scholarly journals The Interplay of Conjugation and Metal Coordination in Tuning the Electron Transfer Abilities of NTA-Graphene Based Interfaces

2022 ◽  
Vol 23 (1) ◽  
pp. 543
Author(s):  
Magdalena Kaźmierczak ◽  
Bartosz Trzaskowski ◽  
Silvio Osella
Keyword(s):  
Electron Transfer ◽  
Charge Transfer ◽  
Self Assembly ◽  
Surface Coverage ◽  
Theoretical Calculations ◽  
Nitrilotriacetic Acid ◽  
Graphene Monolayer ◽  
Coverage Density ◽  
Efficient Charge ◽  
A Minor

An artificial leaf is a concept that not only replicates the processes taking place during natural photosynthesis but also provides a source of clean, renewable energy. One important part of such a device are molecules that stabilize the connection between the bioactive side and the electrode, as well as tune the electron transfer between them. In particular, nitrilotriacetic acid (NTA) derivatives used to form a self-assembly monolayer chemisorbed on a graphene monolayer can be seen as a prototypical interface that can be tuned to optimize the electron transfer. In the following work, interfaces with modifications of the metal nature, backbone saturation, and surface coverage density are presented by means of theoretical calculations. Effects of the type of the metal and the surface coverage density on the electronic properties are found to be key to tuning the electron transfer, while only a minor influence of backbone saturation is present. For all of the studied interfaces, the charge transfer flow goes from graphene to the SAM. We suggest that, in light of the strength of electron transfer, Co2+ should be considered as the preferred metal center for efficient charge transfer.

scholarly journals Construction of UiO-66/Bi4O5Br2 Type-II Heterojunction to Boost Charge Transfer for Promoting Photocatalytic CO2 Reduction Performance

2021 ◽  
Vol 9 ◽  
Author(s):  
Dongsheng Li ◽  
Bichen Zhu ◽  
Zhongti Sun ◽  
Qinqin Liu ◽  
Lele Wang ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Self Assembly ◽  
Co2 Reduction ◽  
Clean Energy ◽  
High Photocatalytic Activity ◽  
Type Ii ◽  
Co Catalysts ◽  
Tight Contact ◽  
Assembly Method ◽  
Efficient Charge

One of the basic challenges of CO2 photoreduction is to develop efficient photocatalysts, and the construction of heterostructure photocatalysts with intimate interfaces is an effective strategy to enhance interfacial charge transfer for realizing high photocatalytic activity. Herein, a novel UiO-66/Bi4O5Br2 heterostructure photocatalyst was constructed by depositing UiO-66 nanoparticles with octahedral morphology over the Bi4O5Br2 nanoflowers assembled from the Bi4O5Br2 nanosheets via an electrostatic self-assembly method. A tight contact interface and a built-in electric field were formed between the UiO-66 and the Bi4O5Br2, which was conducive to the photo-electrons transfer from the Bi4O5Br2 to the UiO-66 and the formation of a type-II heterojunction with highly efficient charge separation. As a result, the UiO-66/Bi4O5Br2 exhibited improved photocatalytic CO2 reduction performance with a CO generation rate of 8.35 μmol h−1 g−1 without using any sacrificial agents or noble co-catalysts. This work illustrates an applicable tactic to develop potent photocatalysts for clean energy conversion.

scholarly journals Effects of co-adsorption on interfacial charge transfer in a quantum dot@dye composite

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Peng Cui ◽  
Yuan Xue
Keyword(s):  
Electron Transfer ◽  
Charge Transfer ◽  
Quantum Dot ◽  
Charge Separation ◽  
Density Functional ◽  
Co Adsorption ◽  
Hole Transfer ◽  
Interfacial Charge Transfer ◽  
Efficient Charge ◽  
Interfacial Charge

