Imidazolium and quaternary ammonium-functionalized poly(fluorenyl ether ketone sulfone)s were synthesized successfully with the same degree of cationic functionalization and identical polymer ...backbones for a comparative study of anion exchange membranes (AEMs) for solid-state alkaline membrane fuel cells (AMFCs). Both anion exchange membranes were synthesized using a new methyl-containing monomer that avoided the use of toxic chloromethylation reagents. The polymer chemical structures were confirmed by 1H NMR and FTIR. The derived AEMs were fully characterized by water uptake, anion conductivity, stability under aqueous basic conditions, and thermal stability. Interestingly, both the cationic groups and the polymer backbone were found to be degraded in 1 M NaOH solution at 60 °C over 48 h as measured by changes of ion exchange capacity and intrinsic viscosity. Imidazolium-functionalized poly(fluorenyl ether ketone sulfone)s had similar aqueous alkaline stability to quaternary ammonium-functionalized materials at 60 °C but much lower stability at 80 °C. This work demonstrates that quaternary ammonium and imidazolium cationic groups are not stable on poly(arylene ether sulfone) backbones under relatively mild conditions. Additionally, the poly(arylene ether sulfone) backbone, which is one of the most common polymers used in ion exchange membrane applications, is not stable in the types of molecular configurations analyzed.
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IJS, KILJ, NUK, PNG, UL, UM
We present a study of two isomeric thermally activated delayed fluorescence (TADF) emitters 9,9′-(sulfonylbis(pyrimidine-5,2-diyl))bis(3,6-di-tert-butyl-9H-carbazole) (pDTCz-DPmS) and ...9,9′-(sulfonylbis(pyrazine-5,2-diyl))bis(3,6-di-tert-butyl-9H-carbazole) (pDTCz-DPzS). The use of pyrimidine and pyrazine as bridging units between the electron donor and acceptor moieties is found to be advantageous compared to the phenyl- (pDTCz-DPS) and pyridine-based analogues (pDTCz-3DPyS and pDTCz-2DPyS). Conformational modulation of the donor groups as a function of the bridge results in high photoluminescence quantum yields (ΦPL > 68%) and small energy gaps between singlet and triplet excited states (ΔE ST < 160 meV). OLEDs using pDTCz-DPmS and pDTCz-DPzS as emitters exhibit blue and green electroluminescence, respectively, with higher maximum external quantum efficiencies (EQEmax of 14% and 18%, respectively) and a reduced efficiency roll-off as compared to the reference devices using pDTCz-DPS, pDTCz-3DPyS, and pDTCz-2DPyS as the emitters. Our results provide a more complete understanding on the impact of the bridge structure in D-A-D TADF systems on the optoelectronic properties of the emitter and how the balance between color purity and EQE in the devices can be controlled, advancing the design strategies for TADF emitters.
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Two thermally activated delayed fluorescence (TADF) emitters bearing a new dipyridylsulfone core as the electron-accepting unit and di-
tert
-butyl carbazoles as electron-donating units are reported. ...The two emitters,
pDTCz-2DPyS
and
pDTCz-3DPyS
, differ in the regiochemistry of the substitution about the pyridine rings
pDTCz-2DPyS
= 9,9′-(sulfonylbis(pyridine-6,3-diyl))bis(3,6-di-
tert
-butyl-9
H
-carbazole);
pDTCz-3DPyS
= 9,9′-(sulfonylbis(pyridine-5,2-diyl))bis(3,6-di-
tert
-butyl-9
H
-carbazole). Both compounds show blue emission in the range of 450-465 nm, which is in line with theoretical calculations. They have very similar singlet-triplet energy (Δ
E
ST
) gaps (Δ
E
ST
= 0.22 eV and 0.21 eV for
pDTCz-3DPyS
and
pDTCz-2DPyS
, respectively).
pDTCz-2DPyS
has a much larger proportion of delayed emission (26.2%) than
pDTCz-3DPyS
(1.2%). The two compounds show comparable photoluminescence quantum yields of 60% in 2,8-bis(diphenylphosphoryl)dibenzo
b
,
d
thiophene (PPT) doped films. The performance of organic light-emitting diodes (OLEDs) depends on the host used. The maximum external quantum efficiency (EQE) in the PPT host of
pDTCz-3DPyS
is 7.0%, whilst for
pDTCz-2DPyS
it is 12.4%. High performance is obtained for both materials when bis2-(diphenylphosphino)phenylether oxide (DPEPO) is used as the host, with a maximum EQE of 13.4% for
pDTCz-3DPyS
and 11.4% for
pDTCz-2DPyS
, which is a significant improvement from 4.6% for the reference
pDTCz-DPS
. In addition,
pDTCz-3DPyS
shows pure blue electroluminescence with CIE color coordinates of (0.15, 0.12) compared to
pDTCz-2DPyS
with coordinates of (0.15, 0.19).
