Energy Transfer Mechanism Research Articles

Deciphering the Energy Transfer Mechanism Across Metal Halide Perovskite-Phthalocyanine Interfaces.

Energy transfer processes in nanohybrids are at the focal point of conceptualizing, designing, and realizing novel energy-harvesting systems featuring nanocrystals that absorb photons and transfer their energy unidirectionally to surface-immobilized functional dyes. Importantly, the functionality of these dyes defines the ultimate application. Herein, CsPbBr3 perovskite nanocrystals (NCs) are interfaced with zinc phthalocyanine (ZnPc) dyes featuring carboxylic acid. The functionality is the photosensitization of singlet oxygen. The CsPbBr3@ZnPc nanohybrid is to the best of our knowledge the first example, in which an unusual Dexter-type singlet energy transfer between metal halide perovskite nanocrystals and phthalocyanine dyes enables singlet oxygen generation as a proof-of-concept application. A detailed temporal picture of the singlet energy transfer mechanism is made possible by combining key time-resolved spectroscopic techniques, that are, femtosecond, nanosecond, and microsecond transient absorption spectroscopy as well as time-correlated single photon counting, and target analyses. In fact, three excitonic components in the NCs govern a concerted Dexter-type energy transfer. The work illustrates the potential of CsPbBr3@ZnPc as a singlet photosensitizer of ZnPc to produce singlet oxygen (1O2) almost quantitatively while photoexciting CsPbBr3.

The Impact of Silver Codoping on Tb3+ Luminescence in Lithium Tetraborate Glasses.

Spectroscopic properties of Tb-doped and Tb-Ag codoped lithium tetraborate (LTB) glasses with Li2B4O7 (or Li2O-2B2O3) composition are investigated and analysed using electron paramagnetic resonance (EPR), optical absorption, photoluminescence (PL) and photoluminescence excitation (PLE) spectra, PL decay kinetics and absolute quantum yield (QY) measurements. PL spectra of the investigated glasses show numerous narrow emission bands corresponding to the 5D4 → 7FJ (J = 6-0) and 5D3 → 7FJ (J = 5-3) transitions of Tb3+ (4f8) ions. The most intense PL band of Tb3+ ions at 541 nm (5D4 → 7F5 transition) is characterised by a lifetime slightly exceeding 2.6 ms. PL spectra of the Ag-containing glass show two broad weakly resolved emission bands in the violet-green spectral range attributed to Ag+ ions and nonplasmonic Ag nanoclusters. Decay kinetics of these bands are nonmonoexponential, characterised by an average lifetime in the microsecond range. A significant enhancement of the PL intensity and PL QY of Tb3+ ions was observed in Tb-Ag codoped LTB glass in comparison with Tb-doped LTB glass. The excitation energy transfer (EET) mechanisms from Ag+ ions and Ag nanoclusters to Tb3+ ions were explored.

Unraveling the competition between charge and energy transfer in 0D/2D nanographene-graphene heterojunctions

The charge and energy transfer processes in photoexcited 0D/2D donor/graphene heterojunctions occur through multiple different pathways. A donor deexcitation event occurring in the most prevalent Förster energy transfer mechanism (strongly favored over Dexter transfer in van der Waals heterojunctions) prevents charge transfer from taking place, thus creating a competition between the two processes. By applying a robust computational approach, we describe the two processes from first principles and quantify their rates using Förster and Marcus theories. We consider nanojunctions where the donor are nanographenes with varying size and symmetry, and discern important trends, e.g., the symmetry-induced quenching, or the enhancement due to increased size. We observe that heterojunctions where nanographenes do not have a center of symmetry show decreased photoinduced hole and energy transfer rates, which can then be recovered by increasing the delocalization length, whereas for centrosymmetric nanographenes both hole and energy transfer processes are enhanced. Nevertheless, the hole transfer rate dominates over the energy transfer process, providing a new computation-driven design principle for obtaining a high-charge transfer junction with minimized contribution of the competing energy transfer.

Luminescent cyclometalated gold(iii) complexes covalently linked to metal-organic frameworks for heterogeneous photocatalysis.

