Journal of the American Chemical Society,
Journal Year:
2024,
Volume and Issue:
146(35), P. 24526 - 24536
Published: Aug. 23, 2024
A
novel
series
of
excited-state
intramolecular
proton
transfer
(ESIPT)
emitters,
namely,
DPNA,
DPNA-F,
and
DPNA-tBu,
endowed
with
dual
hydrogen
bonds,
were
designed
synthesized.
In
the
condensed
phase,
DPNAs
exhibit
unmatched
absorption
emission
spectral
features,
where
minor
0–0
peak
becomes
a
major
one
in
emission.
Detailed
spectroscopic
dynamic
approaches
conclude
fast
ground-state
equilibrium
among
enol–enol
(EE),
enol–keto
(EK),
keto–keto
(KK)
isomers.
The
ratio
can
be
fine-tuned
by
varying
substitutions
DPNAs.
Independent
isomers
excitation
wavelength,
ultrafast
ESIPT
takes
place
for
all
DPNAs,
giving
solely
KK
tautomer
maximized
at
>650
nm.
temporal
evolution
was
resolved
state-of-the-art
technique,
transient
grating
photoluminescence
(TGPL),
rate
EK*
→
KK*
is
measured
to
(157
fs)−1
while
stepwise
process
EE*
KK*,
(72
fs)−1.
For
shows
narrowband
high
quantum
yields
(PLQY,
∼62%
DPNA
toluene)
red,
offering
advantages
fabricate
deep-red
organic
light-emitting
diodes
(OLED).
resulting
OLEDs
give
external
efficiency
full
width
half-maximum
(FWHM)
as
narrow
∼40
nm
centered
666–670
fully
satisfying
BT.
2020
standard.
unique
properties
highly
intense
small
fwhm
thus
establish
benchmark
reaching
red
electroluminescence.
Chemical Science,
Journal Year:
2025,
Volume and Issue:
unknown
Published: Jan. 1, 2025
Developing
high-performance
ultraviolet
organic
light-emitting
diodes
with
low
efficiency
roll-off
and
high
color
purity
remains
challenging
due
to
their
inherent
wide-bandgap
characteristics.
In
this
work,
we
present
an
intramolecular
noncovalent
bond
locking
strategy
modulate
donor-acceptor-donor'
(D-A-D')
type
fluorophores
(mPImCZ2F,
mPIoCZ2F
mPImCP2F)
a
hot-exciton
mechanism.
Notably,
these
asymmetric
emitters
exhibit
significantly
enhanced
bipolar
transport
capacity
fluorescence
compared
counterparts.
Among
them,
exhibits
more
remarkable
effect
multiple
C-H⋯F
interactions
ortho-substitution-induced
steric
hindrance,
which
endows
it
higher
radiation
rate,
narrower
emission
spectrum,
balanced
charge
transport.
Consequently,
the
mPIoCZ2F-based
non-doped
device
achieves
electroluminescence
(EL)
peak
at
393
nm
maximum
external
quantum
(EQE)
of
6.62%.
Moreover,
in
doped
device,
emits
stable
light
EL
391
full
width
half
(FWHM)
40
nm,
corresponding
coordinates
(0.167,
0.025).
It
also
exceptionally
EQE
8.71%
minimal
(7.95%
1000
cd
m-2),
ranking
among
best
efficiencies
reported
for
UV-OLEDs
brightness
levels.
Advanced Optical Materials,
Journal Year:
2025,
Volume and Issue:
unknown
Published: April 11, 2025
Abstract
Luminescent
boron‐nitrogen
(BN)‐type
multi‐resonance
(MR)
materials
have
been
first
reported
by
Hatakeyama
and
co‐workers
in
2016.
BN‐type
MR
attracted
a
lot
of
attention,
because
their
unique
photophysical
properties,
including
narrowband
emissions,
high
photoluminescent
quantum
yields,
thermally
activated
delayed
fluorescent
(TADF)
properties.
