Regional Functionalization Molecular Design Strategy: A Key to Enhancing the Efficiency of Multi-Resonance OLEDs.

Herein, we propose a regional functionalization molecular design strategy that enables independent control of distinct pivotal parameters through distinct segments of the molecule. Three novel blue emitters A-BN, DA-BN, and A-DBN, have been successfully synthesized by integrating highly rigid and three-dimensional adamantane-containing spirofluorene units into the MR framework. These molecules form two distinctive functional parts: part 1 comprises a boron-nitrogen (BN)-MR framework with adjacent benzene and fluorene units forming a central luminescent core characterized by an exceptionally rigid planar geometry, allowing for narrow FWHM values; part 2 includes peripheral mesitylene, benzene, and adamantyl groups, creating a unique three-dimensional "umbrella-like" conformation to mitigate intermolecular interactions and suppress exciton annihilation. The resulting A-BN, DA-BN, and A-DBN exhibit remarkably narrow FWHM values ranging from 18 to 14 nm and near-unity photoluminescence quantum yields. Particularly, OLEDs based on DA-BN and A-DBN demonstrate outstanding efficiencies of 35.0% and 34.3%, with FWHM values as low as 22 nm and 25 nm, respectively, effectively accomplishing the integration of high color purity and high device performance.

Triple Plexcitonic Nonreciprocity of Magnetochiral Plexcitons.

Nonreciprocal quantum devices, allowing different transmission efficiencies of light-matter polaritons along opposite directions, are key technologies for modern photonics, yet their miniaturization and fine manipulation remain an open challenge. Here, we report on magnetochiral plexcitons dressed with geometric-time double asymmetry in compact nonreciprocal hybrid metamaterials, leading to triple plexcitonic nonreciprocity with flexible controllability. A general magnetically dressed plexcitonic Born-Kuhn model is developed to reveal the hybrid optical nature and dynamic energy evolution of magnetochiral plexcitons, demonstrating a plexcitonic nonreciprocal mechanism originating from the strong coupling among photon, electron, and spin degrees of freedom. Moreover, we introduce the temperature-controlled knob/switch for magnetochiral plexcitons, achieving precise magnetochiral control and nonreciprocal transmission in a given system. We expect this mechanism and approach to open up a new route for the integration and fine control of on-chip nonreciprocal quantum devices.

Quantitative evaluation of soil water balance under a ridge-furrow rainwater harvesting system in Chinese rainfed agroecosystem.

BACKGROUND: The ridge-furrow rainwater harvesting system (RFRH) is an advanced farmland management technology that plays a vital role in making full use of rainwater resources. However, it is not clear that RFRH affects crop yield and water use efficiency (WUE) by regulating soil water storage (SWS). Therefore, the present study conducted a meta-analysis to make a large compilation of previous studies and indirectly quantify the impact of RFRH on crop yield and WUE by analysing the effect of RFRH on SWS. RESULTS: The results showed that RFRH improved crop yield and WUE by 26.71% and 25.86%, respectively, by increasing SWS by 3.93% compared to the traditional flat cultivation. RFRH had a significant effect on increasing crop yield and WUE and improving SWS. A low ridge-furrow ratio and ridge-furrow mulching were recommended to obtain positive effects on crop yield and WUE when potatoes are grown in areas with high precipitation (600-800 mm). Furthermore, when nitrogen fertilization is applied during the crop growth period, we also found that a medium nitrogen fertilizer rate is recommended to achieve a significant positive effect on crop yield and WUE. Importantly, a win-win analysis showed the proportions of various groups in the target zone (zone I) to determine the appropriate strategy for RFRH of crops. CONCLUSION: The present study provides a scientific reference for the future application of the RFRH. The study provides scientific recommendations on crop types, ridge-furrow configurations, plastic mulching patterns and nitrogen fertilizer rate for future RFRH applications. © 2024 Society of Chemical Industry.

Design of an ultrafast plasmonic nanolaser for high-intensity broadband emission operating at room temperature.

We propose a plasmonic nanolaser based on a metal-insulator-semiconductor-insulator-metal (MISIM) structure, which effectively confines light on a subwavelength scale (∼λ/14). As the pump power increases, the proposed plasmonic nanolaser exhibits broadband output characteristics of 20 nm, and the maximum output power can reach 20 µW. Furthermore, the carrier lifetime at the upper energy level in our proposed structure is measured to be about 400 fs using a double pump-probe excitation. The ultrafast characteristic is attributed to the inherent Purcell effect of plasmonic systems. Our work paves the way toward deep-subwavelength mode confinement and ultrafast femtosecond plasmonic lasers in spaser-based interconnected, eigenmode engineering of plasmonic nanolasers, nano-LEDs, and spontaneous emission control.

