Latest ArticlesLead-free perovskite has become a shining pearl in the field of direct X-ray detection due to its non-toxicity and excellent optoelectronic properties. However, the high limit of detection (LoD) of X-ray detectors due to high current noise caused by high operating voltages is a major challenge to overcome. Here, we utilized a zero-dimensional lead-free perovskite ferroelectric material (NMP)3Sb2Br9 (1, NMP = N-methylpyrrolidine) to achieve ultra-low LoD self-driven X-ray detection. The self-driven detection mode without external bias has been proven to be an effective means of reducing LoD due to its low current noise characteristics. Additionally, the zero-dimensional distinctive isolated framework results in a high resistivity of 1.39 × 1011 Ω cm, which effectively reduces the current noise and suppresses ion migration. By further combining the ferroelectric-induced bulk photovoltaic effect, the 1-based detector achieves an ultra-low LoD X-ray detection of 84.1 nGyair/s under the self-driven mode, which represents a quite advanced level in the lead-free perovskite X-ray detection region. Our work successfully achieved ultra-low LoD self-driven X-ray detection by combining ferroelectricity with high resistance, providing a promising avenue for the development of low LoD X-ray detectors.
Rechargeable aqueous zinc-ion batteries (AZIBs) draw intensive attention due to their high security, low price and the abundant zinc source. However, the electrochemical behaviors of AZIBs are seriously affected by the cathode materials. Mn-based oxide cathodes have been extensively investigated owing to the superior electrochemical performances such as large theoretical capacity and high working voltage. In this work, we rationally design a high-performance cathode material using organic-inorganic co-modification strategy. The inorganic Al3+ ions and organic poly-vinylpyrrolidone (PVP) are successfully incorporated into the tunnel α-MnO2 structure. Structural characterizations and DFT calculations indicates that the Zn2+ adsorption energy in the Al3+/PVP co-intercalated tunnel α-MnO2 is effectively lowered when compared with the original material, facilitating fast ion diffusion and stable Zn2+ ion storage. Electrochemical tests indicate that the PVP-Al-MnO2 electrode exhibits excellent electrochemical performances, a capacity of 306.8 mAh/g at 0.3 A/g and 93.1% capacity retention over 2000 cycles at 1.0 A/g. In addition, the aqueous PVP-Al-MnO2||ZnClO4||Zn battery is able to operate properly at low temperature (-45 ℃). This work shows an encouraging strategy to the modification of materials for AZIBs and other multivalent ion systems.
The gas separation performance of metal-organic framework (MOF) adsorbents could be enhanced by tuning the pores, whereas the presence of moisture usually compromises the efficiency. Herein, two MOFs, Fe-BDC-TPT-BF4, Ni-BDC-TPT-TMA (TMA+ = (CH3)4N+), were synthesized by exchanging countering ions in parent MOFs, Fe-BDC-TPT-Cl and Ni-BDC-TPT-Me2NH2, respectively. Fe-BDC-TPT-BF4 and Ni-BDC-TPT-TMA exhibited a high C2H2 adsorption uptake of 203.1 cm3/g and 200.1 cm3/g at 298 K and 1 bar, and high C2H2/CO2 selectivity of 4.6 and 4.4. Humid breakthrough experiments revealed that high C2H2 productivity of high C2H2 purity was achieved on Ni-BDC-TPT-TMA at 35% relative humidity. Cycling dynamic breakthrough experiments demonstrate good recyclability of Ni-BDC-TPT-TMA for humid C2H2/CO2 separation. The alteration of countering ions changed the pore size and chemistry, leading to high C2H2 uptake, high C2H2 selectivity, and retained performance in the presence of moisture, making it a promising candidate for practical applications. This work highlights that ion exchange modification of MOFs has been developed as a facile and powerful strategy to optimize the inner pores for better performance in challenging separations.