MR‐TADF
are
considered
as
the
next‐generation
luminescent
for
efficient,
stable,
narrow‐emission
organic
light‐emitting
diodes
(OLEDs).
Herein,
comprehensive
review
recent
progress
is
provided
highlighting
structures,
device
performances.
Moreover,
future
perspective
development
will
be
discussed.
Advanced Science,
Journal Year:
2025,
Volume and Issue:
unknown
Published: April 26, 2025
Abstract
Although
gold‐TADF
(thermally
activated
delayed
fluorescence)
emitters
have
attractive
prospects
as
next‐generation
practical
OLED
emitters,
the
performance
of
OLEDs
utilizing
gold(I)‐
and
gold(III)‐TADF
lags
behind
requirements
applications,
device
lifetime
has
become
a
bottleneck.
Here,
novel
pincer
that
are
easily
fabricated
with
tunable
donor
acceptor
ligands
presented.
These
exhibit
an
extended
molecular
π‐distance
along
transition
dipole
moment,
resulting
in
significant
reduction
electron
exchange
energy
between
S
1
T
excited
states,
thus
narrowing
singlet–triplet
gap
(Δ
E
ST
).
The
combination
small
Δ
heavy‐atom
(Au,
S)
effect
greatly
enhances
spin‐flip
dynamics
produces
efficient
TADF
(photoluminescence
quantum
yields
up
to
90%)
high
radiative
decay
rate
constants
(
k
r
10
6
s
−1
),
short
lifetimes
τ
less
than
1.2
µs)
thin
films
at
room
temperature.
Vacuum‐deposited
based
on
these
demonstrate
impressive
stability,
achieving
i)
maximum
external
efficiency
(EQE
max
)
22.2%,
ii)
record‐
long
operational
(LT
95
3831
h
initial
luminance
1000
cd
m
−2
.
This
excellent
durability
makes
emitter
promising
competitive
alternative
iridium
platinum
for
applications.
Chemical Reviews,
Journal Year:
2025,
Volume and Issue:
unknown
Published: May 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.
Journal of the American Chemical Society,
Journal Year:
2025,
Volume and Issue:
unknown
Published: May 22, 2025
Achieving
narrowband
fluorescence
in
polycyclic
aromatic
hydrocarbons
(PAHs)
is
crucial
for
ultrahigh-definition
organic
light-emitting
diodes
(UD-OLEDs),
yet
the
underlying
structure-property
relationships
that
dictate
emission
bandwidth
remain
insufficiently
understood.
In
this
study,
we
introduce
aromaticity
localization
as
a
predictive
framework
identifying
emitters.
Using
nucleus-independent
chemical
shift
(NICS)
analysis,
uncover
strong
correlation
between
localized
and
reduced
vibrational
coupling,
demonstrating
restricting
π-electron
delocalization
effectively
suppresses
shoulder
peaks,
thereby
minimizing
spectral
broadening.
To
validate
concept,
designed
new
class
of
imine-amine-type
PAHs
(IA-PAHs)
integrates
electron-deficient
imine
electron-rich
amine
units,
generating
multiple-resonance-type
electronic
structure.
Building
on
steric-hindrance-guided
C-H
activation
strategy,
precisely
controlled
regioselectivity
pyridine
fusion
within
triphenylamine
framework,
leading
to
discovery
red-emitting
II-b
green-emitting
III-c
featuring
aromaticity.
Notably,
exhibited
an
exceptionally
red
at
660
nm
with
full
width
half-maximum
only
35
(0.10
eV).
OLEDs
incorporating
demonstrated
high
efficiency
minimal
roll-off
fully
met
stringent
BT.2020
standard,
Commission
Internationale
de
l'Eclairage
(CIE)
coordinates
[0.71,
0.29].
This
work
not
establishes
empirical
intuitive
design
principle
fluorophores
but
also
represents
significant
advancement
deep-red
OLED
technology,
setting
benchmark
conventional
fluorescent
