
the
constraints
imposed
by
energy‐gap
law.
In
this
study,
an
asymmetric
pyrene‐azaacene
derivative,
named
PBCNT,
is
prepared
and
characterized,
featuring
strong
electron‐donating
tert
‐butyl
diphenylamine
moiety
electron‐withdrawing
cyano
group.
PBCNT
exhibits
intense
emission
with
peak
wavelength
of
664
nm
in
toluene
solution.
It
demonstrates
evident
TADF
character
solid
state,
attributed
small
energy
difference
0.04
eV
between
its
lowest
singlet
triplet
states.
By
employing
multi
resonance‐type
molecule
as
host
matrix,
solution‐processed
organic
light‐emitting
diode
(OLED)
based
on
achieved
record‐high
maximum
external
quantum
efficiency
(EQE)
28.5%,
at
608
nm,
facilitated
effective
Förster
transfer,
good
horizontal
emitting
dipole
orientation
managed
intermolecular
interactions
dopant.
This
represents
one
highest
EQE
values
reported
among
OLEDs
electroluminescence
wavelengths
greater
than
600
nm.
paper
introduces
promising
pathway
for
developing
efficient
that
overcome
limitations
Язык: Английский
Molecular Engineering Accelerating Reverse Intersystem Crossing Endowed by Confining Donor to Ensure Low Efficiency Roll-Off OLEDs
ACS Materials Letters,
Год журнала:
2025,
Номер
unknown, С. 787 - 795
Опубликована: Янв. 30, 2025
Язык: Английский
Theoretical study on acridine-thioxanthene bridged TADF molecules presenting TSCT and TBCT features and the design for full-color emission
Spectrochimica Acta Part A Molecular and Biomolecular Spectroscopy,
Год журнала:
2025,
Номер
333, С. 125844 - 125844
Опубликована: Фев. 1, 2025
Язык: Английский
Lone Pairs-Mediated Multiple Through-Space Interactions for Efficient Room-Temperature Phosphorescence
Journal of the American Chemical Society,
Год журнала:
2025,
Номер
unknown
Опубликована: Март 18, 2025
The
simultaneous
generation
and
stabilization
of
triplet
excitons
are
the
key
to
realizing
efficient
organic
room
temperature
phosphorescence
(RTP),
which
is
challenging
owing
obscure
mechanism
structure-property
relationships.
Herein,
a
strategy
lone-pair-mediated
multiple
through-space
interactions
(TSIs)
proposed
availably
induce
RTP.
By
incorporating
heteroatoms
facilitate
n-n
n-π
interactions,
lone
pairs
delocalized
throughout
structure,
resulting
in
dense
splitting
excited-state
energy
levels.
Thus,
more
matched
levels
with
small
gap
between
singlet
states
(ΔEST)
emerge,
intersystem
crossing
(ISC)
transition
channels
that
assist
generation.
strong
TSIs
also
effectively
rigidify
molecular
structures
thus
stabilize
for
radiation.
Furthermore,
manipulation
TSI
intensity
allows
efficiency
enhancement,
persistent
time
prolongation,
tolerance
high
temperatures
This
work
not
only
explores
fundamental
principle
RTP
from
new
view
but
provides
universal
ISC
promotion
triple
stabilization.
Язык: Английский
Synergetic Multiple Charge‐Transfer Excited States for Anti‐Quenching and Rapid Spin‐Flip Multi‐Resonance Thermally Activated Delayed Fluorescence Emitter
Advanced Materials,
Год журнала:
2025,
Номер
unknown
Опубликована: Март 29, 2025
The
development
of
multiple
resonances
thermally
activated
delayed
fluorescence
(MR-TADF)
emitters
exhibiting
high
efficiency,
narrowband
emission,
rapid
reverse
intersystem
crossing
rate
(kRISC),
and
suppressed
concentration
quenching
simultaneously
is
great
significance
yet
a
formidable
challenge.
Herein,
an
effective
strategy
presented
to
realize
the
above
target
by
synergizing
charge-transfer
excited
states,
including
short-range
charge
transfer
(SRCT),
through-bond
(TBCT),
through-space
(TSCT).
proof-of-concept
emitter
4tCz2B
exhibits
bright
green
emission
with
narrow
full
width
at
half
maximum
(FWHM)
21
nm
(0.10
eV)
in
solution,
photoluminescence
quantum
yield
97%,
fast
kRISC
7.8
×
105
s-1
significantly
film
state.
As
result,
sensitizer-free
organic
light-emitting
diodes
(OLEDs)
achieve
external
efficiencies
(EQEmaxS)
over
34.5%
together
unaltered
peak
508
FWHM
26
doping
concentrations
ranging
from
3
20
wt.%.
Even
ratio
50
wt.%,
EQEmax
still
as
25.5%.
