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With the highly integrated development of photonic technology, conventional annealing methods can no longer meet the demand for the selective and controlled optimization of nanomaterials due to their low spatial resolution and inability to achieve real-time in situ non-destructive monitoring of the crystal structure and local temperature. Here, a thermo-plasmonic assisted rapid in situ heat treatment scheme for micro/nanocrystals is established using Eu3+ ions as sensitive spectroscopic probes of the local structure, the specific crystal transformation rate as local temperature sensors, and Au nanoparticles as effective light absorbers and photothermal converters. The results have demonstrated that thermo-plasmonics can not only assist in the precise control of ion doping in nanostructures but also modulate nanomaterials from polycrystalline to single crystalline and reverse disruption to amorphous. The plasmonic thermal effect is effectively modulated by the irradiation beam, composite plasmonic structure, and ambient temperature, and the role of thermo-plasmonics in the structural manipulation and elemental distribution regulation of micro/nanocrystals is explored. The thermo-plasmonic assisted rapid in situ heat treatment scheme has great potential for precise manipulation in the micro/nano-region, materials preparation, and crystallinity optimization, facilitating the locally controlled repair of micro/nanomaterials and promoting the construction of novel optoelectronic integrated systems. [ABSTRACT FROM AUTHOR]

In this study, a capillary device based on the surface plasmon-enhanced Raman scattering effect was prepared by a simple and easy method. First, the capillary was treated with APTES solution. Due to the electrostatic effect, gold nanoparticles could be easily and tightly assembled in the capillary inner wall. On this basis, the effects of changing the concentration of APTES, the concentration of colloids and the soaking time of the capillary in the colloids on the assembly of gold nanoparticles on the inner wall of the capillary were studied, and the SERS enhancement effect under different conditions was analyzed, and the optimal solution was successfully found. At the same time, the reason why the capillary substrate shows better SERS performance than the traditional planar substrate is deeply discussed. Since the nanoparticles can be attached to the upper and lower surfaces of the inner wall of the capillary, the utilization rate of nanoparticles and laser is improved, thereby achieving higher enhancement. For the detection of the probe molecule rhodamine 6G, it was proved that the substrate has good uniformity and the lowest detection limit can reach 10−10 M. Finally, the real-life pesticide thiram and the food additive aspartame were tested, and the detection limits could reach 10−6 M and 0.25 g L−1. It is confirmed that the prepared capillary shows excellent SERS performance and can be used for rapid detection in various fields. [ABSTRACT FROM AUTHOR]

Induced circular dichroism (ICD) is widely used in miniature polarizers, molecular detection, and negative refractive index media. However, enhancing and the dynamic regulation of ICD signals of achiral nanostructures in the visible and near-infrared range remain the current challenges. Here, monolayer borophene (MB) with anisotropic conductance was incorporated into achiral nanostructures, which consisted of achiral dielectric elliptical hole arrays (DENAs) placed on a silver substrate. Two narrowband ICD signals for DENAs/MB were achieved in the near-infrared range under different circularly polarized lights. The distributions of the magnetic field of DENAs/MB could explain the two narrowband ICD signals originating from the coupling of surface plasmon polariton resonances along the x- and y directions. Not only could the ICD signals be tuned by the structural parameters of DENAs/MB, but they could also be actively tuned by the incident angles of the excitation light and the carrier concentration of MB. In addition, the sensitivity and the figure of merit of DENAs/MB could reach 302/RIU and 61.0. These results provide a concise method for the design of dynamically adjustable chiral devices based on borophene and promote its application in molecular recognition and chiral catalysis. [ABSTRACT FROM AUTHOR]

