Charge Separation Phenomena Research Articles

Search for the chiral magnetic effect in Au+Au collisions at [formula omitted] GeV with the STAR forward event plane detectors

A decisive experimental test of the Chiral Magnetic Effect (CME) is considered one of the major scientific goals at the Relativistic Heavy-Ion Collider (RHIC) towards understanding the nontrivial topological fluctuations of the Quantum Chromodynamics vacuum. In heavy-ion collisions, the CME is expected to result in a charge separation phenomenon across the reaction plane, whose strength could be strongly energy dependent. The previous CME searches have been focused on top RHIC energy collisions. In this Letter, we present a low energy search for the CME in Au+Au collisions at sNN=27 GeV. We measure elliptic flow scaled charge-dependent correlators relative to the event planes that are defined at both mid-rapidity |η|<1.0 and at forward rapidity 2.1<|η|<5.1. We compare the results based on the directed flow plane (Ψ1) at forward rapidity and the elliptic flow plane (Ψ2) at both central and forward rapidity. The CME scenario is expected to result in a larger correlation relative to Ψ1 than to Ψ2, while a flow driven background scenario would lead to a consistent result for both event planes. In 10-50% centrality, results using three different event planes are found to be consistent within experimental uncertainties, suggesting a flow driven background scenario dominating the measurement. We obtain an upper limit on the deviation from a flow driven background scenario at the 95% confidence level. This work opens up a possible road map towards future CME search with the high statistics data from the RHIC Beam Energy Scan Phase-II.

Preliminary Study of Photoelectrochemical Properties of Electrosyntetized Cerium Dioxide (CeO2) to Pollutant Treatment

1. IntroductionIn this work a systematic procedure to synthetize of cerium dioxide and evaluation and its photoelectrochemical properties for dye degradation in aqueous media is shown. First, electrochemical synthesis of CeO2 methodology is presented as function of annealing temeprature and concentration of Ce3+ precursors in the plating. Next, Raman spectra and FTIR analysis were presented to evaluate structural properties of films. Lineal sweep voltammetry (LSV) and chronoamperometry (CA) results are shown to evaluate the photocurrent and its stability of CeO2 and finally all the results were analyzed in function of excitons production, charge separation and recombination phenomena.2. Methodology 2.1. Electrochemical synthesis of CeO2 First, cerium hydroxide (Ce(OH)3) was obtained from a CeCl3.7H2O solution (5 and 25 mM) with 0,05 M of NaNO3 as support electrolyte by applying of a constant potential of -1,2 V vs AgCl during 300 s to an FTO electrode (1,3 x 0,6 cm). A reference electrode (Ag/AgCl 3,0 M and a Pt wire as a counter electrode were used in the electrochemical cell connected to a potenciostat-galvanostat AUTOLAB N65 Series. After deposition of cerium hydroxide form, the FTO substrates were alienated at different temperatures (200 – 700 oC) for 1 hour to obtain the oxide cerium form. Finally, FTO photoelectrodes were dried with air and stored at room temperature. 2.2. Photoelectrochemical characterization of CeO2 films LSV and CA were used to evaluate the photo-response and stability of produced photocurrent of CeO2 photoanodes. In the LSV experiment, a range of potential from +0,5 V to 1,2 V was used with a sweep of 10 mV/s. Meanwhile, a bias potential of +1,2 V during 300 s with light-dark cycles of 30 s was used in CA experiments. A system of three electrode (FTO-CeO2 as a working electrode, Ag/AgCl 3,0 M and a Pt wire) were used in an electrochemical with a quartz window. The cell was irradiated with a light source of 100 mW/cm2. The solution of the electrochemical cell was Na2SO4 0,1 M.3. ResultsElectrochemical measurements show that there is a great influence in the temperature treatment to obtain high photocurrent using CeO2 photoanodes. Besides, CeO2 increase its photoelectroactivity when small concentration of Ce3+ precursor is used in the electrochemical formation of hydroxide. This could be attributed to a decrease of size particle and therefore a favorable change of band gap of CeO2. Stability of photocurrent of CeO2 photoelectrode changes slowly across the time this process could be product of electronic saturation in the process of charge separation or structural changes during the photoelectrocatalytic process due to applying of potential bias.4. REFERENCES(1) Ma, R.; Zhang, S.; Wen, T.; Gu, P.; Li, L.; Zhao, G.; Niu, F.; Huang, Q.; Tang, Z.; Wang, X. A Critical Review on Visible-Light-Response CeO2-Based Photocatalysts with Enhanced Photooxidation of Organic Pollutants. Catalysis Today 2019, 335, 20–30. https://doi.org/10.1016/j.cattod.2018.11.016.(2) Liu, Z.; Guo, S.; Hong, C.; Xia, Z. Synthesis and Photocatalytic Properties of CeO2 Nanocubes. Journal of Materials Science: Materials in Electronics 2016, 27 (2), 2146–2150. https://doi.org/10.1007/s10854-015-4004-1.(3) Muñoz-Batista, M. J.; Gómez-Cerezo, M. N.; Kubacka, A.; Tudela, D.; Fernández-García, M. Role of Interface Contact in CeO2-TiO2 Photocatalytic Composite Materials. ACS Catalysis 2014, 4 (1), 63–72. https://doi.org/10.1021/cs400878b.