Optimizing the energy level alignment for achieving record-breaking efficiency in hot exciton deep red OLEDs.

To effectively compete with the quenching process in long-wavelength regions like deep red (DR) and near-infrared (NIR), rapid radiative decay is urgently needed to address the challenges posed by the "energy gap law". Herein, we confirmed that it is crucial for hot exciton emitters to attain a narrow energy gap (ΔES1-T2) between the lowest singlet excited (S1) state and second triplet excited (T2) state, while ensuring that T2 slightly exceeds S1 in the energy level. Two proofs-of-concept of hot exciton DR emitters, namely αT-IPD and ßT-IPD, were successfully designed and synthesized by coupling electron-acceptors N,N-diphenylnaphthalen-2-amine (αTPA) and N,N-diphenylnaphthalen-1-amine (ßTPA) with an electron-withdrawing unit 5-(4-(tert-butyl) phenyl)-5H-pyrazino[2,3-b]indole-2,3-dicarbonitrile (IPD). Both emitters exhibited a narrow ΔES1-T2, with T2 being slightly higher than S1. Additionally, both emitters showed significantly large ΔET2-T1. Moreover, due to their aggregation-induced emission characteristics, J-aggregated packing modes, moderate strength intermolecular CN⋯H-C and C-H⋯π interactions, and unique, comparatively large center-to-center distances among trimers in the crystalline state, both αT-IPD and ßT-IPD emitters exhibited remarkable photoluminescence quantum yields of 68.5% and 73.5%, respectively, in non-doped films. Remarkably, the corresponding non-doped DR-OLED based on ßT-IPD achieved a maximum external quantum efficiency of 15.5% at an emission peak wavelength of 667 nm, representing the highest reported value for hot exciton DR-OLEDs.

The macrophage polarization in allergic responses induced by tropomyosin of Macrobrachium nipponense in cell and murine models.

Macrophages are one of the important immune cells, which play important roles in innate and adaptive immune. However, the roles of macrophages in food allergy are not thoroughly understood. To investigate the roles of macrophages during food allergy, we focused on the relationship between macrophage polarization and allergic responses induced by tropomyosin (TM) in the present study. Arg 1 and CD206 expressions in the TM group were significantly higher than those of the PBS group, while iNOS and TNF-α expressions were no obvious difference, moreover, the morphology of macrophages stimulated by TM was similar to that of M2 macrophages. These results indicated macrophages were mainly polarized toward M2 phenotypes in vitro. The antibodies, mMCP-1, histamine and cytokines, revealed that macrophages could participate in food allergy, and macrophage polarization was associated with changes in allergic-related factors. The cytokine levels of M2 phenotypes were significantly higher than those of M1 phenotypes in peripheral blood. The mRNA expressions and protein levels of Arg1 and iNOS in the jejunum and peritoneal cells indicated that M2 phenotypes were the major macrophage in these tissues compared with M1 phenotypes. Hence, macrophage polarization plays an important role in food allergy.

Effects of Curing Conditions on Splitting Tensile Behavior and Microstructure of Cemented Aeolian Sand Reinforced with Polypropylene Fiber.

Aeolian sand is widely distributed in the Takramagan Desert, Xinjiang, China, which cannot be directly used as railway subgrade filling. It is beneficial for environmental protection to use fiber and cement-reinforced aeolian sand as railway subgrade filling. The present work is to explore the enhancement of tensile strength in cemented aeolian sand via the incorporation of polypropylene fibers under conditions of elevated temperature and drying curing. The purpose Is to delve into the examination of the temperature's impact on not only the mechanical attributes but also the microstructure of cemented aeolian sand reinforced with polypropylene fiber (CSRPF). For this, a comprehensive set of tests encompassing splitting tensile strength (STS) assessments and nuclear magnetic resonance (NMR) examinations is conducted. A total of 252 CSRPF specimens with varying fiber content (0, 6‱, 8‱, and 10‱) are tested at different curing temperatures (30 °C, 40 °C, 50 °C, 60 °C, 70 °C, and 80 °C). The outcomes of the NMR examinations indicate that elevating the curing temperature induces the expansion of pores within CSRPF, both in size and volume, consequently contributing to heightened internal structural deterioration. STS tests demonstrate that the STS of CSRPF decreases as the curing temperature increases. Meanwhile, the STS of CSRPF increases with fiber content, with optimal fiber content being 8‱. Regression models accurately predict the STS, with the curing temperature exhibiting the greatest influence, followed by the fiber content according to sensitivity analysis. The research results provide a valuable reference for the use of CSRPF as railway subgrade filling under high temperature and drying conditions.

