Energy Charge Research Articles

Recent Advances in Understanding Triplet States in Metal Nanoclusters: Their Formation, Energy Transfer, and Applications in Photon Upconversion.

Recent experimental findings, rapidly accumulating over the past few years, has revealed that in the electronic excited states of metal nanoclusters (MNCs) composed of noble metal atoms (e.g., Cu, Ag, or Au), triplet states are generated with remarkably high efficiency, exerting a pivotal influence over the photophysical properties of the MNCs, notably their photoluminescence characteristics. As a result, MNCs are increasingly recognized as promising luminescent nanomaterials that exhibit room-temperature phosphorescence and thermally activated delayed fluorescence. Furthermore, the significance of triplet-state-mediated energy transfer and charge transfer in intermolecular photophysical processes is gaining increasing recognition, particularly in the applications of MNCs as photosensitizers for singlet oxygen and organic molecular triplets. This Perspective focuses on recent advances in understanding of the formation and photophysics of triplet states in MNCs. Additionally, a brief overview is provided of a series of studies exploring the use of MNCs as triplet sensitizers for photon upconversion via triplet-triplet annihilation, and future prospects for this emerging application are discussed.

Revealing mercury species-specific transfer and toxicity mechanisms in placental trophoblasts

Environmental mercury (Hg) follows a biogeochemical cycle resulting in a variety of Hg species. Therefore, human exposure to the three Hg species inorganic Hg via crops and air, methyl mercury through fish consumption and ethyl mercury due to the use as antiseptic agent in medical application is a rising concern. Especially pregnant women and their developing fetus present a vulnerable population. However, little is known about its transfer and toxicity in placental barrier building cells. Here, Hg species-specific transfer and toxicity in placental trophoblasts, which are the main cell type involved in nutrient transfer, were investigated by using the established BeWo b30 in vitro model. The transfer of inorganic Hg was much lower compared to the organic Hg species and all three species were able to perturb barrier integrity. This was accompanied by a less pronounced cytotoxicity of HgCl2 compared to the two organic species. The energy charge value indicated an increase for inorganic Hg and a decrease for organic Hg compounds. Regarding antioxidative defense, inorganic Hg elevated GSSG levels, while organic Hg decreased GSH. Activity of antioxidative defense related enzymes showed a decrease upon Hg species treatment and all three species induced either apoptotic and necrotic cell death.

New regime of the Coulomb blockade in quantum dots

We consider how the absence of thermalization affects the classical Coulomb blockade regime in quantum dots. By solving the quantum kinetic equation in the experimentally accessible regime when the dot has two relevant occupation states, we calculate the current–voltage characteristics for arbitrary coupling to the leads. If the couplings are strongly asymmetric, the Coulomb staircase is practically reduced to the first step, which is independent of the charging energy, when the Fermi energy is comparatively small, while the standard thermalized results are recovered in the opposite case. When the couplings are of the same order, the absence of thermalization has a new, striking signature—a robust additional peak in the differential conductance.

Spectrometers of Neutrons and Fast Atoms of Tokamak Thermonuclear Plasma Based on CVD Synthesized Diamond Single-Crystal Films

High radiation resistance, chemical inertness, the ability to operate at elevated temperatures, high mobility and efficiency of charge-carrier collection are important properties of diamond for designing detectors and spectrometers of ionizing radiation. Currently, diagnostics of neutrons and neutral particle fluxes based on diamond detectors for the ITER thermonuclear reactor are justified and developed. This work presents the results of a Raman spectroscopy and photoluminescence spectroscopy study of the electronic quality of synthesized epitaxial diamond films obtained by vapor deposition in a hydrogen and methane mixture in the ARDIS reactor on boron-doped single-crystal diamond substrates. To confirm their electronic quality, detectors have been made from films selected by spectrometric methods and the charge collection efficiency and energy resolution have been measured when irradiated with alpha particles from a 241Am source and 14.7 MeV fast neutrons from the ING-07T2 neutron generator.