Bridge-Length- and Solvent-Dependent Charge Separation and Recombination Processes in Donor-Bridge-Acceptor Molecules.

The photoinduced intramolecular charge separation (CS) and charge recombination (CR) phenomena in a series of donor-bridge-acceptor (D-B-A) molecules are intensively investigated as a means of understanding electron transport through the π-B. Pyrene (Pyr) and triarylamine (TAA) moieties connected via phenylene Bs of various lengths are studied because their CS and CR behaviors can be readily monitored in real time by femtosecond transient absorption (fs-TA) spectroscopy. By combining the steady-state and fs-TA spectroscopic measurements in a variety of solvents together with chemical calculations, the parameters that govern the CS behaviors of these dyads were obtained, such as the solvent effects on free energy and the B-length-dependent electronic coupling (VDA) between D and A. We observed the sharp switch of the CS behavior with the increase of the solvent polarity and B-linker lengths. Furthermore, in the case of the shortest distance between D and A when the electron coupling is sufficiently large, we observed that the CS phenomenon occurs even in low-polar solvents. Upon increasing the length of B, CS occurs only in strong polar solvents. The distance-dependent decay constant of the CS rate is determined as ∼0.53 Å-1, indicating that CS is governed by superexchange tunneling interactions. The CS rate constants are also approximately estimated using Marcus electron transfer theory, and the results imply that the VDA value is the key factor dominating the CS rate, while the facile rotation of the phenylene B is important for modulating the lifetime of the charge-separated state in these D-B-A dyads. These results shed light on the practical strategy for obtaining a high CS efficiency with a long-lived CS state in TAA-B-Pyr derivatives.

Temporal and Spectral Characterization of Electromagnetic Pulse Emitted From Nanosecond Pulsed Laser Produced Aluminum Plasma

The electromagnetic pulse (EMP) emitted from the plasma produced by interaction of 5-ns pulsed Nd:YAG ( $\lambda =532$ nm) laser with the aluminum target was measured. The laser irradiance at the target was varied in the range of $3.12\times 10^{9} - 4.56\times 10^{10}$ W/cm2 and its influence on the temporal and spectral parameters of the EMP was investigated. The EMP starts well after the termination of laser pulse and the duration of EMP is up to several hundred nanoseconds. The EMP start time was found to decrease from approximately 150 to 60 ns with the rise of laser irradiance. The rise time of EMP (~50 ns) does not seem to vary with the laser irradiance. The signal consists of several resonance peaks in the frequency bin of 20–200 MHz, whose intensity also depends on the laser irradiance. The observed dependence of EMP intensity on the laser irradiance and frequency of fundamental-mode emission is compared with the theoretical predictions. The considerable delayed emission of EMP indicates that its origin can be related to the macroscopic charge separation phenomena during the plasma expansion.

Numerical simulation of the plasma acceleration process in a magnetically enhanced micro-cathode vacuum arc thruster

A particle-in-cell simulation is conducted to investigate the plasma acceleration process in a micro-cathode vacuum arc thruster. A coaxial electrode structure thruster with an applied magnetic field configuration is used to investigate the effects of the distribution of the magnetic field on the acceleration process and the mechanism of electrons and ions. The modeling results show that due to the small Larmor radius of electrons, they are magnetized and bound by the magnetic field lines to form a narrow electron channel. Heavy ions with a large Larmor radius take a long time to keep up with the electron movement. The presence of a magnetic field strengthens the charge separation phenomenon. The electric field caused by the charge separation is mainly responsible for the ion acceleration downstream of the computation. The impact of variations in the distribution of the magnetic field on the acceleration of the plasma is also investigated in this study, and it is found that the position of the magnetic coil relative to the thruster exit has an important impact on the acceleration of ions. In order to increase the axial velocity of heavy ions, the design should be considered to reduce the confinement of the magnetic field on the electrons in the downstream divergent part of the applied magnetic field.

