Low Energy Levels Research Articles

Sensitive Detection of Hg2+ and l-Cysteine through Optical Asymmetry-Tuned Fluorescence Switch Off-On Behavior in N-Doped Chiral Carbon Dot.

Blue-emissive nitrogen-doped chiral carbon dots (d-NCD230 and l-NCD230) exhibiting antipodal chiroptical activity, synthesized from the thermal pyrolysis of citric acid and d/l-aspartic acid in 1:2 molar ratios, have been explored as chirality-based fluorescent turn-off/on probes for the detection of Hg2+ and l-cysteine (l-Cys). Circular dichroism (CD) spectroscopy revealed that the chiroptical activity originates from a synergy among intrinsic chirality, chiral precursors on the NCD surface, and hybridization of lower energy levels within the embedded chiral chromophore. Quantitative analysis of optical asymmetry using the Kuhn asymmetry factor (g) at the CD signal of 312 nm showed a higher value for d-NCD230 (1.03 × 10-4) compared to l-NCD230 (1.13 × 10-5). Moreover, we have demonstrated chirality transfer and chiral inversion phenomena in d/l-NCDs by preparing carbon dots with different precursor ratios at different temperatures and probing them through CD spectroscopy. The NCDs exhibited selective fluorescence quenching in the presence of Hg2+, demonstrating linearity in the Stern-Volmer plot. Limits of detection (LODs) for Hg2+ were calculated to be 129 and 192 nM for d-NCD230 and l-NCD230, respectively, in the 0-150 μM concentration range. The quenching mechanism involves nonradiative electron transfer due to Hg2+ binding to oxygen-rich functional groups on the d/l-NCD230 surface. The slight variation in LOD values between d-NCD230 and l-NCD230 indicates the negligible effect of the chirality on Hg2+ sensing. Notably, the fluorescence intensity of d/l-NCD230 could be restored upon adding l-cysteine, with d-NCD230 showing a more pronounced enhancement than l-NCD230. This differential response is attributed to a preferential stereoselective interaction arising from the homochirality of d-NCD230/Hg2+ and l-cysteine. These findings demonstrate the potential of chiral nitrogen-doped carbon dots as sensitive and selective probes for Hg2+ and l-cysteine, with implications for environmental monitoring and biological sensing applications.

Efficient and Ultralong Room Temperature Phosphorescence from Isolated Molecules under Visible Light Excitation.

Visible-light-excited ultralong organic phosphorescence (UOP) materials hold significant potential for various practical applications. Red-shifted excitation wavelength can be achieved by introducing large π-conjugation structures into organic molecules, thereby increasing intermolecular interactions and coupling. However, generating visible-light-excited UOP from isolated molecules poses a great challenge. Herein, we pioneered a strategy to achieve visible-light-excited UOP by doping organic molecules into a rigid polymer. The resulting materials exhibit an ultralong lifetime of up to 2.226 s and a high phosphorescence efficiency of 42.6% under ambient conditions. Impressively, poly(vinyl alcohol) films doped with 1 wt % different guests demonstrate blue and green visible-light-excited UOP. Moreover, they show long-persistent luminescence, lasting over 30 min at room temperature. Through control experiments and theoretical calculations, we discovered that hydrogen bonding between the guests and PVA confines the molecular motion, promoting efficient UOP. The intramolecular charge transfer within the single molecular state contributes to the low energy level, thus leading to the red-shifted absorption. This work will open a new way for developing visible-light-excited UOP based on amorphous polymers, offering highly efficient UOP and long-persistent luminescence under ambient conditions.

