Antenna Effect Research Articles

An Ultrasensitive Duplex Aptasensor Featuring the Target-Triggered Lanthanide Luminescence Antenna Effect for Wash-Free Detection of Epithelial Cancerous Exosomes.

Fluorescence sensing is widely used in in vitro detection due to its high sensitivity and rapid result delivery. However, detection systems based on nanomaterials involving complex and cumbersome purification steps can lead to sample loss and significantly reduce the accuracy of the results. To address this issue, we proposed a lanthanide-based aptasensor featuring the target-triggered antenna effect to significantly enhance the time-resolved luminescence (TRL) of chelated Tb3+ combined with a wash-free strategy. This sensor enabled highly sensitive detection of the epithelial cell adhesion molecule (EpCAM) on exosomes from epithelial tumors, eliminating the necessity for purification steps and thereby delivering more stable and reliable results. Specifically, using computer-aided design, a sequence capable of self-folding into a stable hairpin structure (Antenna-Hairpin-Tb) was obtained. After hybridization with an EpCAM-specific aptamer (AptEpCAM), a duplex aptasensor (Probe-Tb) was constructed for detection. When the targeted binding occurred between the AptEpCAM and exosomes, the Antenna-Hairpin-Tb dehybridized from the Probe-Tb and underwent self-folding, leading to a significant sensitized TRL signal due to the antenna effect-induced energy transfer from the antenna ligand to the chelated Tb3+. Over a broad range of exosome concentrations (spanning from 6.19 × 102 to 6.19 × 108 particles/mL), the emission intensity of chelated Tb3+ at 543 nm linearly increased with the exosome concentration (linear relationship: Y = 332.62 lg(Nexosomes) + 3690.5, R2 = 0.9956), achieving a theoretical detection limit as low as 17 particles/mL in the buffer. Furthermore, Probe-Tb enabled a swift and effective differentiation of all epithelial cancer serum samples from nonepithelial ones within just 30 min of a wash-free operation, achieving 100% sensitivity, 100% specificity, and 100% accuracy.

A sensitized dual-response ratiometric fluorescent sensor integrated smartphone platform for accurate discrimination and detection of tetracycline homologues based on N-CDs‒Eu3+ complex.

Asensitized dual-response ratiometric fluorescent sensor integrated smartphone platform for accurate discrimination and detection of tetracycline(TC) homologues was fabricated based on N-CDs-Eu3+ complex. In the sensing system, N-CDs act as a sensitizer of Eu3+ and significantly enhance the fluorescence of TC-Eu3+ complex approximate 40-fold owing to the synergistic effect of antenna effect (AE) and fluorescence resonance energy transfer (FRET). A paper sensor integrated with a smartphone platform is further fabricated for on-site measurement of TC. The proposed sensing platform exhibits an obvious color change from blue to red with limit of detection (LOD) of 1.5 and 63.2 nM for spectrofluorimetry and paper sensor, respectively. In addition, to eliminate the interference from TC homologues, a simple and effective sensor array was constructed by regulating thepH of the system. The different fluorescence responses to four tetracycline homologues used widely (TC, OTC, CTC, and DOX) were examined and dealt with principal component analysis, and accurate differentiation of TC homologues was therefore achieved. This work provides an integrated method for identification and synchronous quantitative detection of TCs, and a potential application for visual and on-site detection of TCs in environmental monitoring and food safety.

Suppression of Photoexcited Small Polarons-Mediated Energy Transfer to Boost Photoluminescence of Lanthanide-Titanium Nanoclusters.

Lanthanide (Ln3+)-titanium-based molecular nanoclusters (NCs) have attracted much attention due to their atomically precise total structure and promising optical behavior, while there is still minimal cognition of structure-dictated electron relaxation dynamics in such an NCs regime with unsatisfied photoluminescence quantum yield (PLQY, in general below 20%). Herein, the photoexcited small polarons (i.e., local electron-phonon coupling) are identified and emphasized in modulating the emission of Ln3+ NCs. Taking 4-tert-butylbenzoate coordinated Eu2Ti4 NCs as a model, the excited electron is capable of being captured by the Ti4+ to form the Ti3+-dominated small polarons, which allows influencing the ligands-sensitive antenna effect for Eu3+ emission. Most importantly, by chelating the Eu2Ti4 NCs with Eu3Ti3 units bilaterally, the evolved Eu8Ti10 NCs perform suppressed lattice vibration and therefore eliminate the photoexcited small polaron-mediated energy transfer, giving a remarkable enhancement in PLQY, from 17.6% to 73.1%.

