High Energy Transfer Efficiency Research Articles

High Quantum Yields and Energy Transfer Efficiency of Lanthanide‐Based Coordination Polymers as Luminescent Thermometer in Low Temperature Range

ABSTRACTLuminescent lanthanide‐based coordination polymers (LnCPs) present great potential in low‐temperature detection due to their convenience in contactless readout. High quantum yields and energy transfer efficiency are favored by LnCPs as luminescent thermometer. In this work, based on the thermogravimetric analysis and temperature‐dependent powder x‐ray diffraction, coordinated and isolated molecules of [Ln2(mip)3(H2O)8·4H2O]∞ (abbreviated as Ln2MIP) were removed by dehydration process. Combining luminescent measurement and calculation, both quantum yields and energy transfer efficiency between Tb3+ and Eu3+ have been greatly enhanced. Additionally, the Eu3+ intensity of dehydrated Gd0.2Tb1.08Eu0.72MIP displays excellent temperature sensing ability from 77 to 300 K with enhanced relative sensitivity. These results demonstrate the potential of LnCPs in low‐temperature sensing with high quantum yields and energy transfer efficiency.

Tetraarylpyrrolo[3,2-b]pyrrole-BODIPY dyad: a molecular rotor for FRET-based viscosity sensing.

With the aim to develop a FRET-based viscosity sensor, two dyad molecules, 4 and 5, comprising tetraarylpyrrolo[3,2-b]pyrrole (TAPP) (donor) and naked boron-dipyrromethene (BODIPY) dyes (acceptor), were designed. Dyads were synthesized via acid-catalyzed multicomponent reactions followed by Sonogashira coupling. In both dyads, the BODIPY and TAPP moieties are linked through phenylethynyl groups, which allow free rotation of the BODIPY dyes; that is, they can act as molecular rotors. This was supported by X-ray crystallographic and DFT-optimized structures. Spectroscopic studies also confirmed the presence of both TAPP and BODIPY dyes in dyads with no electronic interactions that are suitable for fluorescence resonance energy transfer (FRET). Very high energy transfer efficiency (ETE >99%) from the donor TAPP moiety to the acceptor BODIPY moiety on excitation at the TAPP part was observed. However, due to the non-fluorescent nature of naked BODIPY dyes, no fluorescence emission was observed from the BODIPY moiety in both dyads. With increasing solvent viscosities, emission from the BODIPY moieties increases due to the restricted rotation of the BODIPY moieties. Plotting the logarithms of the fluorescent intensity of dyad 5 and the viscosity of the solution showed a good linear correlation obeying a Förster-Hoffmann equation. Non-fluorescent dyad 5 in methanol became greenish-yellow fluorescent in a methanol/glycerol (1:1) solvent. Furthermore, with an increase in the temperature of the methanol/glycerol (1:1) system, as the viscosity decreases, the fluorescence also starts decreasing. Thus, dyad 5 is capable of sensing the viscosity of the medium via a FRET-based "Off-On" mechanism. This type of viscosity sensor with a very large pseudo-Stokes shift and increased sensitivity will be useful for advancing chemo-bio sensing and imaging applications.

A FRET probe based on flavonol-benzothiazole for the detection of viscosity and SO2 derivatives

Sulfur dioxide (SO2) and viscosity play important roles in living organisms, and abnormal levels of them are associated with many diseases. Hence, a bifunctional fluorescence probe (E)-3-(2-(4-(4-(4-(6-fluoro-3-hydroxy-4-oxo-4H-chromen-2-yl)benzoyl)piperazin-1-yl)styryl)benzo-[d]thiazol-3-ium-3-yl)propane-1-sulfonate (HFBT) with fluorescence resonance energy transfer (FRET) properties was successfully constructed by using 3-hydroxyflavonol as the energy donor and benzothiazole sulphonate derivatives as the energy acceptor, and it can be used for the detection of SO2 derivatives (HSO3−/HSO32−) and viscosity. HFBT exhibits a large Stokes shift (245 nm), high resonance energy transfer efficiency (95.56 %), and excellent selectivity, anti-interference and low limit of detection (LOD = 0.057 μM) for HSO3−. The fluorescence intensity of HFBT at 608 nm gradually increases with the increase of viscosity. Interestingly, a visual HSO3− detection platform was successfully constructed and applied to the quantitative detection of HSO3− in food. Additionally, HFBT was successfully applied to imaging endogenous and exogenous HSO3− in cells. The successful development of HFBT provides an effective tool for the detection and imaging of HSO3− in food and cells.

