Site Energy Research Articles

Unraveling the charge transfer variation of tetrathiafulvalene-based organic crystals through fragment charge difference calculation

Organic crystals assembled by a well-established family of electron donors, tetrathiafulvalene (TTF)-based molecules, hold great potential for electronics, smart materials, and superconductors. Combining with Marcus' theory and first-principles calculations, we have adopted a fragment charge difference (FCD) method to investigate the charge transfer properties of the TTF-based crystals. Our FCD predictions are highly consistent with those obtained from a well-accepted site energy correction method. We have demonstrated the significant influence of both structure and chemistry on the charge transfer properties using polymorphs, i.e., α-phase tetrathiafulvalene (1) versus β-phase tetrathiafulvalene (2), and crystals with homologous molecular packings, i.e., 1 versus dithiophene-TTF (3). We have also introduced multiple factors to provide further insights into the variation in charge transfer properties of the TTF-based crystals, including energy gap (∆E), centroid distance (ri), orbital distribution correction factor (Hs), and reorganization energy (λ). By taking advantage of our analysis, we have rationalized high mobility in hexamethylene-TTF (4) and low mobility in bis(ethylenedithio)-TTF (5). Our multiple-factor evaluation could support an approach to designing electrically conducting TTF-based materials and provide a method to estimate charge transfer properties effectively.

Electron Transport in Donor-Acceptor Copolymer and Methanofullerene Derivative Organic Photovoltaic Blend

Recently, organic photovoltaics (OPVs) based on the blends of donor–acceptor (D–A) copolymers as efficient p-type materials and fullerene derivatives as acceptors have attracted considerable attention. In this paper, electron transport and electrical properties in a blend of D–A copolymer DTS-C0(F2) and methanofullerene derivative PC71BM are investigated. From an analysis of the temperature dependence of the current density–voltage (J − V) characteristics of electron-only device based on DTS-C0(F2):PC71BM blend, it is found that consistent descriptions for the experimental measurements are obtained using both the improved extended Gaussian disorder model (IEGDM) and the extended correlated disorder model (ECDM), within which spatial correlations between the transport site energies are absent and are included, respectively. By comparing the model parameters with the typical values of organic semiconductors, we view the more realistic intersite distance obtained using the IEGDM (1.9 nm) compared to the value obtained using the ECDM (0.48 nm) as an indication that in DTS-C0(F2):PC71BM blend correlations between the transport site energies are absent. Furthermore, it is shown that the effective mobility in DTS-C0(F2):PC71BM blend gradually increases with increasing temperature.

Bioexcitons by Design: How Do We Get There?

Biological pigment-protein complexes (PPCs) exhibit a remarkable ability to tune the optical properties of biological excitons (bioexcitons) through specific pigment-protein interactions. While such fine-tuning allows natural systems (e.g., photosynthetic proteins) to carry out their native functions with near-optimal performance, native function itself is often suboptimal for applications such as biofuel production or quantum technology development. This perspective offers a look at near-term prospects for the rational reoptimization of PPC bioexcitons for new functions using site-directed mutagenesis. The primary focus is on the "structure-spectrum" challenge of understanding the relationships between structural features and spectroscopic properties. While recent examples demonstrate that site-directed mutagenesis can be used to tune nearly all key bioexciton parameters (e.g., site energies, interpigment couplings, and electronic-vibrational interactions), critical challenges remain before we achieve truly rational design of bioexciton properties.