Effects of Surface Transition and Adsorption on Ionic Liquid Capacitors.

Room-temperature ionic liquids (RTILs) are synthetic electrolytes with electrochemical stability superior to that of conventional aqueous-based electrolytes, allowing a significantly enlarged electrochemical window for application as capacitors. In this study, we propose a variant of an existing RTIL model for solvent-free RTILs, accounting for both ion-ion correlations and nonelectrostatic interactions. Using this model, we explore the phenomenon of spontaneous surface charge separation in RTIL capacitors and find that this transition is a common feature for realistic choices of the model parameters in most RTILs. In addition, we investigate the effects of asymmetric preferential ion adsorption on this charge separation transition and find that proximity of the transition in this case can result in greatly enhanced energy storage. Our work suggests that differential chemical treatment of electrodes can be a simple and useful means for optimizing energy storage in RTIL capacitors.

(Invited) Reversible Asymmetric Structure Evolution and Battery Performance in Layered Sodium Transition Metal Oxides

Layered sodium transition metal oxide system of NaMO2 (M = 3d transition metal ions and their mixtures) forms a unique material platform to study the interactions between transition metal, oxygen and sodium sublattices. Specifically, Fe and Mn, which are not stable in layered LiMO2, become much more stable in NaMO2. In this talk, I will show that the interplay between these different sublattices at low Na composition modulates the electrochemical performance of NaxMO2 through the generation of novel high voltage phases. A combined in situ (synchrotron) XRD, X-ray absorption spectroscopy, atomic resolution (scanning) TEM, neutron diffraction and density functional theory (DFT) simulation techniques are used to understand the structural and functional details in crystallographic, electronic and magnetic properties. For the Fe containing mixed transition metal system of Na(FexTM1-x)O2, a rippling phase at high voltage was developed due to the unique electronic property of FeO6­ octahedra, while at low voltage it goes back to the normal flat phase through an asymmetric structural evolution pathway, giving high discharge rate capability. For NaMnO2 a unique phenomenon of super charge separation is reported, where an emergent structural unit of charge superplane related to the collective Jahn-Teller activity of Mn3+ was found to dominate the entire electrochemical evolution, giving asymmetric charge discharge behavior and high discharge capacity. The underlying connection between these reversible asymmetric systems will be discussed to further facilitate the design of advanced cathode materials for sodium ion batteries. [1]Advanced Functional Materials, 1805105 (2018) [2]Advanced Functional Materials, 1803896 (2018)

Solar Energy Conversion: Pt-doped Mesoporous Ceria as an Efficient Electro-photocatalyst for Hydrogen Production from Water Splitting

Abstract In terms of solar energy conversions, mesoporous materials disclose with significant advantages over charge separation phenomenon. In this study, we have explored the synthesis and characterization of mesoporous CeO2 for photoelectrochemical (PEC) investigations. We also examined the electronic band structure and density of states for modified CeO2 (as per lattice parameters of meso-CeO2), which was further compared with un-modified CeO2. Under this investigation, PEC studies showed the significant impact of visible light with enhancement in charge carrier of meso-CeO2 and Pt/Meso-CeO2 as compared to the dark conditions. Further, the current-potential measurement showed significant photocurrent difference in dark and light, in which Pt/meso-CeO2 displayed higher photocurrent difference than that of meso-CeO2. The negative value of Vfb and generated current suggest that meso-CeO2 and Pt/Meso-CeO2 could be used as n-type photocathode during PEC H2 evolution reaction. Furthermore, a plausible inverse PEC mechanism for n-type photocathodes is described.

Super Charge Separation and High Voltage Phase in NaxMnO2

Na x MnO2 shows Mn3+ and Mn4+ charge separation with the charge stripe ordering upon Na deintercalation at x = 5/8. In this paper it is shown that, surprisingly, at lower Na compositions of 5/8 > x ≥ 1/18 the phase evolution pathway of Na x MnO2 upon Na deintercalation shows a unique phenomenon of super charge separation, where the Mn3+ and Mn4+ ions fully charge-separate into charge superplanes formed by succession of charge stripes in the third dimension. The Mn3+ superplanes attract Na ions electronically, and dominate the antiferromagnetic interactions in NaMnO2. Na ions in Mn3+ superplanes also naturally pillar the MnO2 layers to form the unusual O1 phases with large interlayer distances at x < 1/3, which dominates the unique electrochemical behavior of NaMnO2.