In this paper, a new series of donor-acceptor coordination polymers (DACPs), [Cd(dppz)(R-ndc)(H2O)]n (R = none, DZU-400; R = F, DZU-400-F; R = Br, DZU-400-Br; DZU is short for Dezhou University), [Cd(dppz)(adc)(H2O)]n (DZU-401), and {[Cd(dppz)(adb)0.5(HCOO)(H2O)]}n (DZU-402), have been successfully constructed through the combination of electron-deficient dipyrido[3,2-a: 2′,3′-c]phenazine (dppz) as an acceptor and various dicarboxylic ligands (H2ndc = 2,3-naphthalenedicarboxylic acid, F-H2ndc = 6,7-difluoronaphthalene-2,3-dicarboxylic acid, Br-H2ndc = 6,7-dibromonaphthalene-2,3-dicarboxylic acid, H2adc = 9,10-anthracenedicarboxylic acid, and H2adb = 4,4′-(anthracene-9,10-diyl)dibenzoic acid) with electron-rich planar aromatic rings as donors. Structural analyses reveal closely parallel arrangement of the planar acceptor and donor units in these DACPs, which could facilitate the through-space charge transfer (TSCT) interactions of the D-A systems and the corresponding luminescent properties. Interestingly, the DACPs show highly regulable donor dependent photoluminescence from blue to orange. Based on the TSCT based luminescence and the high thermal stability of the DACPs, their thermal-stimuli responsive emission properties were further studied. Photoluminescence intensity of the DACPs all present good linearity with temperature (298–473 K), as proved by variable temperature fluorescence spectra. Importantly, the temperature sensing process is reversible and recyclable, suggesting the promising applications of the DACPs as thermal-stimuli responsive materials.
Electrochemical two-electron oxygen reduction reaction (2e- ORR) is a green and attractive method for hydrogen peroxide synthesis. However, rapid and efficient development of high-performance catalyst remains a great challenge. Different from traditional trial and error methods, this study employs density functional theory and machine learning method to efficiently screen the promising main-group metal single-atom catalysts (SACs) and systematically investigate the influence of electronegativity of coordination atoms on the adsorption behavior of key intermediates in ORR process. It is found that the K SAC with N/B in the first coordination sphere and Sn SAC with N/C in the first coordination sphere and O in the second coordination sphere exhibit both excellent 2e- ORR activity and selectivity by showing extremely low overpotentials of 0.029 V and 0.064 V, respectively, as well as barrier-free processes from *OOH to H2O2. Bagging displays prominent advantages among seven popular algorithms because of its ensemble strategy. This provides a low-cost approach for designing and screening electrocatalyst candidates, and it will be informative for experimental study in the future to accelerate the development of catalysts for oxygen reduction and other types of reactions.
Cutting-edge high/pulsed power capacitors with satisfactory power density are fundamental units in modern power storage systems. However, a persistent challenge is how to overcome the trade-off between recoverable energy storage density (Wrec) and efficiency (η) for meeting the miniaturization and integration of advanced applications. Here, multiple local distortions including inhomogeneous functional nanoclusters, (anti)ferro-distortions and highly dynamic polar nanoregions are modulated through a high-entropy strategy to design a stable ergodic-relaxor-state-dominated structure. Of great importance, this strategy delay polarization saturation, reduces hysteresis and improves breakdown strength, so that an ultrahigh Wrec ~11.94 J/cm3 with a η ~ 82.4% is realized in Pb-free ergodic-relaxors. Moreover, a significant Vickers hardness of 10.04 GPa as well as superior temperature, cycling and frequency stabilities are also obtained. This work demonstrates that designing multiple local distortions via a high-entropy strategy is a promising way to realize superior comprehensive energy storage properties in high/pulsed power capacitors.
Nickel-rich layered oxides are considered highly promising cathode materials for all-solid-state batteries (ASSBs) due to their high theoretical specific capacity and energy density. In this study, a comparison between polycrystalline and single-crystalline cathode materials was conducted. It was found that, during the charging process, ion transport at the interface of polycrystalline cathodes is significantly influenced by phase transitions and side reactions with the electrolyte, resulting in an irreversible increase in impedance after cycling. Furthermore, the structural stability of the cathode material affects internal ion diffusion kinetics, thereby influencing its electrochemical performance. Unlike single-crystalline materials, ion migration in polycrystalline materials must traverse anisotropic grain boundaries, which, due to anisotropic lattice contraction, evolve into intergranular cracks, leading to reduced ion diffusion kinetics and degraded electrochemical performance. In contrast, single-crystalline cathodes exhibit more stable interfacial resistance and uniform ion transport during charging, ensuring structural stability over long-term cycling. Consequently, at a 0.5 C rate, the single-crystalline cathode maintains a specific capacity of 143 mAh/g after 500 cycles, with a capacity retention of 89.2%, while preserving its intact single-crystal morphology. This study provides valuable new insights into the localized lithium-ion transport behavior in single-crystalline and polycrystalline cathode materials for sulfide-based all-solid-state batteries.
