scholarly journals Electronic Structure of the Perylene–Zinc Oxide Interface: Computational Study of Photoinduced Electron Transfer and Impact of Surface Defects

2015 ◽  
Vol 119 (33) ◽  
pp. 18843-18858 ◽  
Author(s):  
Jingrui Li ◽  
Hong Li ◽  
Paul Winget ◽  
Jean-Luc Brédas
Keyword(s):  
Electron Transfer ◽  
Zinc Oxide ◽  
Electronic Structure ◽  
Photoinduced Electron Transfer ◽  
Surface Defects ◽  
Computational Study ◽  
Oxide Interface

A computational study of a fluorescent photoinduced electron transfer (PET) sensor for cations

2004 ◽  
Vol 100 (5) ◽  
pp. 753-757 ◽  
Author(s):  
S. A. De Silva ◽  
M. L. Kasner ◽  
M. A. Whitener ◽  
S. L. Pathirana
Keyword(s):  
Electron Transfer ◽  
Photoinduced Electron Transfer ◽  
Computational Study

Electronic structure in the transition metal block and its implications for light harvesting

Science ◽  
2019 ◽  
Vol 363 (6426) ◽  
pp. 484-488 ◽  
Author(s):  
James K. McCusker
Keyword(s):  
Electron Transfer ◽  
Electronic Structure ◽  
Excited State ◽  
Transition Metal ◽  
Solar Energy ◽  
Photoinduced Electron Transfer ◽  
Chemical Processes ◽  
Transition Series ◽  
Earth Abundant ◽  
Metal Block

Transition metal–based chromophores play a central role in a variety of light-enabled chemical processes ranging from artificial solar energy conversion to photoredox catalysis. The most commonly used compounds include elements from the second and third transition series (e.g., ruthenium and iridium), but their Earth-abundant first-row analogs fail to engage in photoinduced electron transfer chemistry despite having virtually identical absorptive properties. This disparate behavior stems from fundamental differences in the nature of 3d versus 4d and 5d orbitals, resulting in an inversion in the compounds’ excited-state electronic structure and undermining the ability of compounds with first-row elements to engage in photoinduced electron transfer. This Review will survey the key experimental observations establishing this difference in behavior, discuss the underlying reasons for this phenomenon, and briefly summarize efforts that are currently under way to alter this paradigm and open the door to new opportunities for using Earth-abundant materials for photoinduced electron transfer chemistries.

Iron Nanoparticles Embedded in Silica Glass: A Computational Study

2006 ◽  
Vol 959 ◽  
Author(s):  
Peter Kroll ◽  
Jens Theuerkauf ◽  
Thomas Wieland
Keyword(s):  
Electronic Structure ◽  
Silica Glass ◽  
Density Functional ◽  
Computational Study ◽  
Oxide Interface ◽  
Dynamic Simulations ◽  
Functional Theory ◽  
Icosahedral Clusters ◽  
Small Clusters ◽  
Homo Lumo

ABSTRACTWe performed electronic structure calculations within density functional theory including ab initio molecular dynamic simulations of isolated Fe13 and Fe55 clusters. We observed the energy preference of icosahedral clusters over cuboctahedrons for both Fe13 and Fe55. The magnetic structure is ferromagnetic for Fe13, but anti-ferromagnetic for Fe55. But isolated clusters exhibit a HOMO-LUMO gap. Subsequently, we embedded the clusters into models of silica glass of different size. For embedded clusters we observed the formation of an iron oxide interface between cluster and dielectric matrix. Though many different models were computed, they show a very homogeneous trend. The magnetization of optimized embedded models is close or larger than the magnetization of free clusters. The small clusters retain their electronic structure around the Fermi-level despite some major distortions.

Relation Between Local Structure, Electric Dipole and Charge Carrier Dynamics in DHICA Melanin, a Model for Biocompatible Semiconductors

2019 ◽  
Author(s):  
Micaela Matta ◽  
Alessandro Pezzella ◽  
Alessandro Troisi
Keyword(s):  
Electronic Structure ◽  
Degrees Of Freedom ◽  
Structural Model ◽  
Computational Study ◽  
Oxidative Polymerization ◽  
Radical Scavenging ◽  
Charge Carriers ◽  
Electronic Charge ◽  
Polymer Semiconductors ◽  
Synthetic Pigments

<div><div><div><p>Eumelanins are a family of natural and synthetic pigments obtained by oxidative polymerization of their natural precursors: 5,6 dihydroxyindole and its 2-carboxy derivative (DHICA). The simultaneous presence of ionic and electronic charge carriers makes these pigments promising materials for applications in bioelectronics. In this computational study we build a structural model of DHICA melanin considering the interplay between its many degrees of freedom, then we examine the electronic structure of representative oligomers. We find that a non-vanishing dipole along the polymer chain sets this system apart from conventional polymer semiconductors, determining its electronic structure, reactivity toward oxidation and localization of the charge carriers. Our work sheds light on previously unnoticed features of DHICA melanin that not only fit well with its radical scavenging and photoprotective properties, but open new perspectives towards understanding and tuning charge transport in this class of materials.<br></p></div></div></div>

Computationally Assisted Design of High Signal-to-Noise Photoinduced Electron Transfer-Based Voltage-Sensitive Dyes

2020 ◽  
Author(s):  
Rishikesh Kulkarni ◽  
Anneliese Gest ◽  
Chun Kei Lam ◽  
Benjamin Raliski ◽  
Feroz James ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Dft Calculations ◽  
Photoinduced Electron Transfer ◽  
Density Functional ◽  
Embryonic Stem ◽  
High Sensitivity ◽  
Md Simulations ◽  
High Signal ◽  
Signal To Noise ◽  
Green Fluorescent

<p>High signal-to-noise optical voltage indicators will enable simultaneous interrogation of membrane potential in large ensembles of neurons. However, design principles for voltage sensors with high sensitivity and brightness remain elusive, limiting the applicability of voltage imaging. In this paper, we use molecular dynamics (MD) simulations and density functional theory (DFT) calculations to guide the design of a bright and sensitive green-fluorescent voltage-sensitive fluorophore, or VoltageFluor (VF dye), that uses photoinduced electron transfer (PeT) as a voltage-sensing mechanism. MD simulations predict an 11% increase in sensitivity due to membrane orientation, while DFT calculations predict an increase in fluorescence quantum yield, but a decrease in sensitivity due to a decrease in rate of PeT. We confirm these predictions by synthesizing a new VF dye and demonstrating that it displays the expected improvements by doubling the brightness and retaining similar sensitivity to prior VF dyes. Combining theoretical predictions and experimental validation has resulted in the synthesis of the highest signal-to-noise green VF dye to date. We use this new voltage indicator to monitor the electrophysiological maturation of human embryonic stem cell-derived medium spiny neurons. </p>

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