Artículos de Revistas

URI permanente para esta colección

https://repositorio.uft.cl/handle/20.500.12254/2442

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Examinando Artículos de Revistas por Materia "1.3.9 - Otras Especialidades de la Física||2.5.1 - Ingeniería de los Materiales"

Mostrando 1 - 2 de 2
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    Ítem
    Beyond Bloch: A Theoretical Blueprint of Conjugated Polymer Optoelectronics
    (IOP Publishing, 2026-03-31) Lagos, Miguel
    Conjugated polymers have recently regained strong interest because of their potential in organic electronic devices such as organic light-emitting diodes (OLEDs), field-effect transistors (FETs), and organic photovoltaics (OPVs). Unlike inorganic semiconductors where electrons are commonly treated as delocalized or quasi-free Bloch states,electrons in conjugated polymers occupy strongly coupled, localized σ and π orbitals and interact intensely with the ionic lattice. These materials therefore deviate markedly from the assumptions underlying Bloch-based approaches, motivating the development of alternative theoretical descriptions of charge transport. Here we present a many-body model that explicitly includes electron-electron interactions, both on-site and between π states on alternating chain sites. The model naturally explains semiconducting behavior in the undoped polymer and predicts two novel flat bands of excited bonding states. These excited states exhibit bosonic character and enable an unconventional charge-transport channel. The model also quantitatively reproduces experimental observations, yielding excellent fits to measured UV-Vis absorption and electro-luminescence spectra.
  • Miniatura
    Ítem
    Mathematical framework for the plastic flow of fine-grained solids, from yield to fracture
    (Elsevier, 2024-12-15) Lagos, Miguel
    A newly proposed mathematical approach to plastic flow, holding from yield to fracture, of a fine-grained polycrystal with no voids or cracks is reviewed and applied to commercial steels. The formalism models the polycrystal by a continuum array of random deformable polyhedra leaving no voids between them, which can slide past each other along the shared faces when the shear stress resolved in the face plane exceeds a finite threshold. Grain reshaping for preserving matter continuity induces local forces assumed much weaker than those causing sliding. The relative velocity of adjacent sliding grains is taken as proportional to the local shear stress resolved in the common boundary plane. Explicit equations are derived for the plastic deformation, from yield to fracture. The analysis of mechanical tests of two commercial stainless steels is shown to illustrate how well the theory agrees with practice.