An Artificial Light-Harvesting System based on Supramolecular AIEgen Assembly.

Photosynthesis is a complex multi-step process in which light collection is the initial step of photosynthesis and plays an important role in the utilization of solar energy. In order to improve the utilization of sunlight, researchers have developed a variety of artificial light-harvesting systems to simulate photosynthesis in nature. Here, we report a supramolecular artificial light-harvesting system in aqueous solution. Since β-cyclodextrin (β-CD) has a hydrophobic cavity and a hydrophilic outer surface, we adopt β-cyclodextrin (β-CD) as the host molecule and use adamantane as the guest molecule. At the same time, we modified β-CD with the donor molecule naphthalimide and adamantane with the tetraphenylethylene molecule which has aggregation-induced emission (AIE) effects. By using fluorescent molecules with AIE, the self-quenching effect caused by aggregation in aqueous solution can be effectively avoided. Due to the host-guest interaction of β-CD and adamantane, nanoparticles with stable structure and uniform size can be spontaneously assembled in water. Because of the close distance and strong spectral overlap between naphthalimide and tetraphenylethylene, Förster resonance energy transfer (FRET) was realized, and artificial light-harvesting system was successfully constructed in aqueous solution. Therefore, this study provides a new strategy for constructing artificial light-harvesting system, and the artificial light-harvesting system shows broad application prospects in aqueous solutions.

Enhancing MPPT efficiency in PV systems under partial shading: A hybrid POA&PO approach for rapid and accurate energy harvesting

Partial shading in operational environments introduces multiple peaks in the output characteristics of photovoltaic (PV) systems, presenting significant challenges to energy harvesting. This study introduces a novel meta-heuristic algorithm, termed POA&PO, which aims to address the maximum power point tracking (MPPT) issues in PV systems. The algorithm capitalizes on the global search capability of the POA method to quickly pinpoint the range with the maximum power, followed by the fast convergence of the PO method to ensure both rapidity and accuracy of the solution. Extensive simulation tests, conducted in MATLAB/SIMULINK, have demonstrated the efficacy of the POA&PO algorithm, achieving an average tracking efficiency of 99.97 % with a convergence time of 0.3 s in step response tests; under the EN50530 test standard, the algorithm also showed sustained and stable tracking of ramp signals. Moreover, practical testing utilizing a new, low-cost indoor PV simulator confirmed the algorithm’s high performance under controlled conditions, yielding an average tracking efficiency of 97.03 % and a convergence time of 0.18 s. This paper highlights the capacity of the developed algorithm to reliably, accurately, and swiftly achieve high energy transfer efficiency. Additionally, the innovative and economical experimental testing methods employed are emphasized, contributing to the practical applicability and cost-effectiveness of the proposed solution.

Cascade–Assembly–Confined Multilevel Supramolecular Assemblies for Multicolor Luminescence Information Storage and Cells Imaging Based on Slipped Pseudo[5]rotaxane

Multilevel green fluorescent supramolecular assemblies that derived from macrocyclic confinement–activated yellow fluorescent pseudo[5]rotaxane and subsequently assembled with anionic cyclodextrin derivative sulfobutylether–β–cyclodextrin (SBE–β–CD) were reported. Possessing four cationic coumarin arms, the coumarin–modified dibenzo–24–crown–8 guest (G) could be encapsulated by cucurbit[7]uril (CB[7]) at a 4:1 host–guest stoichiometry to form pseudo[5]rotaxane (G@CB[7]4) in the manner of dynamic slipping, which not only extended the fluorescence intensity of G by 53 times, but also increased the fluorescence lifetime by 5.8–fold from 0.65 to 3.76 ns. Subsequently, SBE–β–CD was co–assembled with G@CB[7]4 to control the topological morphology from small nanoparticles to larger ones, further enhancing fluorescence by 9.9 times along with a blue shift from 530 nm to 515 nm through cascade confinement. Compared with the direct assembly of G and SBE–β–CD through electrostatic interactions, only slight fluorescence increase was shown. After doping the NIR dye sulforhodamine 101 (SR101) acceptor, the G@CB[7]4@SBE–β–CD/SR101 exhibited high energy transfer efficiency to 79%, accompanied by the color changed from green to red under 365 nm irradiation. Moreover, the multicolor tunable emission could be achieved by adding dibenzylammonium chloride to the solution of G@CB[7]4, G@CB[7]4@SBE–β–CD and G@CB[7]4@SBE–β–CD/SR101. Ultimately, the final assemblies were used in multicolor luminescence information storage and cells imaging.

