High Energy Transfer Efficiency Research Articles

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.

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 efficiency of solar energy utilization. In order to improve the utilization of sunlight, researchers have developed a variety of artificial light-harvesting system to simulate photosynthesis in nature. Here, we report a supramolecular self-assembly artificial light-harvesting system in aqueous solution. We modified β-CD with the donor molecule naphthalimide and adamantane with the tetraphenylethylene molecule which has aggregation-induced emission effects (AIE). 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. The light-harvesting system has a high energy transfer efficiency (ΦET). Therefore, this study provides a new strategy for constructing artificial light-harvesting system.

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.

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

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.

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.

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.

A highly sensitive ratiometric fluorescent probe for detecting HSO3−/SO32− and viscosity change based on FRET/TICT mechanism

BackgroundSulfur dioxide (SO2) is a significant gas signaling molecule in organisms, and viscosity is a crucial parameter of the cellular microenvironment. They are both involved in regulating many physiological processes in the human body. However, abnormalities in SO2 and viscosity levels are associated with various diseases, such as cardiovascular disease, lung cancer, respiratory diseases, neurological disorders, diabetes and Alzheimer's disease. Hence, it is essential to explore novel and efficient fluorescent probes for simultaneously monitoring SO2 and viscosity in organisms. ResultsWe selected quinolinium salt with good stability, high fluorescence intensity, good solubility and low cytotoxicity as the fluorophore and developed a highly sensitive ratiometric probe QQD to identify SO2 and viscosity changes based on Förster resonance energy transfer/twisted intramolecular charge transfer (FRET/TICT) mechanism. Excitingly, compared with other probes for SO2 detection, QQD not only identified HSO3−/SO32− with a large Stokes shift (218 nm), low detection limit (1.87 μM), good selectivity, high energy transfer efficiency (92 %) and wide recognition range (1.87–200 μM), but also identified viscosity with a 26-fold fluorescence enhancement and good linearity. Crucially, QQD was applied to detect HSO3−/SO32− and viscosity in actual water and food samples. In addition, QQD had low toxicity and good photostability for imaging HSO3−/SO32− and viscosity in cells. These results confirmed the feasibility and reliability of QQD for HSO3−/SO32− and viscosity imaging and environmental detection. SignificanceWe reported a unique ratiometric probe QQD for detecting HSO3−/SO32− and viscosity based on the quinolinium skeleton. In addition to detecting HSO3−/SO32− and viscosity change in actual water and food samples, QQD could also monitor the variations of HSO3−/SO32− and viscosity in cells, which provided an experimental basis for further exploration of the role of SO2 derivatives and viscosity in biological systems.

Exploiting multi-stiffness combination inspired absorbers for simultaneous energy harvesting and vibration mitigation

In scenarios where wide-amplitude shock excitation is encountered, a routine bistable configuration struggles to achieve satisfactory energy transfer, and a sensible combination of multiple nonlinear oscillators with different stiffness mechanisms can be exploited to achieve optimal vibration mitigation performance. In this paper, a nonlinear energy conversion and multi-stiffness combination inspired dynamic vibration absorber (NECMC-DVA) is proposed with a magnetic-spring tunable nonlinear stiffness element as the substructure. Parametric studies are performed for different modes of magnet-spring tunable nonlinear stiffness unit arrays considering transient impulses and harmonic excitation. The NECMC-DVA device, which comprises bistable oscillators, cubic stiffness oscillators, and hybrid stiffness oscillators, is also experimentally demonstrated for its synergistic performance in vibration mitigation and energy harvesting. The performance of the NECMC-DVA is measured under transient impulses and harmonic excitations. It has been found that the NECMC-DVA, which consists of a bistable oscillator, a cubic stiffness oscillator, a hybrid stiffness oscillator, energy-capture elements, and motor sequences, achieves high-efficiency nonlinear energy transfer and significant shock robustness in wide-amplitude impulsive scenarios. The NECMC-DVA with hybrid energy sinks demonstrates more remarkable targeted energy transfer and energy conversion performance than its pure bistable oscillator counterpart. Furthermore, the NECMC-DVA prototype can achieve adaptive vibration control modulation and energy conversion management through motion control boards by monitoring ambient excitation signals. Therefore, the NECMC-DVA enables integrated active and passive mitigation and energy harvesting to simultaneously accommodate multi-source indeterminate vibration and shock environments.

