High-Efficiency Photo-Induced Charge Transfer for SERS Sensing in N-Doped 3D-Graphene on Si Heterojunction

Nitrogen-doped three-dimensional graphene(N-doped 3D-graphene)is a graphene derivative with excellent adsorption capacity,large specific surface area,high porosity,and optoelectronic properties.Herein,N-doped 3D-graphene/Si heterojunctions were grown in situ directly on silicon(Si)substrates via plasma-assisted chemical vapor deposition(PACVD),which is promising for surface-enhanced Raman scattering(SERS)substrates candidates.Combined analyses of theoretical simulation,incorporating N atoms in 3D-graphene are beneficial to increase the electronic state density of the system and enhance the charge transfer between the substrate and the target molecules.The enhancement of the optical and electric fields benefits from the stronger light-matter interaction improved by the natural nano-resonator structure of N-doped 3D-graphene.The as-prepared SERS substrates based on N-doped 3D-graphene/Si heterojunctions achieve ultra-low detection for various molecules:10^(-8)M for methylene blue(MB)and 10^(-9)M for crystal violet(CRV)with rhodamine(R6G)of 10^(10)M.In practical detected,10^(-8)M thiram was precisely detected in apple peel extract.The results indicate that N-doped 3D-graphene/Si heterojunctions based-SERS substrates have promising applications in low-concentration molecular detection and food safety.

Influence of O-O formation pathways and charge transfer mediator on lipid bilayer membrane-like photoanodes for water oxidation

Inspired by the function of crucial components in photosystemⅡ(PSⅡ),electrochemical and dyesensitized photoelectrochemical(DSPEC)water oxidation devices were constructed by the selfassembly of well-designed amphipathic Ru(bda)-based catalysts(bda=2,2'-bipyrdine-6,6'-dicarbonoxyl acid)and aliphatic chain decorated electrode surfaces,forming lipid bilayer membrane(LBM)-like structures.The Ru(bda)catalysts on electrode-supported LBM films demonstrated remarkable water oxidation performance with different O-O formation mechanisms.However,compared to the slow charge transfer process,the O-O formation pathways did not determine the PEC water oxidation efficiency of the dyesensitized photoanodes,and the different reaction rates for similar catalysts with different catalytic paths did not determine the PEC performance of the DSPECs.Instead,charge transfer plays a decisive role in the PEC water oxidation rate.When an indolo[3,2-b]carbazole derivative was introduced between the Ru(bda)catalysts and aliphatic chain-modified photosensitizer in LBM films,serving as a charge transfer mediator for the tyrosine-histidine pair in PSⅡ,the PEC water oxidation performance of the corresponding photoanodes was dramatically enhanced.

Reversed charge transfer induced by nickel in Fe-Ni/Mo_(2)C@nitrogen-doped carbon nanobox for promoted reversible oxygen electrocatalysis

The interaction between metal and support is critical in oxygen catalysis as it governs the charge transfer between these two entities,influences the electronic structures of the supported metal,affects the adsorption energies of reaction intermediates,and ultimately impacts the catalytic performance.In this study,we discovered a unique charge transfer reversal phenomenon in a metal/carbon nanohybrid system.Specifically,electrons were transferred from the metal-based species to N-doped carbon,while the carbon support reciprocally donated electrons to the metal domain upon the introduction of nickel.This led to the exceptional electrocatalytic performances of the resulting Ni-Fe/Mo_(2)C@nitrogen-doped carbon catalyst,with a half-wave potential of 0.91 V towards oxygen reduction reaction(ORR)and a low overpotential of 290 m V at 10 mA cm^(-2)towards oxygen evolution reaction(OER)under alkaline conditions.Additionally,the Fe-Ni/Mo_(2)C@carbon heterojunction catalyst demonstrated high specific capacity(794 mA h g_(Zn)~(-1))and excellent cycling stability(200 h)in a Zn-air battery.Theoretical calculations revealed that Mo_(2)C effectively inhibited charge transfer from Fe to the support,while secondary doping of Ni induced a charge transfer reversal,resulting in electron accumulation in the Fe-Ni alloy region.This local electronic structure modulation significantly reduced energy barriers in the oxygen catalysis process,enhancing the catalytic efficiency of both ORR and OER.Consequently,our findings underscore the potential of manipulating charge transfer reversal between the metal and support as a promising strategy for developing highly-active and durable bi-functional oxygen electrodes.