Reducing Lithium‐Diffusion Barrier on the Wadsley–Roth Crystallographic Shear Plane via Low‐Valent Cation Doping for Ultrahigh Power Lithium‐Ion Batteries

AbstractRapid‐charging niobium–tungsten oxide Nb14W3O44 (NbWO) anodes with a Wadsley–Roth crystallographic shear (WRCS) structure possess 3D interconnected open tunnels. However, the anisotropic Li+ diffusion paths lead to a high lithium‐diffusion barrier of hooping between window sites across edge‐shared octahedrons, as the rate‐limiting step of hooping. To improve the rate capability of NbWO, doping it with low‐valent cations (with valences lower than W6+) to reduce the high lithium‐diffusion barrier is proposed. Electron energy loss spectroscopy reveals that low‐valent V5+, V4+, Tb4+, and Ce4+ tend to distribute on the crystallographic shear plane under electrostatic repulsion forces. The reduction in steric hindrance resulting from the increased long bond length ratio of doped edge‐shared octahedrons, coupled with coordination environment modification of [LiO5] on the crystallographic shear plane due to the low energy level of V5+, enhances Li+ diffusion kinetics and cyclic stability. V5+‐ and Tb4+‐doped NbWOs achieve rate capacities of 83 and 63 mAh g−1, at 200 C (1C = 0.178 Ag−1) and retain 75.42% and 86.79% of their capacities, respectively, after 3700 cycles at 20 C. Thus, the proposed doping strategy is promising for preparing WRCS‐type niobium‐based oxides for ultrafast lithium storage.

Investigations of optoelectronic, magnetic, and transport properties of Zintl-phosphides BaX2P2 (X=Cd, Sn, Cu) for green technology: First principle calculations

One way to decarbonize the world's energy generation is through thin-film photovoltaics (PV), there are significant problems with elemental abundance, stability, or performance with the thin-film solar absorbers that are now on the market. We present the optoelectronic and transport properties of Zintl-phosphides BaX2P2 (X = Cd, Sn, Cu) using first-principles calculations based on density functional theory. Our calculations show that increasing the band gap of Cd/Sn and Cu-based phosphides from 0.5 to 4.0 eV enables fine adjustment of bandgaps, structure, and optoelectronics, broadening the material's potential applications in the semiconducting industry. Strong absorption occurs in the energy range of 4–8 eV; it concluded that their optical characteristics, such as natural and imaginary dielectric functions, refractive index, and absorption coefficient, might make them useful in optoelectronic and photovoltaic applications. In the 50–800 K temperature range, power factor (PF), electrical conductivity, thermal conductivity, and Seebeck coefficient were investigated. With PFs of approximately 7.5 × 1010 W/K2ms, respectively, the compound demonstrated a considerable potential utility in thermoelectric devices. An assessment of radiation shielding performance was conducted using the XCOM tool across a broad energy range ranging from 15 keV to 15 MeV. The findings indicated that the mass attenuation coefficient (GMAC) values increased proportionately of BaCd2P2, BaSn2P2, and BaCu2P2 samples. The GMAC peaked for all sample compositions at around 0.015 MeV, with values spanning from 42.94 cm2/g for BaCd2P2 to 51.96 cm2/g for BaCu2P2. Nevertheless, when elevating the energy level beyond 15 keV, a notable decline in GMAC values was observed. This is likely mostly attributable to the predominance of photoelectric interactions at lower energy levels. These compounds' strong absorption patterns and high PF make them promising materials for thermoelectric and photovoltaic applications.

Radiative decay rates for magnetic dipole (M1) and electric quadrupole (E2) transitions between low-lying levels within the 4f3 ground configuration of Pr III

Abstract A new set of theoretical radiative decay rates characterizing forbidden transitions in doubly charged praseodymium (Pr III) is reported in the present paper. More precisely, transition probabilities were computed for all magnetic dipole (M1) and electric quadrupole (E2) lines involving the lowest energy levels of the 4f$^3$ ground configuration located below 20000 cm$^{-1}$ since the levels above this limit are preferentially depopulated by allowed electric dipole (E1) transitions. The calculations were carried out using different computational strategies based firstly on the pseudo-relativistic Hartree-Fock (HFR) method and secondly on the fully relativistic Multiconfiguration Dirac-Hartree-Fock (MCDHF) method. The comparison between the results obtained by these independent approaches makes it possible to estimate their reliability. Comparisons with the few previously published data were also made. In addition, some astrophysical implications were deduced from the new atomic parameters computed in the present work, such as the possible presence of [Pr III] lines in the infrared spectra recorded by the {\it James Webb Space Telescope} ($JWST$) in the context of the investigation of kilonovae in their nebular phase, i.e. several days after neutron star mergers.

