Self‐assembled monolayers (SAMs) offer the advantage of facile interfacial modification, leading to significant improvements in device performance. In this study, we report the design and synthesis ...of a new series of carboxylic acid‐functionalized porphyrin derivatives, namely AC‐1, AC‐3, and AC‐5, and present, for the first time, a strategy to exploit the large π‐moiety of porphyrins as a backbone for interfacing the indium tin oxide (ITO) electrode and perovskite active layer in an inverted perovskite solar cell (PSC) configuration. The electron‐rich nature of porphyrins facilitates hole transfer and the formation of SAMs, resulting in a dense surface that minimizes defects. Comprehensive spectroscopic and dynamic studies demonstrate that the double‐anchored AC‐3 and AC‐5 enhance SAMs on ITO, passivate the perovskite layer, and function as conduits to facilitate hole transfer, thus significantly boosting the performance of PSCs. The champion inverted PSC employing AC‐5 SAM achieves an impressive solar efficiency of 23.19 % with a high fill factor of 84.05 %. This work presents a novel molecular engineering strategy for functionalizing SAMs to tune the energy levels, molecular dipoles, packing orientations to achieve stable and efficient solar performance. Importantly, our comprehensive investigation has unraveled the associated mechanisms, offering valuable insights for future advancements in PSCs.
We have developed a series of new self‐assembled monolayers (SAMs) based on ZnII porphyrin for use as hole‐selective layer (HSL) in inverted perovskite solar cells (PSCs). Our study successfully demonstrates the superior performance of dual carboxylic acid functionalized porphyrins can boost the solar efficiency of PSCs. The outstanding performance of these porphyrin SAMs lies in their inherent self‐assembled properties and the presence of dual carboxylic acid groups that facilitate effective anchoring to both the ITO surface and perovskites.
A massive number of biological entities, such as genes and mutations, are mentioned in the biomedical literature. The capturing of the semantic relatedness of biological entities is vital to many ...biological applications, such as protein-protein interaction prediction and literature-based discovery. Concept embeddings-which involve the learning of vector representations of concepts using machine learning models-have been employed to capture the semantics of concepts. To develop concept embeddings, named-entity recognition (NER) tools are first used to identify and normalize concepts from the literature, and then different machine learning models are used to train the embeddings. Despite multiple attempts, existing biomedical concept embeddings generally suffer from suboptimal NER tools, small-scale evaluation, and limited availability. In response, we employed high-performance machine learning-based NER tools for concept recognition and trained our concept embeddings, BioConceptVec, via four different machine learning models on ~30 million PubMed abstracts. BioConceptVec covers over 400,000 biomedical concepts mentioned in the literature and is of the largest among the publicly available biomedical concept embeddings to date. To evaluate the validity and utility of BioConceptVec, we respectively performed two intrinsic evaluations (identifying related concepts based on drug-gene and gene-gene interactions) and two extrinsic evaluations (protein-protein interaction prediction and drug-drug interaction extraction), collectively using over 25 million instances from nine independent datasets (17 million instances from six intrinsic evaluation tasks and 8 million instances from three extrinsic evaluation tasks), which is, by far, the most comprehensive to our best knowledge. The intrinsic evaluation results demonstrate that BioConceptVec consistently has, by a large margin, better performance than existing concept embeddings in identifying similar and related concepts. More importantly, the extrinsic evaluation results demonstrate that using BioConceptVec with advanced deep learning models can significantly improve performance in downstream bioinformatics studies and biomedical text-mining applications. Our BioConceptVec embeddings and benchmarking datasets are publicly available at https://github.com/ncbi-nlp/BioConceptVec.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Marine biofouling is a severe problem with a wide‐reaching impact on ship maintenance, the economy, and ecosystem safety, among others. Inspired by complex multifunctional frogskins, wrinkled ...slippery coatings are created that exhibit remarkable antifouling, anti‐icing, and self‐cleaning properties through a combination of degradable di‐block copolymer self‐assembly i.e., polystyrene‐b‐polylactide (PS‐b‐PLA) and hydrolysis‐driven dynamic release‐induced surface wrinkling. Microwrinkled patterns can generate curved surfaces that are resistant to biofouling. Gyroid‐forming PS‐b‐PLA can be used to produce nanoporous templates with cocontinuous nanochannels, which generate strong capillary forces for trapping and storing infiltrated lubricants. In this study, block‐copolymer‐derived hierarchically wrinkled slippery liquid‐infused nanoporous surfaces (i.e., micro wrinkles with nanochannels infused with slippery fluids) are successfully fabricated after silicone oil infiltration. The antibiofouling performance of these surfaces is examined against different foulers under various conditions. The produced coatings exhibited flexible, stable, transparent, and easily tunable antibiofouling characteristics. In particular, the formation of an eco‐friendly silicon‐based lubricant layer without the use of fluorinated compounds and costly material precursors is an advantage in industrial practice that can be adopted in various applications, such as fuel transport, self‐cleaning windows, anticorrosion protection, nontoxic coatings for medical devices, and optical instruments.
