Angewandte Chemie,
Journal Year:
2024,
Volume and Issue:
unknown
Published: Dec. 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.
Advanced Materials,
Journal Year:
2024,
Volume and Issue:
36(45)
Published: Sept. 10, 2024
Abstract
Fast
and
efficient
exciton
utilization
is
a
crucial
solution
highly
desirable
for
achieving
high‐performance
blue
organic
light‐emitting
diodes
(OLEDs).
However,
the
rate
efficiency
of
in
traditional
OLEDs,
which
employ
fully
closed‐shell
materials
as
emitters,
are
inevitably
limited
by
spin
statistical
limitations
transition
prohibition.
Herein,
new
sensitization
strategy,
namely
doublet‐sensitized
fluorescence
(DSF),
proposed
to
realize
deep‐blue
electroluminescence.
In
DSF‐OLED,
doublet‐emitting
cerium(III)
complex,
Ce‐2,
utilized
sensitizer
multi‐resonance
thermally
activated
delayed
emitter
ν
‐DABNA.
Experimental
results
reveal
that
holes
electrons
predominantly
recombine
on
Ce‐2
form
doublet
excitons,
subsequently
transfer
energy
singlet
state
‐DABNA
via
exceptionally
fast
(over
10
8
s
−1
)
(≈100%)
Förster
resonance
emission.
Due
circumvention
spin‐flip
DSF
mechanism,
near‐unit
remarkably
short
residence
time
1.36
µs
achieved
proof‐of‐concept
achieves
Commission
Internationale
de
l'Eclairage
coordinate
(0.13,
0.14),
high
external
quantum
30.0%,
small
roll‐off
14.7%
at
luminance
1000
cd
m
−2
.
The
device
exhibits
significantly
improved
operational
stability
compared
with
unsensitized
reference
device.
Advanced Functional Materials,
Journal Year:
2024,
Volume and Issue:
unknown
Published: July 28, 2024
Abstract
Narrow‐band
deep‐blue
light‐emitting
diodes
(LEDs)
(CIE
y
coordinate<0.08,
full
width
at
half
maximum
(FWHM)<20
nm)
are
important
for
the
next
generation
of
LED‐based
displays.
It
remains
a
significant
challenge
design
narrow‐band
emitters.
Herein,
new
strategy
is
proposed
constructing
LEDs
that
not
dependent
on
emitter,
but
only
need
to
dope
n‐type
carbon
dots
(n‐CDs)
in
active
emission
layer
(EML)
wide‐band
blue
LEDs.
The
n‐CDs‐LEDs
show
an
ultra‐narrow
430
nm
with
color
coordinates
(0.15,
0.04)
and
FWHM
19
nm.
Wherein
EML
constructed
by
doping
n‐CDs
Poly(9,9‐dioctylfluorene‐co‐N‐(4‐butylphenyl)
diphenylamine)
(TFB),
which
neither
changes
band
structure
TFB
nor
produces
energy
levels.
Transient
photovoltage
(TPV)
various
photoelectrochemical
characterizations
jointly
reveal
can
trap
holes
realize
carrier
injection
into
single
level
achieve
light
emission.
This
work
provides
brand‐new
simple
way
Nano Letters,
Journal Year:
2025,
Volume and Issue:
unknown
Published: Feb. 12, 2025
Circularly
polarized
thermally
activated
delayed
fluorescence
materials
not
only
possess
high
exciton
utilization
efficiency
but
also
have
the
capability
to
emit
circularly
light
for
potential
information
storage
and
sensing.
In
this
work,
chiral
blue
TADF
enantiomers
are
prepared.
The
energy
difference
between
singlet
triplet,
ΔEST,
increases
with
strength
of
chirality.
orbit-induced
spin
degeneracy
elimination
could
enhance
relaxation,
where
flip
easily
lead
an
effective
transition
from
triplet
states.
This
induces
a
pronounced
enhancement
in
quantum
yield.