Comparison of X-Ray Absorption in Mandibular Tissues and Tissue-Equivalent Polymeric Materials Using PHITS Monte Carlo Simulations

This study investigates the absorption of X-rays in mandibular tissues by comparing real tissues with tissue-equivalent materials using the PHITS Monte Carlo simulation program. The simulation was conducted over a range of X-ray photon energies from 50 to 100 keV, with increments of 5 keV, to evaluate the dose absorbed by different tissues. Real tissues, such as the skin, parotid gland, and masseter muscle, were compared with their tissue-equivalent polymeric materials, including PMMA, Parylene N, and Teflon. The results showed that the real tissues generally absorbed more X-rays than their corresponding equivalents, especially at lower energy levels. For instance, at 50 keV, differences in the absorbed doses reached up to 50% for the masseter muscle and its equivalent, while this gap narrowed at higher energies. The study highlights the limitations of current tissue-equivalent materials in accurately simulating real tissue behavior, particularly in low-energy X-ray applications. These discrepancies suggest that utilizing tissue-equivalent materials may lead to less accurate medical imaging and radiotherapy dose calculations. Future research should focus on improving tissue-equivalent materials and validating simulation results with experimental data to ensure more reliable dosimetric outcomes. This study provides a foundation for refining radiation dose calculations and improving patient safety in clinical applications involving X-rays.

N-Type Conjugated Polymers Based on Double B←N Bridged Bipyridine Unit.

ConspectusBoth p-type conjugated polymers and n-type conjugated polymers are required for organic optoelectronic devices, such as organic solar cells (OSCs), organic field-effect transistors (OFETs), organic thermoelectrics (OTEs), etc. The development of n-type conjugated polymers lags far behind that of the p-type counterparts in view of material diversity and optoelectronic device performance. This is mainly due to the lack of strong electron-withdrawing building blocks, which are always based on the imide unit. Double boron-nitrogen coordination bond (B←N) bridged bipyridine (BNBP), which was first developed in 2016, is an alternative kind of electron-withdrawing building block based on a B←N unit. BNBP itself possesses a planar and fixed configuration, low-lying electronic energy levels, strong fluorescence, and facile functionalization. A family of BNBP-based conjugated polymers has been developed. They show excellent and tunable optoelectronic properties, such as high electron mobility, low-lying and tunable lowest unoccupied molecular orbital (LUMO) energy level (ELUMO), medium bandgap, narrow absorption spectra in the visible range, high fluorescence quantum efficiency, etc. With rational molecular design of BNBP-based conjugated polymers, they have been widely used in organic optoelectronic devices with high performance, including OSCs, OFETs, and OTEs, indoor photovoltaics (IPVs), organic light-emitting diodes (OLEDs), organic photodetectors (OPDs), etc. Therefore, BNBP-based conjugated polymers have become an important class of optoelectronic materials. In this Account, we summarize the research progress on BNBP-based conjugated polymers.At first, we discuss BNBP itself, including its molecular design, synthesis, chemistry, and optoelectronic properties. Then we introduce the optoelectronic properties of BNBP-based conjugated polymers, including their light absorption property, fluorescence, electron mobility, and frontier electronic energy levels. We have systematically elucidated the relationship between the chemical structures, optoelectronic properties, and optoelectronic device performance of BNBP-based n-type conjugated polymers. The unique property of BNBP-based conjugated polymers is the high electron mobility in the amorphous state. Other noteworthy properties of these polymers are the medium bandgap and absorption spectra in the visible range. Next, we discuss the applications of BNBP-based conjugated polymers in OSCs, IPVs, OFETs, OTEs, OPDs, and OLEDs. The excellent optoelectronic device performance is noteworthy, such as power conversion efficiency (PCE) of 10% in OSCs, PCE of 26% in IPVs, electron mobility of 0.3 cm2 V-1 s-1 in OFETs, power factor of 25 μW m-1 K-2 in OTEs, specific detectivity of 1.79 × 1013 cm Hz1/2 W-1 in OPDs. Finally, we propose that great attention should be paid to the deep understanding of the electronic structures of BNBP itself and BNBP-based conjugated polymers as well as the new applications of BNBP-based conjugated polymers.