Phosphorescent gold(iii) complexes possess long-lived emissive excited states, making them ideal for use as molecular sensors and photosensitizers for organic transformations. Literature reports indicate that gold(iii) emitters exhibit good catalytic activity in homogeneous photochemical reactions. Heterogeneous metal-organic framework (MOF)-supported gold(iii) photocatalysts are considered to show high recyclability in photochemical reactions and potentially provide new selectivities. Here, we report the design and development of visible-light-absorbing MOF-covalently linked gold(iii) photocatalysts. A MOF-supported gold(iii) complex exhibits a longer phosphorescence lifetime than its homogeneous counterpart, reaching approximately 110 μs under argon and 12 μs under air when suspended in acetonitrile. This is attributed to the localization of the gold(iii) complex within the MOF nano-cages. The MOF-derived gold(iii) photosensitizer exhibits good catalytic performance in intramolecular and intermolecular [2 + 2] cycloaddition reactions to construct functionalized cyclobutanes and azetidines, both of which are important building blocks for pharmaceuticals. These photochemical [2 + 2] cycloaddition reactions catalyzed by the gold(iii)-MOF are governed by an energy transfer mechanism and do not require redox modulators. Under similar reaction conditions, the crossed [2 + 2] photocycloaddition reaction of two activated alkenes proceeds smoothly, and the cyclobutane product is obtained within 3 hours of irradiation under dilute conditions (0.2 mol dm-3 of alkene).

High-Quantum-Efficiency Pr3+-Doped Li7La3Zr2O12 Garnet and Associated Temperature-Sensing Performance.

The understanding of energy transfer mechanisms between different excited states of Pr3+ is closely bound up with exploiting high-quantum-efficiency Pr3+-doped luminescent thermometers and optimizing their temperature-sensing performances. Herein, we propose a new-type Pr3+-doped tetragonal-phase Li7La3Zr2O12 (Pr3+:LLZO) garnet luminescent thermometer and study accompanied photoluminescence (PL) properties. Combining composition optimization, we gain a fantastic room-temperature PL quantum efficiency within Pr3+:LLZO phosphors (77.48%), a value obviously superior to those of traditional Pr3+-doped garnet-type phosphors. The thermally induced fluorescence quenching of 3P0 emissions within Pr3+:LLZO mainly originates from phonon-assisted thermal ionization, differing from the Pr3+-doped Y3Al5O12 garnet. By contrast, the 1D2 case is akin to most Pr3+-doped materials in that the quenching behavior is seriously associated with the cross-relaxation between the 3P0 and 1D2 states. On that basis, we propose a Pr3+:LLZO luminescence thermometry strategy by utilizing different quenching mechanisms of steady-state 3P0 and 1D2 emissions, performing a comparable temperature-sensing capability to those Pr3+-based garnet-type luminescent thermometers. Our findings strengthen the importance of discerning the quenching mechanisms of Pr3+ emissions and provide a valuable perspective for designing high-quantum-efficiency Pr3+-doped garnet-type luminescent materials and relevant luminescence thermometry.

Bio-Inspired Multiple Responsive NIR II Nanophosphors for Reversible and Environment-Interactive Information Encryption.

Inspired by the natural responsive phenomena, herein the multiple responsive persistent luminescent Zn1.2Ga1.6Ge0.2O4:Ni2+ (ZGGO:Ni) nanoparticles with near-infrared (NIR) IIemission peak ≈1330nm derived from the Ni2+ doping through controlled synthesis based on hydrothermal method are obtained. The obtained NIR II persistent luminescent ZGGO:Ni can not only respond to temperature but also the specific solvent stimulus. The results demonstrate that the NIR II persistent luminescence intensity decreases in hydroxyl containing solvent such as water (H2O) and ethyl alcohol (C2H6O), while the PL intensity remains in solvent without hydroxyl groups such as n-hexane (C6H14) and deuterated water (D2O). This NIR II luminescence quenching is attributed to the adsorption of interaction hydroxyl groups in specific solvents with the amino group on the surface of ZGGO:Ni and the subsequent fluorescence resonance energy transfer mechanism. Benefiting from the multiple responsive properties, the obtained NIR II persistent luminescent ZGGO:Ni is utilized for high-order dynamic optical information encryption, providing increased security level. The multi-responsive NIR II persistent luminescence strategy outlined in this study is anticipated to offer a straightforward methodology for optimizing the optical characteristics of NIR II persistent luminescent materials. Moreover, it is set to expand the scope of their applications in the realm of dynamic and environment-interactive information encryption, thereby opening frontiers for their utilization in advanced security measures.

