Development of charge-transport and thermoelectric simulation methodology based on density functional theory and application to organic materials

Physics is constantly evolving. It is a field that attempts to create calculations and theories capable of completely describing an observable phenomenon. The ability of various materials to conduct heat and electricity can vary wildly. Insulators can be 20 orders of magnitude less conductive than the best conductors, with everything in between also possible. Conductivity is related to the creation of a material capable of providing free electrons for the transfer of a current through the material. However, the current theories for the calculation of these conductive capacity have proved insufficient in the face of novel compounds such as carbon nanostructures and organic semiconductors. Professor Hiroyuki Ishii of Faculty of Pure and Applied Physics, University of Tsukuba, Japan, is attempting to address this disparity with the support of a team of physicists based at the Faculty of Pure and Applied Physics, University of Tsukuba.

Download Full-text

Cryogenic Exfoliation of 2D Stanene Nanosheets for Cancer Theranostics

Nano-Micro Letters ◽

10.1007/s40820-021-00619-1 ◽

2021 ◽

Vol 13 (1) ◽

Author(s):

Jiang Ouyang ◽

Ling Zhang ◽

Leijiao Li ◽

Wei Chen ◽

Zhongmin Tang ◽

...

Keyword(s):

Biomedical Applications ◽

Density Functional ◽

Biomedical Application ◽

Density Functional Theory Calculations ◽

Free Electrons ◽

Functional Theory ◽

New Approach ◽

New Type ◽

Average Size ◽

Cancer Theranostics

Abstract Stanene (Sn)-based materials have been extensively applied in industrial production and daily life, but their potential biomedical application remains largely unexplored, which is due to the absence of the appropriate and effective methods for fabricating Sn-based biomaterials. Herein, we explored a new approach combining cryogenic exfoliation and liquid-phase exfoliation to successfully manufacture two-dimensional (2D) Sn nanosheets (SnNSs). The obtained SnNSs exhibited a typical sheet-like structure with an average size of ~ 100 nm and a thickness of ~ 5.1 nm. After PEGylation, the resulting PEGylated SnNSs (SnNSs@PEG) exhibited good stability, superior biocompatibility, and excellent photothermal performance, which could serve as robust photothermal agents for multi-modal imaging (fluorescence/photoacoustic/photothermal imaging)-guided photothermal elimination of cancer. Furthermore, we also used first-principles density functional theory calculations to investigate the photothermal mechanism of SnNSs, revealing that the free electrons in upper and lower layers of SnNSs contribute to the conversion of the photo to thermal. This work not only introduces a new approach to fabricate 2D SnNSs but also establishes the SnNSs-based nanomedicines for photonic cancer theranostics. This new type of SnNSs with great potential in the field of nanomedicines may spur a wave of developing Sn-based biological materials to benefit biomedical applications.

Download Full-text

Exposing unsaturated Cu1-O2 sites in nanoscale Cu-MOF for efficient electrocatalytic hydrogen evolution

Science Advances ◽

10.1126/sciadv.abg2580 ◽

2021 ◽

Vol 7 (18) ◽

pp. eabg2580

Author(s):

Weiren Cheng ◽

Huabin Zhang ◽

Deyan Luan ◽

Xiong Wen (David) Lou

Keyword(s):

Hydrogen Evolution ◽

Density Functional ◽

Metal Organic Framework ◽

Density Functional Theory Calculations ◽

Active Centers ◽

Functional Theory ◽

Hollow Nanostructure ◽

Metal Organic ◽

X Ray Absorption ◽

A Current

Conductive metal-organic framework (MOF) materials have been recently considered as effective electrocatalysts. However, they usually suffer from two major drawbacks, poor electrochemical stability and low electrocatalytic activity in bulk form. Here, we have developed a rational strategy to fabricate a promising electrocatalyst composed of a nanoscale conductive copper-based MOF (Cu-MOF) layer fully supported over synergetic iron hydr(oxy)oxide [Fe(OH)x] nanoboxes. Owing to the highly exposed active centers, enhanced charge transfer, and robust hollow nanostructure, the obtained Fe(OH)x@Cu-MOF nanoboxes exhibit superior activity and stability for the electrocatalytic hydrogen evolution reaction (HER). Specifically, it needs an overpotential of 112 mV to reach a current density of 10 mA cm−2 with a small Tafel slope of 76 mV dec−1. X-ray absorption fine structure spectroscopy combined with density functional theory calculations unravels that the highly exposed coordinatively unsaturated Cu1-O2 centers could effectively accelerate the formation of key *H intermediates toward fast HER kinetics.

Download Full-text

Modeling of Quasi-One-Dimensional Carbon Nanostructures with Density Functional Theory

Handbook of Computational Chemistry ◽

10.1007/978-94-007-0711-5_24 ◽

2012 ◽

pp. 901-938 ◽

Cited By ~ 2

Author(s):

Veronica Barone ◽

Oded Hod ◽

Juan E. Peralta

Keyword(s):

Density Functional Theory ◽

Carbon Nanostructures ◽

Density Functional ◽

Functional Theory ◽

One Dimensional

Download Full-text

Balancing Density Functional Theory Interaction Energies in Charged Dimers Precursors to Organic Semiconductors

Journal of Chemical Theory and Computation ◽

10.1021/acs.jctc.9b01193 ◽

2020 ◽

Vol 16 (6) ◽

pp. 3530-3542

Author(s):

Alberto Fabrizio ◽

Riccardo Petraglia ◽

Clemence Corminboeuf

Keyword(s):