Metal Organic Framework Based on Photoactivated Aggregation-Induced Emission Molecule for Achieving Photoexcitation Regulation.

Ln-MOFs, composed of lanthanide ions and functional organic ligands, are porous materials with tunable structures and unique luminescent properties. However, the interplay between ligand AIE properties and the framework's "antenna effect" on MOF morphology is understudied. Here, Tb-D-Cam-TPTB was synthesized via solvothermal method using TPTB (persulfurated arene) as the primary ligand, D-Cam as the auxiliary ligand, and Tb3+ as the metal ion. Photoexcitation of TPTB, a typical AIE molecule, promotes conformational changes, enhancing molecular aggregation and luminescence. Comprehensive photophysical investigations of TPTB in solution and crystal states, Tb3+-TPTB coordination, and Tb-D-Cam-TPTB MOF were conducted using various spectroscopic and imaging techniques. This study explores the interaction between ligand AIE and the "antenna effect" on Ln-MOF luminescence and crystal structure. The results indicate that, when the ligand is a photoexcitation-induced AIE molecule, UV irradiation of the precursor solution prior to crystal growth can alter the crystal structure, luminescence intensity, and color, holding great promise for applications in anti-counterfeiting, sensing, and other related fields.

Rare Earth Complex-Based Functional Materials: From Molecular Design and Performance Regulation to Unique Applications.

ConspectusRare earth (RE) elements, due to their unique electronic structures, exhibit excellent optical, electrical, and magnetic properties and thus have found widespread applications in the fields of electronics, optics, and biomedicine. A significant advancement in the use of RE elements is the formation of RE complexes. RE complexes, created by the coordination of RE ions with organic ligands, not only offer high molecular design flexibility but also incorporate features such as a broad absorption band and efficient energy transfer of organic ligands. Through the "antenna effect", organic ligands can transfer energy to RE ions, enhancing their luminescence efficiency. Moreover, the modification of the ligands can influence the local environment of the RE ions, thereby regulating their electronic structures and energy-level distributions. This makes it one of the important avenues for the efficient development and utilization of RE resources.The meticulous design of organic ligands during molecular synthesis enables the precise construction and regulation of RE complex structures, which are essential for probing molecular-level structure-performance relations and developing functional materials in fields such as optoelectronics, sensing, and catalysis/energy. Despite notable advancements, challenges persist in refining synthesis methodologies, innovating RE complex-based materials, enhancing stability, gaining better control over device functionality, and realizing high-value applications. This Account summarizes the recent advancements in molecular design and performance regulation achieved by our research group, particularly focusing on the synthesis and functional regulation of RE complex-based materials. We have employed strategies such as coordination self-assembly, in situ coordination, and microstructural evolution to achieve the precise synthesis and functional modulation of RE complex-based materials. These approaches have allowed us to finely tune properties such as the luminescence, electrical performance, and catalytic performance of various material systems. Consequently, we have made considerable strides in multidimensional optical information storage, the development of intelligent biological probes, the preparation of nanocatalysts, and the enhancement of inorganic-organic hybrid perovskite solar cell devices. Finally, we are committed to conducting an in-depth analysis of the challenges and opportunities that arise from the precise synthesis methods, performance regulation strategies, and innovative applications of RE complex-based functional materials. Additionally, we aim to propose potential solutions to current issues. This Account comprehensively summarizes the developments in RE complex-based materials to stimulate innovative thinking and new research directions and to establish a foundation for function-oriented precise synthesis methods.

Portable and real-time detection for tetracycline antibiotics using europium-doped LDH gel intercalated graphene quantum dots.

