Angewandte Chemie International Edition,
Journal Year:
2023,
Volume and Issue:
63(7)
Published: Dec. 8, 2023
Abstract
Luminescent
metal
complexes
based
on
earth
abundant
elements
are
a
valuable
target
to
substitute
4d/5d
transition
as
triplet
emitters
in
advanced
photonic
applications.
Whereas
Cu
I
have
been
thoroughly
investigated
the
last
two
decades
for
this
purpose,
no
structure‐property‐relationships
efficient
luminescence
involving
excited
states
from
Zn
II
established.
Herein,
we
report
design
of
monomeric
carbene
zinc(II)
dithiolates
(CZT)
featuring
donor‐acceptor‐motif
that
leads
highly
thermally
activated
delayed
fluorescence
(TADF)
with
compounds
unprecedented
radiative
rate
constants
k
TADF
=1.2×10
6
s
−1
at
297
K.
Our
high‐level
DFT/MRCI
calculations
revealed
relative
orientation
ligands
involved
ligand‐to‐ligand
charge
transfer
(
1/3
LLCT)
is
paramount
control
process.
Specifically,
dihedral
angle
36–40°
very
reverse
intersystem‐crossing
(rISC)
order
10
9
due
spin‐orbit
coupling
(SOC)
mediated
by
sulfur
atoms
combination
small
ΔE
S1‐T1
ca.
56
meV.
Journal of the American Chemical Society,
Journal Year:
2024,
Volume and Issue:
146(26), P. 18095 - 18103
Published: June 24, 2024
A
triplet-triplet
annihilation-based
upconversion
(TTA-UC)
system,
employing
a
multichromophore
assembly,
is
convenient
to
harvest
low-energy
photons
for
light
energy
conversion
and
optoelectronic
applications.
The
primary
donor
in
the
TTA-UC
typically
low-bandgap
semiconductor,
captures
transfers
triplet
an
annihilator
dye
molecule,
which
turn
generates
high-energy
singlet
excited
state
via
T-T
annihilation.
We
have
now
succeeded
revealing
kinetic
mechanistic
details
of
multistep
transfer
processes
CsPbI
Advanced Optical Materials,
Journal Year:
2024,
Volume and Issue:
12(29)
Published: July 19, 2024
Abstract
Reasonable
energy
level
alignment
of
molecules
is
conducive
to
constructing
high‐performance
blue
emitter.
Pyrene
a
common
building
unit
in
emitters
with
big
gap
between
S
1
and
T
(
ΔE
S1‐T1
)
small
S1‐Tn
(n
=
2‐3).
By
introducing
donor
acceptor
groups
pyrene,
the
high‐lying
triplet
excitons
are
utilized
through
reverse
intersystem
crossing
(RISC)
channel
obtained
“hot
exciton”
emitter
CPPCN.
Herein,
changing
linking
type
ortho‐substituted,
derivatives
o‐CPPCN
exhibited
deeper
emission
λ
max
448
nm)
higher
k
risc
(3.1×10
8
s
−1
).
The
non‐doped
device
based
on
demonstrates
maximum
external
quantum
efficiency
EQE
10.3%
CIEy
0.11,
along
an
exciton
utilization
55%.
Photophysical
measurements
indicate
performance
difference
CPPCN
originates
from
difference.
Compared
(0.26
eV),
S1‐T2
has
been
reduced
0.10
eV,
proving
smaller
2
state
can
promote
RISC
process.
Hence,
be
employed
as
host
prepare
sensitized
OLED
due
its
wide
band
high
.
corresponding
doped
further
improved
11.8%.
Advanced Optical Materials,
Journal Year:
2022,
Volume and Issue:
11(4)
Published: Dec. 11, 2022
Abstract
The
reverse
intersystem
crossing
(RISC)
process
from
triplet
to
singlet
manifold
can
efficiently
improve
the
efficiencies
of
organic
light‐emitting
diodes
(OLEDs).
relevant
RISC
rate
(
k
)
is
one
key
factors
that
affect
efficiency
roll‐off
and
stability
devices.
Here,
a
new
blue
“hot
exciton”
material,
CPPCN,
with
pyrene
as
core,
designed
synthesized.
Photophysical
studies
indicate
there
are
multiple
high‐lying
states
near
lowest
excited
state
S
1
which
facilitate
(hRISC)
state.
corresponding
hRISC
constant
determined
be
high
2.86
×
10
8
s
−1
,
value
some
two
three
orders
magnitude
higher
than
typical
thermally
activated
delayed
fluorescence
materials
emitters.
Benefiting
this
ultrafast
process,
non‐doped
OLED
based
on
CPPCN
reaches
maximum
external
quantum
(EQE)
11.64%
suppressed
(begin
at
brightness
3732
cd
m
−2
retains
EQE
>8.5%
000
).
T
95
lifetime
CPPCN‐based
device
structure
commercial
applications
evaluated
≈368
h
1000
.
Angewandte Chemie International Edition,
Journal Year:
2023,
Volume and Issue:
63(7)
Published: Dec. 8, 2023
Abstract
Luminescent
metal
complexes
based
on
earth
abundant
elements
are
a
valuable
target
to
substitute
4d/5d
transition
as
triplet
emitters
in
advanced
photonic
applications.
Whereas
Cu
I
have
been
thoroughly
investigated
the
last
two
decades
for
this
purpose,
no
structure‐property‐relationships
efficient
luminescence
involving
excited
states
from
Zn
II
established.
Herein,
we
report
design
of
monomeric
carbene
zinc(II)
dithiolates
(CZT)
featuring
donor‐acceptor‐motif
that
leads
highly
thermally
activated
delayed
fluorescence
(TADF)
with
compounds
unprecedented
radiative
rate
constants
k
TADF
=1.2×10
6
s
−1
at
297
K.
Our
high‐level
DFT/MRCI
calculations
revealed
relative
orientation
ligands
involved
ligand‐to‐ligand
charge
transfer
(
1/3
LLCT)
is
paramount
control
process.
Specifically,
dihedral
angle
36–40°
very
reverse
intersystem‐crossing
(rISC)
order
10
9
due
spin‐orbit
coupling
(SOC)
mediated
by
sulfur
atoms
combination
small
ΔE
S1‐T1
ca.
56
meV.