Plasmon-enhanced hydrogen production from photocatalytic methanol aqueous-phase reforming over novel nickel-tin intermetallic compounds photocatalyst

Hydrogen production from the aqueous phase reforming (APR) of methanol is promising to reduce the global carbon dioxide emission, but it is still a great challenge for hydrogen production with high catalytic efficiency at low reaction temperature. Here we report that Al2O3 supported Ni3Sn1 intermetallic compounds nanoparticles as new class of plasmonic photocatalyst and enables low temperature (150–190 °C), efficient hydrogen production (277μmol g−1 min−1) and low CO and CH4 selectivity (≤ 0.1 %) through APR with the help of light irradiation. The hydrogen production rate of Ni3Sn1/Al2O3 is 8 times higher than that of conventional noble metal 3 wt% Pt/Al2O3 catalyst under the same optimized reaction conditions. The exceptional photocatalytic performance for hydrogen production can be attribute to higher efficiency of “hot electron” transference into the reactant due to the higher energy level of “hot electron” and the lower energy level of metal-reactant adsorption bond induced by Sn doping in Ni3Sn1 under light irradiation, which not only improve the reactivity via enhanced methanol dissociation and the sequential water–gas shift (WGS) reaction, but also suppressed catalyst poisoning via accelerated CO2 desorption over the Ni sites.

Benzobisthiazole and rhodanine based low energy level small molecule donors for organic solar cells

At present, high-performance small molecule donors for organic solar cells (OSCs) are almost entirely composed of the electron donating core benzodithiophene (BDT), which has resulted in a lack of material diversity and further improvement. In this article, we constructed an A-π-A′-π-A conjugated structure using electron withdrawing group benzobisthiazole (BBT) core and rhodanine end group, and synthesized two small molecule donors BBTSM-3 and BBTSM-4. Under the dual electron withdrawing effects of BBT and rhodanine, the HOMO energy levels of BBTSM-3 and BBTSM-4 reached extremely low levels (−5.60 eV and −5.64 eV), but still matched well with the acceptor Y6. In addition, through reasonable side chain regulation, BBTSM-3 exhibited stronger crystallinity and weaker aggregation at the same time. This provides a reference point for the use of the electron withdrawing core and the regulation of side chains among small molecule donors.

The formation of exciplex and triplet-triplet transfer in organic room temperature phosphorescent guest-host materials.

Organic materials typically do not phosphoresce at room temperature because both intersystem crossing (ISC) and phosphorescence back to the electronic ground state are slow, compared to the nonradiative decay processes. A group of organic guest-host molecules breaks this rule. Their phosphorescence at room temperature can last seconds with a quantum efficiency of over 10%. This extraordinary phenomenon is investigated with comprehensive static and transient spectroscopic techniques. Time-resolved vibrational and fluorescence spectral results suggest that a singlet guest-host exciplex quickly forms after excitation. The formation of exciplex reduces the singlet-triplet energy gap and helps facilitate charge separation that can further diffuse into the host matrix. The heavy atoms (P or As) of the host molecule can also help enhance the spin orbital coupling of the guest molecule. Both boost the rate of ISC. After the singlet exciplex transforms into the triplet exciplex through the ISC process, UV-visible transient absorption spectroscopic measurements support that the triplet exciplex quickly transforms into the guest molecule triplet state that is at a lower energy level, thereby reducing the reverse ISC-induced triplet population loss. Finally, the long-lasting separated charges that diffused into the host matrix can diffuse back to the guest hole to form new triplets, and the dilution effect of the host molecules can effectively reduce the triplet quenching. All these factors contribute to the dramatic enhancement of phosphorescence at room temperature.