Energy Transfer Studies on Red Emitting CaGdSbWO8: Sm3+/Eu3+ Phosphor for w-LEDs and Indoor Plant Growth Lighting System.

In the present research work, a solid-state reaction method was employed to synthesize a series of CaGd(0.95-x)SbWO8:Sm0.05Eux (x = 1, 1.5, 2, 3 and 4mol%) phosphors. The phase purity, crystallinity, morphological and compositional studies were analysed via X-ray diffraction (XRD), scanning electron microscopy (SEM) imaging, and energy dispersive spectroscopy (EDS) analysis. The Fourier transform infrared (FT-IR) spectroscopy was utilized to measure OH content in the prepared phosphor material. The diffused reflectance spectroscopy (DRS) analysis was applied to measure the optical energy band gap. The photoluminescence (PL) spectroscopy at excitation wavelengths 275 and 405nm was carried out to analyze the luminescence properties of the prepared phosphors. The intensity of emission peaks of Sm3+ ions decreased as the concentration of Eu3+ ions increased showing the energy transfer mechanism from Sm3+ to Eu3+ ions. The dipole-dipole interaction mechanism is responsible for the energy transfer between Sm3+ to Eu3+ ions as assessed using the Reisfeld approximation. The CIE coordinates of the prepared samples lie in the warm red region represented by the relatively low (3200K) value of correlated color temperature. These results show the suitability of the prepared phosphor for white light emitting diode (w-LEDs) and also in indoor plant growth lighting systems.

The interplay of energy and motion of coupled pendulums: a high school student exploration

Abstract The experiment of string-coupled pendulums offers high school students a hands-on opportunity to explore fundamental principles of physics while developing critical skills. In this experiment, students investigate how an oscillating pendulum transfers kinetic energy to a stationary one, resulting in a cyclical exchange marked by role reversals. The motion of the coupled pendulum is studied using a simple smartphone equipped with free software. Pendulums of equal length and point-mass are arranged in three different configurations: pendulum on a fixed rod, pendulum on a string, and string-coupled pendulum. These configurations not only exhibit varying time periods but also significantly different amplitude decay patterns. Despite inevitable energy dissipation due to frictional losses and air resistance, the oscillations exhibited by the coupled pendulums clearly demonstrate the interplay between synchronization and energy transfer. This initial hands-on investigation serves as a springboard for a more comprehensive exploration of the captivating energy transfer mechanisms and dynamical characteristics inherent to string-coupled pendulums.

Multinuclear Antimony-Bismuth-Lanthanide Cluster-Connected Polyoxometalate for the Detection of 5-Hydroxyindoleacetic Acid via Luminescence.

The judicious selection and combination of multicomponents provide great potential for the further exploration of new polyoxometalate (POM) materials. Here, a delicate control on tungstate, SbIII and BiIII sources, Eu3+ ions, and organic molecules led to the discovery of a novel multimetal cluster-embedded POM [H2N(CH3)2]9Na8H5{[Eu4(H2O)6Sb4Bi2W2O12](SbW9O33)2(SbW8O31)2}·78H2O (1). The polyoxoanion of 1 was constructed from four in situ-formed [SbW8O31]11- and [SbW9O33]9- building blocks connected by two hexa-metallic [Eu2(H2O)3Sb2BiWO6]9+ clusters, to be a rare member of Sb- and Bi-coexisting POM. The most impressive characteristic of 1 is the intricate [Eu2(H2O)3Sb2BiWO6]9+ cluster linker, which contains a SbIII-BiIII coinserted [Sb2BiWO6]3+ core grasping one [Eu1(H2O)2]3+ cation and one [Eu2(H2O)]3+ cation on both sides through Sb-O-Eu and Bi-O-Eu bonds. Functionalized by luminescence centers of Eu3+ ions, 1 can emit intense emission in water and be capable of detecting the biomarker of carcinoids, 5-hydroxyindoleacetic acid (5-HIAA) with a low limit of detection of 0.43 μM, high selectivity, and excellent anti-interference, as well as fast response (12 s). The high detectability of 1 for 5-HIAA is relevant to the underlying dynamic quenching and energy-transfer mechanism. In urine conditions, remarkable recognition of 1 for 5-HIAA and satisfactory recoveries were achieved, indicative of the possibility of 1 in detecting 5-HIAA in a real environment. This work reveals the special clustering effect of SbIII and BiIII atoms in the assembly of neoteric POM species and also promotes the application of POMs as potential diagnostic tool in the early detection of carcinoids.