Analysis and Study of credits for IGBC Green New Building

The green building movement in India has gained significant momentum with over 8,669 registered projects under the Indian Green Building Council. The LEED standards influence the design and construction of environmentally sustainable structures with a focus on resource conservation, waste reduction, and creating healthy spaces. The IGBC criteria encompasses aspects such as sustainable architecture and design, site selection, energy and water conservation, building materials, indoor environmental quality, and innovation. Energy efficiency and water conservation are emphasized through eco-friendly refrigerants, renewable energy sources, and water-wise practices. The use of certified green building materials, products, and equipment helps reduce environmental impact. Indoor environmental quality is maintained through adequate ventilation, low-emitting materials, and indoor air quality testing. Building owners and contractors can employ various strategies to improve the well-being of occupants. Key Words: Green building, Sustainable, Conservation, Environment, Eco-friendly, Renewable

Energy Dispatching Based on an Improved PSO-ACO Algorithm

In order to improve the comprehensive performance of energy dispatching between different sites, the optimization research of particle swarm optimization (PSO) algorithm and ant colony optimization (ACO) algorithm is carried out. We proposed a new improved PSO-ACO algorithm based on the idea of hybrid algorithm to solve the problem of poor energy dispatching efficiency between sites. First, the multiobjective performance indicators were introduced to transform the sites’ energy dispatching problem into a multiobjective optimization problem. Second, the vitality factor was introduced into the PSO strategy to solve the local optimal problem, and in the PSO-ACO fusion strategy, the PSO routes were transformed into the ant colony enhancement pheromone to accelerate the accumulation speed of the ACO initial pheromone. Then, the angle guidance function was introduced into the state transition probability of the ACO strategy to improve the global search capability, and a high-quality pheromone update rule was proposed to improve the convergence speed of the algorithm. Finally, simulation experiments were carried out on the improved PSO-ACO algorithm, Min–Max Ant System (MMAS) algorithm, ACO algorithm, PSO algorithm, and PSO update algorithm in a variety of complex site scenarios. The simulation results show that the improved PSO-ACO algorithm can plan a site energy dispatching route with shorter route, less time-consuming, and higher security and realize the comprehensive and global optimization of energy dispatching.

Sensor Incipient Fault Impacts on Building Energy Performance: A Case Study on a Multi-Zone Commercial Building

Existing studies show sensor faults/error could double building energy consumption and carbon emissions compared with the baseline. Those studies assume that the sensor error is fixed or constant. However, sensor faults are incipient in real conditions and there were extremely limited studies investigating the incipient sensor fault impacts systematically. This study filled in this research gap by studying time-developing sensor fault impacts to rule-based controls on a 10-zone office building. The control sequences for variable air volume boxes (VAV) with an air handling unit (AHU) system were selected based on ASHRAE Guideline 36-2018: High-Performance Sequences of Operation for HVAC Systems. Large-scale simulations on cloud were conducted (3600 cases) through stochastic approach. Results show (1) The site energy differences could go −3.3% lower or 18.1% higher, compared with baseline. (2) The heating energy differences could go −66.5% lower or 314.4% higher, compared with baseline. (3) The cooling energy differences could go −11.5% lower or 65.0% higher, compared with baseline. (4) The fan energy differences could go 0.15% lower or 6.9% higher, compared with baseline.

Structural phase stability and thermodynamical properties of transition metal complex hydrides Na2MgTMH7 (TM=Sc−Cu) for hydrogen storage applications

In order to predict ground state structure as well as thermodynamical properties of transition metal-based complex hydrides (TMCHs) and identify potential hydrogen storage materials for energy storage applications, we have performed first-principles density functional spin polarized total energy calculations for Na2MgTMH7 where TM ​= ​Sc, Ti, V, Cr, Mn, Fe, Co, Ni, and Cu. To investigate the thermodynamical properties of transition metal-based complex hydrides (TMCHs) and to find potential hydrogen storage materials for energy storage applications. Our spin-polarized calculations show that all these materials are having a finite magnetic moment at the transition metal site with ferromagnetic or anti−ferromagnetic ordering as ground state configuration except the cases where TM ​= ​Sc, Co, Ni, and Cu. Our calculated enthalpy of formation and hydrogen site energy of TMCHs suggest that these systems are stable and the hydrogen is expected to release at a relatively low temperature compared to that of pure binary hydrides. We have performed the chemical bonding analyses between the constituents of TMCHs through density of states, charge density, electron localization function, Born effective charge, Bader effective charge, Mulliken charge, and COHP and these analyses suggest that there is an ionic bonding between hydrogen with Na, Mg, and transition metal with noticeable covalent bonding between hydrogen and Mg/TM.