AbstractThe sensitive electronic environment at the quantum dot (QD)–dye interface becomes a roadblock to enhancing the energy conversion efficiency of dye-functionalized quantum dots (QDs). Energy alignments and electronic couplings are the critical factors governing the directions and rates of different charge transfer pathways at the interface, which are tunable by changing the specific linkage groups that connect a dye to the QD surface. The variation of specific anchors changes the binding configurations of a dye on the QD surface. In addition, the presence of a co-adsorbent changes the dipole–dipole and electronic interactions between a QD and a dye, resulting in different electronic environments at the interface. In the present work, we performed density functional theory (DFT)-based calculations to study the different binding configurations of N719 dye on the surface of a Cd33Se33 QD with a co-adsorbent D131 dye. The results revealed that the electronic couplings for electron transfer were greater than for hole transfer when the structure involved isocyanate groups as anchors. Such strong electronic couplings significantly stabilize the occupied states of the dye, pushing them deep inside the valence band of the QD and making hole transfer in these structures thermodynamically unfavourable. When carboxylates were involved as anchors, the electronic couplings for hole transfer were comparable to electron transfer, implying efficient charge separation at the QD–dye interface and reduced electron–hole recombination within the QD. We also found that the electronic couplings for electron transfer were larger than those for back electron transfer, suggesting efficient charge separation in photoexcited QDs. Overall, the current computational study reveals some fundamental aspects of the relationship between the interfacial charge transfer for QD@dye composites and their morphologies which benefit the design of QD-based nanomaterials for photovoltaic applications.

Peripheral phenothiazine induced suppression of charge separation from the singlet excited zinc phthalocyanine to coordinated C60 in supramolecular donor–acceptor conjugates

2017 ◽  
Vol 21 (12) ◽  
pp. 870-881 ◽  
Author(s):  
Sairaman Seetharaman ◽  
Youngwoo Jang ◽  
Chandra B. KC ◽  
Paul A. Karr ◽  
Francis D’Souza
Keyword(s):  
Electron Transfer ◽  
Charge Transfer ◽  
Charge Separation ◽  
Ion Pairs ◽  
Binding Constants ◽  
Free Energy Calculations ◽  
Zinc Phthalocyanine ◽  
Stable Complex ◽  
Efficient Charge ◽  
Donor Acceptor

Self-assembled donor–acceptor conjugates featuring zinc phthalocyanine carrying four entities of peripheral phenothiazine entities, (PTZ)[Formula: see text]ZnPc, axially coordinated to either phenyl imidazole or pyridine functionalized fulleropyrrolidine (C[Formula: see text]Im or C[Formula: see text]Py) has been newly designed, synthesized and characterized. Due to the direct connectivity of the phenothiazine entities to the ZnPc [Formula: see text]-system, efficient charge transfer type interactions suppressing fluorescence of ZnPc in (PTZ)[Formula: see text]ZnPc was observed. Axial coordination of C[Formula: see text]Im or C[Formula: see text]Py to the metal center of (PTZ)[Formula: see text]ZnPc served as an electron acceptor in the conjugates. Optical absorption studies revealed stable complex formation wherein the evaluated binding constants [Formula: see text] were found to be 3.9 × 10[Formula: see text] M[Formula: see text] for (PTZ)[Formula: see text]ZnPc:ImC[Formula: see text] and 3.3 × 10[Formula: see text] M[Formula: see text] for (PTZ)[Formula: see text]ZnPc:PyC[Formula: see text] conjugates with 1:1 molecular stoichiometry. Computational studies performed at the HF/[6-311G(d,p) for H, C, and N, and 6-311G(2df) for S and Zn] level revealed stable structures of the conjugates. The evaluated center-to-center and edge-to-edge distances for the (PTZ)[Formula: see text]ZnPc:ImC[Formula: see text] were 13.6 and 10.4 Å, while for the (PTZ)[Formula: see text]ZnPc:PyC[Formula: see text] conjugate these distances were 10.2 and 7.3 Å. That is, the C[Formula: see text] was about 3̃ Å closer to ZnPc in the latter conjugate. From the free-energy calculations, photoinduced electron transfer from the [Formula: see text]ZnPc* to fullerene within the conjugates was established to be an exothermic process, however, a hole transfer from ZnPc[Formula: see text] to peripheral PTZ was found to be energetically an uphill process. From femtosecond transient absorbance studies, occurrence of photoinduced charge separation in (PTZ)[Formula: see text]ZnPc:ImC[Formula: see text] was found to be weak due to the competing charge transfer interactions within the (PTZ)[Formula: see text]ZnPc and longer donor–acceptor distance while in the case of the (PTZ)[Formula: see text]ZnPc:PyC[Formula: see text] conjugate, electron transfer occurred competitively to yield radical ion-pairs. From nanosecond transient spectroscopy, lifetime of the (PTZ)[Formula: see text]ZnPc[Formula: see text]:PyC[Formula: see text] charge separated state was found to be in the 200 ns range, revealing charge stabilization to some extent.

