Rational design of long-wavelength absorbing and emitting carbostyrils aided by time-dependent density functional calculations

2015 ◽  
Vol 1055 ◽  
pp. 25-32 ◽  
Author(s):  
Anne-Marie Kelterer ◽  
Georg Uray ◽  
Walter M.F. Fabian
Keyword(s):  
Density Functional Calculations ◽  
Density Functional ◽  
Rational Design ◽  
Time Dependent ◽  
Long Wavelength ◽  
Dependent Density

scholarly journals Plasmon Character Index: An Accurate and Efficient Metric for Identifying and Quantifying Plasmons in Molecules

2021 ◽  
Author(s):  
James Langford ◽  
Xi Xu ◽  
Yang Yang
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Rational Design ◽  
Charge Carriers ◽  
Time Dependent ◽  
Classical Electrodynamics ◽  
Computationally Efficient ◽  
Functional Theory ◽  
Solar Energy Harvesting ◽  
Dependent Density

Plasmons, which are collective and coherent oscillations of charge carriers driven by an external field, play an important role in applications such as solar energy harvesting, sensing, and catalysis. Plasmons can be found in bulk and nanomaterials, and in recent years, plasmons have also been identified in molecules and these molecules have been utilized to build plasmonic devices. As molecular plasmons can no longer be described by classical electrodynamics, a description using quantum mechanics is necessary. Many methods have been developed to identify and quantify molecular plasmons based on the properties of plasmonic excitations. However, there is not currently a method that is widely accepted, connects to collectivity and coherence, and is computationally practical. Here we develop a metric to accurately and efficiently identify and quantify plasmons in molecules. A number, which we call plasmon character index (PCI), can be calculated for each electronic excited state and describes the plasmonicity of the excitation. PCI is developed from the collective and coherent excitation picture in orbitals and shows excellent agreement with the predictions from scaled time-dependent density functional theory but is vastly more computationally efficient. Therefore, PCI can be a useful tool in identifying and quantifying plasmons and will inform the rational design of plasmonic molecules and small nanomaterials.

Introducing Color Centers to Silicon Carbide Nanocrystals for In Vivo Biomarker Applications: A First Principles Study

2013 ◽  
Vol 740-742 ◽  
pp. 641-644
Author(s):  
Bálint Somogyi ◽  
Viktor Zólyomi ◽  
Adam Gali
Keyword(s):  
Silicon Carbide ◽  
First Principles ◽  
Density Functional Calculations ◽  
Density Functional ◽  
Near Infrared ◽  
Living Cells ◽  
Time Dependent ◽  
Color Centers ◽  
Dependent Density

Molecule-sized fluorescent emitters are much sought-after to probe biomolecules in living cells. We demonstrate here by time-dependent density functional calculations that the experimentally achievable 1-2 nm sized silicon carbide nanocrystals can emit light in the nearinfrared region after introducing appropriate color centers in them. These near-infrared luminescent silicon carbide nanocrystals may act as ideal fluorophores for in vivo bioimaging.

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