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The integration of cost-effective and highly efficient oxygen evolution catalysts (OECs) profoundly impacts the performance of semiconductor photoharvesters in solar-driven water splitting. Drawing inspiration from the advantages of various transition metal oxides and hydroxide-based OECs, we demonstrate that the remarkable activity of nanostructured NiFe-(OH)x catalysts can significantly enhance the oxygen evolution efficiency of BiVO4 photoanodes. The optimized BiVO4/NiFe-(OH)x photoanode exhibits an above 300% increase in the photocurrent density over BiVO4, reaching a high value of 4.02 mA cm–2 at 1.23 V vs reversible hydrogen electrode (RHE) under simulated solar light illumination (100 mW cm–2, AM 1.5 G) in a near neutral electrolyte. Our investigations reveal that the NiFe-(OH)x catalyst serves as an effective photohole-extracting layer, leading to the improved separation of photocarriers. The coupling of nanostructured NiFe-(OH)x catalysts also enhances the applied bias photon-to-current conversion efficiency of the BiVO4 photoanodes to 0.78% (at 0.87 V vs RHE). It reduces the water-splitting onset potential by 280 mV. Consequently, the BiVO4/NiFe-(OH)x photoanode exhibits a 2-fold increase in the photocatalytic hydrogen production rate compared to pristine BiVO4. This work underscores the effectiveness of pairing facile NiFe-(OH)x OECs with BiVO4 photoanodes, leading to exceptional photoelectrochemical water oxidation. [ABSTRACT FROM AUTHOR]

In this work, we have done the comparative analysis of Single Gate and Dual Gate pentacene-based organic phototransistors (OPT). The opto-electrical simulations were done using 2-D Silvaco TCAD ATLAS device simulator. The SG-OPT and DG-OPT were simulated to provide deeper insight into behaviour of the two from both device physics perspective and quantitative standpoints. We have conducted an evaluation of both OPTs on account of the various important performance parameters at different electrical and optical bias over a wide spectral range. Our results shows how these different configurational OPT designs can influence the essential performance parameters while observing the variations in drain current, Current density, Energy band Diagrams and the various essential performance parameters such as Responsivity, photosensitivity, spectral response, quantum efficiency etc. [ABSTRACT FROM AUTHOR]

Epitaxial layers of SiC 80 nm thick were grown on a silicon substrate by molecular beam epitaxy at 950°C. The Raman spectra contain a peak at 793 cm–1, which corresponds to the transverse optical phonon mode of the cubic SiC polytype. It was shown that the increase of photocurrent in the ranges of 1.25–1.4 and 1.5–2.0 eV is due to defects in the heterostructure of SiC/Si. It was found that the photoluminescence spectra of SiC/Si and Pt2Si/SiC/Si heterostructures contain two main emission bands in the blue (2.8 eV) and red (1.9 eV) regions. [ABSTRACT FROM AUTHOR]

Here, we report on using chemical vapor deposition to generate three kinds of gallium sulfide nanosheets, with thicknesses of approximately 10, 40, and 170 nm. Next, we performed Raman imaging analysis on these nanosheets to evaluate their properties. The 10 nm GaS nanosheets exhibited a nearly equal distribution of Raman imaging intensity, whereas the 40 and 170 nm GaS nanosheets exhibited an inclination toward the edges with higher Raman intensity. When the polarization of the laser was changed, the intensity of Raman imaging of the 10 nm thick GaS nanosheets remained consistent when illuminated with a 532 nm laser. Notably, a greater Raman intensity was discernible at the edges of the 40 and 170 nm GaS nanosheets. Three distinct GaS nanosheet devices with different film thicknesses were fabricated, and their photocurrents were recorded. The devices were exposed to light of 455 nm wavelength. The GaS nanosheet devices with film thicknesses of 40 and 170 nm exhibited a positive photoresponse even though the photocurrents were fairly low. In contrast, the GaS nanosheet device with a film thickness of 10 nm had a considerable current without light, even though it had a weak reaction to light. This study reveals the different spatial patterns of Raman imaging with GaS thickness, the wavelength of excitation light, and polarization. Remarkably, the I-V diagram revealed a higher dark-field current of 800 nA in the device with a GaS nanosheet thickness of approximately 10 nm, when using a voltage of 1.5 V and a laser of 445 nm wavelength. These findings are comparable with those theretical pretictions in the existing literature. In conclusion, the observation above could serve as a catalyst for future exploration into photocatalysis, electrochemical hydrogen production through water splitting, energy storage, nonlinear optics, gas sensing, and ultraviolet selective photodetectors of GaS nanosheet-based photodetectors. [ABSTRACT FROM AUTHOR]