Synthesis and enhanced electron transfer of supramolecular nano-composite containing dendritic dye and surface-modified ZnO nano-rods

Supramolecular nano-composites 15T5N/ZnOx-PNH containing enhanced compatibilities of dendritic dye 15T5N and surface-modified nano-rod ZnOx-PNH were developed in this study. The physical properties of supramolecular nano-composites have been well investigated by theoretical calculation and various measurements, including UV–visible, PL, TEM, TCSPC, FT-IR, and CV. H-bonded nano-composite 15T5N/ZnO30-PNH possessed the saturated quenched fluorscence as dendritic dye 15T5N complexed with surface-modified nano-rod ZnO30-PNH. In contrast to nano-rod mixture 15T5N/ZnO (without surface-modification), more widened visible absorption band to promote more efficient photo-induced charge separation phenomenon was observed in supramolecular nano-composite 15T5N/ZnO30-PNH. Compared with surfactant T-PNH, less efficient electron transfer of surfactant T-PC6 was observed in TCSPC and PL measurements because of the steric hindrance of long alkyl chains (-C6H13) attached to surfactant T-PC6. Therefore, the triple H-bonds between dendritic dye 15T5N and surface-modified nano-rod ZnO30-PNH are verified to result in the desirable effective electron transfer in supramolecular nano-composite 15T5N/ZnO30-PNH.

Constraints on the chiral magnetic effect using charge-dependent azimuthal correlations in pPb and PbPb collisions at the CERN Large Hadron Collider

Charge-dependent azimuthal correlations of same- and opposite-sign pairs with respect to the second- and third-order event planes have been measured in pPb collisions at sNN=8.16TeV and PbPb collisions at 5.02 TeV with the CMS experiment at the LHC. The measurement is motivated by the search for the charge separation phenomenon predicted by the chiral magnetic effect (CME) in heavy ion collisions. Three- and two-particle azimuthal correlators are extracted as functions of the pseudorapidity difference, the transverse momentum (pT) difference, and the pT average of same- and opposite-charge pairs in various event multiplicity ranges. The data suggest that the charge-dependent three-particle correlators with respect to the second- and third-order event planes share a common origin, predominantly arising from charge-dependent two-particle azimuthal correlations coupled with an anisotropic flow. The CME is expected to lead to a v2-independent three-particle correlation when the magnetic field is fixed. Using an event shape engineering technique, upper limits on the v2-independent fraction of the three-particle correlator are estimated to be 13% for pPb and 7% for PbPb collisions at 95% confidence level. The results of this analysis, both the dominance of two-particle correlations as a source of the three-particle results and the similarities seen between PbPb and pPb, provide stringent constraints on the origin of charge-dependent three-particle azimuthal correlations and challenge their interpretation as arising from a chiral magnetic effect in heavy ion collisions.18 MoreReceived 4 August 2017DOI:https://doi.org/10.1103/PhysRevC.97.044912Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.©2018 CERN, for the CMS CollaborationPhysics Subject Headings (PhySH)Research AreasRelativistic heavy-ion collisionsNuclear Physics

Dielectric spectroscopy of Pyr14TFSI and Pyr12O1TFSI ionic liquids

Due to the conductivity of ionic liquids (IL), the dipolar dynamics are covered by charge separation phenomenon, which leads to difficulties extracting necessary parameters, i.e. static dielectric permittivity. We suggest a procedure, which allows relatively easy extracting parameters of dipolar dynamics of IL. Our experiments were performed on Pyr14TFSI and Pyr12O1TFSI ILs. Obtained results allowed comparing the dipolar dynamics of both materials. The factor, which makes the static dielectric permittivity of Pyr12O1TFSI to be higher than that of Pyr14TFSI may be accounted for the permanent dipole of Pyr12O1+ cation.