Toward Accurate Prediction of Ion Mobility in Organic Semiconductors by Atomistic Simulation.

A multiscale scheme (MLMS: Multi-Level Multi-Scale) to predict the ion mobility (μ) of amorphous organic semiconductors is proposed, which was successfully applied to the hole mobility predictions of 14 organic systems. An inverse relationship between μ and reorganization energy is observed due to local polaronic distortions. Another moderate inverse correlation between μ and distribution of site energy change exists, representing the effects of geometric flexibility. The former and the latter represent the intramolecular and intermolecular geometric effects, respectively. In addition, a linear correlation between transfer coupling and μ is observed, showing the importance of orbital overlaps between monomers. Especially, the highest hole mobility of C6-2TTN is due to its large transfer coupling. On the other hand, another high hole mobility of CBP turned out to come from the high first neighbor density (ρFND) of its first self-solvation, emphasizing the proper description of amorphous structural configurations with a sufficiently large number of monomers. In general, systems with either unusually high transfer coupling or high first neighbor density can potentially have high μ regardless of geometric effects. Especially, the newly suggested design parameter, ρFND, is pointing to a new direction as opposed to the traditional π-conjugation strategy.

Photoaging processes of polyvinyl chloride microplastics enhance the adsorption of tetracycline and facilitate the formation of antibiotic resistance

Microplastics (MPs), antibiotics and microorganism ubiquitously coexist in aquatic environments. MPs inevitably undergo photoaging processes in aquatic environments, affecting the interactions between MPs and antibiotics and the antibiotic resistance of microorganism. In this study, the impact of photoaging processes of MPs on their adsorption behavior of tetracycline (TC) and related formation of antibiotic resistance were investigated. It was found that the photoaging processes significantly increased the adsorption capacity of TC onto MPs, with the Qe increasing from 0.387 to 0.507 mg/g at 288 K and from 0.507 to 0.688 mg/g at 308 K. The site energy distribution (SED) analysis further confirmed that the enhanced adsorption capacity was attributed to more high-energy adsorption sites acquired from MPs photoaging processes. Moreover, the enhanced adsorption of TC further facilitated the formation of seven antibiotic resistance genes (i.e., tetA, tetB, tetC, tetD, tetE, tetG, tetK) when MPs adsorbed with TC was covered by biofilm. This study helps comprehensively understand the environmental behaviors of co-existing MPs, antibiotics and microorganisms, providing a theoretical basis for evaluating and mitigating their coexistence risks.

Assessment of Green Practices in Sentra Timur Apartment, Jakarta Based on Greenship Rating of the Green Building Council of Indonesia

Before the Paris meeting on climate change, most United Nations member submitted their Intended Nationally Determined Contributions on carbon emission reductions by 2030. The Indonesian government needs to adjust its national policies and regulations to achieve its commitments. The residential building sector, in particular apartment buildings, plays an essential role in contributing to the country's energy-related carbon emissions profile. Therefore, this study aims to determine the extent to which apartments in Sentra Timur comply with the green building (GB) indicators, based on the standard of the Green Building Council Indonesia (GBCI). The analysis generates points that define a green building's predicate. Furthermore, the appropriate credit for Site Development, Energy Efficiency and conservation, Water Conservation, as well as Indoor Health and Comfort are 12 points out of 17, 16 points out of 26, 10 points out of 21, 16.5 points out of 26, respectively. The overall score is 54.5, with a percentage of 46.58%. Therefore, the Sentra Timur Apartment has been awarded a silver rating. After analyzing the collected data, recommendations were made on how each category can be improved to meet GB standards.

