Organic electronic materials for nanoscale systems: from luminescent bottlebrush copolymers to ultrastable fluorophores
Bibliographic record
Abstract
Synthesis of multicomponent nanoscale structures with precisely addressable function is critical to discover new phenomena and new applications in nanotechnology. Though self-assembly offers a route such materials, these methods often require building blocks with particular structural motifs, limiting the scope of nanomaterials that can be prepared. Work described in the thesis uses a bottom-up approach based on covalent chemistry to synthesize a series of bottlebrush copolymers (BBCPs) – polymeric side chains attached covalently to a linear backbone – from organic semiconductors. Methods are also presented for the efficient synthesis of planar thermally activated delayed fluorescence (TADF) materials and stable organic fluorophores, incorporating them into nanoscale systems for biological imaging. A series of acrylic monomers was synthesized based on p-type organic semiconductor motifs found commonly in organic electronic devices. These monomers were polymerized by Cu(0)-reversible deactivation radical polymerization (RDRP), the kinetics of which are described in detail. By combining Cu(0)-RDRP and ring opening metathesis polymerization, narrowly dispersed multiblock bottlebrush fibers were prepared from monotelechelic dye-functionalized acrylate polymers with polymerizable norbornene end-functions (macromonomers). This strategy was used to construct nanofibers with the structure of phosphorescent organic light emitting diodes (OLEDs) on single macromolecules, such that the photophysical properties of each component of an OLED could be independently observed. Red, green, and blue (RGB) luminescent macromonomers were prepared using Cu(0)-RDRP, which were used to prepare multiblock organic nanofibers structurally analogous to nanoscale RGB pixels and multilayer white OLEDs. Changes in energy transfer efficiency and interchromophore distance were quantified using a Förster resonance energy transfer model. Additionally, donor-acceptor dyes were prepared using a novel acceptor based on N-phenylbenzimidazole constrained in a coplanar fashion with a methylene tether (IMAC). Emitters were designed with a twisted conformation between donor and acceptor resulting in effective spatial separation of the highest occupied molecular orbital and lowest unoccupied molecular orbital and small singlet-triplet energy gaps to give TADF. In fluorescent IMAC derivatives, locking these chromophores into planar configurations was demonstrated to improve their cross-section for two-photon excited fluorescence and reduce the rate of photobleaching. Proof-of concept studies incorporating these dyes into water-soluble polymer dots suitable for biological imaging was also demonstrated.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".