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A photoelectrochemical (PEC) cell composed of two semiconductor electrodes, a photocathode, and a photoanode is a potentially effective means of obtaining hydrogen through spontaneous overall water splitting under light irradiation. However, the long-term stability (that is, operation for more than one day) of a PEC cell has not yet been demonstrated. In addition to the corrosion of both photoelectrodes, the gradual migration of heavy metal cations from the photoanode into the electrolyte can also result in degradation of the cell by contamination of the photocathode surface. In the present work, BiVO4-based photoanodes were used in conjunction with two different modifications: dispersion of a chelating resin in the electrolyte and coating of the photoanode surface with an anion-conducting ionomer. The chelating resin was found to capture Bi3+ cations in the electrolyte before they became deposited on the cathode surface. Consequently, a PEC cell incorporating a BiVO4-based photoanode and a (ZnSe)0.85(CuIn0.7Ga0.3Se2)0.15-based photocathode showed stable overall water splitting over a span of two days under simulated sunlight. To the best of our knowledge, this represents the longest period over which stable PEC cell performance has been established. A considerable decrease in the performance of the BiVO4-based photoanode was still observed due to the continuous dissolution of Bi species, but surface coating of the photoanode with an anion-conducting ionomer prevented the movement of Bi3+ ions into the electrolyte because of the selective conduction of ions. The coating also served as a protective layer that improved the durability of the photoanode. This study therefore suggests a simple yet effective method for the construction of stable PEC cells using semiconductor photoelectrodes. [ABSTRACT FROM AUTHOR]

A tight binding model is used to investigate photoinduced tunneling current through a molecular bridge coupled to two semiconductor electrodes. A quantum master equation is developed within a non-Markovian theory based on second-order perturbation theory with respect to the moleculesemiconductor electrode coupling. The spectral functions are generated using a one dimensional alternating bond model, and the coupling between the molecule and the electrodes is expressed through a corresponding correlation function. Since the molecular bridge orbitals are inside the bandgap between the conduction and valence bands, charge carrier tunneling is inhibited in the dark. Subject to the dipole interaction with the laser field, virtual molecular states are generated via the absorption and emission of photons, and new tunneling channels open. Interesting phenomena arising from memory are noted. Such a phenomenon could serve as a switch. [ABSTRACT FROM AUTHOR]

Many natural patterns and shapes, such as meandering coastlines, clouds, or turbulent flows, exhibit a characteristic complexity that is mathematically described by fractal geometry. Here, we extend the reach of fractal concepts in photonics by experimentally demonstrating multifractality of light in arrays of dielectric nanoparticles that are based on fundamental structures of algebraic number theory. Specifically, we engineered novel deterministic photonic platforms based on the aperiodic distributions of primes and irreducible elements in complex quadratic and quaternions rings. Our findings stimulate fundamental questions on the nature of transport and localization of wave excitations in deterministic media with multi-scale fluctuations beyond what is possible in traditional fractal systems. Moreover, our approach establishes structure–property relationships that can readily be transferred to planar semiconductor electronics and to artificial atomic lattices, enabling the exploration of novel quantum phases and many-body effects. Emergent multifractality is the object of both fundamental and technology-oriented research. Here, the authors demonstrate and characterize multifractality in the optical resonances of aperiodic arrays of nanoparticles designed from fundamental structures of algebraic number theory. [ABSTRACT FROM AUTHOR]

In this paper, nano-CuO films, fabricated using the simple "doctor blade" technique, are studied as photoelectrodes in a two-electrode PEC cell for water photolysis. SEM analysis confirm the nanometric size of film grains and the photoelectrode porosity. The photocurrent behavior is studied, particularly, photocurrent transients for non-assisted and assisted water photolysis. Existing defects acting as carrier traps explain the different transient behaviors found. The existence of defects is explored using X-ray diffraction technique and the Williamson-Hall method. [ABSTRACT FROM AUTHOR]

Electrical and electrocatalytic properties of two series of double perovskites, LnCo1-xCrxO3 (Ln = Pr, Gd, and x = 0, 0.5 and 1), were investigated and discussed in the light of perovskite composition. Studied perovskites were synthesized by the solution combustion method, and powder XRD patterns showed that all compounds crystallize in the GdFeO3-structure type. The morphology of perovskite crystals was studied by SEM, whereas obtained microphotographs implied porous microstructure. The conductivity of both perovskite series spanned in the range of semiconductors as revealed from electrical measurements. The electrocatalytic activity toward oxygen evolution reaction, oxidation of hydrogen peroxide, and methanol was studied in alkaline solutions by cyclic voltammetry. The influence of electronic, structural and morphological factors to the electrical and electrocatalytic properties is discussed. The praseodymium series showed higher electrocatalytic activity than the gadolinium one, while the most pronounced activity was detected for PrCoO3. [ABSTRACT FROM AUTHOR]

Exploring efficient photocatalysts for water oxidation is highly demanded because of their significant role in artificial photosynthesis. The research of metal-organic frameworks (MOFs) based photoelectrochemical (PEC) water splitting is promising but still in its infancy due to the challenge to fabricate high-quality MOFs photoelectrode. Here an Fe 2 O 3 /Fe-based MOF core/shell nanorod is prepared for efficient PEC water oxidation via a facile surfactant-assisted solvothermal method. With polyvinylpyrrolidone (PVP) molecules as intermedia, an ultrathin MOF shell of several nanometers thick can be controllably grown on the surface of Fe 2 O 3 nanorod. Charge dynamical behaviors study by ultrafast transient absorption spectroscopy (TAS) and photoelectrochemical impedance spectroscopy (PEIS), reveal that the ultrathin MOF shell is crucial to promote the charge separation by providing a cascade band level, but also accelerate the hole injection efficiency via exposing more accessible Fe-oxo cluster active sites. Accompanied with good visible-light response, the Ti-doped Fe 2 O 3 /NH 2 -MIL-101(Fe) photoanode delivers a boosted photocurrent density of 2.27 mA cm −2 at 1.23 V vs. RHE, which is about 2.3 folds of that of pristine Fe 2 O 3 . This study provides new insights into the rational design of semiconductor/MOFs hybrid materials for photo/photoelectrochemical catalysis. [ABSTRACT FROM AUTHOR]