Optical, thermal, and radiation shielding characterization of bismuth-modified zinc-lithium-tungsten-borate glass

Abstract This study examines the optical, thermal, and radiation attenuation properties of zinc-tungsten-lithium-borate glass modified with Bi2O3, synthesized using melt-quench techniques. The resulting glass samples display a significant physical property, with density increasing from 3.22 g/cm³ to 4.84 g/cm³ as Bi2O3 concentration increase from 2 to 16 mol%. The optical band gap narrows from 2.9 eV to 2.55 eV, while the refractive index increases from 2.42 to 3.49, indicating a shift in absorption to lower energy levels. Higher Bi2O3 concentrations reduce optical non-linearity while enhancing the linear optical properties of the synthesized glasses. The formation of orthoborate anions suggests that Bi3+ ions in the glasses act as network modifiers, disrupting the borate framework and introducing structural disorder. Additionally, thermal properties, including glass transition temperature (T_g), crystallization temperature (T_c), and melting temperature (T_m), decrease with increasing Bi2O3 concentration. The radiation shielding effectiveness is significantly improved, with the linear attenuation coefficient (LAC) increasing from 0.56 cm⁻¹ to 1.35 cm⁻¹ at 0.284 MeV and from 0.127 cm⁻¹ to 0.186 cm⁻¹ at 2.506 MeV as Bi2O3 content rises from 2 mol% to 16 mol%. For a glass thickness of 1 cm, the radiation protection efficiency reaches approximately 74% for a photon energy of 0.284 MeV in the sample doped with 16 mol% Bi2O3. The glass's remarkable combination of high transparency and effective radiation attenuation, positions it as a promising option for radiation shielding applications.

Unravelling the monomer molar ratio modulation of the optoelectronics of Poly(propylene imine) tetra(thiophen-2-ylmethylene-amine)-co-poly(3-hexylthiophene-2,5-diyl) copolymer

Tuning the molecular structure of a copolymer is of considerable importance for optimizing its optoelectronic and morphological properties. This will enormously help in improving and understanding the performance of a copolymer as a donor material in organic photovoltaic cells (OPVs). Herein, we reported a simple synthetic approach for developing a polypropylene imine tetra(thiophen-2-ylmethylene-amine)-co-poly(3-hexylthiophene-2,5-diyl) (P3HT-PT) using chemical oxidation polymerization. To the best of our knowledge, the investigations of monomer molar ratio have never been reported for synthesis of dendritic copolymers. Different concentrations of hexylthiophene (3HT) as a monomer for poly(3-hexylthiophene (P3HT) chains growth on the branches of polypropylene imine tetra(thiophen-2-ylmethylene-amine) (PPIT) as a dendritic core were studied. Nuclear magnetic resonance spectroscopy (NMR) confirmed that P3HT-PT has mixture of P3HT chains arrangements with different chain lengths. More head-to-tail arrangement was achieved at low concentration of 3HT. This study revealed that concentration of 3HT alter with optical, microscopic, electrochemical and thermal properties of P3HT-PT. Synthesized P3HT-PT polymers were further investigated as donor materials in OPVs. The investigations indicated that the P3HT-PT40 based OPV has better photovoltaic performance due to fewer aggregates and high crystallinity of P3HT-PT40, low LUMO energy levels offset and sufficient charge separation in comparison with P3HT-PT60 and P3HT-PT80 based OPVs.