Tetracyclines (TCs) residues pose a significant threat to the aquatic environment and human health, therefore this study aims to develop a simple, rapid, and sensitive TCs detection method. Herein, a dual-responsive gel probe (LDH-CES@N) was designed, consisting of the intercalation of graphene quantum dots into europium-doped layered double hydroxide (LDH). In the presence of TCs, the as-prepared probe exhibited dual emission fluorescence at 504 nm and 616 nm due to the synergistic effect of aggregation-induced emission and antenna effect. Meanwhile, the density functional theory was employed to validate the mechanism underlying TC-induced electron transfer from graphene quantum dots. The dual-signal response fluorescence probe has excellent detection ability of oxytetracycline, including a wide detection range (0-60 μM), low detection limit (0.145 μM), and rapid response time (120 s). Furthermore, combined with the smartphone, a portable and real-time detection platform was established for the visual detection of oxytetracycline in tap water and honey samples with desirable recovery rates (97.8 %-105.4 %). Therefore, this work provides a new strategy for fluorescence detection of trace pollutants, demonstrating considerable practical application potential.

Synergistic microwave hyperthermia treatment for subcutaneous deep in situ breast cancer using conformal array antennas and a microwave-thermal-sensitive nanomaterial.

When microwave hyperthermia (MWH) array antenna technology is used to treat breast cancer, how to effectively target and heat deep tumors and reduce thermal damage to healthy tissues is still a challenge in clinical applications. In this study, the synergistic MWH effect of conformal-array antennas (CAA) and a novel microwave-thermal-sensitive nanomaterial (MTSN) was investigated for the treatment of subcutaneous deep in situ breast cancer. At the beginning of the study, the thermal damage score was used to evaluate the therapeutic efficacy of the CAA. It was found that although array antenna technology can achieve effective heating of deep tumors, its damage to healthy tissues is unacceptable. Consequently, we developed a novel MTSN, ZIF-8@HA, whose unique structure significantly enhanced the absorption of MW energy and MW thermal conversion efficiency in the local tumor region. The MW thermal conversion efficiency of ZIF-8@HA achieved was as high as 46.46% in in vivo MW heating experiments. In the phantom that simulates the electromagnetic environment of the human body, the microwave-thermal sensitization (MTS) effect is also significant, and the reduction in the average thermal damage score of healthy tissues by more than 10% was verified through measurements using the coaxial probe method and COMSOL simulations. Cellular experiments confirmed that the combination of ZIF-8@HA and MW irradiation could significantly reduce the survival rate of tumor cells. In addition, cross-tissue MW heating experiments revealed the advantages of ZIF-8@HA combined with the CAA. Finally, phantom experiments confirmed that the synergistic use of the CAA with ZIF-8@HA significantly accelerated the local heating rate of deep tumors, reduced the time required for the tumor region to achieve 100% thermal damage, and effectively minimized the thermal damage to healthy tissues.

Effectiveness and Characteristics of Virtual Antennas in the Multiple Signal Classification Algorithm

This paper proposes a novel direction of arrival (DoA) estimation method based on the Multiple Signal Classification (MUSIC) algorithm using virtual antennas. The MUSIC method is a widely used DoA estimation technique known for its high accuracy and high resolution. However, it has a fundamental limitation: when the necessary condition of having more antenna elements at the base station than users is not met, DoA estimation becomes infeasible. To address this limitation, we introduce the concept of virtual antennas, allowing DoA estimation, even under restricted conditions. Virtual antennas are not physically present but can be virtually arranged, enabling the generation of virtual-received signals similar to those of real array antennas. Through simulation experiments, we demonstrate that our approach enables DoA estimation with the MUSIC algorithm even when its necessary conditions are not satisfied. Additionally, this paper explores the characteristics of virtual antennas in detail. We conduct simulation experiments to examine the differences in estimation accuracy between real and virtual antennas, as well as the impact of virtual antenna arrangement and count on estimation accuracy. The results show that, although virtual antennas provide lower estimation accuracy compared to real antennas, their flexible arrangement allows for improved resolution when signal sources are closely spaced by increasing the spacing between virtual antennas. Furthermore, under Additive White Gaussian Noise (AWGN) conditions, increasing the number of virtual antennas enhances estimation accuracy.

Synergistic Enhancement of Plasma-Driven Ammonia Synthesis Using a AuCu3/Cu Composite Catalyst.