Semiconductor electrodes integrated with cocatalysts are key components of photoelectrochemistry (PEC)‐based solar‐energy conversion. However, efforts to optimize the PEC device have been limited by an inadequate understanding of the interface interactions between the semiconductor–cocatalyst (sem|cat) and cocatalyst–electrolyte (cat|ele) interface. In our work, we used ferrihydrite (Fh)‐modified Ti–Fe2O3 as a model to explore the transfer process of photogenerated charge carriers between the Ti–Fe2O3–Fh (Ti–Fe2O3|Fh) interface and Fh‐electrolyte (Fh|ele) interface. The results demonstrate that the biphasic structure (Fh/Ti–Fe2O3) possesses the advantage that the minority hole transfer from Ti–Fe2O3 to Fh is driven by the interfacial electric field at the Ti–Fe2O3|Fh interface; meanwhile, the holes reached at the surface of Fh can rapidly inject into the electrolyte across the Fh|ele interface. As a benefit from the improved charge transfer at the Ti–Fe2O3|Fh and Fh|ele interface, the photocurrent density obtained by Fh/Ti–Fe2O3 can reach 2.32 mA cm−2 at 1.23 V versus RHE, which is three times higher than that of Ti–Fe2O3. Water splitting: The excellent performance of ferrihydrite (Fh)/Ti–Fe2O3 is attributed to the unhindered charge transfer at the Ti–Fe2O3|Fh and Fh|electrolyte interfaces. As a benefit from this improved charge transfer, the photocurrent density obtained by Fh/Ti–Fe2O3 can reach 2.32 mA cm−2 at 1.23 V versus the reversible hydrogen electrode, which is three times higher than that of Ti–Fe2O3. [ABSTRACT FROM AUTHOR]

Ferroelectric tunnel junctions (FTJs) have attracted enormous interests as one of the promising candidates for next‐generation non‐volatile resistance memories. In this work, we report a novel FTJ employing both two‐dimensional material and semiconductor electrode, in the graphene/BaTiO3/Nb:SrTiO3 heterostructure, yielding an interesting tunneling electroresistance (TER) effect. We investigate the TER dependence on Nb doping concentrations from 0.1 to 1.0 wt% in the semiconductor electrode. In addition to modulating barrier height by ferroelectric polarization reversal, the ON/OFF resistance ratio can be tuned by adjusting Nb doping concentrations due to further modulation of barrier width. An optimized ON/OFF ratio above 103 of the device is observed when introducing 0.1 wt% Nb concentration at room temperature. Furthermore, good retention property and switching reproducibility can be achieved in the devices. The results provide a novel pathway to design the graphene‐based FTJ at the nanoscale, which is useful for developing non‐volatile memory devices with enhanced performance. [ABSTRACT FROM AUTHOR]

The performance and reliability of semiconductor electronics require that thermal management hardware be used to adequately cool devices, components, and packages. A vital component of many devices, including but not limited to PAs, CPUs, GPUs, and LEDs, is the integrated heat spreader (IHS). IHSs are implemented to spread the heat from the small electronic component to a larger area in order to facilitate sufficiently low thermal resistance active or passive cooling to the final fluid-cooled heat sink in the stack. One question that still needs to be addressed for electronics packaging is “Under what circumstances do vapor chamber heat spreaders outperform solid IHSs?” This paper is aimed at providing a straightforward approach to addressing this question, specifically during the early “scoping” design stage. Sufficiently accurate steady-state thermal network models for both solid and vapor chamber IHSs are proposed for estimating the overall stack resistance of a package, including TIM1, IHS, TIM2, and convective heat sink. In this way, the performance of both heat spreading technologies can be compared and contrasted over a range of geometric and operating parameters without having to resort to complex numerical models, which may require specialized expertise and/or be too expensive and time-consuming for early-stage design phases of electronic packages. [ABSTRACT FROM AUTHOR]

A laterally extended dc-driven system of planar gas discharge with a high-ohmic semiconductor electrode is considered. Numerical models are based on the fluid equations of plasma with drift-diffusion approximation for particle fluxes. The effect of different modelling approaches (with simpler and more detailed treatment of the electron transport and plasma chemical reactions) is analyzed. Bifurcation diagrams separating stable stationary states of the system from oscillatory states are derived and compared with the experimental data. [ABSTRACT FROM AUTHOR]

Semiconductors have been successfully demonstrated as the electrolytes for solid oxide fuel cells (SOFCs) in recent years. Many such semiconductors have shown their potentials as a competent ionic conductor for fuel cell operation, indicated by the appreciable ionic conduction and electrochemical performance. In the present study, we depart from traditional electrolyte concept to introduce a new semiconductor electrolyte, Li-doped ZnO to low-operating-temperature SOFCs. The used material was synthesized via a co-precipitation method and investigated from phase structure, morphology and UV–vis absorption perspectives. Utilizing Li-doped ZnO as electrolyte layer, we found the corresponding fuel cell exhibited a remarkable maximum power density of 443 mW cm −2 along with open circuit voltage (OCV) of 1.07 V at 550 °C, and represented a lower-temperature operation feasibility with power outputs of 138–165 mW cm −2 at 425–450 °C. Besides, high ionic conductivities of 0.028–0.087 S cm −1 and low activation energy of 0.5 eV were also found in the synthesized Li-doped ZnO at 425–550 °C. Our investigation in terms of electrochemical impedance spectra (EIS) analysis manifested that Li-doped ZnO as the electrolyte layer boosted the electrode reactions of the device, which resulted in rather small polarization resistances and eventually realized good low-temperature performances. Further study based on the rectification characteristic of Ni/Li-doped ZnO contact verified the Schottky junction formation of Li-doped ZnO with anodic Ni, which can avoid the underlying electronic short-circuiting problem. These findings show a profound significance of using doped semiconductor for the future exploitation of SOFC electrolytes. [ABSTRACT FROM AUTHOR]

The first principles calculations based on self-consistent charge density functional tight-binding have performed to investigate the electrical properties and rectification behavior of the graphene self-switching diodes (GSSD). The devices contained two structures called CG-GSSD and DG-GSSD which have metallic or semiconductor gates depending on their side gates have a single or double hydrogen edge functionalized. We have relaxed the devices and calculated I-V curves, transmission spectrums and maximum rectification ratios. We found that the DG-MSM devices are more favorable and more stable. Also, the DG-MSM devices have better maximum rectification ratios and current. Moreover, by changing the side gates widths and behaviors from semiconductor to metal, the threshold voltages under forward bias changed from +1.2 V to +0.3 V. Also, the maximum currents are obtained from 1.12 μA to 10.50 μA. Finally, the MSM and SSS type of all devices have minimum and maximum values of voltage threshold and maximum rectification ratios, but the 769-DG devices don't obey this rule. [ABSTRACT FROM AUTHOR]