Semi-Transparent Luminescent Solar Concentrators Based on Intramolecular Energy Transfer in Polyurethane Matrices.

Luminescent solar concentrators (LSCs) are spectral conversion devices offering interesting opportunities for the integration of photovoltaics into the built environment and portable systems. The Förster-resonance energy transfer (FRET) process can boost the optical response of LSCs by reducing energy losses typically associated to non-radiative processes occurring within the device under operation. In this work, a new class of FRET-based thin-film LSC devices is presented, in which the synthetic versatility of linear polyurethanes (PU) is exploited to control the photophysical properties and the device performance of the resulting LSCs. A series of luminescent linear PUs are synthesized in the presence of two novel bis-hydroxyl-functionalized luminophores of suitable optical properties, used as chain extenders during the step-growth polyaddition reaction for the formation of the linear macromolecular network. By synthetically tuning their composition, the obtained luminescent PUs can achieve a high energy transfer efficiency (≈90%) between the covalently linked luminophores. The corresponding LSC devices exhibit excellent photonic response, with external and internal photon efficiencies as high as ≈4% and ≈37%, respectively. Furthermore, their optimized power conversion efficiency combined with their enhanced average visible-light transmittance highlight their suitability for potential use as transparent solar energy devices.

Intermolecular Protein-Water Coupling Impedes the Coupling Between the Amide A and Amide I Mode in Interfacial Proteins.

The coupling between different vibrational modes in proteins is essential for chemical dynamics and biological functions and is linked to the propagation of conformational changes and pathways of allosteric communication. However, little is known about the influence of intermolecular protein-H2O coupling on the vibrational coupling between amide A (NH) and amide I (C═O) bands. Here, we investigate the NH/CO coupling strength in various peptides with different secondary structures at the lipid cell membrane/H2O interface using femtosecond time-resolved sum frequency generation vibrational spectroscopy (SFG-VS) in which a femtosecond infrared pump is used to excite the amide A band, and SFG-VS is used to probe transient spectral evolution in the amide A and amide I bands. Our results reveal that the NH/CO coupling strength strongly depends on the bandwidth of the amide I mode and the coupling of proteins with water molecules. A large extent of protein-water coupling significantly reduces the delocalization of the amide I mode along the peptide chain and impedes the NH/CO coupling strength. A large NH/CO coupling strength is found to show a strong correlation with the high energy transfer rate found in the light-harvesting proteins of green sulfur bacteria, which may understand the mechanism of energy transfer through a molecular system and assist in controlling vibrational energy transfer by engineering the molecular structures to achieve high energy transfer efficiency.

Supramolecular confinement effect enabling light-harvesting system for photocatalytic α-oxyamination reaction

The supramolecular Förster resonance energy transfer (FRET) is seen as a promising approach for organic photocatalysis using dyes as catalysts, because it combines the high efficiency of energy transfer with the dynamic responsiveness based on non-covalent interactions. Here we propose a supramolecular FRET photocatalysis strategy for α-oxyamination reaction based on supramolecular confinement effect. The well-designed benzothiadiazole-based cationic monomer as energy donor and the dyes of Nile Red as acceptor are doped into the amphiphilic surfactants of sodium dodecyl sulfate (SDS). Benefitting from the supramolecular confinement space provided by SDS in aqueous environment, the FRET process between the monomer and Nile Red is effectively achieved (exciton migration rate: 3.99 × 1014 L mol‒1 s‒1). On this basis, the supramolecular FRET system is used as an efficient energy source to catalyze α-oxyamination reactions between a series of 1,3-dicarbonyl compounds and 2,2,6,6-tetramethylpiperidine-1-oxyl under white LED light, showing a yield as high as 94 % and a turnover frequency value of 3.92 h‒1. This photocatalytic result shows a great enhancement compared to that of Nile Red alone.

Chemiluminescent Conjugated Polymer Nanoparticles for Deep-Tissue Inflammation Imaging and Photodynamic Therapy of Cancer.