Future Arctic: how will increasing coastal erosion shape nearshore planktonic food webs?

AbstractArctic regimes. Currently, warming accelerates the erosion of permafrost coasts and the associated discharge of sediment, carbon, and nutrients into the Arctic Ocean. However, the impacts of coastal erosion on planktonic food webs remain understudied. We aimed to (1) understand how coastal erosion impacts nearshore carbon, nutrient, and light regimes; (2) investigate the effects on primary production and energy transfer; and (3) predict how increased erosion will impact the productivity of consumers, and the overall food web interactions. We found that sediment discharge increases turbidity (darkening). This darkening is expected to hamper phytoplankton productivity, while additional carbon input will provide bacteria with direct energy sources, and shift the balance between basal autotrophic and heterotrophic production. Since the heterotrophic pathway has a lower efficiency, its dominance might negatively affect mesozooplankton. Increased Arctic coastal erosion might therefore influence planktonic food webs by changing mechanisms of energy mobilization and transfer to higher trophic levels.

A white light emitting Li2SiO3:Tb3+, Eu3+ phosphors: structural, thermal, spectroscopic properties and energy transfer mechanism

A white light emitting Li2SiO3:Tb3+, Eu3+ phosphors: structural, thermal, spectroscopic properties and energy transfer mechanism

Triplet Electron Exchange in Carbon Nanodots-assisted Long-persistent near-infrared Chemiluminescence for Oncology Synergistic Imaging and Therapy.

In classical photodynamic therapy, tumor cells are killed by the cytotoxic species via type-I/II photochemical reactions, seriously limited by the external photoexcitation and hypoxia. Herein, the electron transfer mechanism between fluorophores and peroxalate-H2O2 reaction is investigated and the singlet/triplet electron exchange is utilized to achieve long-persistent chemiluminescence imaging and synergistic type-I/II/III photodynamic therapy. As a proof-of-concept, the photosensitizers of carbon nanodots (CDs)-loaded chlorin e6 (CDs-Ce6) are designed and integrated with the peroxalate molecules, and the as-prepare polymer carbon nanodots (p-CDs) exhibit novel tumor microenvironment (TME)-responsive long-persistent near-infrared CL and photochemical reactions, evoking the in vivo imaging and synergistic dynamic therapy in tumor tissue. Mechanistically, the excess reactive oxygen species in TME can trigger the chemically initiated singlet/triplet electron exchange between the hydrophobic CDs-Ce6 and peroxalate-derived 1,2-dioxetanes and thus the excess excited singlet/triplet electron of the CDs-Ce6 can ensure the long-persistent near-infrared CL, type I/II photochemical production of hydroxyl radicals, superoxide radical and singlet oxygen, and type III photochemical damage of maladjusted biomacromolecules, enabling the long-persistent near-infrared biological imaging and enhanced cancer therapy. These results shed a new sight into the energy transfer mechanism in chemiluminescence and pave a new sight into the architecture of multifunctional theragnostic nanoplatforms.

Effects of Hall Current and Thermal Radiation on the Time-Dependent Swirling Flow of Hybrid Nanofluids over a Disk Surface: A Bayesian Regularization Artificial Neural Network Approach

For automobile and aerospace engineers, implementing Hall currents and thermal radiation in cooling systems helps increase the performance and durability of an engine. In the case of solar energy systems, the effectiveness of heat exchangers and solar collectors can be enhanced by the best use of hybrid nanofluids and the implementation of a Hall current, thermophoresis, Brownian motion, a heat source/sink, and thermal radiation in a time-dependent hybrid nanofluid flow over a disk for a Bayesian regularization ANN backpropagation algorithm. In the current physical model of Cobalt ferrite CoFe2O4 and aluminum oxide Al2O3 mixed with water, a new category of the nanofluid is called the hybrid nanofluid. The study uses MATLAB bvp4c to unravel such intricate relations, transforming PDEs into ODEs. This analysis enables the numerical solution of several BVPs that govern the system of the given problem. Hall currents resulting from the interaction between magnetic fields and the electrically conducting nanofluid, and thermal radiation as an energy transfer mechanism operating through absorption and emission, are central factors for controlling these fluids for use in various fields. The graphical interpretation assists in demonstrating the character of new parameters. The heat source/sink parameter is advantageous to thermal layering, but using a high Schmidt number limits the mass transfer. Additionally, a backpropagation technique with Bayesian regularization is intended for solving ordinary differential equations. Training state, performance, error histograms, and regression demonstration are used to analyze the output of the neural network. In addition to this, there is a decrease in the fluid velocity as magnetic parameter values decrease and a rise in the fluid temperature while the disk is spinning. Thermal radiation adds another level to the thermal behavior by altering how the hybrid nanofluid receives, emits, and allows heat to pass through it.

