Research Square (Research Square),
Journal Year:
2025,
Volume and Issue:
unknown
Published: April 17, 2025
Abstract
Multi-resonance
thermally
activated
delayed
fluorescence
(MR-TADF)
materials
open
a
heavy-metal-free
avenue
toward
highly
efficient,
narrowband
organic
light-emitting
diodes
(OLEDs).
However,
their
slow
reverse
intersystem
crossing
(RISC)
kinetics
lead
to
severe
efficiency
roll-off
at
practical
driving
currents,
and
existing
strategies
improve
RISC
often
require
emitter-specific
chemical
modifications.
Here
we
demonstrate
general
strategy
by
integrating
heavy-atom
germanium
into
hole-transporting/electron-transporting
hosts
construct
an
exciplex
system
that
accelerates
spin-flip
dynamics.
This
design
enhances
rates
in
diverse
MR-TADF
emitters
via
Förster
resonance
energy
transfer
without
altering
electronic
structure.
The
resulting
blue
green
OLEDs
achieve
external
quantum
efficiencies
exceeding
40%
with
markedly
suppressed
relative
silicon-based
counterparts.
Notably,
the
device
exhibits
half-lifetime
of
241
h
initial
luminance
1,000
cd
m-2,
surpassing
previously
reported
employing
non-metallic
heavy
atoms.
host-guest
advances
systems
high-performance
displays.
Advanced Optical Materials,
Journal Year:
2025,
Volume and Issue:
unknown
Published: Feb. 8, 2025
Abstract
Organic
light‐emitting
diodes
(OLEDs)
exhibit
significant
advantages
in
the
fields
of
ultra‐high‐definition
(UHD)
displays
and
wearable
devices.
However,
developing
low‐cost,
high‐efficiency,
high‐purity
blue
emission
materials
remains
a
challenge
for
academia
industry.
While
thermally
activated
delayed
fluorescence
(TADF)
meet
low‐cost
manufacturing
needs
achieve
100%
internal
quantum
efficiency,
their
charge‐transfer
excited
states
lead
to
broad
spectra
that
don't
BT.2020
standard.
Fortunately,
multiple
resonance
(MR)
strategy
offers
an
effective
solution
creating
TADF
with
high
color
purity.
Through
careful
structural
design
precise
tuning
state
energy
levels,
MR‐TADF
can
easily
full‐width
at
half‐maximum
(FWHM)
less
than
30
nm.
Nevertheless,
it
still
faces
challenges,
such
as
severe
aggregation‐induced
quenching
efficiency
roll‐off.
Herein,
this
work
overviews
recent
progress
devices,
introduce
representative
molecular
strategies
aimed
suppressing
concentration
quenching,
enhancing
reverse
intersystem
crossing
rates,
achieving
deep
emission,
which
will
aid
future
endeavors
develop
more
efficient,
stable
devices
suitable
UHD
display
applications.
Advanced Materials,
Journal Year:
2025,
Volume and Issue:
unknown
Published: Feb. 11, 2025
Abstract
The
hyperfluorescence
(HF)
technology
holds
great
promise
for
the
development
of
high‐quality
organic
light‐emitting
diodes
(OLEDs)
their
excellent
color
purity,
high
efficiency,
and
low‐efficiency
roll‐off.
Sensitizer
plays
a
crucial
role
in
performance
HF
devices.
However,
designing
sensitizers
with
simultaneous
photoluminescence
quantum
yield
(PLQY),
rapid
radiative
decay
(
k
r
),
fast
reverse
intersystem
crossing
rate
RISC
)
poses
challenge,
particularly
thermally
activated
delayed
fluorescence
(TADF)
targeting
deep‐blue
device.
Herein,
by
introducing
boron‐containing
multi‐resonance‐type
acceptor
into
multi‐
tert
‐butyl‐carbazole
encapsulated
benzene
molecular
skeleton,
two
TADF
emitters
featuring
hybridized
multi‐channel
charge‐transfer
pathways,
including
short‐range
multi‐resonance,
weakened
through‐bond,
compact
face‐to‐face
through‐space
charge‐transfer.
Benefiting
from
rational
design,
proof‐of‐concept
exhibit
5.3
×
10
7
s
−1
,
up
to
5.9
5
PQLY
near‐unity,
as
well
ideal
emission
both
solution
film.
Consequently,
corresponding
devices
not
only
achieve
chromaticity
coordinates
that
fully
comply
latest
BT.
2020
standards,
but
also
showcase
record‐high
maximum
external
efficiencies
nearing
40%,
along
suppressed
efficiency
Advanced Optical Materials,
Journal Year:
2025,
Volume and Issue:
unknown
Published: Feb. 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.
Science Advances,
Journal Year:
2025,
Volume and Issue:
11(12)
Published: March 21, 2025
Multiresonance
thermally
activated
delayed
fluorescence
(MR-TADF)
emitters
are
promising
candidates
for
organic
light-emitting
diodes
(OLEDs)
with
high
color
quality.
However,
in
most
cases,
noble
metal–containing
phosphors
required
as
sensitizers
MR-TADF
to
improve
their
electroluminescence
(EL)
performances,
which
may
lead
cost
and
environmental
pollution.
Herein,
an
efficient
purely
room-temperature
phosphorescence
(RTP)
material,
3,2-PIC-TXT,
fast
radiation
is
developed.
