Latest ArticlesFluorescence Anisotropy (FA) is an effective biochemical detection method based on molecular rotations. Graphene oxide (GO) has been extensively used as an FA amplifier. However, the enhancement of FA by GO alone is limited and the strong scattering of GO will easily make the measurement of FA inaccurate. In order to address these problems, an octopus-like DNA nanostructure (ODN) was designed and coupled with GO to enhance the FA together in this work. By mimicking the multi-clawed structure of the octopus, the ODN can be adsorbed on GO tightly, which not only could improve the sensitivity because of the double FA enhancement abilities of GO and ODN, but also could improve the specificity due to the decrease of the nonspecific interaction in complex samples. Furthermore, ODN could maintain a certain distance between the fluorophore and GO to reduce the fluorescence quenching efficiency of GO, which could improve the accuracy. This method has been applied for the detection of hepatitis B virus DNA (HBV-DNA) in a range of 1–50nmol/L and the limit of detection (LOD) was 330pmol/L. In addition, the proposed method has been successfully utilized to detect HBV-DNA in human serum, indicating that this method has a great practical application prospect.
The microstructure of the active layer in organic photovoltaics (OPVs), such as the size of phase separation, purity of the phases, and molecular packing within each phase, plays a crucial role in influencing the behavior of excitons and charge carriers within the active layer. It is also a key determinant of the photovoltaic performance of the device. During the optimization of OPV devices, the use of additives has been demonstrated to be an effective strategy in microstructure control, leading to enhanced performance. Therefore, the quest for stable and efficient novel additives, along with an exploration and summarization of the mechanisms underlying additive-induced microstructure control, is essential for a better understanding of the developmental trends of high-performance additives. In this review, we categorize additives based on their chemical structures and discuss their effects on the microstructure of the active layer from both thermodynamic and kinetic perspectives. Furthermore, we elaborate on the working mechanisms and their impact on the photovoltaic performance of the devices. This review provides an overview of recent advances in additives for OPVs, offering potential guidance for the future development of additives and further optimization of the active layer in photovoltaic devices.
Herein, a novel molecular tweezer based on 2,2′-bipyridine-bridged porphyrin subunits was constructed for efficient fullerenes recognition. The syn conformation of the molecule, which was obtained by Zn(Ⅱ) coordination, gives rise to a proper cavity to interact with fullerene guests to form a stable 1:1 complex in toluene solution. It exhibits distinct binding selectivity towards C60 over C70. Moreover, the fullerene recognition capacity can be adequately suppressed by importing H2PO4− to competitively capture Zn(Ⅱ) along with syn-anti conformational conversion. Subsequently, the molecular tweezer regenerated to bind the fullerene by introducing the Ca2+ into the system. Significantly, the association-disassociation process can be switched reversibly and repeatedly.
Inspired by biological ion channels, numerous artificial asymmetric ion channels have been synthesized to facilitate the fabrication of ionic circuits. Nevertheless, the creation of biomimetic asymmetric ion channels necessitates expensive scientific apparatus and intricate material processing procedures, which constrains its advancement within the realm of ionic devices. In this study, we have devised dynamic asymmetric ion channels with mechanical responsiveness by combining polymers of varying elastic modulus along the longitudinal axis of carbon nanotube fiber (CNTF). The ion rectification can be modulated via the disparate response of CNTF-based ion channels to mechanical stress. We have effectively employed these asymmetric ion channels with mechanical sensitivity in the design of a logic gate device, achieving logic operations such as “AND” and “OR”. The conception of these dynamic asymmetric ion channels with mechanical sensitivity offers a straightforward, cost-effective, and versatile approach for generating ion channels, highlighting their potential application in intricate, highly integrated ionic circuits.
To mitigate the water pollution problem by photocatalytic degradation of typical antibiotics of tetracycline (TC), we prepared defective Bi2Sn2O7 (BSO) quantum dots (QDs) with a full spectral response due to Bi metal deposition, using a one-pot hydrothermal method, labeled as Bi@BSO-OV. The optimized Bi@BSO-OV showed 73.4% removal of TC in 1 h under irradiation with a 50 W LED lamp in the wavelength band in the visible-near-infrared (vis-NIR) light, a rate that is substantially greater than that of pure BSO (14.7%). The synergistic interaction of Bi metal and oxygen vacancies (OVs) is crucial to boosting photocatalytic performance. The near-infrared region of the photo-response is extended by the surface plasmon resonance (SPR) effect of Bi metal, enhancing the photocatalytic performance and dramatically raising the efficiency of solar energy utilization. In addition to inducing defect levels in BSO, the OVs also activate the surface adsorbed O2 to promote the production of •O2− and 1O2. DFT calculations reveal that Bi metal and OVs can mutually tune the charge transfer pathways. On the one hand, Bi metal can act as both a charge transfer bridge and an electron donor to assist charge separation. On the other hand, OVs-induced defect levels allow electrons that leap to the conduction band (CB) to first leap from the valence band (VB) to the defect levels, notably improving interfacial charge separation and transfer. The concept of design executed in this study for altering the catalyst by introducing both OVs and Bi metal can provide a rational design idea and potential insight for improving the photocatalytic activity for environmental applications.