We report the clear observation of the quantum size effect in an Fe quantum well (QW) detected by resonant tunneling carriers injected from a p-type Ge semiconductor electrode in fully epitaxial double-barrier magnetic tunnel junctions, which are composed of Co/Fe/MgO/Fe QW/MgO/Ge:B grown on a p+-Ge(001) substrate. A large tunnel magnetoresistance (TMR) ratio up to 137% (237%), which is comparable to that in Fe/MgO/Fe, is obtained at 297 K (3.5 K). The quantum oscillations are clearly observed in the dI/dV–V and d2I/dV2–V curves of our devices, and the resonance voltages are in good agreement with the resonant levels calculated by the phase accumulation model. Following these oscillations, the TMR is modulated by the quantum size effect. Our results are promising for realizing future quantum spintronics devices based on semiconductor/metal hybrid heterostructures with advanced functionalities. [ABSTRACT FROM AUTHOR]

Abstract: It is very important to develop ambipolar field effect transistors to construct complementary circuits. To obtain balanced hole‐ and electron‐transport properties, one of the key issues is to regulate the energy levels of the frontier orbitals of the semiconductor materials by structural tailoring, so that they match well with the electrode Fermi levels. Five conjugated copolymers were synthesized and exhibited low LUMO energy levels and narrow bandgaps on account of the strong electron‐withdrawing effect of the carbonyl groups. Polymer thin film transistors were prepared by using a solution method and exhibited high and balanced hole and electron mobility of up to 0.46 cm2 V−1 s−1, which suggested that these copolymers are promising ambipolar semiconductor materials. [ABSTRACT FROM AUTHOR]

In this study, we prepared the cubic AgSnSe 2 thin film photoelectrodes on substrates using the selenization of Ag–Sn metal precursors and examined the influence of silver content in samples on their photoelectrochemical properties in the aqueous solution. With the selenization temperature kept at 410   °C for 1 h in the selenization apparatus, the cubic AgSnSe 2 samples can be obtained. The results of phase characterization show that the phase change from the cubic AgSnSe 2 to the cubic Ag 8 SnSe 6 phase takes place at the selenization temperature between 425 to 440 °C. The optical energy band gaps, carrier concentrations, and mobilities of samples are in the range of 1.24–1.30 eV, 1.75 × 10 18 –4.68 × 10 19 cm −3 , and 43–253 cm 2 /V/s, respectively. It was found that the sample with the [Ag]/[Ag + Sn] molar ratio of 0.48 had a maximum photo-enhancement current density of 1.26 mA/cm 2 at an external bias of + 1.23 V vs. the reverse hydrogen electrode in the 0.35 M Na 2 S + 0.25 M K 2 SO 3 aqueous solution. The electrochemical impedance spectra of samples in the aqueous solution containing S 2− and SO 3 2− ions were also employed to examine the possible reaction mechanisms taking place at the sample surfaces. [ABSTRACT FROM AUTHOR]

A more accurate and reliable method is proposed to evaluate the photoelectrochemical (PEC) performance of semiconductor toward water splitting. Conventionally, I-t measurements are conducted at a fixed potential relative to the reference electrode, e.g., 0 V vs. Ag/AgCl, to monitor the photocurrent, which has been regarded as a direct indicator for performance comparison among different electrodes. Considering that the open-circuit potential (OCP) varies from electrode to electrode, the photocurrent comparison at a fixed potential may misrepresent the actual differences between samples. Here, we study the PEC performance by applying two distinct external bias values, one at 0 V vs. Ag/AgCl deriving from the conventional practice and the other at 0.1 V vs. OCP representing the exactly fixed applied overpotential. Two experimental groups are designed to address the arguments, including the influence of heat treatment for ZnO nanorod arrays and the global comparison among ZnO, TiO 2 , Au particle-decorated TiO 2 , and CdS electrodes. Different trends in photocurrent are observed at the two distinct biases, with the results from 0.1 V vs. OCP conforming to the general considerations. The results suggest that application of a fixed potential relative to the OCP will provide a more fair comparison for accurate PEC performance evaluation without under- or over-estimation. [ABSTRACT FROM AUTHOR]

TiO2 nanotube arrays fabricated by anodization and post annealing are extensively studied as an n-type semiconductor electrode for photoelectrochemical (PEC) water splitting owing to their large surface area and efficient electron transport property. The rutile phase is believed to be an inactive component of the TiO2 nanotube's electrode because annealing at high temperatures decreases the PEC efficiency with the transformation of anatase into rutile crystallites. In contrast, herein, we found that photoelectrodes prepared by two-step annealing, in which TiO2 nanotubes annealed in air at 650°C were then treated in a nitrogen atmosphere at a higher temperature, exhibited higher PEC efficiency despite the anatase nanotube structure changes to rutile particles. Sheet resistance measurement and Mott-Schottky analysis showed that the enhanced efficiency is attributed to a significant increase in donor density by partial reduction of rutile TiO2. The second annealing in the reductive atmosphere is essential to provide a columnar arrangement of TiO2 crystallites with high donor density resulting in high PEC properties for the oxidation of water to O2. This suggests that improving the electron transport property by the enhanced electrical conductivity and the interconnected nanocrystalline structure is important to enhance the PEC property of rutile TiO2 particulate photoanodes [ABSTRACT FROM AUTHOR]

Summary: In this review, we highlight recent achievements of polymer binders used for Si‐based anodes in Li‐ion batteries. We classify the polymer binders, depending on their polymer structures and the function on performances of Si‐based anodes, into 3 types: cellulose‐type, conductive‐type and self‐healing‐type binders. The relationship between polymer structures and enhanced electrochemical performances of Si‐based anodes is discussed in details. We investigate how the binders make an extraordinary improvement on the specific capacity, cycling stability and rate performances of Si‐based anodes. The reasons of the noticeable effect on Si‐based anodes especially the controlling of swelling during cycling are also researched. In a word, the main aim of this review is to analyze recent research achievements and propose perspectives of polymer binders used for Si‐based anodes in promising Li‐ion batteries. [ABSTRACT FROM AUTHOR]

