Fuzhou University

Given the significant impact of Fe³⁺ and ascorbic acid (AA) on human health, the development of an efficient sensor for their detection is of critical importance. In this study, a novel fluorescent probe composed of ultrathin boron nanosheets (Ultrathin BNSs) is introduced for the sensitive detection of both Fe³⁺ and AA in human serum. Ultrathin BNSs, exhibiting a fluorescence quantum yield of up to 6.8 % and minimal cytotoxicity, can be directly synthesized from boron through an ultrasound-assisted liquid-phase exfoliation (LPE) method. These Ultrathin BNSs demonstrate a selective and responsive fluorescence "on-off-on" mechanism toward Fe³⁺ and AA, governed by the induction and removal of an electron-transfer effect. The presence of Fe³⁺ induces non-radiative electron transfer, resulting in fluorescence quenching of the Ultrathin BNSs. In contrast, the introduction of AA facilitates the dissociation of Fe³⁺ from the Ultrathin BNSs/Fe³⁺ complex, leading to fluorescence recovery. When utilized as a fluorescent nanoprobe, Ultrathin BNSs exhibit a strong linear correlation with Fe³⁺ concentrations ranging from 0.2 to 150 µM and AA concentrations between 1.5 and 110 µM. Additionally, the limits of detection (LOD) for Fe³⁺ and AA reach 0.2 µM and 1.5 µM, respectively, demonstrating superior performance compared to numerous previously reported fluorescent probes. The feasibility of this Ultrathin BNSs-based sensor for AA detection in human serum was further examined, yielding satisfactory outcomes. It is expected that our strategy may offer a new approach for developing rapid, low cost and sensitive ultrathin BNSs-based sensors for biological sensing and environmetal applications.

The development of flexible zinc-ion batteries (ZIBs) faces a three-way trade-off among the ionic conductivity, Zn2+ mobility, and the electrochemical stability of hydrogel electrolytes. To address this challenge, we designed a cationic hydrogel named PAPTMA to holistically improve the reversibility of ZIBs. The long cationic branch chains in the polymeric matrix construct express pathways for rapid Zn2+ transport through an ionic repulsion mechanism, achieving simultaneously high Zn2+ transference number (0.79) and high ionic conductivity (28.7 mS cm−1). Additionally, the reactivity of water in the PAPTMA hydrogels is significantly inhibited, thus possessing a strong resistance to parasitic reactions. Mechanical characterization further reveals the superior tensile and adhesion strength of PAPTMA. Leveraging these properties, symmetric batteries employing PAPTMA hydrogel deliver exceeding 6000 h of reversible cycling at 1 mA cm−2 and maintain stable operation for 1000 h with a discharge of depth of 71%. When applied in 4 × 4 cm2 pouch cells with MnO2 as the cathode material, the device demonstrates remarkable operational stability and mechanical robustness through 150 cycles. This work presents an eclectic strategy for designing advanced hydrogels that combine high ionic conductivity, enhanced Zn2+ mobility, and strong resistance to parasitic reactions, paving the way for long-lasting flexible ZIBs.

Micro light sources are crucial tools for studying the interactions between light and matter at the micro/nanoscale, encompassing diverse applications across multiple disciplines. Despite numerous studies on reducing the size of micro light sources and enhancing optical resolution, the efficient and simple fabrication of ultra-high-resolution micro light sources remains challenging due to its reliance on precise micro-nano processing technology and advanced processing equipment. In this study, a simple approach for the efficient fabrication of submicron light sources is proposed, namely shadow-assisted sidewall emission (SASE) technology. The SASE utilizes the widely adopted UV photolithography process, employing metal shadow modulation to precisely control the emission of light from polymer sidewalls, thereby obtaining photoluminescent light sources with submicron line widths. The SASE eliminates the need for complex and cumbersome manufacturing procedures. The effects of process parameters, including exposure dose, development time, and metal film thickness, on the linewidth of sources are investigated on detail. It is successfully demonstrated red, green, and blue submicron light sources. Finally, their potential application in the field of optical anti-counterfeiting is also demonstrated. We believe that the SASE proposed in this work provides a novel approach for the preparation and application of micro light sources.