Interleukin-1 receptor-associated kinase 4 (IRAK4), a key target with both enzymatic and non-enzymatic functions, plays a pivotal role in autoimmune diseases. Previous studies have demonstrated that proteolysis-targeting chimera (PROTAC) molecules targeting IRAK4 can effectively eliminate both its enzymatic and non-enzymatic functions, showing promising therapeutic potential. However, the development of highly potent, synthetically accessible IRAK4-targeting degraders remains a challenge. In this work, through three rounds of PROTAC library construction, screening, and optimization, we successfully identified a representative compound, LZ-07, which proved to be a highly potent degrader with a half-maximal degradation concentration (DC50) value of 1.14 nmol/L. Notably, compared with KT-474, LZ-07 demonstrated comparable degradation activity and superior inhibition of cytokine production, while featuring a simpler synthetic route with optimized IRAK4 and cereblon (CRBN) ligands. LZ-07-induced degradation of IRAK4 led to marked suppression of key cytokines, including interleukin-6 (IL-6), IL-1β, tumor necrosis factor alpha (TNF-α), and IL-10. This study presents LZ-07 as a novel, highly efficient, and synthetically straightforward IRAK4-targeting degrader, offering a promising tool compound for the study of the potential treatment of autoimmune diseases.
Classic near-infrared dyes typically enhance their maxima absorption wavelength through the D-A system. Herein, introducing p-trifluoromethylphenyl group at 1,7-sites as electron-withdrawing group and julolidine at 3,5-sites as electron-donating group in aza-borondipyrromethene (aza-BODIPY) system, CF3-JLD with the donor-acceptor-acceptor (D-A-A’) system was prepared, which absorbs at 952 nm and emits at 1069 nm in dimethyl sulfoxide (DMSO) in the near infrared-Ⅱ (NIR-Ⅱ) region. According to the experimental observation and theoretical calculation, the D-A-A’ system for enhancing redshift of maxima absorption is found to be more effective than that of donor-acceptor-donor (D-A-D’) system. NIR-Ⅱ absorbing CF3-JLD was type Ⅰ photodynamic therapy/photothermal therapy (PDT/PTT) co-therapy reagent, with high photothermal conversion efficiency (η = 81%). Self-assembled nanoparticles (CF3-JLD NPs) can effectively induce 4T1 cell death in vitro, and the cellular morphology of tumor was destroyed and the proliferation-related protein was decreased in vivo under NIR irradiation by phototherapy. This strategy of the D-A-A’ system provides a guideline for developing organic fluorophores with enhanced NIR-Ⅱ absorption and type Ⅰ PDT/PTT co-therapy for 4T1 breast tumors.
Quantitative visualization of pivotal biomarkers and accurate delineation of tumor lesion boundary are highly significant to assist surgeon precisely resect the tumors and reduce the risk of recurrence. Activatable fluorescent probes hold great promise for intraoperative guidance of tumor surgery with high signal-to-background ratio (SBR). Here, we report a γ-glutamyl transpeptidase (GGT)-activated fluorogenic probe Indol-Glu for quantitative visualization of GGT and fluorescence-guided tumor resection. The fluorescence of Indol-Glu was initially “off” state but was specifically activated by GGT to produce enhanced near-infrared (NIR) fluorescence (~37-fold at 741 nm). It is also accompanied by the formation of self-assemblies in the tumor microenvironment resulting in prolonged retention in tumor tissues, which was demonstrated to be able to apply for NIR imaging-guided surgical resection of GGT-overexpressed luciferase-transfected hepatocellular carcinoma (HCC/Luc) tumor. More notably, taking advantage of the ratiometric photoacoustic signal (PA690/PA800) characteristic of Indol-Glu under the digestion of GGT, quantitative visual assessment of GGT activities in various tumor models was achieved in living mice. We believe that this research work may offer a powerful tool for precise diagnosis and surgical resection of malignant tumors.
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