Efficient and stable charge transfer channels for photocatalytic water splitting activity of CdS without sacrificial agents

2020 ◽  
Vol 8 (40) ◽  
pp. 20963-20969 ◽  
Author(s):  
Wei Chen ◽  
Guo-Bo Huang ◽  
Hao Song ◽  
Jian Zhang
Keyword(s):  
Charge Transfer ◽  
Water Splitting ◽  
Photocatalytic Water Splitting ◽  
Transfer Channel ◽  
Efficient Charge ◽  
Transfer Channels

An efficient charge transfer channel for improving the photocatalytic water splitting activity and durability of CdS without sacrificial agents.

scholarly journals An In-Situ Reaction Route to Molecular Level Dispersed Bisimide and ZnO Nanorod Hybrids with Efficient Photo-Induced Charge Transfer

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Chunzheng Lv ◽  
Lirong He ◽  
Jiahong Tang ◽  
Feng Yang ◽  
Chuhong Zhang
Keyword(s):  
Charge Transfer ◽  
Electric Field ◽  
Self Assembly ◽  
Molecular Level ◽  
Surface Photovoltage ◽  
Zno Nanorod ◽  
In Situ Reaction ◽  
Perylene Bisimide ◽  
Induced Charge

AbstractAs an important photoconductive hybrid material, perylene/ZnO has attracted tremendous attention for photovoltaic-related applications, but generally faces a great challenge to design molecular level dispersed perylenes/ZnO nanohybrids due to easy phase separation between perylenes and ZnO nanocrystals. In this work, we reported an in-situ reaction method to prepare molecular level dispersed H-aggregates of perylene bisimide/ZnO nanorod hybrids. Surface photovoltage and electric field-induced surface photovoltage spectrum show that the photovoltage intensities of nanorod hybrids increased dramatically for 100 times compared with that of pristine perylene bisimide. The enhancement of photovoltage intensities resulting from two aspects: (1) the photo-generated electrons transfer from perylene bisimide to ZnO nanorod due to the electric field formed on the interface of perylene bisimide/ZnO; (2) the H-aggregates of perylene bisimide in ZnO nanorod composites, which is beneficial for photo-generated charge separation and transportation. The introduction of ordered self-assembly thiol-functionalized perylene-3,4,9,10-tetracarboxylic diimide (T-PTCDI)/ ZnO nanorod composites induces a significant improvement in incident photo-to-electron conversion efficiency. This work provides a novel mentality to boost photo-induced charge transfer efficiency, which brings new inspiration for the preparation of the highly efficient solar cell.

Interfacing RuO2 with Pt to induce efficient charge transfer from Pt to RuO2 for highly efficient and stable oxygen evolution under acidic media

2021 ◽  
Author(s):  
Taehyun Kwon ◽  
Heesu Yang ◽  
Minki Jun ◽  
Taekyung Kim ◽  
Jinwhan Joo ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Acidic Media ◽  
Highly Efficient ◽  
Efficient Charge ◽  
Stable Oxygen ◽  
The Stability

The oxygen evolution reaction (OER) requires a large overpotential which undermines the stability of electrocatalysts, typically IrOx or RuOx. RuOx is particularly vulnerable to high overpotential in acidic media, due...

Impact of vibronic coupling effects on light-driven charge transfer in pyrene-functionalized middle and large-sized Metalloid Gold Nanoclusters from Ehrenfest dynamics.

2021 ◽  
Author(s):  
Adrian Dominguez-Castro ◽  
Thomas Frauenheim
Keyword(s):  
Molecular Dynamics ◽  
Charge Transfer ◽  
Density Functional ◽  
Theoretical Calculations ◽  
Gold Nanoclusters ◽  
Tight Binding ◽  
Time Dependent ◽  
Effective Strategy ◽  
Dynamics Simulations ◽  
Dependent Density

Theoretical calculations are an effective strategy to comple- ment and understand experimental results in atomistic detail. Ehrenfest molecular dynamics simulations based on the real-time time-dependent density functional tight-binding (RT-TDDFTB) approach...

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