scholarly journals Watching the dynamics of electrons and atoms at work in solar energy conversion

2015 ◽  
Vol 185 ◽  
pp. 51-68 ◽  
Author(s):  
S. E. Canton ◽  
X. Zhang ◽  
Y. Liu ◽  
J. Zhang ◽  
M. Pápai ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Solar Energy ◽  
Energy Conversion ◽  
Solar Energy Conversion ◽  
Photochemical Reactions ◽  
Atomic Scale ◽  
Intramolecular Electron Transfer ◽  
X Ray ◽  
Ultrafast Optical ◽  
Quantum Chemistry Calculations

The photochemical reactions performed by transition metal complexes have been proposed as viable routes towards solar energy conversion and storage into other forms that can be conveniently used in our everyday applications. In order to develop efficient materials, it is necessary to identify, characterize and optimize the elementary steps of the entire process on the atomic scale. To this end, we have studied the photoinduced electronic and structural dynamics in two heterobimetallic ruthenium–cobalt dyads, which belong to the large family of donor–bridge–acceptor systems. Using a combination of ultrafast optical and X-ray absorption spectroscopies, we can clock the light-driven electron transfer processes with element and spin sensitivity. In addition, the changes in local structure around the two metal centers are monitored. These experiments show that the nature of the connecting bridge is decisive for controlling the forward and the backward electron transfer rates, a result supported by quantum chemistry calculations. More generally, this work illustrates how ultrafast optical and X-ray techniques can disentangle the influence of spin, electronic and nuclear factors on the intramolecular electron transfer process. Finally, some implications for further improving the design of bridged sensitizer-catalysts utilizing the presented methodology are outlined.

scholarly journals A biophotoelectrochemical approach to unravelling the role of cyanobacterial cell structures in exoelectrogenesis

2021 ◽  
Author(s):  
Laura T. Wey ◽  
Joshua M. Lawrence ◽  
Xiaolong Chen ◽  
Robert Clark ◽  
David J. Lea-Smith ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Solar Energy ◽  
Energy Conversion ◽  
Solar Energy Conversion ◽  
Growth Stages ◽  
Whole Cells ◽  
Analytical Technique ◽  
Type Iv ◽  
Cell Structures ◽  
Cell Electrode

AbstractPhotosynthetic microorganisms can export electrons outside their cells, a phenomenon called exoelectrogenesis, which can be harnessed for solar energy conversion. However, the route electrons take from thylakoid membranes to the cell exterior is not understood. Electrochemistry is a powerful analytical technique for studying electron transfer pathways. Here, we show how photoelectrochemistry can be used to compare electron flux from cyanobacterial cells of different growth stages, species and with the outer layers systematically removed. We show that the periplasmic space contributes significantly to the photocurrent profile complexity of whole cells, indicating that it gates electron transfer in exoelectrogenesis. We found that although components of the type IV pili machinery do not have a role in exoelectrogenesis, they contribute significantly to cell-electrode adherence. This study establishes that analytical photoelectrochemistry and molecular microbiology provide a powerful combination to study exoelectrogenesis, enabling future studies to answer biological questions and advance solar energy conversion applications.

scholarly journals Interfacial Electron Transfer in Dye-Sensitized TiO2 Devices for Solar Energy Conversion

2021 ◽  
Author(s):  
Andressa Müller ◽  
Wendel Wierzba ◽  
Mariana Pastorelli ◽  
André Polo
Keyword(s):  
Electron Transfer ◽  
Solar Energy ◽  
Energy Conversion ◽  
Solar Energy Conversion ◽  
Transport Processes ◽  
Transfer Reactions ◽  
Molecular Devices ◽  
Interfacial Electron Transfer ◽  
Electron Transfer Reactions ◽  
Dye Sensitized