A nonequilibrium kinetic model of high-resolution vibrational energy transfer in RDX from selective IR excitation.

In this paper, we develop a model based on a second quantization-with anharmonic phonon scattering and the phonon Boltzmann transport equation-to study precise high-resolution nonequilibrium vibrational energy transfer (VET) under selective phonon excitation in cyclotrimethylene trinitramine. We simulate mid-infrared pump-probe spectroscopy and observe a prompt appearance (<1ps) of broad-spectrum intensity, which agrees well with experimental data in the literature. The selective excitation of phonons at different frequencies reveals distinct VET pathways and the kinetic evolution of mode occupations as the system reaches a new equilibrium temperature. Three types of transition mechanisms are found to play outsized roles in terms of the amount of energy transferred and the transfer rate: (1) vibrational modes close to the excited frequencies typically respond faster and reach higher temperatures regardless of the excitation frequency; (2) the overtone pathway connecting the modes near 550 and 1150cm-1 is an important bridge between far- and mid-IR; and (3) fast aggregation of energy at 2800cm-1 mediates transfer to/from high frequencies through a second overtone pathway involving modes near 1400cm-1. In addition, by monitoring the temperature of the N-N/N-O stretching modes, strong coupling between those modes and the C-H stretching modes is found. The coupling likely draws the vibrational modes close to both the proton transfer transition state for HONO elimination and the N-N stretching for bond cleavage. The high-resolution understanding of the nonequilibrium kinetics of phonons provides important insight into the energy transfer and initiation mechanisms of molecular solids due to external stimuli.

Defect-Mediated Energy Transfer Mechanism by Modulating Lattice Occupancy of Alkali Ions for the Optimization of Upconversion Luminescence.

The performance optimization of photoluminescent (PL) materials is a hot topic in the field of applied materials research. There are many different crystal defects in photoluminescent materials, which can have a significant impact on their optical properties. The luminescent properties and chemical stability of materials can be effectively improved by adjusting lattice defects in crystals. We systematically studied the effect of doping ions on the energy transfer upconversion mechanism in different defect crystals by changing the matrix alkali metal ions. Meanwhile, the influence mechanism of crystal defect distribution on luminescence performance is explored by adjusting the ratio of Na-Li. The PL spectra indicate that changing the alkaline ions significantly affects the luminescence performance and efficiency of UCNPs. The change in ion radius leads to substitution or gap changes in the main lattice, which may alter the symmetry and strength of the crystal field around doped RE ions, thereby altering the UCL performance. Additionally, we demonstrated the imaging capabilities of the synthesized upconversion nanoparticles (UCNPs) in cellular environments using fluorescence microscopy. The results revealed that Na0.9Li0.1LuF4-Yb, Er nanoparticles exhibited significantly enhanced fluorescence intensity in cell imaging compared to other compositions. We further investigated the mechanism by which structural defects formed by doping ions in UCNPs with different alkali metals affect energy transfer upconversion (ETU). This work emphasizes the importance of defect regulation in the ETU mechanism to improve the limitations of crystal structure on the luminescence performance and promote the future application of upconversion nanomaterials, which will provide important theoretical references for the exploration of high-performance luminescent materials in the future.

Structural insights into the assembly and energy transfer of haptophyte photosystem I–light-harvesting supercomplex

Haptophyta represents a major taxonomic group, with plastids derived from the primary plastids of red algae. Here, we elucidated the cryoelectron microscopy structure of the photosystem I-light-harvesting complex I (PSI-LHCI) supercomplex from the haptophyte Isochrysis galbana. The PSI core comprises 12 subunits, which have evolved differently from red algae and cryptophytes by losing the PsaO subunit while incorporating the PsaK subunit, which is absent in diatoms and dinoflagellates. The PSI core is encircled by 22 fucoxanthin-chlorophyll a/c-binding light-harvesting antenna proteins (iFCPIs) that form a trilayered antenna arrangement. Moreover, a pigment-binding subunit, LiFP, which has not been identified in any other previously characterized PSI-LHCI supercomplexes, was determined in I. galbana PSI-iFCPI, presumably facilitating the interactions and energy transfer between peripheral iFCPIs and the PSI core. Calculation of excitation energy transfer rates by computational simulations revealed that the intricate pigment network formed within PSI-iFCPI ensures efficient transfer of excitation energy. Overall, our study provides a solid structural foundation for understanding the light-harvesting and energy transfer mechanisms in haptophyte PSI-iFCPI and provides insights into the evolution and structural variations of red-lineage PSI-LHCIs.

