Charge-separation in panchromatic, vertically positioned bis(donor styryl)BODIPY–aluminum(iii) porphyrin–fullerene supramolecular triads

Nanoscale ◽  
2018 ◽  
Vol 10 (44) ◽  
pp. 20723-20739 ◽  
Author(s):  
Niloofar Zarrabi ◽  
Christopher O. Obondi ◽  
Gary N. Lim ◽  
Sairaman Seetharaman ◽  
Benjamin G. Boe ◽  
...  
Keyword(s):  
Reaction Center ◽  
Charge Separation ◽  
Broad Band ◽  
Vertically Aligned

Three, broad band capturing, vertically aligned reaction center models have been constructed using aluminum(iii) porphyrin.

Ultrafast charge separation and charge stabilization in axially linked ‘tetrathiafulvalene–aluminum(iii) porphyrin–gold(iii) porphyrin’ reaction center mimics

2015 ◽  
Vol 17 (39) ◽  
pp. 26346-26358 ◽  
Author(s):  
Prashanth K. Poddutoori ◽  
Gary N. Lim ◽  
Serguei Vassiliev ◽  
Francis D'Souza
Keyword(s):  
Electron Transfer ◽  
Reaction Center ◽  
Charge Separation ◽  
Vertically Aligned ◽  
Sequential Electron ◽  
Charge Stabilization

Sequential electron transfer leading to charge stabilization in newly synthesized vertically aligned ‘tetrathiafulvalene–aluminum(iii) porphyrin–gold(iii) porphyrin’ supramolecular triads is reported.

scholarly journals Excitonic structure and charge separation in the heliobacterial reaction center probed by multispectral multidimensional spectroscopy

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yin Song ◽  
Riley Sechrist ◽  
Hoang H. Nguyen ◽  
William Johnson ◽  
Darius Abramavicius ◽  
...  
Keyword(s):  
Reaction Center ◽  
Charge Separation ◽  
Electronic Spectroscopy ◽  
Spectroscopic Studies ◽  
Primary Electron ◽  
Reaction Centers ◽  
Separation Mechanism ◽  
Photosynthetic Reaction Centers ◽  
Density Analysis ◽  
Function Relationship

AbstractPhotochemical reaction centers are the engines that drive photosynthesis. The reaction center from heliobacteria (HbRC) has been proposed to most closely resemble the common ancestor of photosynthetic reaction centers, motivating a detailed understanding of its structure-function relationship. The recent elucidation of the HbRC crystal structure motivates advanced spectroscopic studies of its excitonic structure and charge separation mechanism. We perform multispectral two-dimensional electronic spectroscopy of the HbRC and corresponding numerical simulations, resolving the electronic structure and testing and refining recent excitonic models. Through extensive examination of the kinetic data by lifetime density analysis and global target analysis, we reveal that charge separation proceeds via a single pathway in which the distinct A0 chlorophyll a pigment is the primary electron acceptor. In addition, we find strong delocalization of the charge separation intermediate. Our findings have general implications for the understanding of photosynthetic charge separation mechanisms, and how they might be tuned to achieve different functional goals.

KONDO EFFECT AND SPIN-CHARGE SEPARATION IN QUANTUM DOTS

2001 ◽  
Vol 15 (10n11) ◽  
pp. 1426-1442
Author(s):  
L. I. GLAZMAN ◽  
F. W. J. HEKKING ◽  
A. I. LARKIN
Keyword(s):  
Quantum Dot ◽  
Charge Separation ◽  
Coulomb Blockade ◽  
Kondo Effect ◽  
Broad Band ◽  
Single Mode ◽  
Kondo Temperature ◽  
Average Charge ◽  
Opposite Case ◽  
Anderson Impurity Model

The Kondo effect in a quantum dot is discussed. In the standard Coulomb blockade setting, tunneling between the dot and the leads is weak, the number of electrons in the dot is well-defined and discrete; the Kondo effect may be considered in the framework of the conventional one-level Anderson impurity model. It turns out however, that the Kondo temperature TK in the case of weak tunneling is extremely low. In the opposite case of almost reflectionless single-mode junctions connecting the dot to the leads, the average charge of the dot is not discrete. Surprisingly, its spin may remain quantized: s=1/2 or s=0, depending (periodically) on the gate voltage. Such a "spin-charge separation" occurs because, unlike an Anderson impurity, a quantum dot carries a broad-band, dense spectrum of discrete levels. In the doublet state, the Kondo effect develops with a significantly enhanced TK. Like in the weak-tunneling regime, the enhanced TK exhibits strong mesoscopic fluctuations. The statistics of the fluctuations is universal, and related to the Porter-Thomas statistics of the wave function fluctuations.