Single-chain nanoparticles represent an emerging class of nanomaterials designed to mimic protein's folding paradigm. Intrachain covalent crosslinking toward the formation of single-chain nanoparticles encounters complex energy landscapes, leading to the potential occurrence of misfolding issues. While non-covalent crosslinking can circumvent this issue, the resulting single-chain nanoparticles exhibit lower structural stability compared to their covalently crosslinked counterparts. In this study, we present a novel approach for the synthesis of single-chain nanoparticles, achieved through the combination of non-covalent and covalent intramolecular crosslinking. Cyanostilbenes grafted onto the linear polymer form intrachain non-covalent stacks aided by hydrogen bonds, leading to the formation of non-covalently crosslinked single-chain nanoparticles. These nanoparticles undergo conversion to covalently crosslinked nanostructures through subsequent photo-irradiation using [2 + 2] photocycloaddition, a process facilitated by the supramolecular confinement effect. Consequently, the resulting single-chain nanoparticles demonstrate both intrachain folding efficiency and substantial stability, offering significant potential for advancing applications across diverse fields.
To promote the practices of perovskite photovoltaics, it requires to develop efficient perovskite solar cells (PVSCs) standing long-time operation under the adverse environments. Herein, we demonstrate that the tailor-made conjugated polymers as conductive adhesives stabilized the originally redox-reactive heterointerface between perovskite and metal oxide, facilitating the access of efficient and stable inverted PVSCs. It was revealed that bithiophene and phenyl alternating conjugated polymers with partial glycol chains atop of the metal oxide layer has resulted in effective organic-inorganic hybrid hole transporting bilayers, which allow maintaining efficient hole extraction and transport, meanwhile preventing halide migration to directly contact with the nickel oxide (NiOx) layer. As a result, the corresponding inverted PVSCs with the organic-inorganic hole transporting bilayers have achieved an excellent power conversion efficiency of 23.22%, outperforming 20.65% of bare NiOx-based devices. Moreover, the encapsulated PVSCs with organic-inorganic bilayers exhibited the excellent photostability with 91% of the initial efficiency after 1000-h one-sun equivalent illumination in ambient conditions. Overall, this work provides new insights into stabilizing the vulnerable heterointerface for perovskite solar cells.
Development of hydrothermally stable, low-temperature catalysts for controlling nitrogen oxides emissions from mobile sources remains an urgent challenge. We have prepared a metal oxide-zeolite composite catalyst by depositing Mn active species on a mixture support of CeO2/Al2O3 and ZSM-5. This composite catalyst is hydrothermally stable and shows improved low-temperature SCR activity and significantly reduced N2O formation than the corresponding metal oxide catalyst. Comparing with a Cu-CHA catalyst, the composite catalyst has a faster response to NH3 injection and less NH3 slip. Our characterization results reveal that such an oxide-zeolite composite catalyst contains more acidic sites and Mn3+ species as a result of oxide-zeolite interaction, and this interaction leads to the generation of more NH4+ species bound to the Brønsted acid sites and more reactive NOx species absorbed on the Mn sites. Herein, we report our mechanistic understanding of the oxide-zeolite composite catalyst and its molecular pathway for improving the low-temperature activity and N2 selectivity for NH3-SCR reaction. Practically, this work may provide an alternative methodology for low-temperature NOx control from diesel vehicles.
Electrochemical sensing provides a powerful technological means for the therapeutic drug monitoring of drug-resistant tuberculosis but requires a functionalized electrode to capture the analytes and catalyze their redox reactions. Herein, we construct a nickel–tannic acid supramolecular network (Ni–TA) on the surface of electrospun-derived C–CeO2 nanofiber for the sensitive and simultaneous detection of isoniazid (INZ) and hydrazine (HYD). Mechanistic investigations demonstrate that Ni–TA is electronegative and hydrophilic, thus facilitating an efficient mass and electron transfer. Ni–TA/C–CeO2 has higher adsorption rate constants (0.091 g mg–1 h–1 for INZ, and 0.062 g mg–1 h–1 for HYD) than native C–CeO2 (0.075 g mg–1 h–1 for INZ, and 0.047 g mg–1 h–1 for HYD). Moreover, Ni–TA/C–CeO2 (56 Ω) has lower charge transfer resistances than C–CeO2 (417 Ω). Ni–TA/C–CeO2 performs low detection limits and wide linearity ranges for INZ (0.012 µmol/L and 0.1–400 µmol/L, respectively) and HYD (0.008 µmol/L and 0.015–1420 µmol/L, respectively), coupled with high selectivity, cycle stability and reproducibility. This research demonstrated the promising applications of Ni–TA/C–CeO2 by analyzing human-collected plasma and urine samples.
Carbon materials have been used as the support for catalysts in the field of acetylene hydrochlorination, the influence of inevitable oxygen-containing moieties on the reaction is often ignored and the mechanism of the oxygen-doping structure remains ambiguous. Herein, we explored the effect of the oxygen-containing group (C–O–C) in the support on the activity of single-atom dispersed Cu catalysts. By immersing the Cu single-atom catalyst in an alkaline solution, the epoxy species on the carbon support was cleaved to obtain a pure ether species while the Cu site was modified to a more electron-deficient state. The turnover frequency value of Cu/O-FLP catalyst with epoxy groups was 1.6-fold higher than that of alkaline treated catalyst. Our result indicated that the epoxy groups could assist adjacent single-atom Cu sites to synergistically promote the adsorption and cleavage of the reactant hydrogen chloride toward form C–OH and Cu–Cl bonds, and reduce the reaction energy barrier. The presence of electron deficient Cu sites and ether species could induce competitive adsorption of the acetylene and hydrogen chloride, thereby reducing the activity of the catalyst. This study highlights the influence of surface oxygen species and the tunability of the support, providing the foundation for the fabrication of higher-activity Cu catalysts for acetylene hydrochlorination.
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