scholarly journals Color-tunable bioluminescence imaging portfolio for cell imaging

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shota Tamaki ◽  
Nobuo Kitada ◽  
Masahiro Kiyama ◽  
Rika Fujii ◽  
Takashi Hirano ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Density Functional ◽  
Cell Imaging ◽  
Imaging System ◽  
Visible Region ◽  
Theoretical Background ◽  
Functional Theory ◽  
Color Palette ◽  
Molecular Events ◽  
Color Tunable

AbstractThe present study describes a color-tunable imaging portfolio together with twelve novel coelenterazine (CTZ) analogues. The three groups of CTZ analogues create diverse hues of bioluminescence (BL) ranging from blue to far red with marine luciferases. We found that the hue completes the whole color palette in the visible region and shows red-shifted BL with a marine luciferase: for example, Renilla luciferase 8 (RLuc8) and Artificial Luciferase 16 (ALuc16) show 187 nm- and 105 nm-redshifted spectra, respectively, by simply replacing the substrate CTZ with 1d. The optical properties of the new CTZ analogues were investigated such as the kinetic parameters, dose dependency, and luciferase specificity. The 2-series CTZ analogues interestingly have specificity to ALucs and are completely dark with RLuc derivatives, and 3d is highly specific to only NanoLuc. We further determined the theoretical background of the red-shifted BL maximum wavelengths (λBL) values according to the extended π conjugation of the CTZ backbone using Density Functional Theory (DFT) calculations. This color-tunable BL imaging system provides a useful multicolor imaging portfolio that efficiently images molecular events in mammalian cells.

scholarly journals Tuning the optoelectronic properties of hematite with rhodium doping for photoelectrochemical water splitting using density functional theory approach

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Abdur Rauf ◽  
Muhammad Adil ◽  
Shabeer Ahmad Mian ◽  
Gul Rahman ◽  
Ejaz Ahmed ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
Optical Absorption ◽  
Water Splitting ◽  
Density Functional ◽  
Formation Energy ◽  
Visible Region ◽  
Photoelectrochemical Water Splitting ◽  
Theory Approach ◽  
Functional Theory

AbstractHematite (Fe2O3) is one of the best candidates for photoelectrochemical water splitting due to its abundance and suitable bandgap. However, its efficiency is mostly impeded due to the intrinsically low conductivity and poor light absorption. In this study, we targeted this intrinsic behavior to investigate the thermodynamic stability, photoconductivity and optical properties of rhodium doped hematite using density functional theory. The calculated formation energy of pristine and rhodium doped hematite was − 4.47 eV and − 5.34 eV respectively, suggesting that the doped material is thermodynamically more stable. The DFT results established that the bandgap of doped hematite narrowed down to the lower edge (1.61 eV) in the visible region which enhanced the optical absorption and photoconductivity of the material. Moreover, doped hematite has the ability to absorb a broad spectrum (250–800) nm. The enhanced optical absorption boosted the photocurrent and incident photon to current efficiency. The calculated results also showed that the incorporation of rhodium in hematite induced a redshift in optical properties.

Theoretical Methods

1992 ◽  
Author(s):  
John A. Tossell ◽  
David J. Vaughan
Keyword(s):  
Density Functional Theory ◽  
Quantum Chemistry ◽  
Density Functional ◽  
Point Group ◽  
Theoretical Background ◽  
Wave Functions ◽  
General Reference ◽  
Functional Theory ◽  
Hartree Fock ◽  
Self Consistent Field

