will propose a doctoral thesis entitled,

Spin by Design: Organic Donor-Acceptor-Donor Diradicaloids as Tunable Spin Materials for Quantum and Electronic Applications

On

Wednesday, May 20th at 1:00 p.m.
MoSE Room 1224

and

 Virtually via MS Teams

https://teams.microsoft.com/meet/236993707059203?p=CRYrqctkRiNTJb2eaV 

Committee
Prof. Jason Azoulay – School of Materials Science & Engineering, Chemistry & Biochemistry (advisor)
Prof. Matthew Sfeir – School of Materials Science & Engineering, Chemistry & Biochemistry
Prof. Juan-Pablo Correa-Baena – School of Materials Science & Engineering, Chemistry & Biochemistry
Prof. Scott Danielsen – School of Materials Science and Engineering

       Prof. Martin Mourigal – School of Physics

Abstract

Organic molecules and polymers with open-shell diradical character (y) contain two weakly paired electron spins that interact across their π-conjugated frameworks. They offer a significant opportunity to engineer spin-active electronic states directly into a p-conjugated backbone, providing novel optoelectronic, spintronic, magnetic, and quantum functionalities. Understanding the underlying molecular structure and solid-state physics of these materials is important for exploiting the spin degree of freedom in emerging spintronic and magneto-electronic devices. However, there is a lack of a unifying description of the electronic structure and its correlation to material properties. In donor-acceptor-donor (DAD) diradicaloids, open-shell character, small singlet-triplet energy gaps (DEST), and tunable spin-spin interactions result in material properties that are highly sensitive to chemical structure, morphology, and packing. The latter motivates my research, which focuses on understanding the structure-spin-property relationships in DAD diradicaloids from isolated molecules to solid-state materials and single-molecule devices. I will use variable-temperature and multi-frequency electron paramagnetic resonance (EPR), pulsed EPR, superconducting quantum interference device (SQUID) magnetometry, and single-molecule transport measurements to connect molecular design with magnetic exchange, spin coherence, and charge/spin-state energetics. First, I will determine how donor/acceptor strength, conjugation length, backbone planarity, side-chain structure, and solid-state packing govern intermolecular exchange and magnetic response. Second, I will evaluate whether thermally accessible triplet states in specified DAD diradicaloids can function as high-operating-temperature molecular spin-qubit candidates by measuring relaxation times, coherent spin manipulation, and identifying decoherence pathways. Third, I will investigate how open-shell electronic structure manifests in single-molecule junctions through charge-state addition spectra and excited-state resonances. By establishing design rules that connect diradicaloid chemistry to magnetism, spin coherence, and device-relevant charge transport, this work will advance DAD diradicaloids as tunable organic materials for future magneto-electronic, spintronic, and quantum technologies.