Green ammonia synthesis using fluctuating renewable energy supply in decentralized process is a goal that has been long sought after. Ammonia synthesis with non-thermal plasma under mild conditions is a promising technology, but it faces the critical challenge of low energy efficiency. Herein, we develop an easily-scalable AuCu3/Cu catalyst, which consists of a decimeter-scale metallic Cu antenna and nano-scale AuCu3 catalytic sites on metallic Cu surface, significantly enhancing the energy efficiency and ammonia yield in a radio-frequency (RF) plasma system. Compared to plasma alone, the single-pass ammonia yield over AuCu3/Cu increases by a factor of 20, approaching 10 %. Mechanistic studies indicate that Cu antenna can amplify the millimeter-scale local electric field, thereby facilitating the generation of active nitrogen species, including nitrogen radicals and vibration-excited nitrogen molecules. Due to the downshifted d-band center and unique Cu-Au interface structure, the AuCu3 nanoalloy modified on Cu antenna surface significantly reduces hydrogenation barriers of active NHX (x=0,1,2) species (the rate-determining step) and facilitates ammonia desorption at lower temperature. The synergistic effect of Cu antenna and surface AuCu3 nanoalloy comprehensively enhances ammonia synthesis through both the nitrogen radical-mediated Eley-Rideal pathway and the vibration-excited nitrogen molecule-mediated Langmuir-Hinshelwood pathway.

Synergistic Enhancement of Plasma‐Driven Ammonia Synthesis Using a AuCu3/Cu Composite Catalyst

Green ammonia synthesis using fluctuating renewable energy supply in decentralized process is a goal that has been long sought after. Ammonia synthesis with non‐thermal plasma under mild conditions is a promising technology, but it faces the critical challenge of low energy efficiency. Herein, we develop an easily‐scalable AuCu3/Cu catalyst, which consists of a decimeter‐scale metallic Cu antenna and nano‐scale AuCu3 catalytic sites on metallic Cu surface, significantly enhancing the energy efficiency and ammonia yield in a radio‐frequency (RF) plasma system. Compared to plasma alone, the single‐pass ammonia yield over AuCu3/Cu increases by a factor of 20, approaching 10%. Mechanistic studies indicate that Cu antenna can amplify the millimeter‐scale local electric field, thereby facilitating the generation of active nitrogen species, including nitrogen radicals and vibration‐excited nitrogen molecules. Due to the downshifted d‐band center and unique Cu‐Au interface structure, the AuCu3 nanoalloy modified on Cu antenna surface significantly reduces hydrogenation barriers of active NHX (x=0,1,2) species (the rate‐determining step) and facilitates ammonia desorption at lower temperature. The synergistic effect of Cu antenna and surface AuCu3 nanoalloy comprehensively enhances ammonia synthesis through both the nitrogen radical‐mediated Eley‐Rideal pathway and the vibration‐excited nitrogen molecule‐mediated Langmuir‐Hinshelwood pathway.

Investigations into the residual multipath errors of choke-ring geodetic antennas on GNSS carrier-phase measurements

For about three decades, the Global Navigation Satellite System (GNSS) has been used for high-precision positioning in scientific and engineering applications, such as deformation monitoring for seismicity and volcano eruption. Such high-precision positioning applications require millimeter-level positioning accuracy. There are many man-made and natural reflective surfaces near the GNSS receiving antennas. GNSS signals can be reflected and then arrive at the GNSS antenna. The multipath effect occurs when the direct signal is mixed with the reflected signal at the GNSS receiver. Choke-ring antennas are designed to mitigate the multipath effect of reflected signals from below the horizontal plane of the GNSS receiving antenna. Moreover, GNSS receiving antennas at network/permanent stations are usually installed on tall pillars or monuments to prevent multipath from “ground” reflected signals. However, part of the reflected signals can still arrive at the GNSS antenna center and cause multipath errors in GNSS measurements. How much can the multipath effect be on the real-time GNSS-measured displacements in studies on seismicity and volcano eruption? This work investigates the below-the-horizon multipath effect of choke-ring antennas on GNSS carrier-phase measurements. Here we show the differenced carrier-phase multipath errors of two commonly used GNSS antennas at the International GNSS Service (IGS) tracking stations can reach 8 mm, the maximum, with the mean and SD in a few millimeters at the 95% confidence level. The findings of this work should be applicable to other choke-ring antennas with similar architecture.

