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Not AvailableConventional type I photoinitiators require high-energy ultraviolet (UV) light to generate radicals, whereas most visible-light systems rely on slower, oxygen-sensitive type II photosensitization pathways. We report boron-alkylated boron-dipyrromethenes (BODIPYs) as type I photoinitiators that operate efficiently under green-light-emitting diodes (LEDs) and ambient conditions. Replacing methyl with ethyl at the boron site accelerates photolysis, lowers the B–C bond dissociation energy, and suppresses oxygen sensitization. Consequently, the ethyl derivative doubles the polymerization rate and decreases oxygen inhibition times by over an order of magnitude. Relative to Ivocerin, a leading blue-light type I photoinitiator, the BODIPY system achieves a higher external quantum yield due to stronger absorption. Owing to these performance enhancements, the ethyl derivative enables rapid, ambient, green-light digital light processing (DLP) 3D printing of commercial acrylate resins, achieving 2.5 s exposures per 50 µm layer at 3 mW cm^−2. This oxygen-tolerant platform provides a practical, mild route for photocurable technologies. 

Organic mixed ionic–electronic conductors (OMIECs) are promising materials for bioelectronics, neuromorphic computing, and energy storage due to their dual conductivity. However, the relationship between the film morphology and device performance in the OMIEC-based organic electrochemical transistors (OECTs) remains poorly understood. We investigate the carboxyl-alkyl-functionalized conjugated polymer poly[3-(4-carboxybutyl)thiophene] (P3CBT) and show that the ratio of pyridine (Py) to dimethyl sulfoxide (DMSO) in the precursor solution strongly influences the OECT performance. We find that varying the Py:DMSO ratio significantly alters the electronic mobility (μ), while the volumetric capacitance (C*) remains largely unchanged. Films cast from an 80:20 Py:DMSO mixture yield a μC* product of 110 ± 26 F cm–1 V–1 s–1, a 5-fold enhancement compared to films processed from Py. UV–vis absorption and X-ray scattering measurements reveal that this improvement arises from increased polymer crystallinity and orientational order. These results demonstrate that precursor solvent is a key parameter for optimizing OECT performance. 

Biogenic amines are fundamental for physiological homeostasis and behavioral control in both vertebrates and invertebrates. Monoamine neurotransmitters released in target brain regions conjointly regulate adaptive learning and plasticity. However, our understanding of these multianalyte mechanisms remains nascent, in part due to limitations in measurement technology. Here, during associative conditioning in honey bees, we concurrently tracked subsecond fluctuations in octopamine, tyramine, dopamine, and serotonin in the antennal lobe, where plasticity influences odorant representations. By repeatedly pairing an odorant with subsequent sucrose delivery, we observed individual differences in the conditioned response to odor, which occurred after a variable number of pairings (learners) or not at all (non-learners). The distinction between learners and non-learners was reflected in neurotransmitter responses across experimental conditions. The speed of learning, the number of pairings prior to a proboscis extension reflex, could be predicted from monoamine opponent signaling (octopamine-tyramine), from both the first presentation of the odorant alone, prior to any pairing with sucrose, and the first conditioned response to the odorant, coming after a number of sucrose pairings. These results suggest that monoamine signaling phenotypes may relate directly to the now widely reported socially relevant genetic differences in honey bee learning. 

Abstract Triplet‐triplet annihilation photon upconversion (TTA‐UC) converts low‐energy photons to higher‐energy ones under low‐intensity incoherent excitation, thus enabling applications in fields ranging from medicine to solar energy conversion. Silylethynyl mono‐ and di‐substitution of acenes offers an attractive route to creating new annihilators that operate with minimal energy loss. Here, it is demonstrated that this approach can be extended to pyrene, yielding annihilators that display efficient red‐to‐blue upconversion. While pyrene is the namesake of P‐type delayed fluorescence, the original name for triplet‐triplet annihilation, it is known to be a poor annihilator due to its propensity for forming excimers. By tetra‐substituting pyrene with silylethynyl groups, excimer formation is substantially hindered while simultaneously minimizing the energy gap between the singlet and triplet pair states that participate in TTA‐UC, yielding outstanding annihilators for red‐to‐blue upconversion that operate with quantum yields of upward of 19% (29% when corrected for inner filter effects). Further, it is found that reducing the bulkiness of the silyl substituents is key to achieving high TTA‐UC quantum yields, which highlights the importance of annihilator side group selection when optimizing photon upconversion.