Two thermally activated delayed fluorescence (TADF) emitters bearing a new dipyridylsulfone core as the electron-accepting unit and di-
tert
-butyl carbazoles as electron-donating units are reported.
Under the influence of climate change, the increasing occurrence of extreme weather events, such as heatwaves, has led to an enhanced frequency of ozone (O3) pollution issues. In August 2022, the ...Sichuan Basin (SCB), a typical large-scale geographical terrain located in southwestern China, experienced the most severe heatwave in the last 20 years. The heatwave led to substantial disparities in O3 levels across the region. Here, by integrating observations, machine learning, and numerical simulations, we aim to understand the diverse O3 formation mechanisms in two megacities, Chengdu (western location) and Chongqing (eastern location). Observational data showed that Chengdu experienced a consecutive 17 d period of O3 exceedance, in contrast to Chongqing, where O3 concentrations remained below the standard. Meteorological and precursor factors were assessed, highlighting high temperatures, intense solar radiation, and overnight accumulative pollutants as key contributors to O3 concentrations. The interplay of isoprene, temperature, and O3, alongside the observation-based box model and MEGAN simulations, underscored the significant role of intensified biogenic volatile organic compounds (BVOCs) in O3 formation. Interestingly, Chongqing exhibited nearly double the BVOC emissions of Chengdu, yet contributed less to O3 concentrations. This discrepancy was addressed through CMAQ-DDM (Decoupled Direct Method) simulations and satellite diagnosis by investigating the O3–NOx–VOC sensitivity. Notably, Chengdu displayed a VOC-driven sensitivity, while Chongqing showed a transitional regime. Moreover, the regional transport also played a pivotal role in the spatial divergence of O3 pollution. Cross-regional transport predominantly influenced Chongqing (contributing ∼ 80 %), whereas Chengdu was mainly affected by the emissions within the basin. The local accumulated pollutants gave rise to the atmospheric oxidizing capacity, resulting in a substantial photochemical contribution to O3 levels (49.9 ppbv h−1) in Chengdu. This comparison of the difference provides insights into the complex interplay of meteorology, natural emissions, and anthropogenic sources during heatwaves, guiding the necessity of targeted pollution control measures on regional scales.
•A multiplex fluorescence immunoassay was developed for simultaneous detection OPs based on Au@Pt nanozyme catalysis.•The Au@Pt nanozyme can directly catalyzes non-fluorescent Amplex™ Red into ...fluorescent resorufin without labelling procedure.•The pesticide antibodies and bio-barcodes were labelled on AuNPs to form AuNPs probes for amplify the signal.•The carboxy modified thiol oligonucleotides and amino modified 96-well plate provided a multi-residue detection for pesticides with high sensitivity and selectivity.•The developed method can detect small molecule contaminants without the use of expensive natural enzyme.
Organophosphate pesticides (OPs) are often used as insecticides and acaricides in agriculture, thus improving yields. OP residues may pose a serious threat, duetoinhibitionof the enzymeacetylcholinesterase(AChE). Therefore, a competitive bio-barcode immunoassay was designed for simultaneous quantification of organophosphate pesticide residues using AuNP signal amplification technology and Au@Pt catalysis. The AuNP probes were labelled with antibodies and corresponding bio-barcodes (ssDNAs), MNP probes coated with ovalbumin pesticide haptens and Au@Pt probes functionalized with the complementary ssDNAs were then prepared. Subsequently, pesticides competed with MNP probes to bind the AuNP probes. The recoveries of the developed assay were ranged from 71.26 to 117.47% with RSDs from 2.52 to 14.52%. The LODs were 9.88, 3.91, and 1.47 ng·kg−1, for parathion, triazophos, and chlorpyrifos, respectively. The assay was closely correlated with the data obtained from LC-MS/MS. Therefore, the developed method has the potential to be used as an alternative approach for detection of multiple pesticides.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Drug addiction is a chronic brain disorder characterized by the compulsive repeated use of drugs. The reinforcing effect of repeated use of drugs on reward plays an important role in morphine‐induced ...addictive behaviors. The nucleus accumbens (NAc) is an important site where morphine treatment produces its reinforcing effect on reward. However, how morphine treatment produces its reinforcing effect on reward in the NAc remains to be clarified. In the present study, we studied the influence of morphine treatment on the effects of DA and observed whether morphine treatment could directly change glutamatergic synaptic transmission in the NAc. We also explored the functional significance of morphine‐induced potentiation of glutamatergic synaptic transmission in the NAc at behavioral level. Our results show that (1) morphine treatment removes the inhibitory effect of DA on glutamatergic input onto NAc neurons; (2) morphine treatment potentiates glutamatergic input onto NAc neurons, especially the one from the basolateral amygdala (BLA) to the NAc; (3) blockade of glutamatergic synaptic transmission in the NAc or ablation of projection neurons from BLA to NAc significantly decreases morphine treatment‐induced increase in locomotor activity. These results suggest that morphine treatment enhances glutamatergic input onto neurons of the NAc via both disinhibitory and stimulating effect and therefore increases locomotor activity.