scholarly journals Excitonic Structure and Charge Separation in the Heliobacterial Reaction Center Probed by Multispectral Multidimensional Spectroscopy

2021 ◽  
Author(s):  
Yin Song ◽  
Riley Sechrist ◽  
Hoang Huy Nguyen ◽  
William Johnson ◽  
Darius Abramavičius ◽  
...  
Keyword(s):  
Reaction Center ◽  
Charge Separation ◽  
Electronic Spectroscopy ◽  
Spectroscopic Studies ◽  
Primary Electron ◽  
Reaction Centers ◽  
Separation Mechanism ◽  
Photosynthetic Reaction Centers ◽  
Density Analysis ◽  
Function Relationship

<p>Photochemical reaction centers are the engines that drive photosynthesis. The reaction center from heliobacteria (HbRC) has been proposed to most closely resemble the common ancestor of photosynthetic reaction centers, motivating a detailed understanding of its structure-function relationship. The recent elucidation of the HbRC crystal structure motivates advanced spectroscopic studies of its excitonic structure and charge separation mechanism. We perform multispectral two-dimensional electronic spectroscopy of the HbRC and corresponding numerical simulations, resolving the electronic structure and testing and refining recent excitonic models. Through extensive examination of the kinetic data by lifetime density analysis and global target analysis, we reveal that charge separation proceeds via a single pathway in which the distinct A<sub>0 </sub>chlorophyll <i>a</i> pigment is the primary electron acceptor. In addition, we find strong delocalization of the initial excited state and charge separation intermediate. Our findings have general implications for the understanding of photosynthetic charge separation mechanisms, and how they might be tuned to achieve different functional goals.</p>

scholarly journals De Novo Protein Design of Photochemical Reaction Centers

2021 ◽  
Author(s):  
Nathan Ennist ◽  
Zhenyu Zhao ◽  
Steven Stayrook ◽  
Bohdana Discher ◽  
P Leslie 'Les' Dutton ◽  
...  
Keyword(s):  
Reaction Center ◽  
Charge Separation ◽  
Rational Design ◽  
De Novo ◽  
Metal Cluster ◽  
Protein Structures ◽  
Essential Elements ◽  
Reaction Centers ◽  
Transient Absorption Spectroscopy

Abstract Natural photosynthetic protein complexes capture sunlight to power the energetic catalysis that supports life on Earth. Yet these natural protein structures carry an evolutionary legacy of complexity and fragility that encumbers protein reengineering efforts and obfuscates the underlying design rules for light-driven charge separation. De novo development of a simplified photosynthetic reaction center protein can clarify practical engineering principles needed to build new enzymes for efficient solar-to-fuel energy conversion. Here we report the rational design, X-ray crystal structure, and electron transfer activity of a multi-cofactor protein that incorporates essential elements of photosynthetic reaction centers. This highly stable, modular artificial protein framework can be reconstituted in vitro with interchangeable redox centers for nanometer-scale photochemical charge separation. Transient absorption spectroscopy demonstrates Photosystem II-like tyrosine and metal cluster oxidation, and we measure charge separation lifetimes exceeding 100 ms, ideal for light-activated catalysis. This de novo-designed reaction center builds upon engineering guidelines established for charge separation in earlier synthetic photochemical triads and modified natural proteins, and it shows how synthetic biology may lead to a new generation of genetically encoded, light-powered catalysts for solar fuel production.

scholarly journals Exciton-vibrational resonance and dynamics of charge separation in the photosystem II reaction center

2017 ◽  
Vol 19 (7) ◽  
pp. 5195-5208 ◽  
Author(s):  
Vladimir I. Novoderezhkin ◽  
Elisabet Romero ◽  
Javier Prior ◽  
Rienk van Grondelle
Keyword(s):  
Charge Transfer ◽  
Photosystem Ii ◽  
Excitation Energy ◽  
Reaction Center ◽  
Charge Separation ◽  
Natural Conditions ◽  
Vibrational Resonance ◽  
Laser Experiment

A mixing of the exciton and charge transfer states promoted by a resonant vibrational quantum allows faster penetration of excitation energy into the primary photoproduct in the photosystem II reaction center both in laser experiment and under natural conditions.

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