Donor polarization engineering of conjugated microporous polymers to boost exciton dissociation for photocatalytic degradation of tetracycline

The misuse and inevitable release of antibiotics can cause significant harm to both human health and the environment, and the use of polymeric semiconductors for photodegradation of antibiotics in aqueous environments is one of the most effective strategies to alleviate the current dilemma. Nevertheless, the inherently high exciton binding energy (Eb) and low photogenerated carrier transfer efficiency for most photocatalysts results in unsatisfactory photodegradation performance. Hence, this work proposes a donor polarization strategy to regulate the exciton dissociation of conjugated microporous polymers (CMPs) by minimizing their Eb. Results exhibited that the introduction of the strong donor unit 3,4-ethylenedioxythiophene (EDOT) not only reduces the Eb and effectively promotes exciton dissociation, but also broadens the visible light absorption of CMP. Among them, EdtTz-CMP with the lowest Eb (99 meV) delivered an efficiency of 94.6% in photocatalytic degradation of tetracycline (TC) with in 90 min, significantly higher than those of its analogues. This work provides a viable approach to design CMPs by tuning the intrinsic dipole of the donor for efficient environmental purification.

Second-sphere interactions promote antenna effects for selective sensing of DPA in TbIII-based organic frameworks

Investigating the emission patterns of Ln-metal-organic frameworks (MOFs) is crucial but challenging for rational design and selecting suitable MOFs. Firstly, theoretical calculation was used to predict the energy transfer efficiencies between the central ions (Eu3+/Tb3+) and the ligand (H3BTTC). The result indicates that Eu3+ can be completely sensitized and therefore Eu-BTTC with high energy transfer efficiency shows single-emission, whereas Tb3+ can only be partially sensitized and Tb-BTTC shows dual-emission due to reverse energy transfer. Subsequently, Eu-BTTC and Tb-BTTC with heterogeneous emission properties were successfully constructed. In order to investigate the emission modes of the two LnMOFs, 2,6-dipyridyl acid (DPA) was chosen as the second sphere and triggered the interaction between DPA and MOFs. In Eu-BTTC, the fluorescence remained constant before and after the addition of DPA due to the Eu3+ sensitized completely. In Tb-BTTC, the interaction between MOF and DPA improves the energy transfer efficiency from BTTC to Tb3+, resulting in the fully sensitization of Tb3+ and a significant enhancement of the fluorescence of Tb3+. In response to these results, a series of experiments as well as theoretical simulations were conducted to reveal the mechanism. A rational design mode and a novel sensing mechanism for the sensing platform of Ln-MOFs was provided by this study.

Simulation observation of high effectiveness laser plasma wakefield accelerator using plasma telescope configuration

In the laser wakefield accelerators, the energy transfer efficiency from the laser to the electron beam and the energy spread of the electron beam are parameters of contradiction, which people have not been able to improve simultaneously for a long time. To generate quasi-monoenergetic electron beams, the energy transfer efficiencies are up to the 1% level, while for 10% or higher energy transfer efficiencies, the electron spectra are broad in general. In the series of particle-in-cell simulations shown in this paper, we observe the simultaneous improvement of these two parameters by the self-injection mechanism in uniform plasma using the plasma telescope configuration [Zeng et al., Phys. Plasmas 27, 023109 (2020)]. The energy transfer efficiency is increased to more than 10%, and the energy spread of the electron beam is less than 5%. We also show the possibility to produce an electron beam with the energy of 1.871 GeV, the charge of 2.13 nC, and the energy spread of 2.5% by a 30 J laser.