We successfully fabricated the three-dimensional (3D) hydrogel of titanium dioxide (TiO 2 )-graphene using a simple one-pot method and exhibited enriched adsorption-photoelectrocatalytic degradation ability of low-concentration bisphenol A (BPA). Combined with the unique adsorption of graphene hydrogel and the effective photoelectrocatalytic performance of TiO 2 , we rapidly enriched the organic pollutants and conducted efficient in situ degradation. The low-concentration BPA (20 mg/L) was degraded completely by the TiO 2 -rGH electrode in 5 h through the synergistic effect of adsorption-photoelectrocatalytic. The photogenerated charge on the surface of TiO 2 is rapidly separated by the action of the applied electric field and the graphene sheet. The high conductivity of the graphene makes the TiO 2 -graphene hydrogel rapidly conducting the charge and solves the problem of poor conductivity of the semiconductor electrode. On the basis of these advantages, the TiO 2 -rGH has a cross-porous network structure that favors the anchor of more TiO 2 nanocrystals, the specific surface area and reactive sites are greater than the thin film electrode, and the structure is conducive to significantly improving the BPA removal efficiency. By contrast, the BPA degradation of TiO 2 -rGO thin film electrode was 40% after 4 h of ultraviolet irradiation, whereas the removal rate of BPA over the same mass of TiO 2 -rGH electrode rate was up to 96%. At the same time, the TiO 2 -rGH electrode without filtering can be achieved quickly separated from the recovery due to its special macro-3D network structure. Its removal ability still maintains above 90% after 10 times cyclic experiments with self-regeneration characteristics. It can be achieved rapid separation and recovery without filtering. [ABSTRACT FROM AUTHOR]

In this paper, based on full potential density functional theory calculations, the electronic and optical properties of aluminium and gallium phosphide (AlP and GaP) graphene-like structures are investigated under different biaxial compressive and tensile strain loads. One of the fascinating properties of these new monolayers is their high stretch-ability and high mechanosensitivity of their electronic and optical features. The electronic calculations display that the energy gap of materials versus the exerted strain can be estimated by a second order polynomial equation. Furthermore, the optical calculations indicate that the electronic and optical gap of AlP and GaP monolayers can be tuned by biaxial strain loads. [ABSTRACT FROM AUTHOR]

Ferrocenyl derivatives with perfluorinated organometallic fragments are prospective sensitizers for photovoltaic devices which can provide higher stability and resistance to oxidation in comparison with the known analogs. For the development of the photovoltaic devices based on such molecules, the estimates of probabilities of photoinduced electron transfer both inside the molecule and from the molecule to the internal semiconductor electrode are required. In this work, the structural, electronic, spectral and radiative parameters of trialkylgermyl (alkyl = Me, n -C 3 H 7 , CF 3 , n -C 3 F 7 ) derivatives of 4,4′-diethynylbiphenyl containing ferrocenyl donor group are considered. The spectral and radiative parameters of these compounds were calculated using the TD-DFT theory with the B3LYP, PBE0, BHandHLYP и CAM-B3LYP functionals. For all the molecules, the probabilities of photoinduced electron transfer to the outer molecular fragments inside the sensitizer are estimated on the basis of direct analysis of charge redistributions in the excited states. [ABSTRACT FROM AUTHOR]

Monolayer graphene is used as an electrode to develop novel electronic device architectures that exploit the unique, atomically thin structure of the material with a low density of states at its charge neutrality point. For example, a single semiconductor layer stacked onto graphene can provide a semiconductor-electrode junction with a tunable injection barrier, which is the basis for a primitive transistor architecture known as the Schottky barrier field-effect transistor. This work demonstrates the next level of complexity in a vertical graphene-semiconductor architecture. Specifically, an organic vertical p-n junction (p-type pentacene/n-type N, N′-dioctyl-3,4,9,10-perylenedicarboximide (PTCDI-C8)) on top of a graphene electrode constituting a novel gate-tunable photodiode device structure is fabricated. The model device confirms that controlling the Schottky barrier height at the pentacene-graphene junction can (i) suppress the dark current density and (ii) enhance the photocurrent of the device, both of which are critical to improve the performance of a photodiode. [ABSTRACT FROM AUTHOR]

Efforts have been put forth to grow HgS with cauliflower like surface architecture through simple and low-cost successive ionic layer adsorption and reaction (SILAR) method at room temperature for supercapacitive electrode application. Such a unique morphology facilitates the electrolyte ions to penetrate during electrochemical activities. Maximum specific capacitance of 446 F/g was obtained from cyclic voltammetry measurement at 2 mV/s scan rate in 1 M KCl electrolyte. After initial drop of capacitance up to 500 cycles, reduction was relatively slow up to 2000 cycles during stability analysis. Most importantly, the revealed specific energy of 15.45 Wh/kg of electrode has promised as decent electrode in energy storage field for future scope. [ABSTRACT FROM AUTHOR]

The development of new and inexpensive semiconductor electrodes that possess suitable band gap energies and band positions for solar water splitting is of great interest in the field of solar fuel production. In this study, n-type Cu11V6O26 that has a band gap energy of 1.9 eV was produced as a pure, high-quality photoanode, and its properties and stability for photoelectrochemical water splitting were systematically investigated in pH 9.2 and 13 solutions. As Cu11V6O26 photoanodes appeared to suffer from poor charge transport properties, Mo and W doping into the V site was also examined, which considerably improved the photocurrent generation of Cu11V6O26. The band gap energy, band edge positions, flatband potential, photocurrent generation, and photostability of pristine and doped Cu11V6O26 electrodes are discussed in comparison to elucidate the effect of Mo and W doping and to evaluate the promise and limitations of Cu11V6O26 as a photoanode for use in a water splitting photoelectrochemical cell. [ABSTRACT FROM AUTHOR]

Semiconducting electrodes that are in depletion, can support appreciable electron transfer only when illuminated. This phenomenon has been implemented on silicon electrodes passivated by a protective organic self-assembled monolayer (SAM) to confine electrochemistry to microscale regions on an unstructured electrode surface by shining light only on those regions. This method, referred to as light-activated electrochemistry (LAE), has so far only been studied using electrodes with surface-bound redox mediators that are either covalently or electrostatically attached to a SAM-modified silicon electrode. In the current report, we extend LAE to redox species in solution using gold nanoparticles (AuNPs) attached to the SAM-modified silicon electrodes. Cyclic voltammetry showed that faradaic electron transfer to redox species in solution can be switched on/off using light. Furthermore, the modified silicon electrodes were stable to more than 650 redox cycles, even when scanning to anodic potentials, with negligible oxide growth and no noticeable change in the voltammograms. Using a variety of redox species in solution, it was shown that with n − -Si-SAM-AuNP electrodes negligible current was observed in the dark but appreciable faradaic electrochemistry was observed upon illumination. It was also shown that to ensure electron transfer proceeded via the AuNPs only, nonspecific adsorption of the redox species to the monolayer surface needed to be avoided. [ABSTRACT FROM AUTHOR]

