All-inorganic CsPbX3 (X = Cl, Br, I) perovskite quantum dots (QDs) have great potential for various applications due to their excellent photoluminescence properties. However, poor stability under long-term storage hinders their applications. Herein we report the utilization of porous boron nitride nanofibers (BNNFs) as a promising carrier for anchoring of CsPbBr3 QDs. Due to the good dispersion and immobilization of CsPbBr3 QDs, the resulting CsPbBr3/BNNF composites show excellent photostability and superior long-term storage stability in an air environment. Moreover, the CsPbBr3/BNNF composites exhibit an interesting ammonia-responsive behavior: i.e., a distinct decrease in photoluminescence intensity upon exposure to ammonia gas and the subsequent photoluminescence recovery after post-treatment in nitrogen gas. Even after treatment with ammonia gas for 3 h, the composites can still be recovered under nitrogen gas treatment. The fast response, reversibility, and stability of CsPbBr3/BNNF composites in the presence of ammonia gas could inspire a broader range of applications.
Hongmei He,Yudong Song,Meini Li,Hao Zhang,Jiali Li,Hui Huang,Yongxin Li
In recent years, the use of intelligent and efficient food freshness indicators (FFIs) for monitoring food freshness has been studied widely. In this work, we employed polyacrylonitrile as polymer, blueberry anthocyanins as an indicator, and caffeic acid as a co-pigment and fabricated a novel colorimetric sensing film for real-time monitoring the freshness of fish. The total volatile basic nitrogen (TVB-N) level is one of the potential indicators to evaluate meat freshness. Visual observation confirmed that the polyacrylonitrile–anthocyanin–caffeic acid film changed from pink to light purple, and then to dark purple providing a good indication of spoilage, which correlated well with the TVB-N content and pH values in fish. It is because the volatile ammonia combined with water to form NH3·H2O, and then NH3·H2O is hydrolyzed to form OH− and NH4+. The change of the polyacrylonitrile–anthocyanin film was caused by OH−. Compared with the polyacrylonitrile–anthocyanin film without caffeic acid, the addition of the caffeic acid film had enhanced significantly ammonia responsiveness with a total color difference value of 29.897. And it was also observed that caffeic acid obviously improved the storage stability of the film. This study provided a reference for detecting food freshness using co-pigmentation and electrospinning encapsulation technology in combination.
危险品化学品经营许可证（带存储）