Narrow bandgap covalent–organic frameworks with strong optical response in the visible and infrared

2015 ◽  
Vol 3 (10) ◽  
pp. 2244-2254 ◽  
Author(s):  
Li-Ming Yang ◽  
Eric Ganz ◽  
Song Wang ◽  
Xiao-Jun Li ◽  
Thomas Frauenheim
Keyword(s):  
Density Functional ◽  
Near Infrared ◽  
Density Functional Theory Calculations ◽  
Optical Response ◽  
Covalent Organic Frameworks ◽  
Functional Theory ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Narrow Bandgap ◽  
Potential Applications

We propose a new series of covalent–organic frameworks. These materials have narrow band gaps, leading to strong near infrared optical response. Density functional theory calculations are used to explore their properties. These novel infrared active materials may have potential applications in organic light-emitting devices, chemical and biological sensing, hybrid solar cells, or electroluminescence.

scholarly journals CCCCC pentadentate chelates with planar Möbius aromaticity and unique properties

2016 ◽  
Vol 2 (8) ◽  
pp. e1601031 ◽  
Author(s):  
Congqing Zhu ◽  
Caixia Yang ◽  
Yongheng Wang ◽  
Gan Lin ◽  
Yuhui Yang ◽  
...  
Keyword(s):  
Photothermal Therapy ◽  
Density Functional ◽  
Near Infrared ◽  
Chelating Agent ◽  
Density Functional Theory Calculations ◽  
Infrared Region ◽  
Carbon Chain ◽  
Broad Absorption ◽  
Functional Theory ◽  
Potential Applications

The coordinating atoms in polydentate chelates are primarily heteroatoms. We present the first examples of pentadentate chelates with all binding atoms of the chelating agent being carbon atoms, denoted as CCCCC chelates. Having up to five metal-carbon bonds in the equatorial plane has not been previously observed in transition metal chemistry. Density functional theory calculations showed that the planar metallacycle has extended Craig-Möbius aromaticity arising from 12-center–12-electron dπ-pπ π-conjugation. These planar chelates have broad absorption in the ultraviolet-visible–near-infrared region and, thus, notable photothermal performance upon irradiation by an 808-nm laser, indicating that these chelates have potential applications in photothermal therapy. The combination of facile synthesis, high stability, and broad absorption of these complexes could make the polydentate carbon chain a novel building block in coordination chemistry.

D–A–D-type narrow-bandgap small-molecule photovoltaic donors: pre-synthesis virtual screening using density functional theory

2016 ◽  
Vol 18 (22) ◽  
pp. 15054-15059 ◽  
Author(s):  
Yeongrok Gim ◽  
Daekyeom Kim ◽  
Minkyu Kyeong ◽  
Seunghwan Byun ◽  
Yuri Park ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Virtual Screening ◽  
Small Molecule ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Time Dependent ◽  
Functional Theory ◽  
Narrow Bandgap ◽  
Dependent Density

A new series of D–A–D-type small-molecule photovoltaic donors are designed and screened before synthesis using time-dependent density functional theory calculations.

scholarly journals Zn Doping Induced Band Gap Widening of Ag2O Nanoparticles

2019 ◽  
Author(s):  
Arup Kumar De ◽  
Sourav Majumdar ◽  
Shaili Pal ◽  
Sunil Kumar ◽  
Indrajit Sinha
Keyword(s):  
Metal Ion ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Mole Percent ◽  
Functional Theory ◽  
Ion Density ◽  
Calculated Density ◽  
Zn Doping ◽  
Narrow Bandgap ◽  
Ag2o Nanoparticles

<p></p><p>Semiconductor bandgap widening is a little investigated phenomenon in photocatalysis literature. The present investigation attempts the widening of the narrow bandgap of Ag<sub>2</sub>O to make it a semiconductor with more attractive properties. The synthesis of Zn doped Ag<sub>2</sub>O nanostructures followed a typical hydrothermal synthesis procedure. An increase in the lattice parameters of Ag<sub>2</sub>O with doping indicated the occupation of an interstitial position by the dopant metal ion. Density functional theory calculations also demonstrated the expansion of the Ag<sub>2</sub>O crystal lattice with the dopant at an interstitial location. The bandgap of the Ag<sub>2</sub>O increased to 1.65 eV for 5-mole percent doping. The DFT calculated density of states (DOS) plots also exhibit an increase in the bandgap of Ag<sub>2</sub>O after Zn doping. These doped Ag<sub>2</sub>O nanoparticles were useful in photocatalysis of methyl orange degradation under visible light irradiation.</p><p></p>

Shapes matter: examining the optical response evolution in stretched aluminium nanoparticles via time-dependent density functional theory

2018 ◽  
Vol 20 (1) ◽  
pp. 51-55 ◽  
Author(s):  
Junais Habeeb Mokkath
Keyword(s):  
Density Functional Theory ◽  
First Principles ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Optical Response ◽  
Shape Anisotropy ◽  
Time Dependent ◽  
Functional Theory ◽  
Stretching Process ◽  
Dependent Density

Using first-principles time-dependent density functional theory calculations, we investigate the shape-anisotropy effects on the optical response of a spherical aluminium nanoparticle subjected to a stretching process in different directions.