Techno-economic analysis of green hydrogen production and electric vehicle charging using redundant energy on a solar photovoltaic mini-grid

The trajectory of the world's energy use has moved towards the use of renewable energy to increase energy access. Solar energy's pace of growth as a result of its low cost has resulted in it being used to generate electricity for areas that do not have access to grid electricity. Thus, solar photovoltaic mini-grid systems have been deployed in several areas. Over time, it has been found that these systems generate a significant amount of redundant energy, which translates to low profitability for the mini-grid operators, as only a fraction of the system's capacity is used. This study seeks to investigate the economic feasibility of using this redundant energy for green hydrogen production and electric vehicle charging. The results revealed that both the green hydrogen production and electric vehicle charging are economically viable. Net Present Value, Internal Rate of Return and Simple Payback Period obtained for green hydrogen production are $20,000, 24.6 %, 9 years, while those of the electric vehicle charging are $109,625, 28.41 %, 4 years respectively. Over the projects’ lifetime, levelised cost of hydrogen and levelised cost of energy for charging are $6.88/kg and $0.23/kWh respectively. Furthermore, a sensitivity analysis revealed that the levelised costs for both projects are most sensitive to the plant capacity factor and capital expenditure. The study also shows that the wasted energy of the PV mini-grid could be reduced from as high as 69.95 % to nearly 0 %. This research underscores the potential of other clean energy technologies to reduce the wasted energy on existing PV systems, whiles improving the economic state of mini-grid communities.

Ultra-fast photoelectron transfer in bimetallic porphyrin optoelectrode for single neuron modulation

Shrinking the size of photoelectrodes into the nanoscale will enable the precise modulation of cellular and subcellular behaviors of a single neuron and neural circuits. However, compared to photovoltaic devices, the reduced size causes the compromised efficiencies. Here, we present a highly efficient nanoelectrode based on bimetallic zinc and gold porphyrin (ZnAuPN). Upon light excitation, we observe ultrafast energy transfer (~66 ps) and charge transfer (~0.5 ps) through the porphyrin ring, enabling 97% efficiency in separating and transferring photoinduced charges to single Au-atom centers. Leveraging these isolated Au atoms as stimulating electrode arrays, we achieve significant photocurrent injection in single neurons, triggering action potential with millisecond light pulses. Notably, Extracranial near-infrared light irradiation of the motor cortex induces neuronal firing and enhances mouse movement. These results show the potential of nanoscale optoelectrodes for high spatiotemporal modulation of neuronal networks without the need for gene transfection in optogenetics.

Designing high-performance asymmetric and hybrid energy devices via merging supercapacitive/pseudopcapacitive and Li-ion battery type electrodes

We report a strategic development of asymmetric (supercapacitive–pseudocapacitive) and hybrid (supercapacitive/pseudocapacitive–battery) energy device architectures as generation–II electrochemical energy systems. We derived performance-potential estimation regarding the specific power, specific energy, and fast charge–discharge cyclic capability. Among the conceived group, pseudocapacitor–battery hybrid device is constructed with a high-rate intrinsic asymmetric pseudocapacitive (α − MnO2/rGO) and a high-capacity Li-ion intercalation battery type (po-nSi/rGO) electrodes. The experimental setup was developed to measure the current sharing between the two different active materials in a single device allowing us to distinguish the contribution of each active electrode material. The combined potentiostatic cyclic voltammograms and galvanostatic charge–discharge cycling profiles provided gravimetric capacity exceeding 600 F/g (or 180.5 mAh g−1 and ≥ 35mC/cm2) resulting in higher specific power and specific energy densities of 6.5 kW kg−1 and 33.5 Wh kg−1 with Coulombic efficiency (CE) and capacitance retention exceeding ≥ 85–90%, reported to date for full cell configuration, compared with symmetric or half-cell configurations (ca. 0.1 kW kg−1 and 13.7 Wh kg−1). Other systems studied provided specific energy ranged between 28 Wh kg−1 and 50 Wh kg−1 and specific power between 6.5 kW kg−1and 1.3 kW kg−1. Moreover, the behavior of such asymmetric hybrid devices represented a linear combination of the two active electrode material systems. The use of aqueous (and organic) electrolytes for asymmetric electrodes dramatically improved device performance and stability depending upon the electrode combination forming hybrid energy devices. We attribute the observed efficient performance of these hybrid devices induced by hybridized and emergent redox chemistries of merged electrode materials and dynamical processes at the electrode-electrolyte interfaces (intrinsic electroactivity, optimized double-layer and quantum capacitance) which play multiple roles. These energy devices are commercially relevant due to their potential viability in future hybrid electric vehicles, smart electric grids, electrocatalytic fuel production, space (micro-satellites), and miniaturized flexible electronic and wearable biomedical devices.