Energy-Efficient Data Transmission for Underwater Wireless Sensor Networks: A Novel Hierarchical Underwater Wireless Sensor Transmission Framework.

The complexity of the underwater environment enables significant energy consumption of sensor nodes for communication with base stations in underwater wireless sensor networks (UWSNs), and the energy consumption of nodes in different water depths is unbalanced. How to improve the energy efficiency of sensor nodes and meanwhile balance the energy consumption of nodes in different water depths in UWSNs are thus urgent concerns. Therefore, in this paper, we first propose a novel hierarchical underwater wireless sensor transmission (HUWST) framework. We then propose a game-based, energy-efficient underwater communication mechanism in the presented HUWST. It improves the energy efficiency of the underwater sensors personalized according to the various water depth layers of sensor locations. In particular, we integrate the economic game theory in our mechanism to trade off variations in communication energy consumption due to sensors in different water depth layers. Mathematically, the optimal mechanism is formulated as a complex nonlinear integer programming (NIP) problem. A new energy-efficient distributed data transmission mode decision algorithm (E-DDTMD) based on the alternating direction method of multipliers (ADMM) is thus further proposed to tackle this sophisticated NIP problem. The systematic simulation results demonstrate the effectiveness of our mechanism in improving the energy efficiency of UWSNs. Moreover, our presented E-DDTMD algorithm achieves significantly superior performance to the baseline schemes.

Pioneering research on blue "hot exciton" polymers and their application in solution-processed organic light-emitting diodes.

An innovative novel category of polymeric hybridized local and charge-transfer (HLCT) blue materials prepared via solution processing has yet to be reported. This study introduces three polymers, namely PZ1, PZ2, and PZ3, incorporating donor-acceptor-donor (D-A-D) structures with carbazole functioning as the donor and benzophenone as the acceptor. To regulate the luminescence mechanism and conjugation length, carbonyl and alkyl chains are strategically inserted into the backbone. Theoretical calculation and transient absorption spectroscopy illustrate that the robust spin-orbit coupling between high-lying singlet excited states (Sm: m ⩽ 4) and triplet excited states (Tn: n ⩽ 7) of the polymers hastens and significantly heightens the efficiency of reverse intersystem crossing processes from Tn states. Furthermore, the existence of multiple degenerated frontier molecular orbits and significant overlaps between Tn and Sm states give rise to added radiative pathways that boost the radiative rate. This study marks a fundamental and initial manifestation of HLCT materials within the polymer field and provides a new avenue for the design of highly efficient polymeric emitters.

Hot-Exciton Mechanism and AIE Effect Boost the Performance of Deep-Red Emitters in Non-Doped OLEDs.

Luminescent materials possessing a "hot-exciton" mechanism and aggregation-induced emission (AIE) qualities are well-suited for use as emitting materials in nondoped organic light-emitting diodes (OLEDs), particularly in deep-red regions where their ground state and singlet excited state surfaces are in proximity, leading to the formation of multiple nonradiative channels. However, designing molecules that artificially combine the hot-exciton mechanism and AIE attributes remains a formidable task. In this study, a versatile strategy is presented to achieve hot-exciton fluorescence with AIE property by increasing the first singlet excited (S1 ) state through modulation of the conjugation length of the newly created acceptor unit, matching the energy level of high-lying triplet (Tn ) states, and enhancing exciton utilization efficiency by employing suitable donor moieties. This approach reduces the aggregation-caused quenching (ACQ) in the aggregate state, resulting in the proof-of-concept emitter DT-IPD, which produces an unprecedented external quantum efficiency (EQE) of 12.2% and Commission Internationale de I'Eclairage (CIE) coordinates of (0.69, 0.30) in a deep-red non-doped OLED at 685 nm, representing the highest performance among all deep-red OLEDs based on materials with hot-exciton mechanisms. This work provides novel insights into the design of more efficient hot-exciton emitters with AIE properties.

Reduction of pathogenic bacteria from irrigation water through a copper-loaded porous ceramic emitter.