scholarly journals NaBiS2 as a Novel Indirect Bandgap Full Spectrum Photocatalyst: Synthesis and Application

Catalysts ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 413 ◽  
Author(s):  
Huanchun Wang ◽  
Zheng Xie ◽  
Xuanjun Wang ◽  
Ying Jia
Keyword(s):  
Density Functional ◽  
Near Infrared ◽  
Dft Method ◽  
Full Spectrum ◽  
Functional Theory ◽  
Nir Light ◽  
The Density Functional Theory ◽  
Narrow Bandgap ◽  
Excellent Photocatalytic Activity ◽  
First Time

Photocatalysts with a superior activity range, from ultraviolet (UV) to near-infrared (NIR) light, are attractive for solar utilization. From this perspective, sulfides are promising due to their narrower bandgap than oxides. In this report, NaBiS2 was synthesized hydrothermally under mild conditions by adjusting the alkaline amount. The rough NaBiS2 nanosheets possessed various surface atomic configurations on their surfaces, including amorphous clusters and amorphous nano-domains, revealed by HRTEM. A theoretical investigation of the band structure employing the density functional theory (DFT) method for the first time indicated that NaBiS2 is an indirect bandgap semiconductor with a narrow bandgap of 1.02 eV. Experimentally, it showed excellent photocatalytic activity for the degradation of methyl blue under UV, visible light and NIR light due to its experimental bandgap width of 1.32 eV. A degradation rate of 99.6% was reached after 80 min under full spectrum irradiation.

scholarly journals Unravelling an oxygen-mediated reductive quenching pathway for photopolymerisation under long wavelengths

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Chenyu Wu ◽  
Kenward Jung ◽  
Yongtao Ma ◽  
Wenjian Liu ◽  
Cyrille Boyer
Keyword(s):  
Density Functional ◽  
Near Infrared ◽  
Chain Transfer ◽  
Experimental Studies ◽  
Density Functional Theory Calculations ◽  
Ambient Air ◽  
Functional Theory ◽  
Reversible Addition ◽  
Reversible Deactivation ◽  
Limited Scope

AbstractPhotomediated-reversible-deactivation radical polymerisation (photo-RDRP) has a limited scope of available photocatalysts (PCs) due to multiple stringent requirements for PC properties, limiting options for performing efficient polymerisations under long wavelengths. Here we report an oxygen-mediated reductive quenching pathway (O-RQP) for photoinduced electron transfer reversible addition-fragmentation chain transfer (PET-RAFT) polymerisation. The highly efficient polymerisations that are performed in the presence of ambient air enable an expanded scope of available PCs covering a much-broadened absorption spectrum, where the oxygen tolerance of PET-RAFT allows high-quality polymerisation by preventing the existence of O2 in large amounts and efficient O-RQP is permitted due to its requirement for only catalytic amounts of O2. Initially, four different porphyrin dyes are investigated for their ability to catalyse PET-RAFT polymerisation via an oxidative quenching pathway (OQP), reductive quenching pathway (RQP) and O-RQP. Thermodynamic studies with the aid of (time-dependent) density functional theory calculations in combination with experimental studies, enable the identification of the thermodynamic constraints within the OQP, RQP and O-RQP frameworks. This knowledge enables the identification of four phthalocyanine photocatalysts, that were previously thought to be inert for PET-RAFT, to be successfully used for photopolymerisations via O-RQP. Well-controlled polymerisations displaying excellent livingness are performed at wavelengths in the red to near-infrared regions. The existence of this third pathway O-RQP provides an attractive pathway to further expand the scope of photocatalysts compatible with the PET-RAFT process and facile access to photopolymerisations under long wavelengths.

A New Bis-Cyclometalated Iridium (III) Complex as a Triplet Emitter in Organic Light Emitting Devices

2005 ◽  
Vol 871 ◽  
Author(s):  
Rupasree R Das ◽  
Ohyun Kwon ◽  
Younghun Byun ◽  
Yi-Yeol Lyu ◽  
Myeong Suk Kim ◽  
...  
Keyword(s):  
Density Functional ◽  
Blue Color ◽  
Functional Theory ◽  
Maximum Brightness ◽  
Ancillary Ligands ◽  
Light Emitting ◽  
Light Emitting Devices ◽  
Ligand Charge Transfer ◽  
Center Density ◽  
D Orbitals

AbstractWe report a new Iridium(III) complex and the study of its optical, electrochemical and electroluminescence properties. The crystal structure shows an octahedral environment around Ir(III) center. Density functional theory (DFT) calculations indicate the contribution of the d-orbitals of Ir and the π-orbitals of the cyclometalating and ancillary ligands toward HOMO, whereas LUMO is concentrated on only the cyclometalating ligand. These complexes emit in the sky blue color region from an admixture of triplet metal-to-ligand-charge-transfer (3MLCT) and ligand π-π* states. A maximum external (ηex) quantumefficiency and luminance efficiency of 2.4% and 5.5 cd/A at 0.12 mA/cm2 was obtained from the device consisting of a 5% doped polymeric and low molecular host. A maximum brightness of 10,200 cd/m2 at 14.8 V was obtained from the device.

Sign in / Sign up

Export Citation Format

Share Document