Chelerythrine inhibits HSV-1 infection by suppressing virus binding to the cells

ObjectiveHerpes simplex virus type 1 (HSV-1) is a worldwide pathogen and mainly puts immunocompromised patients at higher risk of various complications. This research aims to demonstrate the antiviral activity of chelerythrine (CHE), an alkaloid compound derived from the traditional Chinese medicine Mcleaya cordata, towards the HSV-1 F strain. MethodsBioassay-guided fractionation was carried out in order to isolate the antiviral compound CHE. The plaque reduction assay was used to evaluate the antiviral activity of CHE. The combination of quantitative PCR (qPCR) and western blot was used to elucidate whether CHE interferes with viral DNA synthesis, followed by time-of-addition assay to examine which steps of HSV-1 infection CHE affected. The immunofluorescent assay and transmission electron microscopy assay were performed to further analyze the intracellular localization and the ultrastructural features of HSV-1 virions with the treatment of CHE. The binding affinity in CHE to targeted viral glycoprotein was investigated by surface plasmon resonance (SPR) assay and docking simulation. ResultsCHE displayed a significant antiviral effect against HSV-1 at 0.312 to 2.5 µM with a viral titer reduction of 29.38% to 61.02%. CHE had an EC50 value of 1.78 µM against HSV-1, and the selectivity index (SI) for CHE was 4.07. Additionally, CHE inhibits ICP0 expression in the immediate early stage of infection, which further affected the early stage of infection, and subsequent viral replication. Results of the SPR assay showed that CHE had strong-binding affinity to gB with a KD value of 7.80 × 107 M, while gD with a value of 1.18 × 106 M. TEM revealed that CHE can clearly inhibit the virion release. In silico experiments further confirmed that CHE had low binding free energy in the activity sites of gB and gD. ConclusionThis study revealed that CHE directly targeted viral gB or gD as a potent glycoprotein inhibitor, which suggested that CHE could be a virus entry inhibitor for HSV-1 treatment.

Cobalt single atom induced catalytic active site shift in carbon-doped BN for efficient photodriven CO2 reduction

Active site tuning in catalyst design is the key to improving the catalyst performance. Herein, we introduce single cobalt atoms into carbon-doped boron nitride (C-BN) and find, to our surprise, that the photocatalytic CO2 reduction site of C-BN shifts from CN3 to CB3. The catalyst Co/C-BN with new active sites exhibits excellent photocatalytic activity and selectivity of CO without adding sacrificial reagents, while the side reaction of hydrogen evolution is significantly inhibited. Theoretical calculations show that the introduced Co atom changes the spin density of the neighboring catalytic site, thus regulating the adsorption energy of the catalytic site for active intermediates (COOH*). Compared with CN3 site, CB3 in Co/C-BN shows superiority in CO* formation elementary step for the conversion of CO2 to CO, and inhibits the generation of adsorbed H2 in the competitive water-splitting reaction. This work provides valuable insights into the design of highly efficient catalysts in the future.

High-efficiency removal of antibiotics through self-assembly formation of layered double hydroxides in wastewater

In this study, to achieve high-efficiency utilization of charges on layered double hydroxides (LDHs), a simple and direct synthesis method of LDHs in wastewater was designed for the removal of the contaminants ciprofloxacin (CIP) and tetracycline (TC). The obtained LDHs structure was characterized by XRD, FT-IR, DLS, SEM and TEM. The removal of CIP/TC using different Mg/Al ratios and stepwise experiments was investigated. With the formation of LDHs structures in wastewater, the CIP/TC molecule was sandwiched between the LDHs layers and removal process was controlled by the positive charges, resulting in a more efficient utilization of the LDHs layer than that of other methods. The removal of CIP was dominant during competitive removal. The isothermal model of the Generalized Langmuir model obtained a good fit with the experimental data in the single and mixed systems, indicating a specific number of adsorption sites on the LDHs layer, and heterogeneous adsorption sites with different adsorption energies. According to the site energy distribution theory, the calculated average energies of CIP and TC were 18.68 and 16.68 J·mmol−1, respectively, under competitive adsorption. Molecular simulation was conducted to explain the interaction between the CIP/TC molecule and LDHs layer based on the electron density and bonding energy. Moreover, the effects of pH, ion coexistence, and antibiotic competition were investigated, which revealed favorable adsorption stability parameters. Therefore, this method for LDHs formation in wastewater allowed the efficient utilization of positive charges and provided a promising method for antibiotic removal.