The increasing pathogenic bacteria threat in irrigation water has become a worldwide concern, prompting efforts to discover a new cost-effective method for pathogenic bacteria eradication, different than those currently in use. In this study, a novel copper-loaded porous ceramic emitter (CPCE) was developed via molded sintering method to kill bacteria from irrigation water. The material performance and hydraulic properties of CPCE are discussed herein, and the antibacterial effect against Escherichia coli (E. coli) and Staphylococcusaureus (S. aureus) was evaluated. The incremental copper content in CPCE improved flexural strength and pore size, which was conducive to enhancing CPCE discharge. Moreover, antibacterial tests showed that CPCE displayed efficient antimicrobial activity, killing 99.99% and more than 70% of S. aureus and E. coli, respectively. The results reveal that CPCE, with both irrigation and sterilization functions, can provide a low-cost and effective solution for bacterial removal from irrigation water.

A New Regularization for Deep Learning-Based Segmentation of Images with Fine Structures and Low Contrast.

Deep learning methods have achieved outstanding results in many image processing and computer vision tasks, such as image segmentation. However, they usually do not consider spatial dependencies among pixels/voxels in the image. To obtain better results, some methods have been proposed to apply classic spatial regularization, such as total variation, into deep learning models. However, for some challenging images, especially those with fine structures and low contrast, classical regularizations are not suitable. We derived a new regularization to improve the connectivity of segmentation results and make it applicable to deep learning. Our experimental results show that for both deep learning methods and unsupervised methods, the proposed method can improve performance by increasing connectivity and dealing with low contrast and, therefore, enhance segmentation results.

Switchable polarization manipulation at the telecom wavelength based on L-shaped hybrid Au-VO2 nanoholes.

We propose to achieve switchable polarization manipulation at the telecom wavelength at nanoscale based on L-shaped plasmonic nanoholes in an Au-VO2 film. The L-shaped nanohole acts as a quarter-wave plate or a half-wave plate owing to the phase differences between different plasmon resonant modes, which is controlled by the insulator or metallic phases of VO2. In addition, by changing the structure and removing the bottom Au layer, a switchable full-/quarter-wave plate can be achieved when VO2 transits from the insulating state to the metallic state. Furthermore, we vary the geometrical parameters of the L-shaped hole to tune its resonant spectra and achieve a switchable full-wave plate/polarizer. The multifunctional switchable polarization manipulation abilities together with large bandwidths enable the proposed structures promising applications in nanophotonics and integrated optics.

Simple-Structured Blue Thermally Activated Delayed Fluorescence Emitter for Solution-Processed Organic Light-Emitting Diodes with External Quantum Efficiency of over 20.

Solution-processed organic light-emitting diodes (OLEDs) are much preferred for the manufacture of low-temperature, low-cost, large-area, and flexible lighting and displaying devices. However, these devices with high external quantum efficiency are still limited, especially for blue ones. In addition, the molecular configurations of emitters are usually complicated, indicative of high costs. In this study, two simple-structured thermally activated delayed fluorescent emitters M1 and its polymer P1 were synthesized with acridine as a donor and benzophenone as an acceptor. Solution-processed OLEDs were prepared based on M1 and P1 as doped light-emitting layer, and M1-based doped device could achieve maximum external quantum efficiency of up to 20.6% with blue-light emission.

Plexcitonic Optical Chirality: Strong Exciton-Plasmon Coupling in Chiral J-Aggregate-Metal Nanoparticle Complexes.

Understanding the unique characteristics of plexcitons, hybridized states resulting from the strong coupling between plasmons and excitons, is vital for both fundamental studies and practical applications in nano-optics. However, the research of plexcitons from the perspective of chiral optics has been rarely reported. Here, we experimentally investigate the optical chirality of plexcitonic systems consisting of composite metal nanoparticles and chiral J-aggregates in the strong coupling regime. Mode splitting and anticrossing behavior are observed in both the circular dichroism (CD) and extinction spectra of the hybrid nanosystems. A large mode splitting (at zero detuning) of up to 136 meV/214 meV in CD/extinction measurements confirms that the systems attain the strong coupling regime. This phenomenon indicates that the formation of plexcitons modifies not only the extinction but also the optical chirality of the hybrid systems. We develop a quasistatic theory to elucidate the chiral optical responses of hybrid systems. Furthermore, we propose and justify a criterion of strong plasmon-exciton interaction: the mode splitting in the CD spectra (at zero detuning) is larger than half of that in the extinction spectra. Our findings give a chiral perspective on the study of strong plasmon-exciton coupling and have potential applications in the chiral optical field.

