4:00 PM - 5:00 PM • CH033
“Andrew Olsson – Qualifying Exam”
Andrew Olsson
Graduate StudentBloomington IN
Hosted by Amar Flood
There is increasing demand for materials with superior optical properties. The creation of materials based on organic molecular fluorophores depends on translating properties from solution to solid state. However, molecular aggregation of fluorophores leads to excitonic coupling, energy migration to quenching sites, and unpredictable changes in absorbance and emission. The serendipitous discovery of small-molecule ionic isolation lattices (SMILES) addresses these limits. The decoupling of dyes is based on the design principles of spatial isolation (through-space decoupling) and electronic isolation (energy alignment of electronic window) of dyes assembled in the solids with a cyanostar-anion complex. We investigate two fundemental aspects of SMILES formation: (1) the elementary structural unit of SMILES assemblies, the contact ion pair, and (2) the generality of electronic isolation. We utilize the triangulenium dye ATOTA, which displays distinct absorption features across levels of assembly, to observe the contact ion pair using NMR, optical spectroscopies, and different solvents. We observe formation of the contact ion pair as a 2:1:1 assembly of the 2:1 cyanostar-anion complex with dye. To investigate the generality of electronic isolation, we use the macrocycle tricarbazole triazolophane (tricarb). Tricarb has a comparably sized bandgap to cyanostar but shifted higher in energy, allowing for different dyes to be accessed. We use dyes with ideal and non-ideal alignments to confirm the generality of the electronic window. Building off investigations into basic aspects of SMILES design, we lay a path for extending the SMILES framework to include dyes of any charges (Inverse SMILES). We also envision a plan to explore SMILES advantages in the space of more nuanced emission events (circularly polarized luminescence, triplet-triplet annihilation photon upconversion). The sum of investigations will be matching demand for new optical materials by transferring properties of molecular fluorophores to technologies containing the SMILES platform.