Method and Implementation of Projected Hybrid Orbitals for Treating Multiple Covalent Bonds in Combined QM/MM Calculations.

The projected hybrid orbital (PHO) method for treatment of multiple boundary atoms introduces a novel solution for handling the covalent connection between quantum mechanical (QM) and molecular mechanical (MM) regions in QM/MM calculations. By projecting the QM basis, typically adequately large for computational accuracy, onto a secondary minimal basis set on the boundary atom, it preserves electronic interactions between the two regions without system-specific parameters. Applicable in both ab initio wave function theory and density functional theory, PHO has been shown to maintain structural and electronic integrity across various systems. It offers key advantages over traditional QM/MM methods, such as avoiding modification of MM charge distribution and energy corrections, while being flexible for biochemical systems and potentially broader QM/QM embedding frameworks.

Optically controlled phase change wood for energy storage and heat release

Molecular solar thermal (MOST) fuels efficiently store solar energy and release it as heat by photoisomerization-induced phase change. However, MOSTs still struggle to meet practical demands due to its slow cis-trans isomerization rate, solvent-assisted charging and low energy storage density. Herein, we develop an optically controlled phase change wood (OCPCW) through impregnating methoxyazobenzene (mAZO) into delignified basswood with light energy storage and thermal energy release. Wood, as supporting frame, accelerates the rate of cis-trans isomerization due to the dispersion of mAZO by wood pores. In addition, the per unit storage energy density of mAZO in OCPCW can reach 307.5 J·g−1, which is higher than that of pure mAZO (229 J·g−1), due to the hydrogen bonding between cellulose and mAZO. Under sunlight irradiation, the cis-OCPCM undergoes isomerization to trans-OCPCM, releasing heat and leading to a temperature increase approximately 2 °C higher than that of delignified basswood under identical conditions. Furthermore, color changing in response to phase change, the OCPCM could be designed for encrypted and decrypted information with dual imaging modes through the color change and exothermic behavior. This work paves the way for the development of phase change wood for efficient solar energy storage and release and application in encrypted information display.

Dye Decorated Ammonium Perchlorate with Fast Decomposition and High Safety Performance

AbstractEnhancing the thermal decomposition efficiency and safety of ammonium perchlorate (AP) is of far‐reaching significance in composite propellants. Most catalysts act well on the thermal decomposition of AP, however, synergistically achievements of fastened decomposition and improved mechanical safety are still in challenge. Herein, neutral red (NR) is selected from typical dyes through theoretical calculations, acting as an organic decoration of AP crystal with improved performances. Among the four organic dyes, NR demonstrated the highest adsorption energy and evident charge transfer at the interface. Following preparations through a freeze‐drying technique obtained a quasi‐homogeneous energetic composite (NR‐AP‐5%). The large interaction force between NR and AP promoted the rupture of chemical bonds between Cl and O as proved by TG‐MS, showing excellent energy‐release performance with the decreased exothermic peak from 437.0 to 355.5 °C. Correspondingly, the activation energy is reduced from 213.59 to 107.72 kJ mol−1, with largely increased heat release from 447.29 to 1014.86 J g−1. In addition, the inert decoration of NR endowed considerable advances in the safety performances of AP, achieving remarkably improved impact and friction sensitivity of 35 J and 288 N, respectively. This unique assembly structure provides a novel strategy to achieve high‐effective catalysis for functional propellants.