Furthermore,
emission
under
different
external
magnetic
fields
studied.
Magnetic
field
control
glum
presents
mirror
symmetry
effect
enantiomers,
which
provides
evidence
photon
electron
spin.
ACS Applied Materials & Interfaces,
Journal Year:
2025,
Volume and Issue:
17(9), P. 14312 - 14321
Published: Feb. 20, 2025
Exciplex,
as
one
of
the
important
categories
thermally
activated
delayed
fluorescence
(TADF),
has
long
been
hindered
from
widespread
application
due
to
lack
stable
exciplex-based
organic
light-emitting
diodes
(OLEDs).
Here,
we
introduce
donor
molecules
improve
OLED
stability,
utilizing
components
diindolo[3,2,1-de:3′,2′,1′-kl]phenazine
(DIPz)
derivatives,
N5,N13-bis(4-(tert-butyl)phenyl)-2,10-dimesityl-N5,N13-diphenyldiindolo[3,2,1-de:3′,2′,1′-kl]phenazine-5,13-diamine
(BDDPD)
and
triazine
3-(9-(3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl)dibenzo[b,d]furan-2-yl)-9-phenyl-9H-carbazole
(DPTBF-PhCz),
2-(3′-(9,9′-spirobi[fluoren]-2-yl)-[1,1′-biphenyl]-3-yl)-4,6-diphenyl-1,3,5-triazine
(Spiro-BDTA),
2,4-diphenyl-6-(3′-(triphenylen-2-yl)-[1,1′-biphenyl]-3-yl)-1,3,5-triazine
(DTBTA),
acceptors.
These
exciplexes
exhibit
high
photoluminescence
quantum
yield
(PLQY)
reverse
intersystem
crossing
(RISC)
rates.
As
a
result,
OLEDs
achieve
maximum
external
efficiency
(EQE)
17.19%
while
also
demonstrating
low
roll-off.
Even
at
brightness
1000
cd
m–2,
EQE
can
still
maintain
16.36%.
A
achieves
an
LT50
over
h
which
is
best
device
lifetimes
OLEDs.
not
only
function
TADF
emitters
but
act
host
material
sensitize
red
fluorescent
molecules.
Red
developed
15%,
with
reduced
This
research
paves
way
for
new
strategy
development
efficient
Advanced Optical Materials,
Journal Year:
2025,
Volume and Issue:
unknown
Published: March 28, 2025
Abstract
One
of
the
most
critical
challenges
in
organic
light‐emitting
diodes
(OLEDs)
is
development
efficient
blue
emitters,
which
require
high
exciton
utilization
efficiency,
short
lifetime,
and
well‐balanced
carrier
mobility.
Herein,
a
hot
emitter,
TPA‐SBF‐OXZ,
synthesized
by
incorporating
triphenylamine
donor
an
oxadiazole
acceptor
into
spirobifluorene
(SBF)
skeleton.
TPA‐SBF‐OXZ
exhibits
photoluminescence
quantum
yield
70.7%,
balanced
hole
electron
mobilities
neat
film.
Additionally,
due
to
anti‐aggregation‐caused‐quenching
characteristics
SBF
skeleton,
non‐doped
OLED
achieves
maximum
external
efficiency
(EQE)
10.6%
at
2396
cd
cm
−2
10.2%
even
11181
,
ranking
leading
position
fluorescent
OLEDs.
The
proof‐of‐concept
phosphorescent
using
as
host
remarkable
performance
metrics,
including
ultra‐low
turn‐on
voltage
2.2
V,
EQE
30.4%,
power
109.1
lm
W
−1
exceptionally
luminance
over
130000
m
.
This
work
offers
feasible
approach
for
high‐performance
electro‐fluorescence
low
power‐consumption
PhOLEDs.
Advanced Materials,
Journal Year:
2025,
Volume and Issue:
unknown
Published: March 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.
Angewandte Chemie International Edition,
Journal Year:
2024,
Volume and Issue:
unknown
Published: Dec. 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.