Ultrabroadband Visible-Near-Infrared Phosphor CaY2Mg2Ge3O12:Ce3+/Cr3+ and Its Temperature Sensing.

With the wide application of phosphor conversion light-emitting diode (pc-LED) in nondestructive testing, spectral illumination, near-infrared (NIR) spectroscopy, agricultural medical care, and other fields, the ultrabroadband visible-NIR tunable emission phosphor is considered as the most promising fluorescent material. In this paper, Ce3+/Cr3+ single-doped and codoped CaY2Mg2Ge3O12 phosphors were successfully prepared by using the high-temperature solid-state method. Ce3+ and Cr3+ codoped phosphors show ultrabroadband visible-NIR emission from 480 to 900 nm with two emission peaks at visible 556 nm and infrared 758 nm. Interestingly, energy transfer and occupation competition are shown in the Ce3+/Cr3+ codoped CaY2Mg2Ge3O12. Additionally, the luminescence of Ce3+/Cr3+ codoped CaY2Mg2Ge3O12 is adjusted with the doping ion concentration or ambient temperature changes. The energy transfer mechanism of Ce3+-Cr3+ is studied according to Dexter's formula, and a dipole-dipole interaction is determined. Furthermore, its superior sensitivity with Sr of 1.331%K-1 at 298 K was calculated by using the fluorescence intensity ratio. The pc-LED device was fabricated by combining a commercial 460 nm blue LED chip with CaY2Mg2Ge3O12:Ce3+, Cr3+ phosphors, producing yellow-white light and broadband NIR light, indicating great potential application in night vision pc-LEDs.

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)

Peniotron: A Promising Microwave Source with Potential That Has Yet to Be Realized

The peniotron is a fast-wave vacuum tube that can generate coherent microwave radiation in the millimeter-wave range. Although it uses a beam of gyrating electrons like other gyro-devices (gyrotron, gyro-TWT, gyro-BWO, etc.), its operating principle is completely different from that of electron cyclotron masers. The theory predicts a very high efficiency (about 95%) of the peniotron mechanism of interaction and energy transfer from the electron beam to the wave. However, this extremely attractive and advantageous property of peniotrons has not yet been realized in practice. In this paper, we present the current state of research on this class of devices and give an overview of the theory and experimental results of peniotrons and gyro-peniotrons with different configurations. We also discuss the main problems and the reasons for the lower efficiency and finally evaluate the potential for solving the problems and revitalizing the work on this promising device.

Solar Flares and the Aether Dynamic

This study investigates the dynamics of Solar flares using the "closed fluid dynamic principle" proposed by Muhammad Aslam Musakhail, which reinforces the pre-Einsteinian aether theory. By defining the "aether force" as the difference between relativistic total mass and rest mass, the principle provides a novel perspective on the relativistic transitions in Solar flare phenomena. The analysis builds on Parker's force-free model and Melrose’s resistive slab theory, extending them to describe the dual-phase dynamics of Solar flares: the Alfvénic phase, where massive fermions (v&lt;c) propagate as Alfvén waves, and the heat-dissipation phase, where fermions transition to massless states (v=c), driven by current sources. Key results reveal that energy dissipation scales with resistivity, and the temporal evolution of Poynting flux and magnetic fields highlights distinct transitions between the phases. Numerical simulations demonstrate the exponential decay of axial magnetic fields and the helical organization of flux tubes. These findings validate theoretical predictions and provide insights into particle acceleration, magnetic reconnection, and energy transfer mechanisms during Solar flares. This work not only advances the understanding of Solar flare energetics but also establishes a mathematical framework that can be extended to other astrophysical phenomena, such as cosmic ray acceleration and stellar flares. Future studies should focus on numerical validation and observational testing to refine the dual-phase model and its broader applicability.