Molecular engineering in thizolo[5,4-d]thiazole-based donor-acceptor covalent organic framework Induced high-efficient photosynthesis of H2O2

Covalent organic frameworks (COFs), as a newly emerging kind of porous and crystalline materials, serve as an ideal template for hydrogen peroxide (H2O2) photosynthesis. However, the vision of achieving high efficiency and selectivity in H2O2 photosynthesis is greatly hindered by the large exciton binding energy and limited charge separation efficiency influenced by the molecular structure of the building blocks. Herein, we developed three newly designed COFs with a donor–acceptor (D-A) structure and incorporated regulatory units (fluorine, F, and methoxyl, OCH3) in the D-A pathway through molecular engineering to optimize electronic structure, the availability of activate sites, charge kinetics and O2 activation capacity. Due to electron-donating effect, OCH3-functionalization (NIES-COF-3) can strengthen the intramolecular electron transfer and interaction with O2. This results in a reduction of the energy barrier of the rate-determining step (*O2 → *OOH) and excellent O2-to-H2O2 photocatalytic activity under visible light irradiation, delivering an H2O2 production rate of 3238.4 μmol g−1h−1 and a high apparent quantum yield of 3.17 %. In addition, F-functionalization (NIES-COF-2) primarily reduces the band-gap energy and improve the O2 adsorption capacity compared to unfunctionalized NIES-COF-1. This work unveils insight into the catalytic activity-optimization mechanism of molecular engineering in the D-A structure and provides important references for photocatalysts.

Engineering the Local Atomic Environments of Te-Modulated Fe Single-Atom Catalysts for High-Efficiency O2 Reduction.

Atomically dispersed metal-nitrogen-carbon materials (AD-MNCs) are considered the most promising non-precious catalysts for the oxygen reduction reaction (ORR), but it remains a major challenge for simultaneously achieving high intrinsic activity, fast mass transport, and effective utilization of the active sites within a single catalyst. Here, an AD-MNCs consisting of defect-rich Fe-N3 sites dispersed with axially coordinated Te atoms on porous carbon frameworks (Fe1Te1-900) is designed. The local charge densities and energy band structures of the neighboring Fe and Te atoms in FeN3-Te are rearranged to facilitate the catalytic conversion of the O-intermediates. Meanwhile, the negative shift of the d-band center in FeN3-Te reduces the energy barrier limit for effective desorption of the final OH* intermediate. In the electrochemical evaluation, Fe1Te1-900 presents a more positive onset potential and half-wave potentials of 1.03 and 0.89V versus the reversible hydrogen electrode, respectively. Furthermore, the liquid zinc-air batteries assembled with Fe1Te1-900 exhibited excellent performances compared to commercial Pt/C. This work opens up new ideas for the development of high-performance ORR electrocatalysts for applications in various energy conversion and storage technologies.

Exploring the Electronic Interactions of Adenine, Cytosine, and Guanine with Graphene: A DFT Study.

This study has provided new insights into the interaction between graphene and DNA nucleobases (adenine, cytosine, and guanine). It compares how each nucleobase interacts with graphene, examining their selectivity and binding energy. The research also explores how these interactions impact the electronic properties of graphene, showing potential applications in graphene-based biosensors and DNA sequencing technologies. Additionally, the findings suggest potential uses in DNA sensing and the functionalization of graphene for various biomedical applications. This study employs density functional theory (DFT) methods, utilizing the B3LYP functional with the 6-311G basis set, to explore the electronic interactions between DNA nucleobases (adenine, cytosine, and guanine) with pure graphene (Gr). We investigate various properties, including adsorption energy, HOMO-LUMO energy levels, charge transfer mechanisms, dipole moments, energy gaps, and density of states (DOS). Our findings indicate that cytosine interacts most favorably with graphene through its oxygen site (Gr-Cyt-O), exhibiting the strongest adsorption. Additionally, adenine's interaction significantly enhances its electronegativity and chemical potential, particularly at the nitrogen position, while decreasing its electrophilicity. Guanine, characterized by the smallest energy gap, demonstrates the highest conductivity among the nucleobases. These results suggest that graphene possesses advantageous properties as an adsorbent for guanine, highlighting its potential applications in biosensor technology.

Optimization Research on the Impact of Charging Load and Energy Efficiency of Pure Electric Vehicles

In this paper, the negative impact of the charging load generated by the disorderly charging scheme of large-scale pure electric vehicles on the operation performance of the power grid system and the problem of reducing its charging energy efficiency are studied and analyzed. First, based on Matlab 2022a simulation software and the Monte Carlo random sampling method, the probability density model of the factors affecting the charging load is constructed, and the total charging load of different quantities is simulated. Second, the IEEE33-node distribution network model is introduced to simulate the influence of charging load on the grid under different permeability schemes. Finally, the multi-objective genetic algorithm is used to optimize the charging cost and battery life. Taking the 20% permeability scheme as an example, the research results show that, compared with the disorderly charging scheme, the multi-objective optimization scheme reduces the peaking valley difference rate by 24.34%, the charging load power generation cost by 29.5%, and the charging cost by 23.9%. The power grid profit increased by 45.8%, and the research conclusion has practical significance for the energy efficiency optimization of pure electric vehicles.