Radiation properties of quantum emitters via a plasmonic waveguide integrated with a V-shaped traveling wave antenna.

We experimentally study the radiation direction and relaxation rate of quantum emitters (QEs) coupled with a plasmonic waveguide integrated with a V-shaped traveling wave antenna. The plasmonic waveguide couples the excitation energy of the nearby QEs into surface plasmons and the connected V-shaped traveling wave antenna converts them into highly directional radiation. The directivity of the radiation depends on the shape of the antenna. The half-power beam widths of the radiation with respect to the azimuthal and polar angles are as small as 15.1° and 13.1°, respectively, when the antenna has a 144° intersection angle. The relaxation rates of the QEs are enhanced up to 33.04 times relative to the intrinsic emission rate. The method to control the fluorescence of QEs is of great significance for optical devices, nanoscale light sources, and integrated optics.

Nanoscale Refractive Index Sensors with High Figures of Merit via Optical Slot Antennas.

Nanoscale refractive index (RI) sensors based on a single nanorod or nanoantenna typically suffer from a low figure of merit (FOM) due to the large full width at half-maximum of the plasmonic dipole resonance. Here, we demonstrate nanosensors with a high FOM and a sensing volume that is much smaller than λ3 using slot antennas. Two configurations, one based on a bowtie slot antenna (BSA) and one based on a slot antenna pair (SAP), are proposed. The RI information is obtained from the extinction dip that is due to the interference of surface plasmon polaritons (SPPs), which are launched at different nodes of a third-order resonant mode of the BSA or different antennas of the SAP. The high FOM is attributed to the dependence of the extinction spectrum on both the amplitude and the phase of the SPPs. There are important applications for these nanosensors, which can measure the local RI beyond the diffraction limit and can be flexibly integrated.

Invertible plasmonic spin-Hall effect at nanoscale based on U-shaped optical slot nanoantenna.

A U-shaped optical slot nanoantenna with a footprint size of 300 nm by 300 nm is proposed to achieve invertible plasmonic spin-Hall effect at nanoscale. The interference between the SPPs excited by the different plasmon resonances in the antenna enables the nanostucture to break the spin degeneracy. Besides, the SPP orbitals for the two spins are invertible while changing the incident wavelength, which is attributed to the dispersive phase shift between the different plasmon resonances in the antenna. The SPP intensity extinction ratio can be improved by employing a U-shaped slot antenna array. The strong spin-orbit coupling property together with the ultra-compact size and invertible spin-controlled SPP orbitals enable the structure promising applications in spin-optoelectronics and plasmonics.

Sub-one-third wavelength focusing of surface plasmon polaritons excited by linearly polarized light.

We report the generation of a subwavelength focal spot for surface plasmon polaritons (SPPs) by increasing the proportion of high-spatial-frequency components in the plasmonic focusing field. We have derived an analytical expression for the angular-dependent contribution of an arbitrary-shaped SPP line source to the focal field and have found that the proportion for high-spatial-frequency components can be significantly increased by launching SPPs from a horizontal line source. Accordingly, we propose a rectangular-groove plasmonic lens (PL) consisting of horizontally-arrayed central grooves and slantingly-arrayed flanking grooves on gold film. We demonstrate both numerically and experimentally that, under linearly polarized illumination, such a PL generates a focal spot of full width half maximum 274 nm at an operating wavelength of 830 nm. The method we describe provides guidance to the further structure design and optimization for plasmonic focusing devices.

Spin-encoded subwavelength all-optical logic gates based on single-element optical slot nanoantennas.

Optical logic gates are important elements in optical computing and optical circuits. However, the footprints of the present optical logic gates are still on the micrometer scale. Further miniaturization of the logic gates to nanometer scale remains challenging. Here we propose, and demonstrate experimentally, subwavelength all-optical logic gates based on single-element optical slot nanoantennas. By employing a spin-encoded scheme, we achieve OR, AND, NOT, NAND and NOR logic gates via an L-shaped optical slot nanoantenna with a footprint of 300 nm by 300 nm, and a XNOR logic gate via a rectangle optical slot nanoantenna with a footprint of 220 nm by 60 nm. The SPP launching and logic operation via mode coupling instead of path interference are integrated together at a single-element nanoantenna, which considerably shrinks the dimensions of the device. The experimental results show the potential of the single optical slot nanoantenna in subwavelength all-optical logic computing and nanophotonic information processing.