The NAc is an important site where morphine treatment produces its reinforcing effect on reward. We found that morphine treatment removes the inhibitory effect of DA on glutamatergic input onto NAc and potentiates glutamatergic input from BLA to NAc. Blockade of glutamatergic transmission in NAc or ablation of projection from BLA to NAc decreases morphine treatment‐induced increase in locomotor activity.
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DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, SIK, UILJ, UKNU, UL, UM, UPUK
An important reasons for drug relapse is the retrieval of drug withdrawal memory induced by conditioned context. Previous studies have suggested that the basolateral amygdala (BLA) plays an important ...role in conditioned context-induced retrieval of morphine withdrawal memory. However, the downstream neuronal circuits of the activation of the BLA in conditioned context-induced retrieval of morphine withdrawal memory remain unknown. Using retrograde labeling, immunohistochemical, and optogenetic approaches, we found that, although BLA neurons projecting to the prelimbic cortex (PrL) played an important role in conditioned context-induced retrieval of morphine withdrawal memory, they do not exhibit increased expression of the neuronal plasticity marker Arc. However, when PrL neurons activated by the BLA send feedback signals to the BLA, a neuronal-related process is induced in other BLA neurons that do not project to the PrL, a finding that is relevant to conditioned context-induced retrieval of morphine withdrawal memory.
Thermally activated delayed fluorescence (TADF) and hot excitons are two distinct exciton harvesting mechanisms that can lead to 100% internal quantum efficiency in organic light-emitting diodes ...(OLEDs). Herein, we show that with judicious molecular engineering, the resulting structurally similar compounds emit
via
distinct photophysical mechanisms, which has a direct consequence on the OLED efficiency. When the pyrazine core is substituted with four carbazoles, the molecule
4CzPyz
shows TADF in doped PPT film, with
Φ
PL
of 75%, Δ
E
ST
of 0.23 eV and
τ
d
of 150 μs. The device based on
4CzPyz
emits in the sky-blue (
λ
EL
= 486 nm) with an EQE
max
of 24.1%. When one carbazole is replaced by an
ortho
-biphenyl, the Δ
E
ST
of
3CzBPz
increases to 0.29 eV, the
Φ
PL
decreases to 56%, and the TADF character is largely suppressed in the PPT film. However, a RISC process between higher-lying triplet excited states and the S
1
state is hypothesized to be operational, supported by a combined photophysical and DFT study, to rationalize how the device with
3CzBPz
shows an EQE
max
of 9.6% (
λ
EL
= 464 nm), reflecting that greater than 86% of the excitons are converted into light in the OLED. When two
ortho
-biphenyl groups are connected to the pyrazine core, the Δ
E
ST
of
2CzBPz
is further increased to 0.34 eV while the
Φ
PL
is reduced to 45% in the PPT film. The DFT and photophysical studies indicate that
2CzBPz
should act as a traditional blue fluorescence emitter. The OLED devices with
2CzBPz
bear this out and exhibit an EQE
max
3.2% at a
λ
EL
of 446 nm. These results show how subtle structural changes modulate the efficiency of the triplet exciton harvesting mechanisms and provide new design directions for highly efficient blue emitters for OLEDs.
We report there pyridine-based emitters where the efficiency of the TADF differs significantly, leading to divergent OLED efficiencies.
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