Since no vacuum systems or expensive equipment are needed in their fabrication, dye sensitized solar cells (DSSCs) are anticipated to be one of the effective solar cells of third generation delivering green energy at low production costs. The structure and operating principles of the dye-sensitized solar cell (DSSC) are reviewed in this work. Optical characterization and extraction of detail is provided on pyrostegia venusta. The preparation steps, dye-based optical and electrical characterization of the DSSC, are all covered. The sensitized solar cell having maximum conversion efficiency (1.99%) is capable of producing an open circuit voltage Voc (1.94V) and a short circuit current isc (1.804mA) when exposed to solar irradiation. [ABSTRACT FROM AUTHOR]

Abstract The quantum geometric Berry curvature results in an anomalous correction to the band velocity of crystal electrons with a corresponding transverse (thermo)electric conductivity. However, time‐reversal symmetry typically constrains the direct observation and exploitation of anomalous transport to magnetic compounds. Here, it is demonstrated the anomalous Hall and Nernst conductivities are essential for describing the optoelectronic transport in thin films of the non‐magnetic, weakly gapped semimetal HfTe5 subject to an external magnetic field. A focused photoexcitation adresses the symmetries of the local Nernst conductivity, which unveils a hitherto hidden, anomalous photo‐Nernst effect of three‐dimensional (3D) massive Dirac fermions. The experimental temperature and density dependencies are compared with a semiclassical Boltzmann transport model. For HfTe5 thin films with the Fermi level close to the gap, the model suggests that the anomalous photo‐Nernst currents originate from an intrinsic Berry curvature mechanism, where the Zeeman interaction effectively breaks time‐reversal symmetry of the massive Dirac fermions already at moderate external magnetic fields.

In this study, the photoelectric properties of a complete series of GaS1−xSex (0 ≤ x ≤ 1) layered crystals are investigated. The photoconductivity spectra indicate a decreasing bandgap of GaS1−xSex as the Se composition x increases. Time-resolved photocurrent measurements reveal a significant improvement in the response of GaS1−xSex to light with increasing x. Frequency-dependent photocurrent measurements demonstrate that both pure GaS crystals and GaS1−xSex ternary alloy crystals exhibit a rapid decrease in photocurrents with increasing illumination frequency. Crystals with lower x exhibit a faster decrease in photocurrent. However, pure GaSe crystal maintains its photocurrent significantly even at high frequencies. Measurements for laser-power-dependent photoresponsivity and bias-voltage-dependent photoresponsivity also indicate an increase in the photoresponsivity of GaS1−xSex as x increases. Overall, the photoresponsive performance of GaS1−xSex is enhanced with increasing x, and pure GaSe exhibits the best performance. This result contradicts the findings of previous reports. Additionally, the inverse trends between bandgap and photoresponsivity with increasing x suggest that GaS1−xSex-based photodetectors could potentially offer a high response and wavelength-selectivity for UV and visible light detection. Thus, this work provides novel insights into the photoelectric characteristics of GaS1−xSex layered crystals and highlights their potential for optoelectronic applications.

BackgroundLaser simulation technology is widely used in the research of transient ionizing radiation effects in semiconductor devices. Fully dielectrically isolated silicon-on-insulator (SOI) devices exhibit different responses to dose-rate gamma irradiation compared to bulk-Si devices.PurposeThis study aims to examine the photocurrents of both Si-based and SOI NMOS transistors, and investigate the performance of a SOI MCU with varying dose rates.MethodAn irradiation experiment was conducted on three types of transistors by using a 1 064 nm/12 ns laser device, and the photocurrent was tested under various laser energies. A pulsed γ-ray source was employed to perform the transient γ dose rate radiation test on an SOI-integrated circuit. The function, electrical parameters, and flipflop chain status of the SOI-integrated circuit under different dose rates were measured. Based on theoretical model for the generation of photocurrent in SOI transistor, the dose-rate threshold for logic flipping and corresponding critical charge were estimated based on theoretical model for the generation of photocurrent in SOI transistor.ResultsThe results indicate that the peak photocurrent of the SOI transistor is approximately 20 times lower than that of the bulk silicon transistor with the same feature size under identical irradiation conditions. This reduction is attributed to the decreased charge collection sensitive area of the SOI transistor. Within a dose rate range from 1.0×109 rad(Si)·s-1 to 4.2×1011 rad(Si)·s-1, the SOI-integrated circuit exhibites no latch-up effect. However, irradiation-induced upsets are observed in the SOI-integrated circuit.ConclusionsThese upsets caused by transient radiation effects manifest as transient functional interruptions, variations in operating current and voltage, and erroneous flip-flop statuses. These irradiation-induced upsets in the SOI-integrated circuit are likely attributable to, among other factors, transistor upsets and circuit-level voltage fluctuations on printed circuit board.