More
importantly,
non-sensitized
devices
exhibit
reduced
efficiency
roll-offs,
minimum
value
13.4%
brightness
1000
cd
m-2.
Язык: Английский
Engineering Nitrogen/Carbonyl MR‐TADF Emitters: Spiro‐Lock and Tert‐Butyl Synergy in Narrowband Blue Emission
Small,
Год журнала:
2025,
Номер
unknown
Опубликована: Март 30, 2025
Abstract
Multi‐resonance
thermally
activated
delayed
fluorescence
(MR‐TADF)
emitters
with
rigid
planar
structures
are
promising
for
their
exceptional
color
purity
and
outstanding
device
efficiency.
However,
as
an
important
MR
unit,
rigidly
interlocked
nitrogen/carbonyl‐based
blue
materials
often
face
challenges
like
spectral
broadening,
red‐shifting,
reduced
efficiency
compared
to
nitrogen/boron
system.
Herein,
a
peripheral
modification
strategy
incorporating
tert
‐butyl
groups
via
spiro‐lock
framework
is
used
synthesize
four
molecules:
QAO‐TF,
TQAO‐TF,
TQAO‐F,
TSOQ.
The
structure
solidifies
the
molecular
framework,
narrows
emission
bandwidth,
elevates
photoluminescence
quantum
yield
over
96%.
Meanwhile,
introduce
steric
hindrance,
isolating
luminescent
core
suppressing
intermolecular
interactions
in
solid
state,
thereby
improving
while
maintaining
narrowband
emission.
Notably,
TQAO‐F
shows
electroluminescence
peak
at
476
nm
25
full
width
half
maximum
(FWHM)
external
(EQE)
of
31.7%.
TSOQ,
its
oxygen‐induced
charge
effect,
achieves
pure
FWHM
20
nm,
surpassing
30%
EQE
without
sensitizers.
This
overall
performance
suggests
potential
rival
classic
Язык: Английский
Comprehensive Review on the Structural Diversity and Versatility of Multi-Resonance Fluorescence Emitters: Advance, Challenges, and Prospects toward OLEDs
Chemical Reviews,
Год журнала:
2025,
Номер
unknown
Опубликована: Май 9, 2025
Fluorescence
emitters
with
a
multiple-resonant
(MR)
effect
have
become
research
hotspot.
These
MR
mainly
consist
of
polycyclic
aromatic
hydrocarbons
boron/nitrogen,
nitrogen/carbonyl,
and
indolocarbazole
frameworks.
The
staggered
arrangement
the
highest
occupied
molecular
orbital
lowest
unoccupied
facilitates
MR,
resulting
in
smaller
internal
reorganization
energy
narrower
emission
bandwidth.
Optimal
charge
separation
suppresses
gap
between
singlet
triplet
excited
states,
favoring
thermally
activated
delayed
fluorescence
(TADF).
MR-TADF
materials,
due
to
color
purity
high
efficiency,
are
excellent
candidates
for
organic
light-emitting
diodes.
Nevertheless,
significant
challenges
remain;
particular,
limitation
imposed
by
alternated
core
configuration
hinders
their
diversity
versatility.
Most
existing
materials
concentrated
blue-green
range,
only
few
red
near-infrared
spectra.
This
review
provides
timely
comprehensive
screening
from
pioneering
work
present.
Our
goal
is
gain
understandings
structure-performance
relationship
both
basic
advanced
perspectives.
Special
emphasis
placed
on
exploring
correlations
chemical
structure,
photophysical
properties
electroluminescent
performance
depth
breadth
an
aim
promote
future
development
emitters.
Язык: Английский
“Impossible Trinity” between Efficiency, Stability, and Color Purity for Blue OLEDs: Challenges and Opportunities
The Journal of Physical Chemistry Letters,
Год журнала:
2024,
Номер
15(51), С. 12571 - 12583
Опубликована: Дек. 16, 2024
Organic
light-emitting
diodes
(OLEDs)
have
become
the
cutting-edge
technology
in
display
market.
However,
compared
with
green
and
red
stacks,
blue
stacks
still
remain
an
obstacle
for
OLED
technology.
There
seems
to
be
"impossible
trinity"
between
efficiency,
stability,
color-purity
OLEDs.
In
this
trilemma,
advances
device
stability
lagged
far
behind.
Perspective,
focusing
on
critical
role
of
bond-dissociation
energy
(BDE),
we
first
summarize
recent
chemical
degradation
mechanism
high-efficiency
materials
then
highlight
strategies
improve
intrinsic
lifetime
from
material
point-of-view.
Finally,
future
challenges
opportunities
developing
robust
devices
are
envisioned,
including
rational
design
high
BDEs,
two-pronged
approaches
both
thermodynamic
kinetic
aspects,
great
need
host
materials,
deep
insights
into
host–guest
interactions,
collaborative
efforts
aspect
devices,
data-driven
screening
iteration
development.
Язык: Английский