Bidirectional hybridized hairpin DNA fluorescent aptasensor based on Au-Pd NPs and CDs for ratiometric detection of AFB1.

Anovel and simple ratiometric fluorescent aptasensor was developed for the sensitive detection of aflatoxin B1 (AFB1). A hairpin DNA (h-DNA) was independently synthesized as the basic skeleton, and the bidirectional hybridization of h-DNA can increase the load of aptamer and signal probes, thereby realizing signal amplification. The high-efficiency fluorescence resonance energy transfer interaction between gold-palladium nanoparticles (Au-Pd NPs) and the self-synthesized fluorescent probe carbon dots (CDs) was utilized. Moreover, the label-free probe SYBR Green I (SG I) dye was introduced to form a double-signal probe with CDs, and a ratiometric sensor with FCDs/FSG I as a response signal was constructed. The ratio strategy can eliminate the fluctuation of external factors, thus improving the accuracy and reliability of the sensor. The quenching effect of Au-Pd NPs on CDs was 1.4 times that of AuNPs and 3.4 times that of Pd NPs, respectively. In the range 1-100ng/mL, FCDs/FSG I showed a good linear relationship with the logarithm of the concentration of AFB1, and the limit of detection was as low as 0.07ng/mL. The sensor was used to detect AFB1 in spiked peanuts and wine samples, and the recovery was between 91 and 115%, indicating that the sensor has high application potential in real sample analysis.

Energy Transfer‐Assisted Color Conversion of Persistent Mechanoluminescence in RhB@SiO2/SrAl2O4:Eu,Dy System for Multilevel Information Encryption

AbstractPersistent mechanoluminescence (PML) is highly desirable for its ability to overcome transient‐emitting behavior, but its applications are hindered by the limited emission wavelengths. Herein, a universal chemical interlinkage‐assisted efficient energy transfer (ET) strategy is introduced to achieve color conversion from green to red in traditional PML materials. A straightforward chemical route to create the RhB@SiO2/SAOED system is established via covalent chemical interlinkage by depositing mesoporous silica‐encapsulated Rhodamine B (RhB) nanoparticles (RhB@SiO2) onto SrAl2O4:Eu, Dy (SAOED) particles. The resulting system exhibits a high ET efficiency of 53.5%. The multicolor PML of the RhB@SiO2/SAOED system remains visible to the naked eye for exceeding 28 s after mechanical stimulation. With this unique PML behavior, the RhB@SiO2/SAOED system demonstrates the potential applications ranging from visualized reading activities to multi‐mode anticounterfeiting. This universal PML color‐conversion strategy provides a new approach to high‐performance mechanical light energy‐conversion systems and may further inspire more diverse functional applications of classical PML materials.

Efficient Quasi-2D Perovskite Based Blue Light-Emitting Diodes with Carbon Dots Modified Hole Transport Layer.

Quasi-2D perovskites based blue light-emitting diodes (LEDs) suffer from its poor electroluminescence performance, mainly caused by the nonradiative recombination in in defect-rich low-n phases and the unbalanced hole-electron injection in the device. Here, we developed a highly efficient quasi-2D perovskite based sky-blue LEDs behaving recorded external quantum efficiency (EQE) of 21.07% by employing carbon dots (CDs) as additives in the hole transport layer (HTL). We ascribe the high EQE to the effective engineering of CDs: (1) The CDs at the interface of HTLs can suppress the formation of low-efficient n = 1 phase, resulting a high luminescence quantum yield and energy transfer efficiency of the mixed n-phase quasi-2D perovskites. (2) The CDs additives can reduce the conductivity of HTL, partially blocking the hole injection, and thus making more balanced hole-electron injection. The CDs-treated devices have excellent Spectral stability and enhanced operational stability and could be a new alternative additive in the perovskite optoelectronic devices.