Modulating charge separation and transfer for high-performance photoelectrodes via built-in electric field

Constructing a built-in electric field has emerged as a key strategy for enhancing charge separation and transfer,thereby improving photoelectrochemical performance.Recently,considerable efforts have been devoted to this endeavor.This review systematically summarizes the impact of built-in electric fields on enhancing charge separation and transfer mechanisms,focusing on the modulation of built-in electric fields in terms of depth and orderliness.First,mechanisms and tuning strategies for built-in electric fields are explored.Then,the state-of-the-art works regarding built-in electric fields for modulating charge separation and transfer are summarized and categorized according to surface and interface depth.Finally,current strategies for constructing bulk built-in electric fields in photoelectrodes are explored,and insights into future developments for enhancing charge separation and transfer in high-performance photoelectrochemical applications are provided.

Decouple charge transfer reactions in the Li-ion battery

In the development of Li-ion batteries(LIBs)with high energy/power density,long cycle-life,fast charging,and high safety,an insight into charge transfer reactions is required.Although electrochemical impedance spectroscopy(EIS)is regarded as a powerful diagnosis tool,it is not a direct but an indirect measurement.With respect to this,some critical questions need to be answered:(i)why EIS can reflect the kinetics of charge transfer reactions;(ii)what the inherent logical relationship between impedance models under different physical scenes is;(iii)how charge transfer reactions compete with each other at multiple scales.This work aims at answering these questions via developing a theory framework so as to mitigate the blindness and uncertainty in unveiling charge transfer reactions in LIBs.To systematically answer the above questions,this article is organized into a three-in-one(review,tutorial,and research)type and the following contributions are made:(i)a brief review is given for impedance model development of the LIBs over the past half century;(ii)an open source code toolbox is developed based on the unified impedance model;(iii)the competive mechanisms of charge transfer reactions are unveiled based on the developed EIS-Toolbox@LIB.This work not only clarifies theoretical fundamentals,but also provides an easy-to-use open source code for EIS-Toolbox@LIB to optimize fast charge/discharge,mitigate cycle aging,and improve energy/power density.

First-Principles Investigation of Charge Transfer Mechanism of B-Doped 3C-SiC Semiconductor Material

This study delves into the charge transfer mechanism of boron (B)-doped 3C-SiC through first-principles investigations. We explore the effects of B doping on the electronic properties of 3C-SiC, focusing on a 12.5% impurity concentration. Our comprehensive analysis encompasses structural properties, electronic band structures, and charge density distributions. The optimized lattice constant and band gap energy of 3C-SiC were found to be 4.373 Å and 1.36 eV respectively, which is in agreement with previous research (Bui, 2012;Muchiri et al., 2018). Our results show that B doping narrows the band gap, enhances electrical conductivity, and influences charge transfer interactions. The charge density analysis reveals substantial interactions between B dopants and surrounding carbon atoms. This work not only enhances our understanding of the material’s electronic properties, but also highlights the importance of charge density analysis for characterizing charge transfer mechanisms and their implications in the 3C-SiC semiconductors.

Recent advances in high charge density triboelectric nanogenerators

Triboelectric materials with high charge density are the building-block for the commercial application of triboelectric nanogenerators(TENGs).Unstable dynamic processes influence the change of the charge density on the surface and inside of triboelectric materials.The charge density of triboelectric materials depends on the surface and the internal charge transfer processes.The focus of this review is on recent advances in high charge density triboelectric materials and advances in the fabrication of TENGs.We summarize the existing strategies for achieving high charge density in triboelectric materials as well as their fundamental properties.We then review current optimization methods for regulating dynamic charge transfer processes to increase the output charge density:first,increasing charge injection and limiting charge dissipation to achieve a high average surface charge density,and second,regulating the internal charge transfer process and storing charge in triboelectric materials to increase the output charge density.Finally,we present the challenges and prospects in developing high-performance triboelectric materials.

Visualization of Metal-to-Ligand and Ligand-to-Ligand Charge Transfer in MetaloLigand Complexes

Three methods including the atomic resolved density of state, charge difference density, and the transition density matrix are used to visualize metal to ligand charge transfer （MLCT） in ruthenium（II） ammine complex. The atomic resolved density of state shows that there is density of Ru on the HOMOs. All the density is localized on the ammine, which reveals that the excited electrons in the Ru complex are delocalized over the ammine ligand. The charge difference density shows that all the holes are localized on the Ru and the electrons on the ammine. The localization explains the MLCT on excitation. The transition density matrix shows that there is electron-hole coherence between Ru and ammine. These methods are also used to examine the MLCT in Os（bpy）2（p0p）Cl （＂Osp0p＂： bpy=2,2-bipyrldyl; p0p=4,4＇- bipyridyl） and the ligand-to-ligand charge transfer （LLCT） in Alq3. The calculated results show that these methods are powerful to examine MLCT and LLCT in the metal-ligand system.