RhB intercalated Zr(VI)-bipyridine architecture for efficient ratiometric fluorescent response toward Cr(VI) analyte and decontamination of Cr(VI) and reactive dye via photochemical REDOX

It is extremely‌ imperative to enhance the sensing accuracy of water-stable Zr-MOFs for Cr(VI), because the single emission signal in a sole Zr-MOF is rather vulnerable to external factors. Interpolation of guest luminous species into Zr-MOF crystals presents a feasible way to achieve dual-emission signals. In this contribution, a highly water-stable Zr-MOF (Zr-bcu-22bipy44dc) which emits bright-blue fluorescence was deployed as matrix to intercalate fluorochrome Rhodamine B (RhB), creating a novel dual-emission (at 410 and 580 nm) luminescent platform, RhB@Zr-MOF. Then, it was utilized as a fluorescence probe to accurately detect trace-level Cr(VI) ions, by assessing the relative fluorescence intensity (IR) difference between the host Zr-MOF (I410) and the guest RhB (I580). Interestingly, the septal interpolation of luminescent species within Zr-MOF matrix effectively suppresses aggregation-induced quenching (ACQ), which tends to occur easily for RhB molecules. Moreover, its determined detection limits (DL) for CrO42- (6.13 ppb) and Cr2O72- (10.04 ppb) ions have been remarkably enhanced by approximately 4.92-fold and 3.66-fold, respectively, compared to the initial Zr-MOF (30.11 and 36.76 ppb). DFT and TD-DFT calculations have confirmed that the orange-yellow photoluminescence exhibited by RhB@Zr-MOF should be attributed to the PET process inherent to the intercalated RhB molecules, rather than the commonly accepted intermolecular Förster resonance energy transfer (FRET) mechanism or the photo-induced electron transfer (PET) effect previously identified by us. Efficient antenna effect of RhB module synergizes with Zr-MOF's appropriate band structure, also enables RhB@Zr-MOF convincing ability to photochemically deoxidize Cr(VI) and bleach reactive dark blue K-R (K-R)

Antenna effect on Zn(II) porphyrin-based molecular ensembles for the detection of 2,4-dinitrophenol through energy and electron transfer process.

Twomodular systems were synthesizedcomposed of triphenylamine (ZnTPAP) and pyrene (ZnPyP) covalently linked at meso position of the Zn(II) porphyrins. Both compounds behaved as energy transfer antenna and orthogonal units to enhance the electron donating ability of Zn(II) porphyrins. Detailed photophysical and aggregation studies reveal that an appreciable electronic interaction exists between peripheral units to the porphyrin π-system so that they behave like strong donor materials. The electrochemical and computational studies demonstrate delocalization of the frontier highest occupied molecular orbital (-5.08eV) over the triphenylamine entities (ZnTPAP) in addition to the porphyrin macrocycle. Fluorescence experiments withZnTPAP and ZnPyP in the presence ofdifferent nitro analytes at various concentrations show turn-off fluorescence behaviour and exhibit superior selectivity towards 2,4-dinitrophenol (DNP) with limit of detection (LOD) of ~ 2.3 and 9.2ppm for ZnTPAP and ZnPyP. Photoinduced electron transfer process is involvedin the static and dynamicfluorescence quenching process. A Stern-Volmer quenching association constant (Ksv) determination revealed that ZnTPAP is more sensitive than the ZnPyP. This is attributed to thestrong donating behaviour of TPA unitscaused by intermolecular interaction through metal center and strong π-π interactions with nitro analytes. The present study provides new insights into the ability to tune the affinity and selectivity of porphyrin-based sensors utilising electronic factors associated with the central Zn(II) ion. Furthermore, a smartphone-interfaced portable fluorimetric method by recognising colour variations in RGB and the luminance (L) values facilitate sensitive and real-time sensing at low concentration levels will have a significant impact on development of a new class of chemosensors.

New Design Scheme for and Application of Fresnel Lens for Broadband Photonics Terahertz Communication.