Photocatalytic back-conversion of CO2 into oxygenate fuels using an efficient ZnO/CuO/carbon nanotube solar-energy-material: Artificial photosynthesis

Fuel shortage, energy crisis and boundless dumping of greenhouse gases into the atmosphere, are some challenging issues of human societies. To overcome these energy-related/environmental problems, solar conversion of CO2 to carbon-based fuels is a promising route, which is achievable through the atomistic hydrogenation of CO2 molecules inside semiconductor-assisted water-photosplitting reactors. In this paper, using a facile hydrothermal method, an eco-friendly, low-price, nanocomposite solar-energy-material was synthesized in the absence and presence of carbon nanotube (CNT), and applied in aqueous media for the photochemical synthesis of ethanol, oxalic acid and formaldehyde. The enhancing power of CNT on the photocatalyst performance was explained in detail in terms of its ability to harvest more incident photons, temporarily store H atoms, increase the surface area and improve the charge separation phenomenon. Based on atomistic hydrogenation hypothesis, a reaction scheme was finally proposed for each photochemically synthesized product.

The Poisson–Boltzmann equation and the charge separation phenomenon at the silica-water interface: A holistic approach

The Poisson Boltzmann equation is known for its success in describing the Debye layer that arises from the charge separation phenomenon at the silica/water interface. However, by treating only the mobile ionic charges in the liquid, the Poisson Boltzmann equation accounts for only half of the electrical double layer, with the other half, the surface charge layer, being beyond its computational domain. In this work, we take a holistic approach to the charge separation phenomenon at the silica/water interface by treating, within a single computational domain, the electrical double layer that comprises both the mobile ions in the liquid and the surface charge density. The Poisson Nernst Planck equations are used as the rigorous basis for our methodology. The holistic approach has the advantage of being able to predict surface charge variations that arise either from the addition of salt and acid to the liquid, or from the decrease of the liquid channel width to below twice the Debye length. As the electrical double layer must be overall neutral, we use this constraint to derive both the form of the static limit of the Poisson Nernst Planck equations, as well as a global chemical potential that replaces the classical zeta potential as the boundary value for the PB equation, which can be re-derived from our formalism. We present several predictions of our theory that are beyond the framework of the PB equation alone, e.g., the surface capacitance and the so-called pK and pL values, the isoelectronic point at which the surface charge layer is neutralized, and the appearance of a Donnan potential that arises from the formation of an electrical double layer at the inlet regions of a nano-channel connected to the bulk reservoir. All theory predictions are shown to be in good agreement with the experimental observations.

Charge separation and isolation in strong water droplet impacts.

Charge separation in condensed matter after strong impacts is a general and intriguing phenomenon in nature, which is often identified and described but not necessarily well understood in terms of a quantitative mechanistic picture. Here we show that charge separation naturally occurs if water droplets/clusters or ice particles with embedded charge carriers, e.g., ions, encounter a high energy impact with subsequent dispersion - even if the involved kinetic energy is significantly below the molecular ionization energy. We find that for low charge carrier concentrations (c < 0.01 mol L(-1)) a simple statistical Poisson model describes the charge distribution in the resulting molecular "fragments" or aggregates. At higher concentrations Coulomb interactions between the charge carriers become relevant, which we describe by a Monte Carlo approach. Our models are compared to experimental data for strong (laser) impacts on liquid micro beams and discussed for the charge generation in cluster-impact mass spectrometry on cosmic dust detectors where particle kinetic energies are below the plasma threshold. Taken together, a simple and intuitive but quantitative microscopic model is obtained, which may contribute to the understanding of a larger range of phenomena related to charge generation and separation in nature.

Spatial charge separation in asymmetric structure of Au nanoparticle on TiO2 nanotube by light-induced surface potential imaging.

Both enhancing the excitons' lifetime and ingeniously controlling the spatial charge transfer are the key to the realization of efficiently photocatalytic and artificially photosynthetic devices. Nanostructured metal/metal-oxide interfaces often exhibit improved energy conversion efficiency. Understanding the surface potential changes of nano-objects under light illumination is crucial in photoelectrochemical cells. Under ultraviolet (UV) illumination, here, we directly observed the charge separation phenomena at the Au-nanoparticle/TiO2-nanotube interfaces by using Kelvin probe force microscopy. The surface potential maps of TiO2 nanotubes with and without Au nanoparticles were compared on the effect of different substrates. We observed that in a steady state, approximately 0.3 electron per Au particle of about 4 nm in diameter is effectively charged and consequently screens the surface potential of the underlying TiO2 nanotubes. Our observations should help design improved photoelectrochemical devices for energy conversion applications.