The salty emission of the intermediate-mass AGB star OH 30.1−0.7

Abstract We analyse continuum and molecular emission, observed with ALMA, from the dust-enshrouded intermediate-mass AGB star OH 30.1 −0.7. We find a secondary peak in the continuum maps, “feature B”, separated by 4.6″ from the AGB star, which corresponds to a projected separation of 1.8 × 104 au, placing a lower limit on the physical separation. This feature is most likely composed of cold dust and is likely to be ejecta associated with the AGB star, though we cannot rule out that it is a background object. The molecular emission we detect includes lines of CO, SiS, CS, SO2, NS, NaCl, and KCl. We find that the NS emission is off centre and arranged along an axis perpendicular to the direction of feature B, indicative of a UV-emitting binary companion (e.g. a G-type main sequence star or hotter), perhaps on an eccentric orbit, contributing to its formation. However, the NaCl and KCl emission constrain the nature of that companion to not be hotter than a late B-type main sequence star. We find relatively warm emission arising from the inner wind and detect several vibrationally excited lines of SiS (v=1), NaCl (up to v=4) and KCl (up to v=2), and emission from low energy levels in the mid to outer envelope, as traced by SO2. The CO emission is abruptly truncated around 3.5″ or 14,000 au from the continuum peak, suggesting that mass loss at a high rate may have commenced as little as 2800 years ago.

Remarkable improvement in radiation shielding efficiency, thermal insulation performance and compressive strength of rigid polyurethane foam composites by synergetic effect of PbO and colemanite fillers

Developing radiation shielding materials is a critical phenomenon for protecting people and the environment with the increment in usage of nuclear technology in today's world. With this sense, PbO/colemanite-filled rigid polyurethane foams were fabricated by one-shut free rise method, and their performances were investigated via the advanced characterization techniques such as ATR-FTIR, SEM-EDS, TGA as well as thermal conductivity, universal mechanical and radiation shielding tests. The characteristic properties of the samples were evaluated in detail depending on the variation in the filler contents. The ATR-FTIR analysis illustrated that RPUF matrices exhibited good compatibility with the fillers by forming the secondary chemical bonds. Furthermore, SEM analysis revealed that the samples with low PbO/colemanite fillers exhibited fairly uniform and regular cellular morphology with anisotropic elliptical apparition thanks to synergetic catalytic effect of the filler particles, whereas, at high content, some local distortions with slightly chaotic appearance were observed accompanied by viewing the little ruptures and bursts in cell face and collapsed in cell plateau borders. TGA measurement indicated that the inclusion of the fillers into RPUF got worse the samples with comparison of neat RPUF due to the reduction in crosslinking density of the foam. Remarkable improvement (about 25 %) was also obtained in thermal insulation performance at the foam composites containing the fillers due to highly augmentation in number of closed cells and presence of more immobile CO2 gas inside the cells. Furthermore, high inclusion of the fillers in RPUF matrix improved compressive strength of the foams by nearly 15 % by enhancing the bending moment and rigidity of RPUF matrices via contributing to the overall stress dispersion. According to linear and mass attenuation coefficients results, the foam composites displayed excellent X-ray radiation shielding performance with increasing of PbO/colemanite content thanks to the density increment and presence of the atoms with high atomic number. Furthermore, at low photon energy levels, better shielding against X-ray radiation was obtained, while vice versa at high energy levels.

Coaxially Bi/ZnO@ZnSe Array Photocathode Enables Highly Efficient CO2 to C1 Conversion via Long-lived High-energy Photoelectrons.