Inspired by complex multifunctional frogskins, wrinkled slippery coatings are created that exhibit remarkable antifouling, anti‐icing, and self‐cleaning properties through a combination of degradable di‐block copolymer self‐assembly (i.e., polystyrene‐b‐polylactide) and hydrolysis‐driven dynamic release‐induced surface wrinkling. The formation of an eco‐friendly silicon‐based lubricant layer with flexible, stable, transparent, and easily tunable antibiofouling characteristics is an advantage in industrial practice.
This study investigated the healing effects of electric current treatment on Ni-rich TiNi shape memory wire after every 100 superelastic cycles. The diameter of the TiNi wire was 0.5 mm. The electric ...current treatment was applied without removing the wire from the tensile machine, aiming for online healing of the shape memory alloy. The electric current treatment showed an obvious healing effect, which restored the superelastic and elastocaloric properties of the functionally degraded TiNi shape memory wire. With treatment conditions of 20.4 A/mm2 and 2 min (the temperature of the wire increased up to 280 °C in 10 s), the elastocaloric temperature rise and drop of the TiNi wire recovered about 14% and 6% after 3–4 treatments, respectively, as compared with the case without any heat treatment. TEM observations indicated that the residual martensite introduced into the TiNi wire during superelastic cycles could be eliminated through the electric current treatment. Experimental results demonstrated that electric current treatment was a promising method to restore the functionality of the TiNi SMA wire after several superelastic cycles without the need to remove the wire from the apparatus, which would thus improve the performance of shape memory alloys during their long-term application.
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•Online electric current treatment heals functional fatigue of shape memory alloy.•Transformation stress increases and residual strain decreases after treatment.•Elastocaloric cooling capacity can be restored after cyclic deformation.•Residual martensite is eliminated by treatment of 20.4 A/mm2 for 2 min.•Online electric current treatment improves performance for long-term application.
A homogenized (TiZrHf)50Ni25Co10Cu15 high entropy shape memory alloy (HESMA) was studied to investigate its transformation behavior and shape memory effect. After solution treatment at 1000 °C, the ...(TiZrHf)50Ni25Co10Cu15 HESMA still contained Ti2Ni-like second phase and (Ti, Zr, Hf) carbide, and thus was not a single solid solution. It exhibited a broad transformation temperature range with Ms = 36.0 °C and Mf = −80.4 °C. In a three-point bending test, the (TiZrHf)50Ni25Co10Cu15 HESMA showed a reversible strain of 4.8% under 650 MPa, which is similar to the performance of Ti50Ni50 alloy but with a much higher output work density.
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Singlet fission (SF) holds great promise for current photovoltaic technologies, where tetracenes, with their relatively high triplet energies, play a major role for application in silicon‐based solar ...cells. However, the SF efficiencies in tetracene dimers are low due to the unfavorable energetics of their singlet and triplet energy levels. In the solid state, tetracene exhibits high yields of triplet formation through SF, raising great interest about the underlying mechanisms. To address this discrepancy, we designed and prepared a novel molecular system based on a hexaphenylbenzene core decorated with 2 to 6 tetracene chromophores. The spatial arrangement of tetracene units, induced by steric hindrance in the central part, dictates through‐space coupling, making it a relevant model for solid‐state chromophore organization. We then revealed a remarkable increase in SF quantum yield with the number of tetracenes, reaching quantitative (196 %) triplet pair formation in hexamer. We observed a short‐lived correlated triplet pair and limited magnetic effects, indicating ineffective triplet dissociation in these through‐space coupled systems. These findings emphasize the crucial role of the number of chromophores involved and the interchromophore arrangement for the SF efficiency. The insights gained from this study will aid designing more efficient and technology‐compatible SF systems for applications in photovoltaics.