In this chapter, the most important quantum-mechanical methods that can be applied to geological materials are described briefly. The approach used follows that of modern quantum-chemistry textbooks rather than being a historical account of the development of quantum theory and the derivation of the Schrödinger equation from the classical wave equation. The latter approach may serve as a better introduction to the field for those readers with a more limited theoretical background and has recently been well presented in a chapter by McMillan and Hess (1988), which such readers are advised to study initially. Computational aspects of quantum chemistry are also well treated by Hinchliffe (1988). In the section that follows this introduction, the fundamentals of the quantum mechanics of molecules are presented first; that is, the “localized” side of Fig. 1.1 is examined, basing the discussion on that of Levine (1983), a standard quantum-chemistry text. Details of the calculation of molecular wave functions using the standard Hartree-Fock methods are then discussed, drawing upon Schaefer (1972), Szabo and Ostlund (1989), and Hehre et al. (1986), particularly in the discussion of the agreement between calculated versus experimental properties as a function of the size of the expansion basis set. Improvements on the Hartree-Fock wave function using configuration-interaction (CI) or many-body perturbation theory (MBPT), evaluation of properties from Hartree-Fock wave functions, and approximate Hartree-Fock methods are then discussed. The focus then shifts to the “delocalized” side of Fig. 1.1, first discussing Hartree-Fock band-structure studies, that is, calculations in which the full translational symmetry of a solid is exploited rather than the point-group symmetry of a molecule. A good general reference for such studies is Ashcroft and Mermin (1976). Density-functional theory is then discussed, based on a review by von Barth (1986), and including both the multiple-scattering self-consistent-field Xα method (MS-SCF-Xα) and more accurate basis-function-density-functional approaches. We then describe the success of these methods in calculations on molecules and molecular clusters. Advances in density-functional band theory are then considered, with a presentation based on Srivastava and Weaire (1987). A discussion of the purely theoretical modified electron-gas ionic models is followed by discussion of empirical simulation, and we conclude by mentioning a recent approach incorporating density-functional theory and molecular dynamics (Car and Parrinello, 1985).

Tailoring of Bandgap to Tune the Optical Properties of Ga1−xAlxY (Y = As, Sb) for Solar Cell Applications by Density Functional Theory Approach

2019 ◽  
Vol 74 (12) ◽  
pp. 1131-1138
Author(s):  
Q. Mahmood ◽  
Syed Awais Rouf ◽  
Muhammad Rashid ◽  
M. Jamil ◽  
M. Sajjad ◽  
...  
Keyword(s):  
Density Functional ◽  
Visible Region ◽  
Maximum Absorption ◽  
Storage Device ◽  
Theory Approach ◽  
First Principle ◽  
Energy Storage Device ◽  
Functional Theory ◽  
Absorption Of Light ◽  
Optical Applications

AbstractThe bandgap was tuned to investigate the electronic and optical aspects using first-principle calculations for solar cells and other optical applications. The bandgap range varies from 1.6 to 2.1 eV for Ga1−xAlxAs and from 0.8 to 1.5 eV for Ga1−xAlxSb (x = 0.0, 0.25, 0.5, 0.75, 1.0). The dispersion, polarisation, and attenuation have been illustrated in terms of transparency and maximum absorption of light. The inversion of polarised atomic planes near the resonance allows the maximum absorption in ultraviolet to visible region. The Penn’s model (ε1(0) ≈ 1 + (ℏωp/Eg)2) and optical relation ${\varepsilon_{1}}\left(0\right)$ = n2(0) confirm the reliability of our finding. The maximum absorption, optical conduction, and minimum optical energy loss increase the credibility of the studied materials for energy storage device manufacture.

Structures and Absorption Spectrum of 1D and 2D ZnS Nanoparticles

2020 ◽  
Vol 5 (1) ◽  
pp. 26-35
Author(s):  
Spyros Papantzikos ◽  
Alexandos G. Chronis ◽  
Fotios I. Michos ◽  
Mihail M. Sigalas
Keyword(s):  
Absorption Spectra ◽  
Density Functional ◽  
Toxic Elements ◽  
Visible Region ◽  
Visible Spectrum ◽  
Zns Nanoparticles ◽  
Major Drawback ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Optimized Geometries

Background: ZnS nanoparticles (NPs) are attractive for quantum dots applications because they consist of abundant and non-toxic elements. Their major drawback is that they absorb in the UV region, ultimately limiting their applications. Objective: In the present study, 1D and 2D ZnS NPs have been found. The goal of this study is to find NPs that have absorption in the visible spectrum. Methods: Calculations based on the Density Functional Theory (DFT) have been used to find the optimized geometries. Their absorption spectra have been calculated with the Time-Dependent DFT. Results: Several shapes were examined, such as nanorod, and it is observed that these shapes move the absorption spectra in lower energies, into the visible spectrum, while the 3D NPs have absorption edges in the UV region. Conclusion: NPs with the shape of nanorod in different directions showed that their absorption spectra moved to lower energies well inside the visible spectrum with significantly high oscillator strength. In contrast with the mostly used CdSe NPs, the ZnS NPs are made from more abundant and less toxic elements. Therefore, by making them absorb in the visible region, they may find significant applications in solar cells and other photonic applications.