DFT Study on the Interaction Between Flotation Agents and Lepidolite-1M Surfaces

The surface chemical properties of Lepidolite-1M crystals are closely related to their flotation properties. This paper uses density functional theory (DFT) to analyze the band structure, population, and state density of ideal Lepidolite-1M crystals. The results show that lepidolite-1M is an insulator, and its most probable positively charged active site is Al, and its negatively charged active sites are O and F. To further investigate the adsorption mechanism of Lepidolite-1M during comminution and flotation processes, we calculated the surface energy, population, state density, and differential charge density of its most common (001) surface. The results show that its surface energy is 0.9934 J/m2, occurred in the valence electron configurations, population values, and bond lengths of the surface atoms. Furthermore, oxygen atoms on the (001) surface showed different activities, with F and O atoms in the lithium-rich region showing significant electron enrichment. Overall, our results demonstrated that anion collectors react mainly with the Al sites on the surface of Lepidolite-1M, and the cationic collectors and metal ion activators can be adsorbed on the surface of Lepidolite-1M to produce better trapping and activation capabilities.

ATP Restoration by ATP-Deprived Cultured Primary Astrocytes

A high cellular concentration of adenosine triphosphate (ATP) is essential to fuel many important functions of brain astrocytes. Although cellular ATP depletion has frequently been reported for astrocytes, little is known on the metabolic pathways that contribute to ATP restoration by ATP-depleted astrocytes. Incubation of cultured primary rat astrocytes in glucose-free buffer for 60 min with the mitochondrial uncoupler BAM15 lowered the cellular ATP content by around 70%, the total amount of adenosine phosphates by around 50% and the adenylate energy charge (AEC) from 0.9 to 0.6. Testing for ATP restoration after removal of the uncoupler revealed that the presence of glucose as exclusive substrate allowed the cells to restore within 6 h around 80% of the initial ATP content, while coapplication of adenosine plus glucose enabled the cells to fully restore their initial ATP content within 60 min. A rapid but incomplete and transient ATP restoration was found for astrocytes that had been exposed to adenosine alone. This restoration was completely prevented by application of the pyruvate uptake inhibitor UK5099, the respiratory chain inhibitor antimycin A or by the continuous presence of BAM15. However, the presence of these compounds strongly accelerated the release of lactate from the cells, suggesting that the ribose moiety of adenosine can serve as substrate to fuel some ATP restoration via mitochondrial metabolism. Finally, the adenosine-accelerated ATP restoration in glucose-fed astrocytes was inhibited by the presence of the adenosine kinase inhibitor ABT-702. These data demonstrate that astrocytes require for a rapid and complete ATP restoration the presence of both glucose as substrate and adenosine as AMP precursor.

Charged fuzzy dark matter black holes

We investigate the impact of fuzzy dark matter (FDM) on supermassive black holes (SMBHs) characterized by a spherical charge distribution. This work introduces a new class of spherically symmetric, self-gravitational relativistic charged models for FDM haloes, using the Einasto density model. This study enables the dark matter (DM) to appear as the matter ingredient, which constructs the black hole and extends the non-commutative mini black hole stellar solutions. By considering the charged anisotropic energy–momentum tensor with an equation of state (EoS) pr=−ρ, we explore various black hole solutions for different values of the Einasto index and mass parameter. Our approach suggests that the central density of the resulting black hole model mimics the usual de Sitter core. Furthermore, we discuss the possibility of constructing a charged self-gravitational droplet by replacing the above-mentioned EoS with a non-local one. However, under these circumstances, the radial pressure is observed to be negative. Ultimately, we consider various possibilities of constructing DM black holes, featuring intermediate masses that could evolve into galaxies. Consequently, some of these theoretical models have the potential to replace the usual black hole solutions of the galactic core. Simultaneously, these models are physically beneficial for being comprised of the fundamental matter component of the cosmos. Due to the outcomes of this paper, we would be able to study the connection between BH and DM by formulating stable stellar structures featuring fuzzy mass distributions derived from the Einasto distribution of DM halos.