A collection of through‐space tetracene oligomers demonstrates sub‐picosecond singlet fission, as revealed by femtosecond‐resolved transient absorption spectroscopy. These oligomers exhibit a remarkably high yield of the triplet pair state, a characteristic seldom observed in tetracene derivatives owing to the unfavorable energetics associated with their singlet and triplet energy levels.
High-harmonic generation driven by femtosecond lasers makes it possible to capture the fastest dynamics in molecules and materials. However, thus far, the shortest isolated attosecond pulses have ...only been produced with linear polarization, which limits the range of physics that can be explored. Here, we demonstrate robust polarization control of isolated extreme-ultraviolet pulses by exploiting non-collinear high-harmonic generation driven by two counter-rotating few-cycle laser beams. The circularly polarized supercontinuum is produced at a central photon energy of 33 eV with a transform limit of 190 as and a predicted linear chirp of 330 as. By adjusting the ellipticity of the two counter-rotating driving pulses simultaneously, we control the polarization state of isolated extreme-ultraviolet pulses—from circular through elliptical to linear polarization—without sacrificing conversion efficiency. Access to the purely circularly polarized supercontinuum, combined with full helicity and ellipticity control, paves the way towards attosecond metrology of circular dichroism.
Highly emissive semiconductor nanocrystals, or so‐called quantum dots (QDs) possess a variety of applications from displays and biology labeling, to quantum communication and modern security. Though ...ensembles of QDs have already shown very high photoluminescent quantum yields (PLQYs) and have been widely utilized in current optoelectronic products, QDs that exhibit high absorption cross‐section, high emission intensity, and, most important, nonblinking behavior at single‐dot level have long been desired and not yet realized at room temperature. In this work, infrared‐emissive MAPbI3‐based halide perovskite QDs is demonstrated. These QDs not only show a ≈100% PLQY at the ensemble level but also, surprisingly, at the single‐dot level, display an extra‐large absorption cross‐section up to 1.80 × 10−12 cm2 and non‐blinking single photon emission with a high single photon purity of 95.3%, a unique property that is extremely rare among all types of quantum emitters operated at room temperature. An in‐depth analysis indicates that neither trion formation nor band‐edge carrier trapping is observed in MAPbI3 QDs, resulting in the suppression of intensity blinking and lifetime blinking. Fluence‐dependent transient absorption measurements reveal that the coexistence of non‐blinking behavior and high single photon purity in these perovskite QDs results from a significant repulsive exciton‐exciton interaction, which suppresses the formation of biexciton, and thus greatly reduces photocharging. The robustness of these QDs is confirmed by their excellent stability under continuous 1 h electron irradiation in high‐resolution transmission electron microscope inspection. It is believed that these results mark an important milestone in realizing nonblinking single photon emission in semiconductor QDs.
MAPbI3 perovskite quantum dots demonstrate remarkable robustness under electron irradiation and photon excitation. They exhibit a high near‐infrared emission quantum yield of up to ≈100% and an unprecedented non‐blinking single photon emission at room temperature. These characteristics promise unique potential in the fields of quantum information and bioimaging.
Generation of octave-spanning spectrum that spans from 570 nm to 1300 nm utilizing 1030 nm 170 fs pulses from a Yb:KGW laser and a two-stage multiple-plate arrangement is demonstrated. 3.21 fs ...sub-single-cycle pulses are obtained after dispersion compensation. The high compression ratio of more than 50 times is achieved for two scenarios with widely different parameters including high input peak power at 1 kHz repetition rate and modest peak power at a high repetition rate of 100 kHz. The output pulses have good spatial mode quality and exhibit long-term stability. The achieved compression ratio and flexibility are unprecedented in ultrafast pulse compression to single-cycle regime. The experiments demonstrate that the technique of multiple-plate pulse compression is versatile and applicable for a wide range of laser pulse parameters.
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