DFT Study of Substituted Effect on Absorption and Emission Spectra of Naphthoquinone Derivatives

2011 ◽  
Vol 233-235 ◽  
pp. 1878-1883 ◽  
Author(s):  
Li Zhi Wang ◽  
Run Zhou Su ◽  
Shuo Qi ◽  
Wei Yu Gong ◽  
Tai Min Cheng
Keyword(s):  
Excited State ◽  
Density Functional ◽  
Visible Region ◽  
Emission Spectra ◽  
Electron Transition ◽  
Functional Theory ◽  
Absorption And Emission ◽  
Absorption And Emission Spectra ◽  
The Density Functional Theory ◽  
Substituted Effect

The density functional theory (DFT) is used to compute the ground-state geometries of naphthoquinone derivatives, and lowest singlet excited-state geometries of them have been investigated by the singles configuration interaction (CIS) method. The absorption and emission spectra are calculated by time-dependent DFT (TDDFT) on the basis of the ground- and excited-state geometries, respectively. Our calculations are in good agreement with the available experimental results. The calculated results show that with the introduction of hydroxyl the red-shift was found in the absorption and emission, and the range of spectra reach the visible region. Furthermore, in the absorptions electron transition type was identified from the point-view of molecular orbitals. Study of the effect of hydroxyl and site on spectra can provide the helpful information on further designing molecular devices.

scholarly journals Excited States Calculations of MoS2@ZnO and WS2@ZnO Two-Dimensional Nanocomposites for Water-Splitting Applications

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 150
Author(s):  
Yin-Pai Lin ◽  
Boris Polyakov ◽  
Edgars Butanovs ◽  
Aleksandr A. Popov ◽  
Maksim Sokolov ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
Water Splitting ◽  
Excited States ◽  
Density Functional ◽  
Visible Region ◽  
Transition Metal Dichalcogenide ◽  
Two Dimensional ◽  
Functional Theory ◽  
Exchange Correlation

Transition metal dichalcogenide (TMD) MoS2 and WS2 monolayers (MLs) deposited atop of crystalline zinc oxide (ZnO) and graphene-like ZnO (g-ZnO) substrates have been investigated by means of density functional theory (DFT) using PBE and GLLBSC exchange-correlation functionals. In this work, the electronic structure and optical properties of studied hybrid nanomaterials are described in view of the influence of ZnO substrates thickness on the MoS2@ZnO and WS2@ZnO two-dimensional (2D) nanocomposites. The thicker ZnO substrate not only triggers the decrease of the imaginary part of dielectric function relatively to more thinner g-ZnO but also results in the less accumulated charge density in the vicinity of the Mo and W atoms at the conduction band minimum. Based on the results of our calculations, we predict that MoS2 and WS2 monolayers placed at g-ZnO substrate yield essential enhancement of the photoabsorption in the visible region of solar spectra and, thus, can be used as a promising catalyst for photo-driven water splitting applications.

The theoretical investigation of the opto-electronic properties of designed molecules having 2-(2-Methylene-3-oxo-indane-1-ylidene)malononitrile as end-capped acceptors

2020 ◽  
Vol 235 (6) ◽  
pp. 785-804
Author(s):  
Amina Tariq ◽  
Hina Ramzan ◽  
Syed Waqas Ahmad ◽  
Ijaz Ahmad Bhatti ◽  
Maryam Ajmal ◽  
...  
Keyword(s):  
Electronic Properties ◽  
Density Functional ◽  
Visible Region ◽  
Potential Surfaces ◽  
Functional Theory ◽  
Photovoltaic Application ◽  
High Ionization ◽  
Donor Acceptor ◽  
Electron Transportation ◽  
Reorganization Energies

Abstract Five acceptor-donor-acceptor molecules having different core units with 2-(2-Methylene-3-oxo-indane-1-ylidene)malononitrile as end capped terminal acceptor unit were designed. The ground state geometries and electronic properties were calculated by using density functional theory (DFT) at MPW1PW91/6-31G(d,p) level of theory. The absorption spectra were computed by using time dependent DFT at MPW1PW91/6-31G(d,p) level of theory. The designed molecules have broad absorption range in visible region. M3 shows relatively lower band gap so that having high light harvesting efficiency (LHE). The molecules consider as better hole blocking materials in term of high ionization potentials. The reorganization energies calculation of M1, M2 and M4 manifests that these molecules are the optimal candidate for electron transportation. High value of Voc has been observed for molecules which would favorably contribute in power conversion efficiency. M1, M2, M4 and M5 are more stable in terms of absolute hardness and electrostatic potential surfaces. All molecules show good opto-electronic properties in the aspect of their use in photovoltaic application.