Knowledge of a semiconductor electrode's band edge alignment is essential for optimizing processes that occur at the semiconductor/electrolyte interface. Photocatalytic processes are particularly sensitive to such alignments, as they govern the transfer of photoexcited electrons or holes from the surface to reactants in the electrolyte solution. Reconstructions of a semiconductor surface during operation, as well as its interaction with the electrolyte solution, must be considered when determining band edge alignment. Here, we employ density functional theory + U theory to assess the stability of reconstructed CuInS2 surfaces, a system which has shown promise for the active and selective photoelectrocatalytic reduction of CO2 to CH3OH. Using many-body Green's function theory combined with calculations of surface work functions, we determine band edge positions of explicitly solvated, reconstructed CuInS2 surfaces. We find that there is a linear relationship between band edge position and net surface dipole, with the most stable solvent/surface structures tending to minimize this dipole because of generally weak interactions between the surface and solvating water molecules. We predict a conduction band minimum (CBM) of the solvated, reconstructed CuInS2 surface of -2.44 eV vs vacuum at the zero-dipole intercept of the dipole/CBM trendline, in reasonable agreement with the experimentally reported CBM position at -2.64 eV vs vacuum. This methodology offers a simplified approach for approximating the band edge positions at complex semiconductor/electrolyte interfaces. [ABSTRACT FROM AUTHOR]

It is necessary to convert AC to DC for the systems that do not work with AC sources. For this reason, diode and thyristor rectifiers were developed and designed. However, these rectifiers are not well suited for industrial applications requiring high performance. With the advances in power electronics and semiconductor technology, Pulse width modulation (PWM) rectifiers have been successfully employed in various industrial applications including variable-speed drives and uninterruptible power supplies. PWM rectifiers have the advantages of being low input current harmonic, adjustable input power factor, and controllable DC voltage and bidirectional energy flow. Because of all these features of the PWM rectifiers, the control and design of these rectifiers are very important topic. The aim of this paper is to control DC-link voltage of PWM rectifier with type-2 fuzzy neural system (T2FNS) instead of PI controller. For this aim, three-phase PWM rectifier with proposed controller is designed and simulated for four scenarios in this paper. A simulation model of the PWM rectifier is designed in MATLAB/Simulink and the performance of PWM rectifier with proposed controller is analyzed. [ABSTRACT FROM AUTHOR]

The impact of the dielectric thickness, forming polarity, and current compliance on the self-rectifying current–voltage ( I – V ) characteristics of Ni/HfO2/n+-Si resistive random access memory (RRAM) devices was investigated. The obtained results indicate that these three aspects not only play a role in the postforming currents but also affect the switching properties of the devices. In the case of 5-nm-thick oxide devices, a self-rectifying ratio of about three orders or magnitude is observed after substrate injection forming (SIF) with current compliance below 500 $\mu$ A. However, similar devices subjected to gate injection forming (GIF) do not exhibit such rectifying feature. This distinctive behavior for SIF is ascribed to the formation of a Schottky-like contact in between the Ni-based conducting filament and the semiconductor electrode. For 20-nm-thick oxide devices, the forming voltage under GIF and the subsequent dielectric degradation are higher than for thinner oxide layers, resulting in a less resistive state, and a negligible role of the referred Schottky barrier. The effect of the temperature on the diffusion of the Ni ions that form the conducting path is also discussed. [ABSTRACT FROM PUBLISHER]

Ti microfibers with a diameter of 20 μm were used as a three dimensional conductive back contact for a tungsten oxide (WO 3 ) photoelectrode. We coated the microfibers with WO 3 nanoparticles by a solution-based dip coating step and heat treatment at 650 °C. A high loading of WO 3 nanoparticles was achieved over a large surface area of the porous microfibers through the use of a high viscosity solution for the dip coating. The prepared WO 3 -coated Ti microfibers exhibited enhanced photoelectrochemical properties. Visible light response was improved in the conductive Ti microfibers owing to increased absorption of visible light and efficient extraction of photoexcited electrons at the large interface. [ABSTRACT FROM AUTHOR]

Herein we show that faradaic electrochemistry can be confined to a discrete region of a monolithic semiconducting electrode by means of locally addressing the kinetics of electron transfer with a focused light-pointer. A Si(100) electrode is modified with a self-assembled monolayer to which ferrocene is attached. The extent to which a model heterogeneous electrochemical reaction can be addressed in two-dimensions was explored at Si(100) photoanodes using scanning electrochemical microscopy operating in surface-generation/tip-collection mode. The link between the experimental radial profile of the catalytic current around the site of illumination and the substrate thickness indicates an inverse relationship between thickness and spatial resolution. We show to which extent the diffusion of charge carriers in the substrate governs the light-addressability. A spatial resolutions for our electrocatalytic system can be as low as ca . 385 μm ( ca . 5-times the size of the light pointer) using a non-structured Si(100) photoanode configured as a single-wire device. [ABSTRACT FROM AUTHOR]

Solar driven photoelectrochemical water splitting (PEC-WS) using semiconductor photoelectrodes represents a promising approach for a sustainable and environmentally friendly production of renewable energy vectors and fuel sources, such as dihydrogen (H2). In this context, titanium dioxide (TiO2) and iron oxide (hematite, α-Fe2O3) are among the most investigated candidates as photoanode materials, mainly owing to their resistance to photocorrosion, non-toxicity, natural abundance, and low production cost. Major drawbacks are, however, an inherently low electrical conductivity and a limited hole diffusion length that significantly affect the performance of TiO2 and α-Fe2O3 in PEC devices. To this regard, one-dimensional (1D) nanostructuring is typically applied as it provides several superior features such as a significant enlargement of the material surface area, extended contact between the semiconductor and the electrolyte and, most remarkably, preferential electrical transport that overall suppress charge carrier recombination and improve TiO2 and α-Fe2O3 photoelectrocatalytic properties. The present review describes various synthetic methods and modifying concepts of 1D-photoanodes (nanotubes, nanorods, nanofibers, nanowires) based on titania, hematite, and on α-Fe2O3/TiO2 heterostructures, for PEC applications. Various routes towards modification and enhancement of PEC activity of 1D photoanodes are discussed including doping, decoration with co-catalysts and heterojunction engineering. Finally, the challenges related to the optimization of charge transfer kinetics in both oxides are highlighted. [ABSTRACT FROM AUTHOR]