Intramolecular Polarization Induces Electron–Hole Charge Separation in Light-Harvesting Molecular Triads

Artificial light-harvesting supramolecular structures reproduce the light-to-electrochemical energy transduction mechanisms observed in natural photosynthesis. Among them the prototypical carotenoid(C)–porphyrin(P)–fullerene(C60) type of structures have been the most studied. Several experiments performed in such structures, and others alike, have shown that the photoexcited state C– 1P–C60 decays to the metastable charge-separated state C– P•+ −C60•– within a few picoseconds, whereas the final charge-separated state, C•+– P −C60•–, is obtained within hundreds of picoseconds. This paper introduces a nonlinear polarizable extended Hückel Hamiltonian that describes the charge dynamics and charge-separation effects in such triads by means of quantum dynamics simulations performed on the photoexcited electron–hole pair. The results are interpreted on the basis of the discrete self-trapping equation and enlighten the role played by the polarizability on charge-separation phenomena.

Characterizing the Influence of TOPO on Exciton Recombination Dynamics in Colloidal CdSe Quantum Dots

Surface ligands play a significant role in the carrier recombination dynamics of colloidal quantum dots (QDs). Trioctylphosphine oxide (TOPO) is a ligand used during CdSe QD synthesis, which binds to surface cadmium atoms, but, despite its widespread use, its effect on exciton relaxation rates is poorly understood. In this work, we extract TOPO–CdSe binding equilibria from isothermal titration calorimetry experiments and use them to study the effect of TOPO concentration on CdSe time-resolved photoluminescence. We develop a quantitative kinetic model of CdSe QD exciton relaxation that is based upon an ensemble probability distribution of bound ligands and show that bound TOPO gives rise to band-edge states that participate in carrier recombination dynamics. Optoelectronic applications of QDs necessitate a good understanding of interfacial dynamics so that charge separation, carrier transport, and other phenomena can be optimized. This technique is a promising step toward that goal that is useful for any l...

The stable nonequilibrium state of bicarbonate aqueous systems

Data obtained by electron paramagnetic resonance (EPR) and chemiluminescence analysis indi� cate that in aqueous solutions of bicarbonates, superoxide radical and other reactive oxygen species (ROS) are constantly produced. The stationary level of the superoxide radical is found to increase when a solution is illuminated. Reactions involving ROS are shown to be accompanied by the generation of electron excitation energy, keeping bicarbonate solutions in a stable nonequilibrium state. The system can emit part of this energy. Variations in emitting activity are found to correlate with variations in the cosmophysical factors. The emitting activity of solutions is found to vary in the presence of low and ultralow concentrations of hydrated fullerenes. It is noted that the phenomenon of spontaneous charge separation in aqueous systems (G. H. Pol� lack) could play a role in maintaining a stable nonequilibrium state in bicarbonate systems where the reac� tions with ROS participation are catalyzed by forms of carbonate. It is concluded that the abovementioned properties of bicarbonate aqueous systems most likely keep living matter whose structural basis is formed by these systems in a stable excited state, thereby making it highly sensitive to the action of external factors with low and ultralow intensities.

Surface plasmon resonance of layer-by-layer gold nanoparticles induced photoelectric current in environmentally-friendly plasmon-sensitized solar cell

Layer-by-layer gold nanoparticles are used to generate photocurrent in an environmentally-friendly plasmon-sensitized solar cell towing to surface plasmon resonance. The efficiency of the photoelectric conversion of gold nanoparticle layers is increased as the intensity of surface plasmon resonance increases. We also explain the experimental results by modeling the phenomenon of charge separation and photocurrent formation, and the relationship between surface plasmon resonance and photocurrent formation, which has potential application in plasmon-sensitized solar cells and plasmonic solar cells in the future. The efficiency of a plasmon-sensitized solar cell can be improved by depositing gold nanoparticles on the cell’s surface. Achieving a high energy-conversion efficiency—the percentage of incident solar energy converted into electrical energy—is the primary goal for any solar cell technology. Yen-Hsun Su and colleagues at National Dong Hwa University in Hualien have now demonstrated that depositing multiple layers of gold nanoparticles on the surface of a plasmon-sensitized solar cell increases the amount of light scattered across its surface, boosting the amount of light absorbed and thus improving its efficiency. Once optimized, such gold-covered plasmonic solar cells have the potential to replace the more popular dye-sensitized solar cells.