While state-of-art models can predict reactions through the transfer learning of thousands of samples with the same reaction types as those of the reactions to predict, how to prepare such models to predict "unseen" reactions remains an unanswered question. We aimed to study the Transformer model's ability to predict "unseen" reactions through "zero-shot reaction prediction (ZSRP)", a concept derived from zero-shot learning and zero-shot translation. We reproduced the human invention of the Chan–Lam coupling reaction where the inventor was inspired by the Suzuki reaction when improving Barton's bismuth arylation reaction. After being fine-tuned with samples from these two "existing" reactions, the USPTO-trained Transformer could predict "unseen" Chan–Lam coupling reactions with 55.7% top-1 accuracy. Our model could also mimic the later stage of the history of this reaction, where the initial case of this reaction was generalized to more reactants and reagents via "one-shot/few-shot reaction prediction (OSRP/FSRP)" approaches. [ABSTRACT FROM AUTHOR]

We describe a graph-convolutional neural network (GCN) model, the reaction prediction capabilities of which are as potent as those of the transformer model based on sufficient data, and we adopt the Baeyer–Villiger oxidation reaction to explore their performance differences based on limited data. The top-1 accuracy of the GCN model (90.4%) is higher than that of the transformer model (58.4%). [ABSTRACT FROM AUTHOR]

A proof-of-concept methodology for addressing small amounts of chemical data using transfer learning is presented. We demonstrate this by applying transfer learning combined with the transformer model to small-dataset Heck reaction prediction. Introducing transfer learning significantly improved the accuracy of the transformer-transfer learning model (94.9%) over that of the transformer-baseline model (66.3%). [ABSTRACT FROM AUTHOR]

An efficient and fast transformation scheme for the matrix crystal of rare-earth doped luminescent micro-nanomaterials is developed by using plasmonic gold/silver nanoislands. The transformation is realized through an oxidation reaction from a polycrystalline sub-microcrystal to a single crystal, accompanied by the optimization of the crystal structure and a significant increase in luminescence. The crystal transformation can be achieved in tens of milliseconds, and the rate is controlled not only by the laser illumination power and wavelength, but also by the size and nanogap of nanoislands. Particularly, single crystal transformation is also achieved even at very low temperature, which provides a new way to obtain single crystal materials in a harsh environment. Moreover, the crystal transformation efficiency of the gold plasmonic islands is very stable in air over at least three months. This plasmon driven crystal transformation rapidly provides highly crystalline nanomaterials, which breaks the dependence of high temperature, long period and high energy consumption in the traditional annealing treatment. [ABSTRACT FROM AUTHOR]

Upconversion luminescence-based waveguides can achieve optical signal transmission and visible light emission with near-infrared light excitation and their quality is highly dependent on the coupling efficiency between the light and waveguide. Here, a new luminescent waveguide formed by a rare-earth doped microtube with beveled ends was designed to increase the optical coupling efficiency for vertical waveguide-excitation. The beveled end enabled the near-infrared light to effectively couple into the waveguide and produce a visible transmission pattern and directional emission, which was not possible using conventional luminescent waveguides without beveled ends. It was found that the beveled end can not only improve the input and the output signal efficiency, but also control the coupling efficiency and transmission pattern. In particular, a coupling efficiency of ∼68% could be obtained with the optimized beveled waveguide with a rotation angle of 30°. The high optical coupling efficiency and multi-channel luminescent waveguide enabled by the microtube with beveled ends allowed for a deeper understanding of vertical waveguide excitation, and it extends the potential applications of luminescent waveguides for bioimaging and optical communication. [ABSTRACT FROM AUTHOR]

Highly dispersed YF3:Eu3+ architectures with different morphologies are obtained via a low temperature solid-state reaction process by tuning the fluoride source. With increase of the calcination temperature from 400 °C to 1000 °C, the products undergo an obvious matrix transformation from yttrium fluoride to yttrium oxide fluoride, and then to yttrium oxide. The local symmetry of the optically active Eu3+ ions decreases with increase of the calcination temperature at the lower calcination temperature region, and then keeps almost unchanged when the temperature is over 700 °C. Different luminescence properties of the as-prepared YF3:Eu3+ architectures and the products calcinated at different calcination temperatures are observed even for the samples with the same contents. The study may have special significance on the large-scale fabrication of other lanthanide fluoride luminescent materials. [ABSTRACT FROM AUTHOR]