The key aspect of the photoelectrochemical CO2 reduction reaction (PEC CO2 RR) lies in designing cathode materials that can generate high-energy photoelectrons, enabling the activation and conversion of CO2 into high-value products. In this study, a coaxially wrapped ZnO@ZnSe array heterostructure was synthesized using a simple anion exchange strategy and metallic Bi nanoparticles (NPs) were subsequently deposited on the surface to construct a Bi/ZnO@ZnSe photocathode with high CO2 conversion capability. This array photocathode possesses a large aspect ratio, which simultaneously satisfies a low charge carrier migration path and a large specific surface area that facilitates mass transfer. Additionally, the barrier formed at the n-n heterojunction interface hinders the transfer of high-energy photoelectrons from ZnSe to lower energy levels, resulting in their rapid capture by Bi while maintaining a relatively long lifetime. These captured electrons act as active sites, efficiently converting CO2 into CO with a Faradaic efficiency above 88.9 % at -0.9 V vs. RHE and demonstrating superior stability. This work provides a novel approach for synthesizing high-energy photoelectrode materials with long lifetimes.

2‐Ethylhexyl‐4,6‐Dibromo‐3‐Cyano‐3‐Thieno[3,4‐b]Thiophene Enables Low HOMO Energy Level Polymer Donor

AbstractThe new halogen‐free donor polymer PCN6 is constructed using 2‐ethylhexyl‐4,6‐dibromo‐3‐cyano‐thieno[3,4‐b]thiophene as acceptor (A) block, and is compared in detail with the commercially available PTB7‐Th. It is found that PCN6 has a wider film absorption (300–700 nm) and lower highest occupied molecular orbital (HOMO) energy levels (−5.52 eV) than PTB7‐Th (−5.34 eV), suggesting a great advantage of the monocyano‐functionalized modification strategy in terms of molecular absorption and energy level tuning. The performance difference between PCN6:Y6‐ and PTB7‐Th:Y6‐based organic solar cells (OSCs) is compared by a series of studies including light intensity dependence, carrier mobility, AFM, TEM, and GIWAXS. The results show that PCN6:Y6‐based OSCs have stronger crystallinity, better charge transport, higher and more balanced carrier mobility, and less exciton complex loss. Therefore, the power conversion efficiency (PCE) of PCN6:Y6‐based OSCs reaches 11.34%, while the PCE of PTB7‐Th:Y6‐based OSCs is only 9.02%. These results suggest that 2‐ethylhexyl‐4,6‐dibromo‐3‐cyano‐thieno[3,4‐b]thiophene is an excellent A block for the construction of halogen‐free donor polymers with low HOMO energy levels, and also demonstrate that the introduction of cyano in the conjugated backbone of polymers is a good strategy to achieve high‐performance OSCs.

Difluorobenzene as an Antisolvent for Fluorinated Electrolyte to Achieve Unparalleled Cycle Life of Lithium Metal Battery.

Electrolytes play a crucial role in enhancing the cycling stability and overall lifespan of lithium metal batteries (LMBs). However, conventional electrolytes achieve ununiform and low ionic conductivity solid electrolyte interphase (SEI), leading to uncontrolled lithium dendrite growth and dead lithium formation, rendering them inadequate for meeting the performance of high energy density LMBs. Herein, a 1,2-difluorobenzene (1,2-dFBn) is introduced as antisolvent in fluorinated electrolyte which is composed of fluoroethylene carbonate (FEC) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). The low energy level of the lowest unoccupied molecular orbital (LUMO) and the high fluorine-donating ability of 1,2-dFBn jointly modify the solvation structure and electrode/electrolyte interphase chemistry. As a result, this simple electrolyte formulation enables the Li||Li symmetric cells exhibit remarkable stability, enduring 700 h of continuous cycling under 2 mA cm-2 and Li||Cu cell achieve an impressive average Coulombic efficiency (CE) of 99.76%. Moreover, the full cell assembled with electrochemically deposited lithium capacity of 5 mAh cm-2 and LiFePO4 (LFP) as cathode achieves exceptional performance, maintaining a discharge specific capacity of 134.9 mAh g-1 while retaining 95.1% capacity at 2C after 1000 cycles. This study offers a plausible ratio design for fluorinated electrolyte, which achieving high CE and long-life LMBs.

Efficacy of Antivascular Ultrasound (AVUS) in Hepatocellular Carcinoma (HCC).