Cofactor regeneration in enzymatic reductions is crucial for the application of enzymes to both biological and energy-related catalysis. Specifically, regenerating NADH from NAD+ is of great interest, and using electrochemistry to achieve this end is considered a promising option. Here, we report the first example of photoelectrochemical NADH regeneration at the illuminated (λ>600 nm), metal-modified, p-type semiconductor electrode Pt/ p-GaAs. Although bare p-GaAs electrodes produce only enzymatically inactive NAD2, NADH was produced at the illuminated Pt-modified p-GaAs surface. At low overpotential (−0.75 V vs. Ag/AgCl), Pt/ p-GaAs exhibited a seven-fold greater faradaic efficiency for the formation of NADH than Pt alone, with reduced competition from the hydrogen evolution reaction. Improved faradaic efficiency and low overpotential suggest the possible utility of Pt/ p-GaAs in energy-related NADH-dependent enzymatic processes. [ABSTRACT FROM AUTHOR]

Climate change is one of the most complex challenges that pose serious threats to livelihoods of poor people who rely heavily on agriculture and livestock particularly in climate-sensitive developing countries of the world. The negative effects of water scarcity, due to climate change, are not limited to productivity food crops but have far-reaching consequences on livestock feed production systems. Selenium (Se) is considered essential for animal health and has also been reported to counteract various abiotic stresses in plants however, understanding of Se regulated mechanisms for improving nutritional status of fodder crops remains elusive. We report the effects of exogenous selenium (Se) supply on physiological and biochemical processes that may influence green fodder yield and quality of maize (Zea mays L.) under drought stress conditions. The plants were grown in lysimeter tanks under natural conditions and were subjected to normal (100% field capacity) and water stress (60% field capacity) conditions. Foliar spray of Se was carried out before the start of tasseling stage (65 days after sowing) and was repeated after one week, whereas water spray was used as a control. Drought stress markedly reduced the water status, pigments and green fodder yield and resulted in low forage quality in water stressed maize plants. Nevertheless, exogenous Se application at 40 mg L-1 resulted in less negative leaf water potential (41%) and enhanced relative water contents (30%), total chlorophyll (53%), carotenoid contents (60%), accumulation of total free amino acids (40%) and activities of superoxide dismutase (53%), catalase (30%), peroxidase (27%) and ascorbate peroxidase (27%) with respect to control under water deficit conditions. Consequently, Se regulated processes improved fodder yield (15%) and increased crude protein (47%), fibre (10%), nitrogen free extract (10%) and Se content (36%) but did not affect crude ash content in water stressed maize plants. We propose that Se foliar spray (40 mg L-1) is a handy, feasible and cost-effective approach to improve maize fodder yield and quality in arid and semi-arid regions of the world facing acute shortage of water.

TiO 2 is a common protection layer on semiconductor electrodes for photoelectrochemical water splitting. We investigate the interface formation of TiO 2 on amorphous silicon tandem solar cells by X-ray photoelectron spectroscopy. In order to optimize the contact properties, we prepare TiO x interface layers with various oxygen content by reactive magnetron sputter deposition. We observe, that a TiO x interface layer can reduce the silicon oxide growth during the film deposition on the amorphous silicon, but it forms a non-ohmic contact. The electrochemical investigation shows, that the benefit due to the reduction of the silicon oxide is counteracted by the unfavorable contact formation of TiO x interface layers prepared with low oxygen content. [ABSTRACT FROM AUTHOR]

In the present study, a novel composite was fabricated by incorporating the semiconductor Ni 0.8 Co 0.15 Al 0.05 LiO 2−δ (NCAL) into the ionic electrolyte Ce 0.8 Sm 0.2 O 2−δ -Na 2 CO 3 (NSDC), and further developed as a mixed-conducting membrane for single layer fuel cell (SLFC) applications. Experimentally, the crystal structure, morphology, chemical composition and thermo-stability of the composite were characterized by XRD, SEM and TGA. The best cell performance was investigated when the NSDC-NCAL membrane was optimized at a weight ratio of 6:4. On this basis, a number of interesting findings were obtained: i) the mixed conducting membrane did not cause any short circuit; on the contrary, the cell reached a decent open circuit voltage (OCV) of ∼1.0 V. ii) a high power density of 1072 mW cm −2 was achieved at 550 °C for the NSDC-NCAL membrane based cell, which was much better than that using a pure NSDC electrolyte membrane. Electrochemical impedance spectroscopy (EIS) showed that the NSDC-NCAL composite exhibited significantly improved grain boundary conduction and reduced electrode polarizations, contributing to the resultant performance. To consolidate the usefulness of the device, we also conducted the durability test. The above findings indicate the strategy of introducing mixed NSDC-NCAL membrane is feasible for high-performance SLFCs operating at low temperatures. [ABSTRACT FROM AUTHOR]

The work focused on improvement of the current response to NO and the reduction of response time of both NO and NO 2 . By adding a layer of TiO 2 catalyst layer, the shortcoming of NO insensitivity of traditional NASICON based amperometric NO 2 sensor was solved. TiO 2 was known as an n-type semiconductor and a high-performance NO oxidation catalyst. We separately applied different types of TiO 2 (rutile and Degussa P25) on the device and compared the test results with the traditional type without a catalyst layer. The results showed that the TiO 2 attached device exhibited a significant improvement to NO response, and P25 was better than rutile TiO 2 on account of the higher activity of anatase TiO 2 . In addition, TiO 2 also played a role of a semiconductor electrode, resulting in the increase of response to NO 2 . The response time of NO and NO 2 was separately shrunk from 153 s, 70 s to 77 s, 43 s owing to the P25 layer. The current responses were found to be barely affected by the coexistence of CO 2 . [ABSTRACT FROM AUTHOR]

In this paper we have investigated the electronic transmission of systems electrode–benzene–electrode using the Landauer approach. The effect of different electrodes made of metal (Au) and semiconductors (Si, TiO 2 ) is investigated. These three electrodes are compared between them and the results show that the electronic transmission of benzene junctions, when using semiconductor electrodes, is associated to a gap in transmission which is due to the electrodes band gap. As a consequence, a threshold voltage is necessary to obtain conducting channels. [ABSTRACT FROM AUTHOR]