The development of cost-effective molecular devices that efficiently capture and convert sunlight into other useful forms of energy is a promising approach to meet the world’s increasing energy demands. These devices are designed through a successful combination of materials and molecules that work synergistically to promote light-driven chemical reactions. Light absorption by a surface-bound chromophore triggers a sequence of interfacial electron transfer processes. The efficiencies of the devices are governed by the dynamic balance between the electron transfer reactions that promote energy conversion and undesirable side reactions. Therefore, it is necessary to understand and control these processes to optimize the design of the components of the devices and to achieve higher energy conversion efficiencies. In this context, this review discusses general aspects of interfacial electron transfer reactions in dye-sensitized TiO2 molecular devices for solar energy conversion. A theoretical background on the Marcus-Gerischer theory for interfacial electron transfer and theoretical models for electron transport within TiO2 films are provided. An overview of dye-sensitized solar cells (DSSCs) and dye-sensitized photoelectrosynthesis cells (DSPECs) is presented, and the electron transfer and transport processes that occur in both classes of devices are emphasized and detailed. Finally, the main spectroscopic, electrochemical and photoelectrochemical experimental techniques that are employed to elucidate the kinetics of the electron transfer reactions discussed in this review are presented.

scholarly journals Ultrafast Dynamics of Charge Transfer and Photochemical Reactions in Solar Energy Conversion

2018 ◽  
Vol 5 (12) ◽  
pp. 1800221 ◽  
Author(s):  
Jing-Yin Xu ◽  
Xin Tong ◽  
Peng Yu ◽  
Gideon Evans Wenya ◽  
Thomas McGrath ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Solar Energy ◽  
Energy Conversion ◽  
Solar Energy Conversion ◽  
Photochemical Reactions ◽  
Ultrafast Dynamics

Recent advances in bioinspired proton-coupled electron transfer

2019 ◽  
Vol 48 (18) ◽  
pp. 5861-5868 ◽  
Author(s):  
Andrea Pannwitz ◽  
Oliver S. Wenger
Keyword(s):  
Electron Transfer ◽  
Solar Energy ◽  
Energy Conversion ◽  
Small Molecule ◽  
Solar Energy Conversion ◽  
Small Molecule Activation ◽  
Reaction Type ◽  
Proton Coupled Electron Transfer ◽  
Recent Advances

Fundamental aspects of PCET continue to attract attention. Understanding this reaction type is desirable for small-molecule activation and solar energy conversion.

scholarly journals Inverted-region electron transfer as a mechanism for enhancing photosynthetic solar energy conversion efficiency

2017 ◽  
Vol 114 (35) ◽  
pp. 9267-9272 ◽  
Author(s):  
Hiroki Makita ◽  
Gary Hastings
Keyword(s):  
Electron Transfer ◽  
Solar Energy ◽  
Energy Conversion ◽  
Quantum Efficiency ◽  
Photosystem I ◽  
Solar Energy Conversion ◽  
Charge Recombination ◽  
Inverted Region ◽  
Transfer Processes ◽  
Electron Transfer Processes

In all photosynthetic organisms, light energy is used to drive electrons from a donor chlorophyll species via a series of acceptors across a biological membrane. These light-induced electron-transfer processes display a remarkably high quantum efficiency, indicating a near-complete inhibition of unproductive charge recombination reactions. It has been suggested that unproductive charge recombination could be inhibited if the reaction occurs in the so-called inverted region. However, inverted-region electron transfer has never been demonstrated in any native photosynthetic system. Here we demonstrate that the unproductive charge recombination in native photosystem I photosynthetic reaction centers does occur in the inverted region, at both room and cryogenic temperatures. Computational modeling of light-induced electron-transfer processes in photosystem I demonstrate a marked decrease in photosynthetic quantum efficiency, from 98% to below 72%, if the unproductive charge recombination process does not occur in the inverted region. Inverted-region electron transfer is therefore demonstrated to be an important mechanism contributing to efficient solar energy conversion in photosystem I. Inverted-region electron transfer does not appear to be an important mechanism in other photosystems; it is likely because of the highly reducing nature of photosystem I, and the energetic requirements placed on the pigments to operate in such a regime, that the inverted-region electron transfer mechanism becomes important.

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