Form and Function: Understanding and Controlling Processes at the Nanoscale Through Synthesis and Spectroscopy

At the nanoscale, magnetic, optical, electronic, and thermal processes can differ drastically from their bulk counterparts. These deviations stem from reduced crystalline domains, large surface areas, and quantum confinement, leading to physical and chemical properties intricately dependent on size, morphology, and ligand identity as opposed to purely compositional structure. This remarkable tunability, combined with their solution processability, positions colloidal nanocrystals as promising candidates for applications including photovoltaics, catalysis, spintronics, and quantum-based technologies. However, before we can input these materials into devices we need to understand and control the fundamental processes governing their formation and function. 

In this talk I will share three short stories about how shrinking materials to the nanoscale can impact their properties in constructive (and destructive) ways. I’ll begin by covering my most recent work on the synthesis of ferrimagnetic CuCr₂Se₄ nanocrystals and how their nanoscale form enables unique redox and cation exchange chemistry. The second story explores how heat, especially generated through photoexcitation, is dissipated in nanomaterials. I will describe how ligand identity, particle size, and crystal structure influence, and are influenced by, thermal processes. In the last story, I will transition to nanocrystal donor – molecular acceptor complexes, which can undergo spin-polarized electron transfer. The unique electronic structure of the nanocrystal dictates the final spin orientation and the potential for these systems to be used as qubits for quantum computing is probed using time-resolved optical and magnetic resonance spectroscopy.