CeO2–MnO composite thin films have been deposited on glass substrates, which were coated with fluorine-doped tin oxide (FTO), by aerosol-assisted chemical vapor deposition (AACVD) using a 1 : 1 mixture of the cerium complex [Ce(OCOCF3)4]−[(CH3)2NHCH2CH2OH]+ (1) and acetatomanganese(ii). X-ray diffraction (XRD), Raman spectroscopy and profilometry were used to investigate the phase purity, stoichiometry and thickness of the films. EDX results confirmed that the Ce : Mn ratio was 1 : 9 in the deposited composite thin films. FEG-SEM analysis illustrated that the morphology of the fabricated films was influenced by the deposition temperature and hence the optoelectronic properties. UV-vis studies of a composite thin film fabricated from methanol solution at 475 °C demonstrate a direct band gap of 2.5 eV. From its current–voltage characteristics it is evident that a CeO2–MnO composite semiconductor electrode exhibits n-type behavior and the photocurrent was strongly dependent on the deposition temperature. A CeO2–MnO photoanode deposited at 475 °C for 45 min from a 0.023 M solution of (1) and acetatomanganese(ii) in methanol gave a maximum photocurrent density of 265 μA cm−2 at 0.65 V vs. Ag/AgCl/3 M KCl using a 0.5 M NaOH electrolyte. [ABSTRACT FROM AUTHOR]

Conjugated polyelectrolytes and related mixed ionic-electronic conductors (MIECs) are being explored for energy applications including solid-state lighting and photovoltaics. Fundamental models of charge injection into MIECs have been primarily developed for MIECs contacted with highly conductive or metal electrodes (MEs), despite many potential applications involving semiconductors. We theoretically and experimentally demonstrate that an appropriate semiconductor electrode (SE), n-type for electron or p-type of hole injection, can limit injection into MIECs. When the SE is the injecting electrode and is under accumulation, there is little difference from a ME. When the SE acts as the extracting electrode, however, injection into the MIEC can be limited because a fraction of any applied bias must support charge depletion in the semiconductor rather than charge injection into the MIEC. In a ME/MIEC/SE system, this can lead to significant asymmetry in current-voltage and injected charge-voltage behavior. [ABSTRACT FROM AUTHOR]

A quasi-classical method for calculating the narrowing of the Hubbard gap between the A and A acceptor bands in a hole semiconductor or the D and D donor bands in an electron semiconductor is suggested. This narrowing gives rise to the phenomenon of a semiconductor transition from the insulator to metal state with an increase in doping level. The major (doping) impurity can be in one of three charge states (-1, 0, or +1), while the compensating impurity can be in states (+1) or (-1). The impurity distribution over the crystal is assumed to be random and the width of Hubbard bands (levels), to be much smaller than the gap between them. It is shown that narrowing of the Hubbard gap is due to the formation of electrically neutral acceptor (donor) states of the quasicontinuous band of allowed energies for holes (electrons) from excited states. This quasicontinuous band merges with the top of the valence band ( v band) for acceptors or with the bottom of the conduction band ( c band) for donors. In other words, the top of the v band for a p-type semiconductor or the bottom of the c band for an n-type semiconductor is shifted into the band gap. The value of this shift is determined by the maximum radius of the Bohr orbit of the excited state of an electrically neutral major impurity atom, which is no larger than half the average distance between nearest impurity atoms. As a result of the increasing dopant concentration, the both Hubbard energy levels become shallower and the gap between them narrows. Analytical formulas are derived to describe the thermally activated hopping transition of holes (electrons) between Hubbard bands. The calculated gap narrowing with increasing doping level, which manifests itself in a reduction in the activation energy ε is consistent with available experimental data for lightly compensated p-Si crystals doped with boron and n-Ge crystals doped with antimony. [ABSTRACT FROM AUTHOR]

The semiconductor-electrode interface impacts the function and the performance of (opto)electronic devices. For printed organic electronics the electrode surface is not atomically clean leading to weakly interacting interfaces. As a result, solution-processed organic ultrathin films on electrodes typically form islands due to dewetting. It has therefore been utterly difficult to achieve homogenous ultrathin conjugated polymer films. This has made the investigation of the correct energetics of the conjugated polymer-electrode interface impossible. Also, this has hampered the development of devices including ultrathin conjugated polymer layers. Here, Langmuir-Shäfer-manufactured homogenous mono- and multilayers of semiconducting polymers on metal electrodes are reported and the energy level bending using photoelectron spectroscopy is tracked. The amorphous films display an abrupt energy level bending that does not extend beyond the first monolayer. These findings provide new insights of the energetics of the polymer-electrode interface and opens up for new high-performing devices based on ultrathin semiconducting polymers. [ABSTRACT FROM AUTHOR]

Electrocatalytic oxidation is a promising process for degrading toxic and biorefractory organic pollutants in wastewater treatment. Selection of electrode materials is crucial for electrochemical oxidation process. In this study, Ti/F-PbO and Ti/Sb-SnO electrodes were chosen to compare their electrocatalytic characterization, which were prepared by electrodeposition and thermal decomposition method, respectively. The surface morphology and crystal structure of two electrodes were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The linear polarization curves show that Ti/Sb-SnO electrodes possess higher oxygen evolution overpotential than Ti/F-PbO electrodes. But the stability and corrosion resistance ability of Ti/F-PbO electrode was higher than that of Ti/Sb-SnO electrode. The electrocatalytic activity of Ti/F-PbO and Ti/Sb-SnO electrodes was examined for the electrochemical oxidation of malachite green (MG). The bulk electrolysis shows that the Ti/Sb-SnO electrodes exhibit the higher electrocatalytic activity for the degradation of MG than Ti/F-PbO electrodes, and the degradation process is good fitting for the pseudo-first order reaction. The higher electrocatalytic activity of Ti/Sb-SnO electrodes can be attributed to the higher oxygen evolution overpotential. [ABSTRACT FROM AUTHOR]

