Publications by authors named "Brenda Vargas"

Band engineering stands as an efficient route to induce strongly correlated quantum many-body phenomena. Besides inspiring analogies among diverse physical fields, tuning on demand the group velocity is highly attractive in photonics because it allows unconventional flows of light. Λ-schemes offer a route to control the propagation of light in a lattice-free configurations, enabling exotic phases such as slow-light and allowing for highly optical non-linear systems.

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CsPbBr nanocrystals (NCs) are promising optoelectronic and catalytic materials. Manipulating their morphology can improve their properties and stability. In this work, an alkene-derived zwitterionic ligand was used to control the morphology of CsPbBr NCs to yield the highly unusual rhombicuboctahedron morphology, showcasing the first example of a surfactant-tail controlled growth.

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The zwitterions resulting from the covalent attachment of 3- or 4-hydroxy benzene to the 1,3-dimethylimidazolium cation represent basic compounds (pKa of 8.68 and 8.99 in aqueous solutions, respectively) that chemisorb in aqueous solutions 0.

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Layered double perovskites have the potential to further expand the vast space of optoelectronic properties and applications of halide perovskites. Among the ∼60 known members, to date only the ⟨111⟩-oriented layered double perovskites, CsCdMnBiCl, have shown efficient photoluminescence (PL). The replacement of Bi with Sb in these materials was investigated, resulting in two new families of layered inorganic perovskite alloys with full solubility.

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The fluorescent properties of MIL-53(Al)-TDC are drastically changed due to the presence of iodine, even in small quantities, as a result of an energy transfer process from the host material (MIL-53(Al)-TDC) to the guest molecule (I). While MIL-53(Al)-TDC's emission spectrum shows a weak and broad band, after I adsorption, it exhibits well-resolved and long-lasting emission lines, which could be exploited for iodine detection. Density Functional Theory periodical calculations demonstrated that in the most stable MIL-53(Al)-TDCI configuration, the I molecule is bonded mainly by an O-HI hydrogen bond.

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Article Synopsis
  • - The study examined how ethanol (EtOH) interacts with a specific material called MIL-53(Al)-TDC, revealing a strong attraction (ΔHads = 69.6 kJ mol-1).
  • - Adding small amounts of water (H2O) increased CO2 capture efficiency, while adding ethanol did not show any improvement.
  • - Computational analyses, including the quantum theory of atoms in molecules (QTAIM), indicated a covalent bond between the MOF and the confined molecules, with no significant differences in hydrogen bonding when comparing confined molecules with CO2.
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Since the establishment of perovskite solar cells (PSCs), there has been an intense search for alternative materials to replace lead and improve their stability toward moisture and light. As single-metal perovskite structures have yielded unsatisfactory performances, an alternative is the use of double perovskites that incorporate a combination of metals. To this day, only a handful of these compounds have been synthesized, but most of them have indirect bandgaps and/or do not have bandgaps energies well-suited for photovoltaic applications.

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