skip to main content

Explore Research Products in the NSF-PAR

  • NSF Public Access
  • Search Results
  • Connecting the dots for fundamental understanding of structure–photophysics–property relationships of COFs, MOFs, and perovskites using a Multiparticle Holstein Formalism
Title: Connecting the dots for fundamental understanding of structure–photophysics–property relationships of COFs, MOFs, and perovskites using a Multiparticle Holstein Formalism
Photoactive organic and hybrid organic–inorganic materials such as conjugated polymers, covalent organic frameworks (COFs), metal–organic frameworks (MOFs), and layered perovskites, display intriguing photophysical signatures upon interaction with light. Elucidating structure–photophysics–property relationships across a broad range of functional materials is nontrivial and requires our fundamental understanding of the intricate interplay among excitons (electron–hole pair), polarons (charges), bipolarons, phonons (vibrations), inter-layer stacking interactions, and different forms of structural and conformational defects. In parallel with electronic structure modeling and data-driven science that are actively pursued to successfully accelerate materials discovery, an accurate, computationally inexpensive, and physically-motivated theoretical model, which consistently makes quantitative connections with conceptually complicated experimental observations, is equally important. Within this context, the first part of this perspective highlights a unified theoretical framework in which the electronic coupling as well as the local coupling between the electronic and nuclear degrees of freedom can be efficiently described for a broad range of quasiparticles with similarly structured Holstein-style vibronic Hamiltonians. The second part of this perspective discusses excitonic and polaronic photophysical signatures in polymers, COFs, MOFs, and perovskites, and attempts to bridge the gap between different research fields using a common theoretical construct – the Multiparticle Holstein Formalism. We envision that the synergistic integration of state-of-the-art computational approaches with the Multiparticle Holstein Formalism will help identify and establish new, transformative design strategies that will guide the synthesis and characterization of next-generation energy materials optimized for a broad range of optoelectronic, spintronic, and photonic applications.  more » « less
Award ID(s):
1704063
NSF-PAR ID:
10388357
Author(s) / Creator(s):
;
Date Published:
Journal Name:
Chemical Science
Volume:
14
Issue:
5
ISSN:
2041-6520
Page Range / eLocation ID:
1040 to 1064
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ( , Chemical Science)
    null (Ed.)
    Understanding the underlying physical mechanisms that govern charge transport in two-dimensional (2D) covalent organic frameworks (COFs) will facilitate the development of novel COF-based devices for optoelectronic and thermoelectric applications. In this context, the low-energy mid-infrared absorption contains valuable information about the structure–property relationships and the extent of intra- and inter-framework “hole” polaron delocalization in doped and undoped polymeric materials. In this study, we provide a quantitative characterization of the intricate interplay between electronic defects, domain sizes, pore volumes, chemical dopants, and three dimensional anisotropic charge migration in 2D COFs. We compare our simulations with recent experiments on doped COF films and establish the correlations between polaron coherence, conductivity, and transport signatures. By obtaining the first quantitative agreement with the measured absorption spectra of iodine doped (aza)triangulene-based COF, we highlight the fundamental differences between the underlying microstructure, spectral signatures, and transport physics of polymers and COFs. Our findings provide conclusive evidence of why iodine doped COFs exhibit lower conductivity compared to doped polythiophenes. Finally, we propose new research directions to address existing limitations and improve charge transport in COFs for applications in functional molecular electronic devices. 
    more » « less
  2. ; ; ; ; ; ( , Advanced Energy Materials)
    Abstract

