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1. Silver ions cause oscillation of bacterial length of Escherichia coli

   https://doi.org/10.1038/s41598-019-48113-4  

   Krishnamurthi, Venkata Rao; Chen, Jingyi; Wang, Yong (August 2019, Scientific Reports)

   Abstract Silver (Ag) in various forms have recently gained broad interest and been revisited due to their promising antimicrobial effects. Here we report our study on the morphological dynamics of live bacteria when subjected to Ag⁺ions. Using time-lapse microscopy, we observed oscillations of cell-length for a large fraction of bacteria exposed to 60μM of Ag⁺ions. In addition, we found that the responses of bacteria to Ag⁺ions were heterogeneous. We quantified the oscillations of cell-length with power spectral density, which appeared different from that of bacteria growing in the absence of Ag⁺ions. Furthermore, a model similar to the predator-prey argument was developed to understand the observed oscillations of cell-length upon exposure to Ag⁺ions. This model not only successfully produced the oscillations but also explained the observed heterogeneity in the bacterial responses to Ag⁺ions. 

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2. Fluorides of Silver Under Large Compression**

   https://doi.org/10.1002/chem.202100028  

   Kurzydłowski, Dominik; Derzsi, Mariana; Zurek, Eva; Grochala, Wojciech (February 2021, Chemistry – A European Journal)

   Abstract The silver‐fluorine phase diagram has been scrutinized as a function of external pressure using theoretical methods. Our results indicate that two novel stoichiometries containing Ag⁺and Ag²⁺cations (Ag₃F₄and Ag₂F₃) are thermodynamically stable at ambient and low pressure. Both are computed to be magnetic semiconductors under ambient pressure conditions. For Ag₂F₅, containing both Ag²⁺and Ag³⁺, we find that strong 1D antiferromagnetic coupling is retained throughout the pressure‐induced phase transition sequence up to 65 GPa. Our calculations show that throughout the entire pressure range of their stability the mixed‐valence fluorides preserve a finite band gap at the Fermi level. We also confirm the possibility of synthesizing AgF₄as a paramagnetic compound at high pressure. Our results indicate that this compound is metallic in its thermodynamic stability region. Finally, we present general considerations on the thermodynamic stability of mixed‐valence compounds of silver at high pressure. 

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3. Rudorffites and Beyond: Perovskite‐Inspired Silver/Copper Pnictohalides for Next‐Generation Environmentally Friendly Photovoltaics and Optoelectronics

   https://doi.org/10.1002/adfm.202203300  

   Chakraborty, Abhisek; Pai, Narendra; Zhao, Jing; Tuttle, Blair_R; Simonov, Alexandr_N; Pecunia, Vincenzo (July 2022, Advanced Functional Materials)

   Abstract In the wake of lead‐halide perovskite research, bismuth‐ and antimony‐based perovskite‐inspired semiconducting materials are attracting increasing attention as safer and potentially more robust alternatives to lead‐based archetypes. Of particular interest are the group IB–group VA halide compositions with a generic formula A_xB_yX_x+3y(A⁺ = Cu⁺/Ag⁺; B³⁺ = Bi³⁺/Sb³⁺; X^– = I^–/Br^–), i.e., silver/copper pnictohalides and derivatives thereof. This family of materials forms 3D structures with much higher solar cell efficiencies and greater potential for indoor photovoltaics than the lower‐dimensional bismuth/antimony‐based perovskite‐inspired semiconductors. Furthermore, silver/copper pnictohalides are being investigated for applications beyond photovoltaics, e.g., for photodetection, ionization radiation detection, memristors, and chemical sensors. Such versatility parallels the wide range of possible compositions and synthetic routes, which enable various structural, morphological, and optoelectronic properties. This manuscript surveys the growing research on silver/copper pnictohalides, highlighting their composition–structure–property relationships and the status and prospects of the photovoltaic and optoelectronic devices based thereon. The authors hope that the insights provided herein might accelerate the development of eco‐friendly and stable perovskite‐inspired materials for next‐generation photovoltaics and optoelectronics. 

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4. Effect of metallic substrates and cavities on emission kinetics of dye-doped polymeric films

   https://doi.org/10.1364/JOSAB.409998  

   Koutsares, S.; Petrosyan, L_S; Prayakarao, S.; Courtwright, D.; Bonner, C_E; Shahbazyan, T_V; Noginov, M_A (December 2020, Journal of the Optical Society of America B)

   We have studied emission kinetics in dye-doped polymeric films (HITC:PMMA), deposited on top of glass and silver and embedded in Fabry–Perot cavities (metal-insulator-metal waveguides). For highly doped films on glass, we observed strong concentration quenching, as evidenced by a dramatic shortening of the emission kinetics, consistent with our previous studies. However, for the same dye-doped films on top of silver, slower emission kinetics were observed despite the high decay rates of individual dye molecules near the metallic surface. The concentration quenching rates in Fabry–Perot cavities were nearly identical to those of HITC:PMMA films deposited on top of silver. These findings are explained within a theoretical model for the inhibition of Förster energy transfer near a metallic surface. Furthermore, the emission kinetics of the dye-doped films on top of silver were approximately single exponential—consistent with the strong coupling of excited molecules with propagating surface plasmons. 

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5. Understanding the Mechanism of Star-Block Copolymers as Nanoreactors for Synthesis of Well-Defined Silver Nanoparticles

   Zhu, Albert; Li, Qiong; Chen, Xiaoyi (August 2018, Journal of emerging investigators)

   Facile and large-scale synthesis of well-defined, thermally stable silver nanoparticles protected by polymer brushes for use in practical applications is still a challenge. Recent work has reported a nanoreactor approach that can be used to synthesize these silver nanoparticles. This approach uses amphiphilic star-block copolymers, which have a hydrophilic core surrounded by a hydrophobic exterior. These polymers thus can serve as the nanoreactors. In this study, we hypothesize that the local high concentration of silver ions in the inner hydrophilic cores of these star-block copolymers facilitates the nucleation and subsequent growth of silver nanoparticles. When all silver nanoparticles nucleate from the cores of the star-block copolymers in solution, the particle size can be controlled by the core size of the polymer. To test this hypothesis, a polyisoprene-b-poly(p-tert-butylstyrene) (PI-b-PtBS) star-block copolymer was functionalized with carboxylic acid groups using a high-efficiency, photo-initiated thiol-ene click reaction. We characterized this modified polymer using proton nuclear magnetic resonance spectroscopy, and the results indicated that ~60% of the double bonds in the polyisoprene block were successfully functionalized with carboxylic acid groups. When silver ions were added to a solution of these functionalized star-block copolymers, the negatively charged carboxylic acid groups would attract the positively charged silver ions. Subsequent reduction of these Ag+ by a tert-butylamine-borane complex at room temperature produced nanosized silver particles. However, transmission electron microscopy images showed that a significant amount of relatively large silver nanoparticles grew outside the star-block copolymer nanoreactors. 

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