Radioluminescence and photoluminescence properties of Sm3+-doped Gd-Ba-Na borate glass scintillator

This study investigates the potential of Gd-Ba-Na borate glasses doped with Sm3+ ions as scintillation materials. The glasses were synthesized using a melt-quenching process, and their luminescence properties were examined. The results demonstrate that the glass sample with 0.5 mol% of Sm3+ exhibits the most promising scintillation performance, achieving the highest integral scintillation efficiency (24.11%) compared to the BGO crystal. For the photoluminescence study, the emission spectra, under 403 nm excitation wavelength, show emission bands centered at 563, 599, 646, and 706 nm, consistent with characteristic Sm3+ transitions. The highest energy transfer efficiency from Gd3+ to Sm3+ (64.37%) is also found in the glass sample with 0.5 mol% Sm3+. The emission color can be tuned by varying the excitation wavelength. Excitation at 403 nm primarily excites Sm3+ ions, resulting in orange emission. In contrast, excitation at 275 nm excites Gd3+ ions, leading to reddish-orange emission. The results demonstrate the potential of this glass composition for use as a highly efficient scintillation material due to its excellent performance in both radioluminescence and photoluminescence properties.

Comprehensive Study of Artificial Light-Harvesting Systems with a Multi-Step Sequential Energy Transfer Mechanism.

Artificial light-harvesting systems (LHSs) with a multi-step sequential energy transfer mechanism significantly enhance light energy utilization. Nonetheless, most of these systems exhibit an overall energy transfer efficiency below 80%. Moreover, due to challenges in molecularly aligning multiple donor/acceptor chromophores, systems featuring ≥3-step sequential energy transfer are rarely reported. Here, a series of artificial LHSs is introduced featuring up to 4-step energy transfer mechanism, constructed using a cyclic peptide-based supramolecular scaffold. These LHSs showed remarkably high energy transfer efficiencies (≥90%) and satisfactory fluorescence quantum yields (ranging from 17.6% to 58.4%). Furthermore, the structural robustness of the supramolecular scaffold enables a comprehensive study of these systems, elucidating the associated energy transfer pathways, and identifying additional energy transfer processes beyond the targeted sequential energy transfer. Overall, this comprehensive investigation not only enhances the understanding of these LHSs, but also underscores the versatility of cyclic peptide-based supramolecular scaffolds in advancing energy harvesting technologies.

Wakefield generation in hydrogen and lithium plasmas at FACET-II: Diagnostics and first beam-plasma interaction results

Plasma wakefield acceleration provides ultrahigh acceleration gradients of tens of GeV/m, providing a novel path toward efficient, compact, TeV-scale linear colliders, and high brightness free electron lasers. Critical to the success of these applications is demonstrating simultaneously high gradient acceleration, high energy transfer efficiency, and preservation of emittance, charge, and energy spread. Experiments at the FACET-II National User Facility at SLAC National Accelerator Laboratory aim to achieve all of these milestones in a single-stage plasma wakefield accelerator, providing a 10 GeV energy gain in a <1 m plasma with high energy transfer efficiency. Such a demonstration depends critically on diagnostics able to measure emittance with mm mrad accuracy, energy spectra to determine both percent level energy spread, and broadband energy gain and loss, incoming longitudinal phase space, and matching dynamics. This paper discusses the experimental setup at FACET-II, including the incoming beam parameters from the FACET-II linac, plasma sources, and diagnostics developed to meet this challenge. Initial progress on the generation of beam ionized wakes in meter-scale hydrogen gas is discussed as well as commissioning of the plasma sources and diagnostics. Published by the American Physical Society 2024

Quantitative guided wave imaging with shear horizontal waves and deep convolutional descent full waveform inversion

Effectively determining the size and thickness distributions of corrosion damages is a vital problem in nondestructive testing (NDT). In this article, a new approach is introduced that employs magnetostrictive transducers (MST) to excite the first dispersive shear horizontal mode (SH1), and utilizes the DCD-FWI (deep convolutional descent full waveform inversion) to provide comprehensive thickness mapping in just 1 s. Compared with traditional imaging techniques, DCD-FWI network is an intrinsically full waveform inversion (FWI) based method, which yields reliable imaging results in large scale finite element simulations. Moreover, the shorter wavelength and resistance to water loading of SH guided waves bring about reliable imaging results. Combined with these advantages, the high energy transfer efficiency of the MST enhances the proposed method's robustness, as demonstrated by guided wave tomography experiments on aluminum plates.