    Materials with dynamically controlled electronic structures (i.e., upon external stimuli) are at the forefront of the renewable energy sector with applications as memory devices, smart supercapacitors, programmable solar cells, and field‐effect transistors. Moreover, their continued development as device components is critical for the field of optoelectronics since their performance is comparable, or could even surpass, the current benchmarks. Adaptive electronic properties are the main focus of this review that discusses recent developments in the modulation of electronic behavior that can be tuned using external stimuli in metal–organic frameworks (MOFs), covalent–organic frameworks (COFs), primarily inorganic hybrids, polymers, and graphitic‐type materials. Triggers to achieve “dynamic” behavior discussed within this manuscript are primarily light‐based switches that include different classes of photochromic molecules such as naphthalene diimide, viologen, diarylethene, azobenzene, and spiropyran. The effect of material dimensionality and photoswitch connectivity achieved through integration of photochromic moieties inside 0D, 1D, 2D, and 3D hybrid matrices is discussed. This review showcases the prospects of advancing the material and energy landscapes through employment of structural motifs with adaptive electronic structures occurring as a function of their dimensionality and connectivity.

     
    more » « less
  3. ; ; ; ; ; ; ; ; ; ; et al ( , Angewandte Chemie International Edition)
    Abstract

    The emergence of conductive 2D and less commonly 3D coordination polymers (CPs) and metal–organic frameworks (MOFs) promises novel applications in many fields. However, the synthetic parameters for these electronically complex materials are not thoroughly understood. Here we report a new 3D semiconducting CPFe5(C6O6)3, which is a fusion of 2D Fe‐semiquinoid materials and 3D cubicFex(C6O6)ymaterials, by using a different initial redox‐state of the C6O6linker. The material displays high electrical conductivity (0.02 S cm−1), broad electronic transitions, promising thermoelectric behavior (S2σ=7.0×10−9 W m−1 K−2), and strong antiferromagnetic interactions at room temperature. This material illustrates how controlling the oxidation states of redox‐active components in conducting CPs/MOFs can be a “pre‐synthetic” strategy to carefully tune material topologies and properties in contrast to more commonly encountered post‐synthetic modifications.

     
    more » « less
  4. ; ; ; ; ; ; ; ; ; ; et al ( , Angewandte Chemie)
    Abstract

    The emergence of conductive 2D and less commonly 3D coordination polymers (CPs) and metal–organic frameworks (MOFs) promises novel applications in many fields. However, the synthetic parameters for these electronically complex materials are not thoroughly understood. Here we report a new 3D semiconducting CPFe5(C6O6)3, which is a fusion of 2D Fe‐semiquinoid materials and 3D cubicFex(C6O6)ymaterials, by using a different initial redox‐state of the C6O6linker. The material displays high electrical conductivity (0.02 S cm−1), broad electronic transitions, promising thermoelectric behavior (S2σ=7.0×10−9 W m−1 K−2), and strong antiferromagnetic interactions at room temperature. This material illustrates how controlling the oxidation states of redox‐active components in conducting CPs/MOFs can be a “pre‐synthetic” strategy to carefully tune material topologies and properties in contrast to more commonly encountered post‐synthetic modifications.

     
    more » « less
  5. ; ; ( , Advanced Functional Materials)
    Abstract

    Covalent organic frameworks (COFs) are an emerging class of organic crystalline polymers with well‐defined molecular geometry and tunable porosity. COFs are formed via reversible condensation of lightweight molecular building blocks, which dictate its geometry in two or three dimensions. Among COFs, 2D COFs have garnered special attention due to their unique structure composed of two‐dimensionally extended organic sheets stacked in layers generating periodic columnar π‐arrays, functional pore space, and their ease of synthesis. These unique features in combination with their low density, high crystallinity, large surface area, and biodegradability have made them an excellent candidate for a plethora of applications ranging from energy to biomedical sciences. In this article, the evolution of 2D COFs is briefly discussed in terms of different types of chemical linkages, synthetic strategies of bulk and nanoscale 2D COFs, and their tunability from a biomedical perspective. Next, the biomedical applications of 2D COFs specifically for drug delivery, phototherapy, biosensing, bioimaging, biocatalysis, and antibacterial activity are summarized. In addition, current challenges and emerging approaches in designing 2D COFs for advanced biomedical applications are discussed.

     
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email