Rational Design of Organic Molecules with Inverted Gaps between First Excited Singlet and Triplet
Bibliographic record
Abstract
One implication of Hund’s first rule for molecules is that the first excited triplet is for the large majority of molecules more stable than the first excited singlet. Only a handful of structural motifs are known to violate it. Recently, the potential of such molecules for emissive materials has been appreciated as their inverted singlet-triplet gaps enable favorable triplet exciton harvesting and low triplet exciton population to be utilized in both efficient and long-lived organic light-emitting diodes. Herein, we report bottom-up design of small organic molecules with inverted singlet-triplet gaps, i.e., INVEST molecules, via the Ring-Bonds-Substitutions (RiBS) ruleset which we introduce in this work. It relies on a few simple rules based on orbital interactions in alternant hydrocarbons to both minimize the exchange integral between highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) and maximize dynamic spin polarization. Using RiBS, we find many new molecules violating Hund’s first rule in their first excited states thereby greatly expanding the chemical space of potential inverted singlet-triplet gap (INVEST) emitters.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
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 teacher head, 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".