An Unusual Fullerene–Carbene Adduct: Thermal Motion, Disorder, or Both?**

AbstractA single‐crystal X‐ray study of a fullerene‐imidazole adduct at nine temperatures (80 K≤T≤480 K), accompanied by energy calculations, strongly suggested thermal motion of the C60 moiety with respect to the imidazolium heterocycle. Analysis of the anisotropic displacement parameters, calculations of frequencies, and the refinement of disorder models for the crystal at four temperatures (230 K≤T≤380 K) lead to the conclusion that the rotator is moving at all temperatures. The rotation barrier is low, with one preferred crystallographic site and several other energy minima.

Prospective oxygen-ion conductors LnaXbOz: Geometry and energy calculations

Using a combined approach based on the geometrical-topological (GT) analysis of crystal structures and bond valence site energy (BVSE) calculations, a high-throughput computer screening was carried out for 2073 compounds of the LnaXbOz composition (X is any chemical element of III-VI periods, excluding elements 1, 16, 17 and 18-groups, P, As, Ba, Sr), which taken from ICSD (version 2021/2). By means GT approach, 720 most promising oxygen-containing compounds with 1D, 2D or 3D migration map of O2−-ions were obtained. According to the BVSE results, 225 most stable compounds were divided to groups based on structural type, in each of which experimental data were established for known oxygen-ion conductors and the migration energy barriers of were calculated by the BVSE method. 46 compounds were found that do not belong to known structural types, while 41 of them had low barriers to migration of oxygen ions (0.10–1.20 eV), which made it possible to identify them as new potential oxygen-ion conductors.

Unitary p-wave interactions between fermions in an optical lattice.

Exchange-antisymmetric pair wavefunctions in fermionic systems can give rise to unconventional superconductors and superfluids1-3. The realization of these states in controllable quantum systems, such as ultracold gases, could enable new types of quantum simulations4-8, topological quantum gates9-11 and exotic few-body states12-15. However, p-wave and other antisymmetric interactions are weak in naturally occurring systems16,17, and their enhancement via Feshbach resonances in ultracold systems has been limited by three-body loss18-24. Here we create isolated pairs of spin-polarized fermionic atoms in a multiorbital three-dimensional optical lattice. We spectroscopically measure elastic p-wave interaction energies of strongly interacting pairs of atoms near a magnetic Feshbach resonance. The interaction strengths are widely tunable by the magnetic field and confinement strength, and yet collapse onto a universal curve when rescaled by the harmonic energy and length scales of a single lattice site. The absence of three-body processes enables the observation of elastic unitary p-wave interactions, as well as coherent oscillations between free-atom and interacting-pair states. All observations are compared both to an exact solution using a p-wave pseudopotential and to numerical solutions using an ab initio interaction potential. The understanding and control of on-site p-wave interactions provides a necessary component for the assembly of multiorbital lattice models25,26 and a starting point for investigations of how to protect such systems from three-body recombination in the presence of tunnelling, for instance using Pauli blocking and lattice engineering27,28.

AutoBPS: A tool for urban building energy modeling to support energy efficiency improvement at city-scale

China has promised to peak carbon emissions by 2030 and become carbon neutral before 2060. Achieving this target requires actions from all sectors, especially the building sector, which accounts for 33 % of the total energy consumption in China. Within this scenario, this paper introduces a new urban building energy modeling tool, Automated Building Performance Simulation (AutoBPS), to calculate urban building energy demands and to analyze energy retrofit and rooftop photovoltaic (PV) potential. AutoBPS uses a building-by-building approach to automatically generate multi-zone (one zone per floor) models based on the city building dataset, considering the shading effect by surrounding buildings. The tool simulates building energy use and PV generation via EnergyPlus. A downtown district of 3633 buildings in Changsha, China, was selected as a case study to demonstrate the features of the tool. Firstly, annual baseline energy uses of 1793 GWh were simulated by inputting Geographic Information System (GIS) data. Then, different energy conservation measures (covering envelope, lighting, cooling system upgrade, etc.) and roof PV generation systems were adopted to explore energy saving potential. The results showed that the window upgrade was the most energy-efficient individual measure for residential buildings, while the lighting upgrade was that one for commercial buildings. Altogether three measures could save 2.7 ∼ 30.7 % of annual site energy use intensity per building. The total energy demand could be reduced by 18.5 % by combining all measures and saved by 38.6 % when PV installation was added. AutoBPS can be easily applied to other cities, supporting urban energy efficiency plans for carbon reduction goal implementation.