Fast and Balanced Charge Transport Enabled by Solution-Processed Metal Oxide Layers for Efficient and Stable Inverted Perovskite Solar Cells

Metal oxide charge transport materials are preferable for realizing long-term stable and potentially low-cost perovskite solar cells(PSCs).However,due to some technical difficulties(e.g.,intricate fabrication protocols,high-temperature heating process,incompatible solvents,etc.),it is still challenging to achieve efficient and reliable all-metal-oxide-based devices.Here,we developed efficient inverted PSCs(IPSCs)based on solution-processed nickel oxide(NiO_(x))and tin oxide(SnO_(2))nanoparticles,working as hole and electron transport materials respectively,enabling a fast and balanced charge transfer for photogenerated charge carriers.Through further understanding and optimizing the perovskite/metal oxide interfaces,we have realized an outstanding power conversion efficiency(PCE)of 23.5%(the bandgap of the perovskite is 1.62 eV),which is the highest efficiency among IPSCs based on all-metal-oxide charge transport materials.Thanks to these stable metal oxides and improved interface properties,ambient stability(retaining 95%of initial PCE after 1 month),thermal stability(retaining 80%of initial PCE after 2 weeks)and light stability(retaining 90%of initial PCE after 1000 hours aging)of resultant devices are enhanced significantly.In addition,owing to the low-temperature fabrication procedures of the entire device,we have obtained a PCE of over 21%for flexible IPSCs with enhanced operational stability.

Regulating the interfacial charge transfer and constructing symmetry-breaking sites for the enhanced N_(2) electroreduction activity

The Haber-Bosch process for industrial NH_(3) production is energy-intensive with heavy CO_(2) emissions.Electrochemical N_(2) reduction reaction(NRR)is an attractive carbon-neutral alternative for NH_(3) synthesis,while the challenge associated with N_(2) activation highlights the demand for efficient electrocatalysts.Herein,we demonstrate that PdCu nanoparticles with different Pd/Cu ratios anchored on boron nanosheet(PdCu/B)behave as efficient NRR electrocatalysts toward NH_(3) synthesis.Theoretical and experimental results confirm that the highly efficient NH_(3) synthesis can be achieved by regulating the charge transfer between interfaces and forming a symmetry-breaking site,which not only alleviates the hydrogen evolution but also changes the adsorption configuration of N_(2) and thus optimizes the reaction pathway of NRR over the separated Pd sites.Compared with monometallic Pd/B and Cu/B,the PdCu/B with the optimized Pd/Cu ratio of 1 exhibits superior activity and selectivity for NH_(3) synthesis.This study provides new insight into developing efficient catalysts for small energy molecule catalytic conversion via regulating the charge transfer between interfaces and constructing symmetry-breaking sites.

Regulated adsorption-diffusion and enhanced charge transfer in expanded graphite cohered with N,B bridge-doping carbon patches to boost K-ion storage

The great challenges are remained in constructing graphite-based anode with well built-in structures to accelerate kinetics and enhance stability in the advanced K-ion batteries(KIBs).Here,we firstly report the design of expanded graphite cohered by N,B bridge-doping carbon patches(NBEG)for efficient K-ion adsorption/diffusion and long-term durability.It is the B co-doping that plays a crucial role in maximizing doping-site utilization of N atoms,balancing the adsorption-diffusion kinetics,and promoting the charge transfer between NBEG and K ions.Especially,the robust lamellar structure,suitable interlayer distance,and rich active sites of the designed NBEG favor the rapid ion/electron transfer pathways and high K-ion storage capacity.Consequently,even at a low N,B doping concentration(4.36 at%,2.07 at%),NBEG anode shows prominent electrochemical performance for KIBs,surpassing most of the advanced carbon-based anodes.Kinetic studies,density functional theory simulations,and in-situ Raman spectroscopy are further performed to reveal the K-ion storage mechanism and confirm the critical actions of co-doping B.This work offers the new methods for graphite-electrode design and the deeper insights into their energy storage mechanisms in KIBs.