Nonlinear behaviour of a direct current (DC) driven semiconductor-gas discharge plasma is investigated experimentally. The setup consists of two planar electrodes separated by a gap of 1 mm. Plasma glow is generated between a semiconductor cathode and a transparent anode using nitrogen gas at partial atmospheric pressure. Nonlinear behavior of the discharge is investigated by varying the applied DC voltage while monitoring the plasma current ( I), voltage ( V), and the optical emission, (i.e., amplified voltage measurements obtained using a photodiode and an amplifier). The discharge behaves oscillatory in time. By increasing the applied voltage, the system evolves into higher frequency oscillations with sub-harmonics. In fact, period doublings are observed in these systems, as shown in earlier publications by our research group. In this study, we investigate the mode coupling nature of these oscillations using a Fourier transform based spectral analysis. [ABSTRACT FROM AUTHOR]

In order to reduce substrate costs and increase light absorption, solar cells based on semiconductor wire arrays are currently being actively studied. Whether built with Si, InP or other semiconductor materials, wire-based cells invariably use a transparent conductive coating for one of the electrodes, which complicates the processing and does not contribute to the reduction of the overall cost of the cell. Here, we propose a totally novel connection process, where the transparent conductive electrode is replaced with an array of in situ grown metallic nanowires. During their growth, these metallic nanowires randomly connect to core–shell p-i-n Si wires previously synthesized by chemical vapor deposition. We demonstrate the feasibility of this new random connection concept by using a coplanar solar cell design with interdigitated base and emitter contacts. We obtain a high fill factor of ~74% and efficiencies of 4.5% with only 33% of the surface covered by p-i-n Si wires. [ABSTRACT FROM AUTHOR]

Templatingnanocrystals into mesoporous electrodes using an organicporogen typically requires thermal oxidation at >400 °C tocompletelyremove the organic material and afford good electronic properties.These oxidation conditions are incompatible with many NC materials.Here, we demonstrate that nitrocellulose can afford mesoporous CdSand CZTS nanocrystal thin film electrodes at only 250–300 °Cin air or under argon. Remarkable control over the surface area andthe average pore size (20–100 nm) in thin films are demonstratedby varying the ratio of preformed nanocrystals and nitrocellulose.Moreover the mesoporous electrodes exhibit excellent optoelectronicproperties. Photoelectrochemical performance is enhanced due to theincreased active surface area, showing an 8-fold photocurrent increaseover compact nanocrystal films, and an IPCE over 70%. [ABSTRACT FROM AUTHOR]

The major challenge of employing photocatalysis for environment protection is to develop high efficient, low cost, and stable semiconductor photocatalysts. In the present study, an in situ annealing strategy is employed for large scale synthesis of two-dimensional (2D) porous graphitic carbon nitride (g-C 3 N 4 ) and efficient g-C 3 N 4 /P25(N) (N doped P25) heterojunction with enhanced quantum effect. The P25 not only serves as the template for g-C 3 N 4 polymerization, but is also modified by the N species to enhance the visible light absorption. Compared to the normal bulk g-C 3 N 4 , the 2D porous g-C 3 N 4 with enhanced quantum effect is found to be more efficient in improving the specific surface area and the electron–hole pair’s separation, even its light absorption edge is blue-shifted. Photocatalytic degradation of Rhodamine B (RhB) and phenol indicates the 2D g-C 3 N 4 and g-C 3 N 4 /P25(N) are very efficient and stable under the xenon lamp irradiation. It is also found that the original mass ratio of urea, which is the precursor for g-C 3 N 4 synthesis and P25 modification, to P25 also plays a significant effect on the photocatalytic activity. The optimized photocatalyst (mass ratio of P25 to urea is 1:8) can decompose total RhB aqueous solution (10 mg/L, 100 ml) in 25 min. Based on systematic characterizations and discussions, a possible photocatalytic mechanism for the excellent photocatalytic performance is proposed. [ABSTRACT FROM AUTHOR]

Nanocomposite cathodes for the hydrogen evolution reaction (HER) were prepared by deposition of RuO x catalyst particles on self-organized titania nanotube (TiNT) arrays of highly developed surface area, following a procedure that involved the initial cathodic intercalation of H + into the TiNT walls and the subsequent two-step ion-exchange process. Transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS) analyses of obtained Ru-TiNT samples revealed that the concentration of RuO x particles in the size range of a few nanometers was the highest at the surface of the TiNT layer and steadily decreased to a minimum value at about 4.5 μm inside the tubes. The capacitive behavior and electrocatalytic activity for the HER of Ru-TiNT nanocomposites, hydrogenated TiNT samples (H-TiNT) and compact TiO 2 were investigated in 1.0 M HClO 4 solution at room temperature by means of cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), Mott-Schottky analysis and steady-state polarization measurements. It was shown that cathodic hydrogenation treatment induced a four orders of magnitude higher concentration of electron donors in TiNT structures providing their quasimetallic behavior in the range of potentials corresponding to the HER. Ru-TiNT cathodes exhibited a more than 250 mV lower overpotential for the HER with respect to bare H-TiNT substrates at the current density of –50 mA cm −2 . A decrease of the Tafel slope from about –120 mV/dec for H-TiNT samples to as low as –70 mV/dec for the Ru-TiNT sample with longer tubes was explained by the formal kinetics approach. [ABSTRACT FROM AUTHOR]

Rubrene single-crystal transistors have achieved one of the highest carrier mobilities in organic semiconductors. However its thin film transistor usually shows inferior performance due to the poor film quality. Therefore how to obtain large-area and high quality rubrene thin film has become a prominent challenge. This work utilized weak epitaxy growth method with new inducing layer 1,3-di(terphenyl) benzene (m-7P), and lager-area highly ordered terrace rubrene film was obtained. Based on this high quality film, the hole mobility of rubrene polycrystalline thin film transistor has been enhanced to 11.6 cm 2 V −1 s −1 with VOPc as buffer layer between semiconductor layer and electrodes. This high device performance was attributed to the flat inducing layer and the single orientation of rubrene domains on m-7P layer, which may reduce grain boundaries and improve the film quality. This easy process to prepare large-area high performance rubrene device supplies a good opportunity for large-area electronic device manufacture. [ABSTRACT FROM AUTHOR]

In this study, we examined the synthesis and the photoelectrochemical characterization of TiO 2 nanotube semiconductor electrodes modified by Prussian Blue (PB) deposits. The PB formation was achieved using cyclic voltammetry. A morphological analysis of the TiO 2 nanotubes and the TiO 2 /PB system was performed using scanning electron microscopy and transmission electron microscopy. Intensity Modulated Photocurrent Spectroscopy (IMPS) measurements were obtained with the goal of determining the charge transfer and recombination constant rates in these systems. [ABSTRACT FROM AUTHOR]