ABSTRACT
Silver nanowires, which have high optoelectronic properties, have the potential to supersede indium tin oxide in the field of electrocatalysis, stretchable electronic, and solar cells. Herein, four mainstream experimental methods, including Mayer-rod coating, spin coating, spray coating, and vacuum filtration methods, are employed to fabricate transparent conductive films based on the same silver nanowires to clarify the significance of preparation methods on the performance of the films. The surface morphology, conductive property, uniformity, and flexible stability of these four Ag NW-based films, are analyzed and compared to explore the advantages of these methods. The transparent conductive films produced by the vacuum filtration method have the most outstanding performance in terms of surface roughness and uniformity, benefitting from the stronger welding of NW-NW junctions after the press procedure. However, limited by the size of the membrane and the vacuum degree of the equipment, the small-size Ag films used in precious devices are appropriate to obtain through this method. Similarly, the spin coating method is suited to prepare Ag NWs films with small sizes, which shows excellent stability after the bending test. In comparison, much larger-size films could be obtained through Mayer-rod coating and spray coating methods. The pull-down speed and force among the Mayer-rod coating process, as well as the spray distance and traveling speed among the spray coating process, are essential to the uniformity of Ag NW films. After being treated with NaBH4 and polymethyl methacrylate (PMMA), the obtained Ag NW/PMMA films show great potential in the field of film defogging due to the Joule heating effect. Taken together, based on the advantages of each preparation method, the Ag NW-based films with desired size and performances are easier to prepare, meeting the requirements of different application fields.
ABSTRACT
Transparent and flexible electronic devices are highly desired to meet the great demand for next-generation devices that are lightweight, flexible, and portable. Transparent conducting oxides (TCOs), such as indium-tin oxide, serve as fundamental components for the design of transparent and flexible electronic devices. However, indium is rare and expensive. Herein, we report the fabrication of low-cost perovskite SrVO3 TCO films on transparent and flexible mica substrates and further demonstrate their utilization as a TCO electrode for building a transparent, flexible, and self-powered perovskite photodetector. Superior stable optical transparency and electrical conductivity are retained in SrVO3 after bending up to 105 cycles. Without an external power source, the constructed all-perovskite photodetector exhibits a high responsivity (42.5 mA W-1), fast response time (3.09/1.23 ms), and an excellent flexibility and bending stability after dozens of cycles of bending at an extreme 90° bending angle. Our results demonstrate that low-cost and structure-compatible transition metal-based perovskite oxides, such as SrVO3, as TCO electrodes have huge potential for building high-performance transparent, flexible, and portable smart electronics.
ABSTRACT
OBJECTIVE: Variable Number of Tandem Repeats (VNTRs) analysis was a recently developed method which could serve as a 'real-time' genotyping tool for Mycobacterium tuberculosis. One hundred and thirteen M. tuberculosis isolates from the patients with tuberculosis in Beijing were analysed using the reference method to study the characters of genetic diversity and genotype. METHODS: Thirteen tandem repeat loci (ETR-A, ETR-C, ETR-D, MIRU10, MIRU16, MIRU27, MIRU31, MIRU40, Mtub21, Mtub30, Mtub38, Qublla, Qubllb) in the total genome of MTB were analyzed by PCR and agarose gel electrophoresis method. The characters of the polymorphism of DNA fingerprinting of one hundred and thirteen MTB strains were analyzed with Gel-Pro analyzer 3.1 software and BioNumerics 3.0 software. Results One hundred and thirteen MTB strains were characterized and classified in to four genotype families(type I , type II , type NV, type V ) based on thirteen tandem repeat loci. One hundred and four isolates(92.0%) belonged to type I , the other three genotypes scattered, five strains(4.4%) remaining with type II , while type IV and type V having the same quantity 1.8% (2/113). M. tuberculosis H37Rv belonged to a unattached genotype(type ll ). Conclusion There was obvious length polymorphism in the M. tuberculosis isolates which implied that type I was the epidemic strain clusters in M. tuberculosis in Beijing. VNTRs analysis seemed to be a simple, rapid, sensitive and valuable tool for epidemiological studies of M. tuberculosis complex organisms.