Density Functional Theory ◽

Organic Semiconductors ◽

Density Functional ◽

Interaction Energies ◽

Functional Theory

Download Full-text

Gold Nanoclusters Grown on MoS2 Nanosheets by Pulsed Laser Deposition: An Enhanced Hydrogen Evolution Reaction

Molecules ◽

10.3390/molecules26247503 ◽

2021 ◽

Vol 26 (24) ◽

pp. 7503

Author(s):

Yuting Jing ◽

Ruijing Wang ◽

Qiang Wang ◽

Xuefeng Wang

Keyword(s):

Active Sites ◽

Density Functional ◽

Au Nanoparticles ◽

Gold Nanoclusters ◽

Density Functional Theory Calculations ◽

Laser Deposition ◽

Mos2 Nanosheets ◽

Functional Theory ◽

The Density Functional Theory ◽

A Current

Au nanoparticles were decorated on a 2H MoS2 surface to form an Au/MoS2 composite by pulse laser deposition. Improved HER activity of Au/MoS2 is evidenced by a positively shifted overpotential (−77 mV) at a current density of −10 mA cm−2 compared with pure MoS2 nanosheets. Experimental evidence shows that the interface between Au and MoS2 provides more sites to combine protons to form an active H atom. The density functional theory calculations found that new Au active sites on the Au and MoS2 interface with improved conductivity of the whole system are essential for enhancing HER activity of Au/MoS2.

Download Full-text

Predicting band gaps of semiconductors with quantum chemistry

EPJ Web of Conferences ◽

10.1051/epjconf/202024600006 ◽

2020 ◽

Vol 246 ◽

pp. 00006

Author(s):

Anneke Dittmer

Keyword(s):

Density Functional Theory ◽

Quantum Chemistry ◽

Band Gap ◽

Organic Semiconductors ◽

Density Functional ◽

Band Gaps ◽

Coupled Cluster ◽

Functional Theory ◽

Coupled Cluster Theory ◽

Electrostatic Embedding

The following article gives a brief introduction to quantum chemistry and its application to the prediction of band gaps of inorganic and organic semiconductors. Two important quantum chemistry concepts —Density Functional Theory (DFT) and Coupled Cluster Theory (CC)— are shortly explained. These two concepts are used to calculate the optical and the transport band gap of a set of semiconductors modelled with an electrostatic embedding approach.

Download Full-text

Balancing DFT Interaction Energies in Charged Dimers Precursors to Organic Semiconductors

10.26434/chemrxiv.11309480.v1 ◽

2019 ◽

Author(s):

Alberto Fabrizio ◽

Riccardo Petraglia ◽

Clemence Corminboeuf

Keyword(s):

Organic Semiconductors ◽

Density Functional ◽

Radical Cations ◽

Closed Shell ◽

Open Shell ◽

Binding Energies ◽

Interaction Energies ◽

Functional Theory ◽

Energy Profiles ◽

London Dispersion

Accurately describing intermolecular interactions within the framework of Kohn-Sham density functional theory (KS-DFT) has resulted in numerous benchmark databases over the past two decades. By far, the largest efforts have been spent on closed-shell, neutral dimers for which today, the interaction energies and geometries can be accurately reproduced by various combinations of dispersion-corrected density functional approximations (DFAs). In sharp contrast, charged, open-shell dimers remain a challenge as illustrated by the analysis of the OREL26rad benchmark set consisting of pi-dimer radical cations. Aside from the methodological aspect, achieving a proper description of radical cationic complexes is appealing due to their role as models for charge carriers in organic semiconductors. In the interest of providing an assessment of more realistic dimer systems, we construct a dataset of large radical cationic dimers (CryOrel) and jointly train the 19 parameters of a dispersion corrected, range-separated hybrid density functional (wB97X-dDsC), with the objective of providing the maximum balance between the treatment of long-range London dispersion and reduction of the delocalization error. These conditions are essential to obtain accurate energy profiles and binding energies of charged, open-shell dimers. Comparisons with the performance of the parent wB97X functional series and state-of-the-art wavefunction based methods are provided. <br>

Download Full-text

Thermal Properties of the FCC Al3Zr : First-Principles Study

Materials Science Forum ◽

10.4028/www.scientific.net/msf.650.313 ◽

2010 ◽

Vol 650 ◽

pp. 313-319 ◽

Cited By ~ 1

Author(s):

Dong Lin Li ◽

Ping Chen ◽

Jian Xiong Yi ◽

Bi Yu Tang ◽

Li Ming Peng ◽

...

Keyword(s):

Perturbation Theory ◽

Thermal Properties ◽

Bulk Modulus ◽

Density Functional ◽

Functional Theory ◽

Density Functional Perturbation Theory ◽

Wide Range ◽

The Face ◽

Ab Inito ◽

Physical Quantities

Ab inito density functional theory (DFT) and density function perturbation theory (DFPT) have been applied to investigate the thermal properties of the face-center-cubic (fcc) Al3Zr alloy over a wide range of pressure and temperature. Phonon dispersions were obtained at equilibrium and strained configurations by density functional perturbation theory. Using the quasiharmonic approximation for the free energy, several interesting physical quantities such as thermal Grüneisen parameter, heat capacity at constant pressure and volume, thermal expansion coefficient and entropy, as well as adiabatic bulk modulus and isothermal bulk modulus, were calculated as a function of temperature and pressure, and the variation features of these quantities were discussed in details.

Download Full-text