Hepatocellular carcinoma (HCC) is a prevalent type of primary liver cancer and one of the leading causes of cancer-related mortality worldwide. Antivascular Ultrasound (AVUS) is a novel therapy approach that utilizes the mechanical and thermal interactions between ultrasound and microbubbles to disrupt tumor vasculature or potentiate effects of chemotherapy or radiation therapy in a dose-dependent fashion. In this review, we aim to illustrate the mechanisms of AVUS, focusing on the preclinical and clinical evidence of AVUS applications in HCC. Peer-reviewed publications pertaining to the use of AVUS in HCC were collected and analyzed. 12 preclinical studies and 1 clinical trial were analyzed. At lower energy levels, AVUS can enhance tumor perfusion, facilitating the delivery of chemotherapy agents and resulting in improved therapeutic outcomes. Conversely, at higher energy levels, AVUS can disrupt tumor perfusion, leading to ischemic damage of the tumors. Combining AVUS with other therapeutic approaches, such as chemotherapy, radiation therapy, and transarterial radioembolization (TARE), can synergistically enhance therapeutic outcomes. AVUS is a promising novel treatment modality for HCC. Current evidence suggests that AVUS exhibits a dose-dependent nature, making it a versatile approach that can be effectively combined with other therapeutic regimens. Further clinical studies and long-term follow-ups are needed to establish the optimal clinical protocol and safety profile of AVUS.

Tetrazaisoindigos:Serpentine Syntheses and Their Expected and Unexpected Photophysical and Electronic Properties.

Isoindigo, an electron-withdrawing building block for polymeric field-effect transistors, has long been considered to be non-fluorescent. Moreover, using electron-deficient heterocycle to replace the phenyl ring in the isoindigo core for better electron transport behaviour is synthetically challenging. Here we report the syntheses of a series of tetrazaisoindigos, including pyrazinoisoindigo (PyrII), pyrimidoisoindigo (PymII) and their hybrid (PyrPymII), and the investigation on their photophysical and electric properties. Proper flanking groups need to be chosen to stabilize these highly electron-deficient bislactams. Both PyrII and PymII derivatives show lower LUMO energy levels than that of naphthalene bisimide (NDI). Interestingly, PyrII is instinctively unstable and can be easily reduced, while both PymII derivatives are stable. More surprisingly, PymII derivatives are highly fluorescent and their photoluminescence quantum yields are around 40 %, 133 times higher than that of reported isoindigo derivatives. UV-vis spectroscopic results and theoretical calculations show that strong intramolecular hydrogen-bond exists in PymII, which prohibits it from non-radiative decay and accounts for its fluorescent behaviour. PymII derivatives are n-type semiconductors, while Ph-PyrII and the hybrid show balanced ambipolar charge transport behaviour, all among the best isoindigo derivatives. Our study not only discloses the structure-property relationship of tetrazaisoindigos, but also provides novel electron-deficient monomers for conjugated polymers.

Unlocking Full-Spectrum Brilliance: Dimensional Regulation in Lead-Free Metal Halides for Superior Photoluminescence.

Lead-free metal halides with tunable structures have emerged as a new class of optoelectronic materials. The arrangement of metal halide polyhedra defines their structural dimensionality and serves as a key factor influencing their optical properties. To investigate this, we synthesized four different antimony (Sb)-doped indium (In)-based metal halides, all of which possess zero-dimensional (0D) electronic structures but exhibit 3D, 2D, 1D, and 0D structural dimensionality at the molecular level. With a decreasing of structural dimensionality, their self-trapped exciton (STE) emission shows a red shift with peak position from 496 to 663 nm. We revealed that the red shift is caused by increased distortion of [SbCl6]3- octahedra as the structural dimensionality decreases, leading to lowered energy levels of STE and a corresponding red shift. The tunable STE emission makes these metal halides promising for anticounterfeiting and white LED applications. These findings provide a new strategy for tuning STE emission in lead-free metal halides.