Design Strategy of Infrared 4-Hydroxybenzylidene-imidazolinone-Type Chromophores based on Intramolecular Charge Transfer:a Theoretical Perspective

Partial genetically encoded 4-hy-droxybenzylidene-imidazolinone(HBI)-type chromophores are new promising fluorescent probes,which are suitable for imaging and detection of living cells.How-ever,the lack of infrared chro-mophores hinders the develop-ment seriously.Here more than 30 HBI-type chromophores with reg-ular structure modifications were employed and typical spectral redshift change laws and mechanisms were investigated by quantum methods.Results show that both one-photon spectrum(OPS,absorption/emission)and two-photon absorption(TPA)can achieve large redshift via either extending conjugated lengths of frag-3 or enlarging conjugated areas of frag-1 of HBI skeleton.Spectral redshifts of all chromophores are highly related to intramolecular charge transfer(ICT),but neutral ones are closely related to the total ICT or electron-accept-ing-numbers of frag-3,and the high correlative factor of anions is the aromaticity of frag-2 bridge.The frag-2 bridge with high aromaticity can open a reverse charge transfer channel in anion relative to neutral,obtaining significant redshift.Based on analysis,a new 6-hydroxyl-naphthalene-imidazolinone(HNI)series,which have larger conjugated area in frag-1,are pre-dicted.The OPS and TPA of anionic HNI ones acquire about 76−96 nm and 119−146 nm red-shift relative to traditional HBI series respectively as a whole.The longest emission of anionic HNI-4 realizes more 244 nm redshift relative to HBI-1.Our work clarifies worthy spectral reg-ularities and redshift mechanisms of HBI-type chromophores and provides valuable design strategy for infrared chromophores synthesis in experiment.

Incomplete charge transfer in CMOS image sensor caused by Si/SiO_(2)interface states in the TG channel

CMOS image sensors produced by the existing CMOS manufacturing process usually have difficulty achieving complete charge transfer owing to the introduction of potential barriers or Si/SiO_(2)interface state traps in the charge transfer path,which reduces the charge transfer efficiency and image quality.Until now,scholars have only considered mechanisms that limit charge transfer from the perspectives of potential barriers and spill back effect under high illumination condition.However,the existing models have thus far ignored the charge transfer limitation due to Si/SiO_(2)interface state traps in the transfer gate channel,particularly under low illumination.Therefore,this paper proposes,for the first time,an analytical model for quantifying the incomplete charge transfer caused by Si/SiO_(2)interface state traps in the transfer gate channel under low illumination.This model can predict the variation rules of the number of untransferred charges and charge transfer efficiency when the trap energy level follows Gaussian distribution,exponential distribution and measured distribution.The model was verified with technology computer-aided design simulations,and the results showed that the simulation results exhibit the consistency with the proposed model.

Anomalous photoluminescence enhancement and resonance charge transfer in type-II 2D lateral heterostructures

Type-Ⅱband alignment can realize the efficient charge transfer and separation at the semiconductor heterointerface,which results in photoluminescence(PL)quenching.Recently,several researches demonstrated great enhancement of localized PL at the interface of type-Ⅱtwo-dimensional(2D)heterostructure.However,the dominant physical mechanism of this enhanced PL emission has not been well understood.In this work,we symmetrically study the exciton dynamics of type-Ⅱlateral heterostructures of monolayer MoS_(2) and WS_(2) at room temperatures.The strong PL enhancement along the one-dimensional(1D)heterointerface is associated with the trion emission of the WS_(2) shell,while a dramatic PL quenching of neutral exciton is observed on the MoS_(2) core.The enhanced quantum yield of WS2trion emission can be explained by charge-transfer-enhanced photoexcited carrier dynamics,which is facilitated by resonance hole transfer from MoS_(2) side to WS_(2) side.This work sheds light on the 1D exciton photophysics in lateral heterostructures,which has the potential to lead to new concepts and applications of optoelectronic device.

Charge-Transfer and SERS Coupling on TiO2

We report the SERS enhancements of Raman forbidden surface modes of TiO2 in different sized TiO2 crystals. This current study utilizes the relationship between the vibronic coupling and the degree of charge-transfer to explain the differences of Surface Enhanced Raman Scattering (SERS) enhancements. Our study shows a direct correlation between the degree of charge-transfer and vibronic coupling. This relationship suggests that charge-transfer between the N-719 dye and TiO2 due to vibronic coupling plays a fundamental role in SERS enhancements. Furthermore, this study shows a strong dependence of the enhancements of the N-719 dye molecular modes to that of the surface modes. This indicates that the mechanism that governs the enhancements of the surface modes in TiO2 crystals most likely also dictates the enhancements of the N-719 dyes.