Modeling Gas Adsorption–Desorption Hysteresis in Energetically Heterogeneous Coal and Shale

Adsorption of gases in porous adsorbents such as coal and shale generally exhibits the phenomenon of hysteresis. Most of the previous studies on desorption hysteresis were conducted via experimental tests. However, few theoretical models that represent adsorption–desorption hysteresis of gases in porous sorbents are available. To address this issue, this work develops a new adsorption–desorption model for describing adsorption and desorption isotherms of gases with hysteresis. Particularly, the energetically heterogeneous surfaces of an adsorbent are considered via the patchwise model. Based on the change in site energy distribution, a logarithmically pressure-dependent hysteresis index, which is used to measure the degree of hysteresis, is derived for quantitative assessment of the degree of hysteresis. Besides, the correlation between the desorption isotherm and initialized pressure for desorption is established. The accuracy of the proposed model to adequately describe the adsorption–desorption hysteresis of gas in coal and shale is demonstrated by validating the model against laboratory experiments obtained from the literature. The results indicate that the adsorption isotherm depends significantly on site energy distribution. By comparing the site energy distributions for adsorption and desorption isotherms, it is found that the desorption hysteresis can be attributed to the change in pore size distribution caused by adsorption-induced deformation. The analyses support that the proposed model can be used as an effective tool to quantitatively predict the amount of released gas during desorption, which is significant for designing coalbed methane or shale gas production and assessing long-term CO2 storage behavior.

Extracting the excitonic Hamiltonian of a chlorophyll dimer from broadband two-dimensional electronic spectroscopy.

We apply Frenkel exciton theory to model the entire Q-band of a tightly bound chlorophyll dimer inspired by the photosynthetic reaction center of photosystem II. The potential of broadband two-dimensional electronic spectroscopy experiment spanning the Qx and Qy regions to extract the parameters of the model dimer Hamiltonian is examined through theoretical simulations of the experiment. We find that the local nature of Qx excitation enables identification of molecular properties of the delocalized Qy excitons. Specifically, we demonstrate that the cross-peak region, where excitation energy is resonant with Qy while detection is at Qx, contains specific spectral signatures that can reveal the full real-space molecular Hamiltonian, a task that is impossible by considering the Qy transitions alone. System-bath coupling and site energy disorder in realistic systems may limit the resolution of these spectral signatures due to spectral congestion.

Study on the Adsorption Properties and Mechanisms of CO on Nickel Surfaces Based on Density Functional Theory

In this work, the adsorption of CO onto the surface of the transition metal Ni at different coverage levels was explored based on the density functional theory (DFT). The corresponding periodic slab plate models were established, and the adsorption parameters and CO electronic states on different nickel surfaces under different coverage (0.11 mL, 0.25 mL and 0.5 mL) were calculated. The results showed that the most stable adsorption sites on Ni (111) and Ni (100) crystal surfaces were valley sites, while the most stable adsorption sites on a Ni (110) surface was a short bridge site. By comparing the energy of the same adsorption sites, it was found that the adsorption of CO on a Ni (100) crystal surface was superior to the other two surfaces. Furtherly, from the perspective of the electronic structure, the density of states (DOSs) of Ni atoms and CO molecules were calculated before and after adsorption. The density of states showed that the main factor of surface adsorption generation originates from hybridization among the orbitals. This article provides insight into the mechanisms of the nickel adsorption of CO.