It
not
only
exhibits
impressive
EL
performances
emitter
outstanding
external
quantum
efficiency
(EQE)
of
33.2%,
higher
than
that
Ir(ppy)
3
(25.2%),
but
also
functions
remarkably
a
sensitizer
green
(BN2,
tCzphB-Ph,
tCzphB-Fl).
The
hyperfluorescence
OLEDs
using
3,2-PIC-TXT
provide
ultrahigh
EQEs
40.9
43.8%,
superior
those
based
on
(37.0
38.0%),
along
superb
purity
excellent
operational
stability.
These
the
best
devices
RTP
materials
reported
so
far.
Advanced Materials,
Journal Year:
2024,
Volume and Issue:
unknown
Published: Oct. 10, 2024
Ultra-narrowband
multiple
resonance
(MR)
emitters
are
a
key
component
in
the
fabrication
of
highly
efficient
and
stable
blue
organic
light-emitting
diodes
(OLEDs).
To
explore
theoretical
boundaries
wavelength
full
width
at
half
maximum
(FWHM)
emitters,
currently
narrowest
boron-based
MR
emitter
is
carefully
designed
by
integrating
superior
v-DABNA
BBCz-DB
structures
under
auspices
ingenious
short-range
charge-transfer
region
regulation
strategy.
The
target
tetraboron
compound
TB-PB
demonstrates
emission
with
an
473
nm,
small
FWHM
12
nm
CIEy
coordinate
0.14.
Benefiting
from
emitter's
high
photoluminescence
quantum
yield
(99%),
low
excited-state
energy
(2.74
eV)
short
delayed
fluorescence
lifetime
(0.53
µs),
corresponding
OLED
achieves
exceptional
efficiencies
36.4%,
49.1
cd
A
Advanced Optical Materials,
Journal Year:
2025,
Volume and Issue:
unknown
Published: Jan. 17, 2025
Abstract
Organoboron‐nitrogen‐carbonyl‐hybridized
(
h
‐BNCO)
frameworks
are
emerging
templates
for
developing
high‐performance
multiresonant
(MR)
emitters,
but
their
potentials
have
not
been
fully
explored.
In
this
study,
a
novel
red
MR
emitter,
namely,
‐BNCO‐3,
is
developed
by
decorating
two
diphenylamine
moieties
onto
‐BNCO
skeleton
‐BNCO‐2).
Compared
with
the
green
backbone,
‐BNCO‐3
achieves
substantial
emission
redshift
of
76
nm
while
retaining
narrow
full
width
at
half
maximum
(FWHM)
45
(0.16
eV)
in
toluene.
Moreover,
common
advantages
integrating
carbonyl
group
B/N‐based
systems,
e.g.,
significant
nπ
*
contribution
triplet
manifolds,
obvious
‐BNCO‐3.
Thus,
obtained
fast
reverse
intersystem
crossing
rate
k
RISC
)
over
10
5
s
−1
.
The
optimized
non‐sensitized
organic
light‐emitting
diode
(OLED)
based
on
achieved
an
external
quantum
efficiency
(EQE)
26.4%.
further
employing
phosphor
as
sensitizer,
‐BNCO‐3‐based
OLED
can
reach
impressive
EQE
38.0%,
which
among
best
results
MR‐OLEDs.
This
work
demonstrates
effectiveness
into
organoboron‐nitrogen‐based
peripheral
decorations
enhancing
,
offering
new
insights
emitters
systems.
Nano Letters,
Journal Year:
2025,
Volume and Issue:
unknown
Published: Feb. 7, 2025
Deep-blue
electroluminescent
light-emitting
diodes
(ELEDs)
are
crucial
for
various
applications,
including
solid-state
lighting,
high-density
information
storage,
and
vibrant
displays.
Currently,
the
development
of
conventional
deep-blue
ELEDs
is
predominantly
based
on
multilayer
evaporation
structures.
Despite
significant
technological
progress,
fabrication
devices
via
low-cost
solution
processing
has
still
not
fully
been
realized.
Given
that,
a
novel
approach
their
emission
carbon
dots
(CDs)
proposed
in
this
study.
The
as-prepared
CDs
exhibited
quantum
yield
close
to
100%
high
exciton
binding
energy.
CDs-based
provided
at
wavelength
450
nm,
with
CIE
coordinates
(0.15,
0.07),
closely
approaching
standard
color
Rec.
2020
specification
(0.131,
0.046).
These
results
provide
sufficient
evidence
that
fabricated
work
one
highest-performing
developed
so
far,
providing
efficiency
over
10%.
The Journal of Physical Chemistry A,
Journal Year:
2025,
Volume and Issue:
unknown
Published: Feb. 6, 2025
Multiple-resonance
thermally
activated
delayed
fluorescence
(MR-TADF)
materials
have
attracted
extensive
attention
due
to
their
100%
exciton
utilization
efficiency
and
narrowband
emissions.
Numerous
tube-shaped
MR-TADF
emitters
with
full-color
emissions
been
reported,
updated
molecular
design
strategies
need
be
proposed
find
more
"recipes"
narrow
the
emission
spectral
range.
Upon
changing
shape
of
fluorophore
from
a
tubular
fan-shaped
structure,
investigated
molecules
exhibit
based
on
analysis
geometric
electronic
structures,
reorganization
energies,
charge
transfer
characters
upon
excitation,
absorption
properties.
The
small
energies
short-range
properties
excitation
are
key
narrowing
range
molecules.
Such
theoretical
investigations
give
an
in-depth
insight
into
structure-property
relationship,
would
provide
important
guidance
for
multiple-resonance