First-principles study on electronic structure and optical properties of In-doped GaN

2014 ◽  
Vol 13 (08) ◽  
pp. 1450070 ◽  
Author(s):  
Xingxiang Ruan ◽  
Fuchun Zhang ◽  
Weihu Zhang
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
First Principles ◽  
Density Functional ◽  
Visible Region ◽  
Solar Spectrum ◽  
Potential Method ◽  
Functional Theory ◽  
The Density Functional Theory ◽  
Structure Density

The In -doped GaN is investigated by first-principles calculations of plane wave ultra-soft pseudo-potential method based on the density functional theory (DFT). The band structure, electronic structure, density of states and optical properties are investigated. The results indicate that the band-gap becomes narrower and the absorption edge of optical properties is red-shifted with the increase in In -doped concentration. Meanwhile, the visible region has strong absorption properties, and the significant absorption peaks are observed near 3.0 eV and 6.1 eV. The other peaks correspond to the wavelength of absorption spectra from the ultraviolet portion extending to the infrared portion, which almost covers the entire solar spectrum. The studied results show that In -doped GaN can be applied as solar cell and transparent conductivity material.

Computational study of Cu2ZnSn(X1−xTex)4 (X = S, Se) for optoelectronic applications

2016 ◽  
Vol 30 (22) ◽  
pp. 1650137 ◽  
Author(s):  
Naeem Ullah ◽  
G. Murtaza ◽  
M. A. Iqbal ◽  
Asif Mahmood ◽  
R. Khenata
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Computational Study ◽  
Visible Region ◽  
Strong Response ◽  
Functional Theory ◽  
Lattice Constants ◽  
Minimization Procedure ◽  
First Time ◽  
Time Density

The [Formula: see text], [Formula: see text] and [Formula: see text] and their alloys have been frequently investigated experimentally owing to their suitable bandgap for the solar cell applications. For the first time, density functional theory is applied to explore the structural, electronic and optical properties of [Formula: see text] and [Formula: see text] [Formula: see text]. The energy minimization procedure reveals that the Kesterite phase is stable compared to the Stannite structure. Lattice constants of the compounds are in good agreement with the previous experimental results. The alloys have direct bandgaps which decrease by increasing the concentration of Te. The chemical bonding among the cations and anion is dominantly covalent. Electronic bandgap dependent optical properties like absorption coefficient and optical conductivity are studied in detail. The materials show strong response in the visible region of energy spectrum indicating the usefulness of these materials for optoelectronic devices.

scholarly journals Fundamentals of Density Functional Theory: Recent Developments, Challenges and Future Horizons

2021 ◽  
Author(s):  
Muhammad Aamir Iqbal ◽  
Naila Ashraf ◽  
Wajeehah Shahid ◽  
Deeba Afzal ◽  
Faryal Idrees ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Electronic Configuration ◽  
Theoretical Background ◽  
Many Body ◽  
Functional Theory ◽  
New Horizons ◽  
Exchange Correlation ◽  
Recent Developments ◽  
Mechanical Tool

Density Functional Theory (DFT) is a powerful and commonly employed quantum mechanical tool for investigating various aspects of matter. The research in this field ranges from the development of novel analytical approaches focused on the design of precise exchange-correlation functionals to the use of this technique to predict the molecular and electronic configuration of atoms, molecules, complexes, and solids in both gas and solution phases. The history to DFT’s success is the quest for the exchange-correlation functional, which utilizes density to represent advanced many-body phenomena inside one element formalism. If a precise exchange-correlation functional is applied, it may correctly describe the quantum nature of matter. The estimated character of the exchange-correlation functional is the basis for DFT implementation success or failure. Hohenberg-Kohn established that every characteristic of a system in ground state is a unique functional of its density, laying the foundation for DFT, which is being utilized to explore the novelty of materials. This chapter is aimed to present an overview of DFT by explaining the theoretical background, commonly used approximations as well as their recent developments and challenges faced along-with new horizons.

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