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Physical Sciences and Mathematics Commons

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Western University

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Energy

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Full-Text Articles in Physical Sciences and Mathematics

Band-Gap Tuning In Acceptor-Donor-Acceptor Boron Difluoride Formazanates, Francis L. Buguis, Michael Anghel, Joe B. Gilroy, Jasveer S. Dhindsa Jan 2021

Band-Gap Tuning In Acceptor-Donor-Acceptor Boron Difluoride Formazanates, Francis L. Buguis, Michael Anghel, Joe B. Gilroy, Jasveer S. Dhindsa

Chemistry Publications

π-Conjugated molecules with acceptor-donor-acceptor (A-D-A) electronic structures are an important class of materials due to their tunable optoelectronic properties and applications in, for example, organic light-emitting diodes, nonlinear optical devices, and organic solar cells. The frontier molecular orbital energies, and thus band gaps, of these materials can be tuned by varying the donor and acceptor traits and π-electron counts of the structural components. Herein, we report the synthesis and characterization of a series of A-D-A compounds consisting of BF2 formazanates as electron acceptors bridged by a variety of π-conjugated donors. The results, which are supported by DFT calculations, demonstrate …


Hierarchical Plasmon Resonances In Fractal Structures, Isobel C. Bicket, Edson P. Bellido, Danielle M. Mcrae, Francois Lagugne-Labarthet, Gianluigi A. Botton Apr 2020

Hierarchical Plasmon Resonances In Fractal Structures, Isobel C. Bicket, Edson P. Bellido, Danielle M. Mcrae, Francois Lagugne-Labarthet, Gianluigi A. Botton

Chemistry Publications

An equilateral triangular prism is used as the fundamental building block to con- struct additive Sierpinski fractals, enabling new surface plasmon resonances (SPR) in the first three generations of Sierpinski triangles, as well as topological intermediaries between generations. The modes are characterized using electron energy loss spectroscopy accompanied by eigenmode calculations and optical finite-difference time domain simulations. The complex fractal geometries present a predictable hierarchy of new resonances, each arising from the previous generational building blocks used to construct the fractal. Intermediate structures break the polarization degeneracy of the equilateral fractals while maintaining a rich multiband spectral response. Engineering defects …


Carving Plasmon Modes In Silver Sierpiński Fractals, Isobel C. Bicket, Edson P. Bellido, Danielle M. Mcrae, Francois Lagugne-Labarthet, Gianluigi A. Botton Sep 2019

Carving Plasmon Modes In Silver Sierpiński Fractals, Isobel C. Bicket, Edson P. Bellido, Danielle M. Mcrae, Francois Lagugne-Labarthet, Gianluigi A. Botton

Chemistry Publications

The surface plasmon resonance (SPR) modes of the first three generations of a Sierpiński fractal triangle are investigated using electron energy loss spectroscopy (EELS) complemented with finite difference time domain simulations. The Sierpiński fractal geometry is created in a subtractive manner, by carving triangular apertures into the triangular prism of the previous fractal generation. The ability of the fractal antenna to efficiently utilize space in coupling to long wavelength excitations is confirmed on the single nanostructure level via redshifting of the primary dipole mode as the fractal generation is increased. Through application of the Babinet principle, it is demonstrated that …