In terahertz communication systems, lens antennas used in transceivers are basically plano-convex dielectric lenses. The size of a plano-convex lens increases as the aperture increases, and thinner lenses have longer focal lengths. Through theory and simulation, we designed a Fresnel lens suitable for the terahertz band to meet the requirements of large aperture and short focal length, and simulated the performance, advantages, and disadvantages of the terahertz Fresnel lens. A 300 GHz terahertz wireless communication system was built to verify the gain effect of the Fresnel lens antenna. The experimental results demonstrate that the Fresnel lens can be used for long-distance terahertz communication with larger aperture diameters, overcoming the limitations of traditional plano-convex lenses. The theoretical gain of a 30 cm Fresnel lens is 48.83 dB, while the actual measured gain is approximately 45 dB.

Intelligent sensing platform based on europium-doped carbon dots for dual-functional detection of ciprofloxacin/Ga3+ and its tracking in vivo

Ciprofloxacin (CIP) and gallium (Ga) are widely used in many fields and their excessive presences will pose serious threats to the environment and life health. Therefore, developing an intelligent detection method for rapidly tracking and determination of CIP and Ga3⁺ concentration in environments and organisms is of great significance. In this work, a europium-doped carbon dots (Eu-CDs) with unique structure and performances was prepared by a one-pot hydrothermal method. Eu-CDs can efficiently overcome the problem of aggregation-induced fluorescence quenching in complex environments to track CIP and Ga3⁺ with highly sensitivity. The "antenna effect" of non-radiative energy transfer is introduced to explain the pathway on fluorescence transition of Eu-CDs through DFT theoretical calculations and mechanism investigations, which provide a theoretical basis for the design and development of novel carbon dots with specific functions. Eu-CDs can successfully be applied to fluorescence imaging in organisms, moreover, it also exhibits excellent application potentials in the field of anti-tumor and antibacterial. In addition, a portable intelligent detection platform based on Eu-CDs-hydrogel device have been developed, which provides a new strategy for rapidly detection of CIP and Ga3⁺ in real samples.

Orthogonal and antenna effects on the chemosensing behaviour of porphyrins towards 2,4,6-trinitrophenol: Colour recognition and portable photodiode device

In this work, we have developed two modular freebase porphyrins containing triphenylamine (H2TPAP) and pyrene (H2PyP) units at meso position to understand the role of antenna and orthogonal effects on photophysical and chemosensing behaviour with different nitroaromatic compounds (NACs). The fluorescence studies demonstrate that H2TPAP exhibit strong electronic coupling over H2PyP to induce energy transfer process from peripheral units to porphyrin π-system and behave like strong donor materials. The sequential energy and electron transfer process upon addition of different NACs reveals that H2TPAP show unprecedented selectivity towards the detection of 2,4,6-Trinitrophenol (TNP) with a limit of detection (LODs) of ∼2.3 and ∼6.8 ppm for H2PyP. The mechanistic investigations through NMR and other spectroscopic methods evident that the strong donor-acceptor interactions, protonation at the central core of H2TPAP show both colorimetric and fluorimetric changes with the order of quenching efficiency as TNP>4-NP>2,4-DNP > DUN>4-NBA. A handheld portable photodetector was developed to monitor the dynamic change in photocurrent response. Further, a smartphone interfaced portable fluorimetric method was developed by recognizing colour variations in terms of RGB and the luminance (L) values facilitate sensitive and real-time sensing at low concentrations levels will have a significant impact on the development of new handheld chemosensor devices for real time detection of explosive compounds.

Dielectric synergistic gradient metamaterials enable exceptional ultra–wideband microwave absorption and antibacterial properties

Interface structure design and multi–component strategies for regulating electromagnetic parameters to achieve efficient microwave absorption remain a challenge. In this study, a composite film with a heterogeneous structure, PAN@PPy@Ti3C2Tx@GO (PPTG) was fabricated through electrospinning, in situ oxidative polymerization, and dip–coating processes, achieving excellent electromagnetic wave absorption and antibacterial properties. When the filler content is only 20 wt%, the PPTG film exhibits an ultra–wide bandwidth, with a minimum reflection loss value (RLmin) of −49.98 dB (2.2 mm, 16.72 GHz), and the maximum effective absorption bandwidth (EAB) reaches 8.0 GHz (2.5 mm). The outstanding absorption performance is attributed to quarter–wavelength theory, polarization, multiple reflections and scattering, impedance matching, metamaterial properties, quasi–antenna effect, conductive loss, and magnetic loss. Excitingly, the radar cross–section (RCS) of the PPTG film can be reduced by up to 25.72 dB•m2, indicating excellent radar stealth properties. Moreover, the PPTG film exhibits excellent antibacterial properties. This research, based on the MXene absorber, provides new insights into the development of lightweight, efficient, and antibacterial microwave–absorbing materials.