Increasing developments on the application of copper complexes as dyes are due to their dual function in dye-sensitized solar cells (DSSCs) as redox mediators and dye sensitizers. The economical (abundance, low cost) and environmentally friendly properties of copper motivate researchers on the use of copper complexes for replacement of ruthenium-based dyes in solar cells. A novel [Cu(I)(2,9-dmp)(phen-dione)]PF6 (A2) bearing polypyridyl ligands, 1,10-phenanthroline-5,6-dione (phen-dione), 2,9-dimethyl-1,10-phenanthroline (dmp) was prepared by metal complexation reaction. The photofunctionality of A2 as a promising photosensitizer in DSSCs was studied. Interestingly, A2 exhibited two absorption peaks, one is detected in the ultraviolet region due to -* transition and the other is a metal-to-ligand charge transfer (MLCT) band at 405nm in the visible region. A2 was compared to the same complex with Cu(II) ion as the metal centre which only absorbed light in the ultraviolet region thereby implying limited use of Cu(II) complex in its light harvesting application. The photofunctionality of A2 was studied by employing it as an active material for photoelectric conversion by engaging it with ITO to create a photoanode. Upon light irradiation, an anodic current was observed. In conclusion, introduction of Cu(I), instead of Cu(II), in polypridyls ligands resulted in successful enhancement of photophysical properties of A2, making the photoanode of A2 suitable for light harvesting applications.

The effects of absorption, barrier, and digital graded layer thickness on dark current and photocurrent in Metal Semiconductor Metal (MSM) photodetectors by using 3D Silvaco TCAD are reported. The photo-dark current ratio (Iphoto/Idark) is calculated using the photocurrent and dark current values obtained by simulation. In study A (absorption layer thickness variation) the photocurrent, dark current and photo-dark current ratio are increased with increased absorption layer thickness, and the dark current is 1.138x10-7 A levels. In Study B (barrier layer thickness variation), when the barrier layer is added to the absorption layer, the dark current is decreased to 1.56x10-11 A levels. It is reported that the photo-dark current ratio with increasing barrier layer thickness increases. In study C (digital graded superlattice layer thickness variation), the dark current increases, and photocurrent decreases with the increase of the digital graded superlattice layer thickness. However, the photo-dark current ratio with increasing digital graded superlattice layer thickness decreases. Furthermore, a similar trend of development is observed on photo-dark current with adding of the barrier layer and digital graded superlattice layer on the absorption layer. These findings demonstrate the importance of optimizing layer thickness in MSM photodetectors for improved device performance.

Photosynthetic microorganisms such as cyanobacteria can convert photons into electrons, providing ideal eco-friendly materials for converting solar energy into electricity. However, the electrons are hardly transported outside the cyanobacterial cells due to the insulation feature of the cell wall/membrane. Various nanomaterials have been reported to enhance extracellular electron transfer of heterotrophic electroactive microorganisms, but its effect on intact photosynthetic microorganisms remains unclear. In this study, we investigated the effect of six different nanomaterials on the photocurrent generation of cyanobacterium Synechocystis sp. PCC 6803. Among the nanomaterials tested, titanium dioxide (TiO 2) nanoparticles increased the photocurrent generation of Synechocystis sp. PCC 6803 up to four-fold at the optimum concentration of 2 mg/mL. Transmission electron microscopy and scanning electron microscopy showed that TiO 2 bound to cyanobacterial cells and likely penetrated inside of cell membrane. Photochemical analyses for photosystems showed that TiO 2 blocked the electrons transfer downstream in PS I, implying a possible extracellular electron pathway mediated by TiO 2. This study provides an alternative approach for enhancing the photocurrent generation of cyanobacteria, showing the potential of photosynthetic-nanomaterial hybrids. [Display omitted] • TiO 2 nanoparticles increase the photocurrent generation of Synechocystis sp. PCC 6803 up to four-fold. • TiO 2 nanoparticles bind to cyanobacterial cells but do not affect the growth of cyanobacteria. • TiO 2 nanoparticles probably create a direct extracellular electron transfer pathway that starts from PS I. [ABSTRACT FROM AUTHOR]