Enhancing PCE above 16.03% via linker engineering of donor layer: A DFT study of binary all-small-molecule organic solar cells

This study investigates the optical and photovoltaic properties of small molecule donors (SMDs) designed by the linker group replacement of a reported SMD (16.03 %) for use in the binary all-small-molecule organic solar cells (ASM-OSCs). The molecular geometries and reactivity parameters confirmed the ideal planarity, stability, and reactivity of designed SMDs. Using UV–Vis spectroscopy, the absorption spectra of these SMDs were analyzed in solvent and gaseous state to assess the optical properties. The study also evaluates transition state properties, revealing efficient charge transfer from donor to acceptor segments. Factors affecting charge mobility were calculated, demonstrating that all new SMDs, particularly H7, exhibit lower binding energy and favorable charge mobility compared to the original donor. The photovoltaic parameters show that all the designed SMDs, especially H7, achieve higher open circuit voltage, fill factor, and current density, suggesting improved PCE. Moreover, H7:PC71 BM, H7:ITIC, and H7:Y6 blends were assessed, confirming the efficient charge transfer characteristics. Overall, the study confirms that the structural modifications in the original SMD led to enhanced optoelectronic properties, and all the designed SMDs, particularly H7, would have a PCE greater than 16.03 %.

Nanohoops Favour Light‐Induced Energy Transfer over Charge Separation in Porphyrin/[10]CPP/Fullerene Rotaxanes

Abstract[2]Rotaxanes offer unique opportunities for studying and modulating charge separation and energy transfer, because the mechanical bond allows the robust, yet spatially dynamic tethering of photoactive groups. In this work, we synthesized [2]rotaxane triads comprising a central (aza)[10]CPP⊃C60 bis‐adduct complex and two zinc porphyrin stoppers to address how the movable nanohoop affects light‐induced charge separation and energy transfer between the rotaxane subcomponents. We found that neither the parent nanohoop [10]CPP nor its electron‐deficient analogue aza[10]CPP actively participate in charge separation. In contrast, the nanohoops completely prevented through‐space charge separation. This result is likely due to supramolecular “shielding”, because charge separation was observed in the thread that acted as reference dyad. On the other hand, the suppression of electron transfer allowed the observation of energy transfer from the porphyrin triplet to the fullerene triplet state with a lifetime of ca. 25 μs. The presence of the interlocked nanohoops therefore leads to a dramatic switch between charge separation and energy transfer. We suggest that our results explain observations made by others in photovoltaic devices comprising nanohoops and may pave the way toward strategic uses of mechanically interlocked architectures in devices that feature (triplet) energy transfer.

Nanohoops Favour Light-Induced Energy Transfer over Charge Separation in Porphyrin/[10]CPP/Fullerene Rotaxanes.

[2]Rotaxanes offer unique opportunities for studying and modulating charge separation and energy transfer, because the mechanical bond allows the robust, yet spatially dynamic tethering of photoactive groups. In this work, we synthesized [2]rotaxane triads comprising a central (aza)[10]CPP⊃C60 bis-adduct complex and two zinc porphyrin stoppers to address how the movable nanohoop affects light-induced charge separation and energy transfer between the rotaxane subcomponents. We found that neither the parent nanohoop [10]CPP nor its electron-deficient analogue aza[10]CPP actively participate in charge separation. In contrast, the nanohoops completely prevented through-space charge separation. This result is likely due to supramolecular "shielding", because charge separation was observed in the thread that acted as reference dyad. On the other hand, the suppression of electron transfer allowed the observation of energy transfer from the porphyrin triplet to the fullerene triplet state with a lifetime of ca. 25 μs. The presence of the interlocked nanohoops therefore leads to a dramatic switch between charge separation and energy transfer. We suggest that our results explain observations made by others in photovoltaic devices comprising nanohoops and may pave the way toward strategic uses of mechanically interlocked architectures in devices that feature (triplet) energy transfer.