Time sequence variation of incoherent and coherent random laser based on positive replica of abalone shell

Besides the scattering structures, the energy transfer (ET) process in the gain medium plays a significant role in the competition between coherent (comprising strongly coherent components) and incoherent (consisting of weakly coherent or “hidden” coherent components) modes of random lasers. In this study, bichromatic emission random lasers were successfully created using polydimethylsiloxane (PDMS) replicas with grooved structures that imitate the inner surface of abalone shells as scattering substrates. The influence mechanism of the ET process from the monomer to dimer in the Rhodamine 640 dye on the competition of random laser modes was thoroughly investigated from both spectral and temporal dimensions. It was confirmed that the ET process can reduce the gain of monomers while amplifying the gain of dimers. By considering the dominant high-efficiency ET processes, an energy transfer factor associated with the pump energy density was determined. Notably, for the first time, it was validated that the statistical distribution characteristics of the time sequence variations in the coherent random laser generated by dimers closely resemble a normal distribution. This finding demonstrates the feasibility of producing high-quality random number sequences.

Catalytic NIR chemiluminescence sensor with enhanced persistence and intensity for in vivo imaging

Chemiluminescence (CL) is a self-illumination phenomenon that involves the emission of light from chemical reactions, and it provides favorable spatial and temporal information on biological processes. However, it is still a great challenge to construct effective CL sensors that equip strong CL intensity, long emission wavelength, and persistent luminescence for deep tissue imaging. Here, we report a liposome encapsulated polymer dots (Pdots)-based system using catalytic CL substrates (L-012) as energy donor and fluorescent polymers and dyes (NIR 695) as energy acceptors for efficient Near-infrared (NIR) CL in vivo imaging. Thanks to the modulation of paired donor and acceptor distance and the slow diffusion of biomarker by liposome, the Pdots show a NIR emission wavelength (λ em, max = 720 nm), long CL duration (>24 h), and a high chemiluminescence resonance energy transfer efficiency (46.5 %). Furthermore, the liposome encapsulated Pdots possess excellent biocompatibility, sensitive response to H2O2, and persistent whole-body NIR CL imaging in the drug-induced inflammation and the peritoneal metastatic tumor mouse model. In a word, this NIR-II CL nanoplatform with long-lasting emission and high spatial-temporal resolution will be a concise strategy in deep tissue imaging and clinical diagnostics.

Adjoint Algorithm Design of Selective Mode Reflecting Metastructure for BAL Applications.

Broad-area lasers (BALs) have found applications in a variety of crucial fields on account of their high output power and high energy transfer efficiency. However, they suffer from poor spatial beam quality due to multi-mode behavior along the waveguide transverse direction. In this paper, we propose a novel metasurface waveguide structure acting as a transverse mode selective back-reflector for BALs. In order to effectively inverse design such a structure, a digital adjoint algorithm is introduced to adapt the considerably large design area and the high degree of freedom. As a proof of the concept, a device structure with a design area of 40 × 20 μm2 is investigated. The simulation results exhibit high fundamental mode reflection (above 90%), while higher-order transverse mode reflections are suppressed below 0.2%. This is, to our knowledge, the largest device structure designed based on the inverse method. We exploited such a device and the method and further investigated the device's robustness and feasibility of the inverse method. The results are elaborately discussed.

A near-infrared fluorescent probe based FRET for ratiometric sensing of H2O2 and viscosity in live cells

Hydrogen peroxide (H2O2) and viscosity play vital roles in the cellular environment as signaling molecule and microenvironment parameter, respectively, and are associated with many physiological and pathological processes in biological systems. We developed a near-infrared fluorescent probe, CQ, which performed colorimetric and ratiometric detection of H2O2 and viscosity based on the FRET mechanism, and was capable of monitoring changes in viscosity and H2O2 levels simultaneously through two different channels. Based on the specific reaction of H2O2 with borate ester, CQ exhibited a significant ratiometric response to H2O2 with a large Stokes shift of 221 nm, a detection limit of 0.87 μM, a near-infrared emission wavelength of 671 nm, a response time of 1 h, a wide detection ranges of 0.87–800 μM and a high energy transfer efficiency of 99.9 %. CQ could also recognize viscosity by the TICT mechanism, and efficiently detect viscosity changes caused by food thickeners. More importantly, CQ could successfully detect endogenous/exogenous H2O2 and viscosity in live HeLa cells, which was expected to be a practical tool for detecting H2O2 and viscosity in live cells.