UV-visible Absorption Studies of Tetrachloro-p-benzoquinone and Tertiary Amines Charge Transfer Complexes in Trichloromcthane

The spectophotometry of charge transfer (CT) complexes of tetrachloro-p-benzoquinone(TCB) with tertiary amine [triethylamine (TEA), triphylamine (TPA), N,N-dimethylphenylamine(DMPA), N-ethylcarbazole (ECZ)] have been studied in dichloromethane in UV-visible region.The CT complexes parameter, molar ratio of reactAnts in complex, molar extinction coefficient equilibrium constant KCT, free energy G and dissociation energy of the CT complex excited stateE, have also been estimated and discussed.

Sensitive Spectrofluorimetric Method for Determination of Fluoroquinolones through Charge-Transfer Complex Formation

A sensitive spectrofluorimetric method was developed for determination of ciprofloxacin (CPFX), levofloxacin (LEV), gatifloxacin (GAT) and moxifloxacin (MOX) in pure, commercial formulations, human urine and plasma. The method is based on charge-transfer (CT) complex with chloranilic acid. Fluorescence intensity of the complexes was measured at emission wavelength ranging from 445-492 nm with excitation wavelengths from 285-330 nm. At optimum experimental conditions, a linear calibration plot was obtained in the concentration range of 20-1000 ng·mL-1, 60-320 ng·mL-1, 20-800 ng·mL-1 and 20 -00 ng·mL-1 for CPFX, LEV, MOX and GAT, respectively with good correlation coefficient in the range of 0.9929-1.0 in methanolic medium. The limit of detection and limit of quantification were found to be 5 ng·mL-1 and 18 ng·mL-1 for CPFX, 12 ng·mL-1 and 40 ng·mL-1 for LEV, 8 ng·mL-1 and 19 ng·mL-1 for MOX, 6 ng·mL-1 and 19 ng·mL-1 for GAT, respectively. The method was found free of interferences from excipients used as additive in pharmaceutical preparations, some common cations and compounds present in urine and plasma as well as co-administered analgesic, vitamins and other drugs. The method was successfully applied for quantification of selected fluoroquinolones in commercial formulations and also in spiked human urine and plasma samples with percent recoveries of 100.0 ± 1.56 and 100.2 ± 1.29 respectively.

Intramolecular Charge Transfer Dual Fluorescence pH Sensing using p-Dibutylaminobenzoic Acid-β-cyclodextrin Inclusion Complex

The intramolecular charge transfer dual fluorescence of p-dibutylaminobenzoic acid-b-cyclodextrin inclusion complex showed a substantially higher sensitivity toward aqueous solution pH variation when compared with that of p-dibutylaminobenzoic acid alone, which established a new principle for direct CT fluorescence sensing in aqueous solution by using the CT fluorophore-cyclodextrin inclusion complex.

Synthesis and Characterization of Charge-transfer Complexes of Aminoethylphosphono-and Dimethylaminoethylphosphono-heteropolytungstic Acids of Keggin Type Structure

Two charge-transfer complexes of 2a and 2b of Keggin type were synthesized and characterized by elemental analysis, IR spectra, UV spectra, XRD, TG-DSC; and were compared with Hquin-PW12. The primary structure of the heteropolyanions had not been changed after the formation of the charge transfer complexes.

Spectroscopic Characterization, Molecular Modeling and DFT/TD-DFT/PCM Calculations of Novel Hydrogen-Bonded Charge Transfer Complex between Chloranilic Acid and 2-Amino-4,6-Dimethylpyridine

A charge transfer hydrogen bonded complex between the electron donor (proton acceptor) 2-amino-4,6-dimethylpyridine with the electron acceptor (proton donor) chloranilic acid has been synthesized and studied experimentally and theoretically. The stability constant recorded high values indicating the high stability of the formed complex. In chloroform, ethanol, methanol and acetonitrile were found the stoichiometric ratio 1:1. The solid complex was prepared and characterized by different spectroscopy techniques. FTIR, 1H and 13C NMR studies supported the presence of proton and charge transfers in the formed complex. Complemented with experimental results, molecular modelling using the density functional theory (DFT) calculations was carried out in the gas, chloroform and methanol phases where the existence of charge and hydrogen transfers. Finally, a good consistency between experimental and theoretical calculations was found confirming that the applied basis set is the suitable one for the system under investigation.