Synthesis, Structural Analysis and Bright Emission Performance of a New Family of 3D Lanthanide Coordination Polymers Based on 1,3‐phenylenediacetic Acid

AbstractA novel series of isostructural lanthanide coordination polymers with the general formula [Ln2(PDA)3(DMF)2] (where Ln3+= La, Nd, Pr, Tb, Sm and Eu, DMF= N,N’‐dimethylformamide and PDA =1,3‐phenylenediacetate) were hydrothermally synthesized and further characterized by vibrational spectroscopy, thermal analysis, scanning electron microscopy (SEM), energy dispersive X‐ray (EDX) analysis, and powder and single‐crystal X‐ray diffraction techniques. In addition, from the crystallographic data, it was possible to determine the topology of the structure, finding that the network consists of 5‐connected nodes with topological type: nov; 5/4/o8 and point symbol (44.66). To study the luminescence properties regarding potential energy transfers among the building blocks, lanthanum‐based samples doped with Tb (III) and Eu (III) (1 %, 2 %, 5 % and 10 %) were analyzed in solid state. Upon ligand sensitization, 4 f transitions could be observed confirming an “antenna effect” of the PDA ligand. These new compounds are potential materials for the construction of photoluminiscent devices.

Performance Analysis of Millimeter-Wave Propagation Characteristics for Various Channel Models in the Indoor Environment

Due to the recent surge in the proliferation of smart wireless devices that feature higher data speeds, there has been a rise in demand for faster indoor data communication services. Moreover, there is a sharp increase in the amount of mobile data being generated worldwide, and much of this data comes from residential wireless applications like high-definition TV, device-to-device communication, and high data rate indoor networks (i.e., local and cellular). These technologies need large capacity, high data rate indoor wireless networks with huge bandwidth. Consequently, a greater interest exists in implementing an effective and trustworthy indoor propagation model for next-generation wireless systems operating in the massively bandwidth-rich millimeter wave (mm-wave) frequency range. The analysis of mm-wave propagation characteristics in an indoor environment using the ray tracing approach is proposed in this paper. Propagation modeling for 60 GHz bands is included. The aspects of wideband propagation characteristics such as angular spread, path loss, delay spread, and power delay profile are modeled in this paper. The position of transceivers, antenna effect, and attenuation, in the hallways, and stairwells will all be considered while determining the propagation parameters. This includes wave propagation characteristics like absorption, reflection, and diffraction by building structures and furniture. The specifications for propagation characteristics are included in the article for developing indoor local and cellular networks. In this paper, the IRT model has been tested at 60 GHz for potential mobile communication and is identified as the best method for predicting signal attenuation caused by objects, barriers, or humans within buildings in internal millimeter wave transmission.

Dynamic Rare-Earth Metal-Organic Frameworks Based on Molecular Rotor Linkers with Efficient Emissions and Ultrasensitive Optical Sensing Performance.

4,4',4″-Triphenylamine tricarboxylate (TPA-COOH) with a distinct molecular rotor structure was reacted with rare-earth (RE) metal ions to obtain seven dynamic RE-based luminescent MOFs (RE-LMOFs) (i.e., emission colors in the blue, yellow-green, red, and near-infrared regions and emission peak wavelengths between 400 and 1600 nm) via the effective transfer of absorbed energy from TPA-COOH to the RE metal ions through the antenna effect. Due to the large energy level difference between RE ions, it was rare in the early days to use the same ligand to construct energy-level matching RE-LMOF homologues with multiple RE metal centers. The uncoordinated oxygen atoms on the molecular rotor linkers in RE-LMOFs provide active sites that can specifically capture highly toxic metal ions and strong oxidative pollutants. The limit of detection (LOD) of RE-LMOF for Al(III) ions is far below the maximum concentration of Al(III) ions in drinking water stipulated by the U.S. Environmental Protection Agency (USEPA) and that for H2O2 is much lower than the H2O2 content in cancer cells, showing excellent application potential for diagnosing early cell cancelation.