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Description
Two-dimensional quantum materials have garnered increasing interest in a wide

variety of applications due to their promising optical and electronic properties. These

quantum materials are highly anticipated to make transformative quantum sensors and

biosensors. Biosensors are currently considered among one of the most promising

solutions to a wide variety of biomedical and environmental problems

Two-dimensional quantum materials have garnered increasing interest in a wide

variety of applications due to their promising optical and electronic properties. These

quantum materials are highly anticipated to make transformative quantum sensors and

biosensors. Biosensors are currently considered among one of the most promising

solutions to a wide variety of biomedical and environmental problems including highly

sensitive and selective detection of difficult pathogens, toxins, and biomolecules.

However, scientists face enormous challenges in achieving these goals with current

technologies. Quantum biosensors can have detection with extraordinary sensitivity and

selectivity through manipulation of their quantum states, offering extraordinary properties

that cannot be attained with traditional materials. These quantum materials are anticipated

to make significant impact in the detection, diagnosis, and treatment of many diseases.

Despite the exciting promise of these cutting-edge technologies, it is largely

unknown what the inherent toxicity and biocompatibility of two-dimensional (2D)

materials are. Studies are greatly needed to lay the foundation for understanding the

interactions between quantum materials and biosystems. This work introduces a new

method to continuously monitor the cell proliferation and toxicity behavior of 2D

materials. The cell viability and toxicity measurements coupled with Live/Dead

fluorescence imaging suggest the biocompatibility of crystalline MoS2 and MoSSe

monolayers and the significantly-reduced cellular growth of defected MoTe2 thin films

and exfoliated MoS2 nanosheets. Results show the exciting potential of incorporating

kinetic cell viability data of 2D materials with other assay tools to further fundamental

understanding of 2D material biocompatibility.
ContributorsTran, Michael, Ph.D (Author) / Tongay, Sefaattin (Thesis advisor) / Green, Matthew (Thesis advisor) / Muhich, Christopher (Committee member) / Arizona State University (Publisher)
Created2019
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Description
Transition metal di- and tri-halides (TMH) have recently gathered research attention owing to their intrinsic magnetism all the way down to their two-dimensional limit. 2D magnets, despite being a crucial component for realizing van der Waals heterostructures and devices with various functionalities, were not experimentally proven until very recently in

Transition metal di- and tri-halides (TMH) have recently gathered research attention owing to their intrinsic magnetism all the way down to their two-dimensional limit. 2D magnets, despite being a crucial component for realizing van der Waals heterostructures and devices with various functionalities, were not experimentally proven until very recently in 2017. The findings opened up enormous possibilities for studying new quantum states of matter that can enable potential to design spintronic, magnetic memory, data storage, sensing, and topological devices. However, practical applications in modern technologies demand materials with various physical and chemical properties such as electronic, optical, structural, catalytic, magnetic etc., which cannot be found within single material systems. Considering that compositional modifications in 2D systems lead to significant changes in properties due to the high anisotropy inherent to their crystallographic structure, this work focuses on alloying of TMH compounds to explore the potentials for tuning their properties. In this thesis, the ternary cation alloys of Co(1-x)Ni(x)Cl(2) and Mo(1-x)Cr(x)Cl(3) were synthesized via chemical vapor transport at a various stoichiometry. Their compositional, structural, and magnetic properties were studied using Energy Dispersive Spectroscopy, Raman Spectroscopy, X-Ray Diffraction, and Vibrating Sample Magnetometry. It was found that completely miscible ternary alloys of Co(1-x)Ni(x)Cl(2) show an increasing Néel temperature with nickel concentration. The Mo(1-x)Cr(x)Cl(3) alloy shows potential magnetic phase changes induced by the incorporation of molybdenum species within the host CrCl3 lattice. Magnetic measurements give insight into potential antiferromagnetic to ferromagnetic transition with molybdenum incorporation, accompanied by a shift in the magnetic easy-axis from parallel to perpendicular. Phase separation was found in the Fe(1-x)Cr(x)Cl(3) ternary alloy indicating that crystallographic structure compatibility plays an essential role in determining the miscibility of two parent compounds. Alloying across two similar (TMH) compounds appears to yield predictable results in properties as in the case of Co(1-x)Ni(x)Cl(2), while more exotic transitions, as in the case of Mo(1-x)Cr(x)Cl(3), can emerge by alloying dissimilar compounds. When dissimilarity reaches a certain limit, as with Fe(1-x)Cr(x)Cl(3), phase separation becomes more favorable. Future studies focusing on magnetic and structural phase transitions will reveal more insight into the effect of alloying in these TMH systems.
ContributorsKolari, Pranvera (Author) / Tongay, Sefaattin (Thesis advisor) / Jiao, Yang (Committee member) / Muhich, Christopher (Committee member) / Arizona State University (Publisher)
Created2020