Deep-tissue optical imaging and photodynamic therapy (PDT) remain a big challenge for the diagnosis and treatment of cancer. Chemiluminescence (CL) has emerged as a promising tool for biological imaging and in vivo therapy. The development of covalent-binding chemiluminescence agents with high stability and high chemiluminescence resonance energy transfer (CRET) efficiency is urgent. Herein, we design and synthesize an unprecedented chemiluminescent conjugated polymer PFV-Luminol, which consists of conjugated polyfluorene vinylene (PFV) main chains and isoluminol-modified side chains. Notably, isoluminol groups with chemiluminescent ability are covalently linked to main chains by amide bonds, which dramatically narrow their distance, greatly improving the CRET efficiency. In the presence of pathologically high levels of various reactive oxygen species (ROS), especially singlet oxygen (1O2), PFV-Luminol emits strong fluorescence and produces more ROS. Furthermore, we construct the PFV-L@PEG-NPs and PFV-L@PEG-FA-NPs nanoparticles by self-assembly of PFV-Luminol and amphiphilic copolymer DSPE-PEG/DSPE-PEG-FA. The chemiluminescent PFV-L@PEG-NPs nanoparticles exhibit excellent capabilities for in vivo imaging in different inflammatory animal models with great tissue penetration and resolution. In addition, PFV-L@PEG-FA-NPs nanoparticles show both sensitive in vivo chemiluminescence imaging and efficient chemiluminescence-mediated PDT for antitumors. This study paves the way for the design of chemiluminescent probes and their applications in the diagnosis and therapy of diseases.

Cy5 Dye Cassettes Exhibit Through-Bond Energy Transfer and Enable Ratiometric Fluorescence Sensing.

The chemosensor literature contains many reports of fluorescence sensing using polyaromatic hydrocarbon fluorophores such as pyrene, tetraphenylethylene, or polyaryl(ethynylene), where the fluorophore is excited with ultraviolet light (<400 nm) and emits in the visible region of 400-500 nm. There is a need for general methods that convert these "turn-on" hydrocarbon fluorescent sensors into ratiometric sensing paradigms. One simple strategy is to mix the responsive hydrocarbon sensor with a second non-responsive dye that is excited by ultraviolet light but emits at a distinctly longer wavelength and thus acts as a reference signal. Five new cyanine dye cassettes were created by covalently attaching a pyrene, tetraphenylethylene, or biphenyl(ethynylene) component as the ultraviolet-absorbing energy donor directly to the pentamethine chain of a deep-red cyanine (Cy5) energy acceptor. Fluorescence emission studies showed that these Cy5-cassettes exhibited large pseudo-Stokes shifts and high through-bond energy transfer efficiencies upon excitation with ultraviolet light. Practical potential was demonstrated with two examples of ratiometric fluorescence sensing using a single ultraviolet excitation wavelength. One example mixed a Cy5-cassette with a pyrene-based fluorescent indicator that responded to changes in Cu2+ concentration, and the other example mixed a Cy5-cassette with the fluorescent pH sensing dye, pyranine.

NBD-based colorimetric and ratiometric fluorescent probe in NIR for bisulfite

This work presented a FRET-ICT based fluorescent probe (named NTC) composed of coumarin-benzothiazole as the acceptor and 4-nitrobenzo[c][1,2,5] oxadiazole (NBD) as the donor for the detection of SO2 derivatives in NIR. Probe NTC possessed superior performance including selectivity, quickly response toward SO32−/HSO3− and high energy transfer efficiency (94 %). The test strips provided a simple and effective tool in detecting the presence of bisulfite. Besides, NTC was applied to test the sulfur dioxide derivatives in food samples and cells.

Stepwise phosphorescence energy transfer for NIR cell imaging based on macrocycle disaggregated amphiphile

A multicolor phosphorescence supramolecular system was constructed based on the complexation of amphiphile (G) and cucurbit[8]uril (CB[8]). The guest G which was composed of hydrophobic coumarin and hydrophilic phosphor 6-bromoisoquinoline can aggregate in water and form large nanosheets accompanying bright fluorescence at 390 nm. After encapsulated by CB[8], the aggregation was prohibited and formed nanosheets with smaller size and the fluorescence peak at 390 nm decreased, meanwhile a phosphorescence peak at 550 nm appeared. Upon the adding of lower-rim dodecyl-modified sulfonatocalix[4]arene (SC4AD), the aggregation was disrupted and particles were formed which were a few 10s of nanometers in size. Subsequently, a stepwise high efficient phosphorescence energy transfer system with a variety of colors was constructed with rhodamine B (RhB) and Sulfo-Cyanine 5 (cy5)/Si-rhodamine (SiR) as acceptors. Finally, the multicolor phosphorescent supramolecular assembly was used to near-infrared cell imaging.