Novel Strategy for High Efficient and Stable Perovskite Solar Cells through Atomic Layer Deposition.

The perovskite material has demonstrated conceivable potential as an absorbing material of solar cells. Although the power conversion efficiency of the device based on perovskite has rapidly come to 26%, there are still many factors that affect the further improvement of the photoelectric conversion efficiency. Interface defects are the dominating concern that influence carrier transportation and stability. Here, we report a novel strategy where B2O3 is deposited on the fresh perovskite film by atomic layer deposition technology. The organic atmosphere during atomic layer deposition can effectively regulate the crystallization kinetics of perovskites and promote crystal growth. The B2O3 adsorbed on the perovskite light-absorption layer can effectively reduce the electropositive defects on the surface of the perovskite, such as uncoordinated Pb2+ and I vacancies due to the electron-donating properties of the side O atoms in B2O3. Consequently, the power conversion efficiency of the perovskite solar cell after B2O3 treatment increases to 21.78% from 18.89%. Simultaneously, B2O3 can improve the stability of devices.

Preparation and application of urea-based derivatized ß-cyclodextrin chiral stationary phase based on diazotized silica microspheres.

Recently, the design and development of efficient chiral stationary phases is still the core and goal of chiral chromatography. In order to quickly separate chiral drugs, we designed and prepared an environmentally friendly small particle chiral stationary phase: p-methylphenylurea-ß-cyclodextrin chiral stationary phase (SiO2@PMPU-ß-CD). Firstly, p-methylphenylurea-ß-cyclodextrin (PMPU-ß-CD) was connected to the surface of mesoporous silica microspheres by diazoresin (DR) to prepare a SiO2@PMPU-ß-CD. In reverse elution mode, the column temperature was set at 25 °C, the flow rate was 0.2 mL/min, and ACNH2O (v/v = 70:30) was used as the elution condition of the mobile phase. The enantiomers of chlorpheniramine maleate, 2-phenylcyclohexanone, and promethazine were separated within 5 min. In addition, the addition of TEAA buffer to the mobile phase improved the enantiomer resolution of chlorpheniramine maleate from 1.03 to 5.69. The experimental results show that the SiO2@PMPU-ß-CD column can be used for the separation of appellant chiral drugs with good repeatability, and the use of DR instead of silane coupling agent has the advantages of being non-toxic, environmentally protected, and easy to operate, which is of great significance for the development of chiral stationary phase.

Synthesis of poly-tetrahydropyrimidine antibacterial polymers and research of their basic properties.

Modern medicine has increasingly higher requirements for antibacterial materials. To overcome this challenge, we use alkynyl monomers, amino monomers, formaldehyde, and acetic acid as raw materials to synthesize a series of poly-tetrahydropyrimidine (P-THP) polymers through multicomponent polymerizations (MCPs). P-THP polymers can effectively inhibit the growth of Gram-positive bacteria (Staphylococcus aureus, S. aureus) and Gram-negative bacteria (Escherichia. coli, E. coli), and can prevent bacteria from developing drug resistance within at least 16 generations. Besides, we prepared P-THP antibacterial coatings and explored their antibacterial properties. In vitro antibacterial experiments showed that P-THP coatings can prevent the formation of bacterial biofilms, and the coatings have a lasting killing effect on E. coli and S. aureus. The mouse wound infection experiments proved that P-THP polymers can significantly accelerate skin tissue regeneration and wound healing. Moreover, the P-THP textile obtained by electrospinning also has antibacterial properties and has great application prospects in the field of N95 masks. Generally speaking, P-THP polymers have considerable application potential in the field of treating bacterial infections and promoting wound healing.

Synthesis of polyacrylonitrile/polytetrahydropyrimidine (PAN/PTHP) nanofibers with enhanced antibacterial and anti-viral activities for personal protective equipment.

Emerging infectious diseases caused by the spread of bacteria and viruses are a major burden on global economic development and public health. At present, most personal protective equipment has weak antibacterial and anti-viral properties. The PAN/PTHP nanofibers reported in this article provide a new method for the development of personal protective equipment. In this study, a mixture of PTHP and PAN was prepared into PAN/PTHP nanofibers with high-efficiency and long-lasting antibacterial effects (>99.999%) through the electrospinning process. Live/dead staining and cell proliferation experiments showed that the preparation of PAN/PTHP nanofibers has good cell compatibility. In addition, PAN/PTHP nanofibers show obvious destructive effects on lentiviruses. Based on these characteristics, PAN/PTHP nanofibers were applied to facial masks, which can be used as the inflatable biocidal layer of facial masks and have an excellent interception effect on particles in the air. The successful synthesis of these fascinating materials may provide new insights for the development of new protective materials.

Composites, Fabrication and Application of Polyvinylidene Fluoride for Flexible Electromechanical Devices: A Review.

The technological development of piezoelectric materials is crucial for developing wearable and flexible electromechanical devices. There are many inorganic materials with piezoelectric effects, such as piezoelectric ceramics, aluminum nitride and zinc oxide. They all have very high piezoelectric coefficients and large piezoelectric response ranges. The characteristics of high hardness and low tenacity make inorganic piezoelectric materials unsuitable for flexible devices that require frequent bending. Polyvinylidene fluoride (PVDF) and its derivatives are the most popular materials used in flexible electromechanical devices in recent years and have high flexibility, high sensitivity, high ductility and a certain piezoelectric coefficient. Owing to increasing the piezoelectric coefficient of PVDF, researchers are committed to optimizing PVDF materials and enhancing their polarity by a series of means to further improve their mechanical-electrical conversion efficiency. This paper reviews the latest PVDF-related optimization-based materials, related processing and polarization methods and the applications of these materials in, e.g., wearable functional devices, chemical sensors, biosensors and flexible actuator devices for flexible micro-electromechanical devices. We also discuss the challenges of wearable devices based on flexible piezoelectric polymer, considering where further practical applications could be.