Photocatalysis has been drawing significant research attention because of its extensive applications in fields such as environmental remediation and renewable energy. In this work, we design a series of BiFe1‐xZnxO3 (x=0, 0.025, 0.05, 0.075, and 0.1) photocatalysts to reveal the photocatalytic mechanism for model Acid Red‐85, a stable textile dye. The bandgap energy of zinc – doped BiFeO3 is ranging from 2.138 to 2.2 eV. We have shown that changing the Fe/Zn ratio by bandgap engineering effectively controls the reaction pathway. Specifically, BiFe0.925Zn0.075O3 (7.5BFZO) presented the best performance for photocatalytic activity (92 %). The magnetic behaviour improves for lower zinc doping concentrations (x=0.025 and 0.05) and declines for higher concentrations (x=0.075 and 0.10). The photocatalytic degradation of Acid Red‐85 dye followed pseudo first order kinetics, with the highest catalytic effect seen in BiFe0.925Zn0.075O3 with 92 % degradation after 2 hours of light exposure. [ABSTRACT FROM AUTHOR]

Herein, the efficiency of generation of unipolar photocurrent pulses under action of obliquely incident nanosecond laser pulses is studied in carbon nanowall (CNW) films on silicon substrate depending on the direction of the wave vector and polarization of the laser radiation. The films consist of flake‐like graphite crystallites of nanometer thickness. Each of the crystallites comprises stacked graphene atomic sheets oriented mostly perpendicular to the substrate surface with random orientation in other directions. The angular and polarization dependencies of the longitudinal and transverse photocurrents at wavelengths of 266, 354.7, 532, and 1064 nm are measured. The longitudinal and transverse photocurrents are odd functions of the incidence angle, and, for a given angle of incidence, they are even and odd functions of the polarization azimuth, respectively. It is noteworthy that with the decrease in exciting radiation wavelength, the conversion coefficients of laser pulse power into longitudinal and transverse photocurrents increase and decrease, respectively. At wavelength of 266 nm, the transverse photocurrent changes its polarity, and the longitudinal photocurrent generated by s‐polarized radiation exceeds the p‐polarized radiation photocurrent. The obtained results are explained by morphology peculiarities of the CNW films and the surface photogalvanic effect photocurrent generation. [ABSTRACT FROM AUTHOR]

Many researchers have shifted their interest towards eco‐friendly, cost effective, and environmental‐based metal oxide nanoparticles. Herein, Cu2O nanoparticles are synthesized via green method for water splitting application. The prepared materials are characterized structurally and morphologically by field emission‐scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), X‐ray photoelectron spectroscopy (XPS) Raman, and UV–visible spectroscopy. It is found that size and morphology depend strongly on OLE concentration and reaction time. The temperature increase leads to the formation of copper oxide (CuO) nanoparticles, which exhibit quantum confinement behavior and have an optical band gap that increases with decreasing size. Photoelectrochemical (PEC) tests of the coated graphite with Cu2O nanoparticles show a severe instability of Cu2O under irradiation due to the oxidation state that can easily change. For that, a protective overlayer of cuprous sulfide Cu2S is successfully grown on the top of Cu2O nanostructures to stabilize the photocathode. After Cu2S deposition, the measured photocurrent is significantly improved. Thus, this material is very promising for hydrogen generation by water splitting. [ABSTRACT FROM AUTHOR]

Dielectric microspheres naturally possess unique optical properties by which the light's focus and confinement can be manipulated on a microscale. Combining microspheres and optical or Raman microscopy, super‐resolution imaging beyond the diffraction limit and enhancement of Raman signals are demonstrated to provide abundant spectroscopic information on materials. However, microsphere‐aided super‐resolution scanning photocurrent imaging remains challenging to date. Here, based on the photonic nanojet mechanism, a super‐resolution photocurrent and spectral microscopy equipped with a scanning tip with silica dielectric microspheres are presented. With such microsphere‐aided microscopy, order of magnitude enhancements for single‐point Raman and photoluminescence signals can be achieved, and the spatial resolutions for photocurrent and spectral mapping surpass the best resolution of the original confocal system restricted by the diffraction limit. This versatile system enables correlative super‐resolution spectral and photocurrent imaging, serving as a reliable tool for comprehensively understanding and uncovering the optoelectronic properties of materials. [ABSTRACT FROM AUTHOR]

Exposing catalytically active metal sites in metal–organic frameworks (MOFs) while maintaining porosity is beneficial for increasing electron transport to achieve better electrochemical energy conversion performance. Herein, we propose an in situ method for MOF formation and loading onto TiO2 nanorods (NR) using a simple solution-processable method followed by annealing to obtain TiO2-Co3O4. The as-prepared TiO2-ZIF-67 based photoanodes were annealed at 350, 450, and 550 °C to study the effect of carbonization on photo-electrochemical water oxidation. The successful loading of ZIF-67 on TiO2 and the formation of TiO2-Co3O4 heterojunction were confirmed by XRD, XPS, FE-SEM, and HRTEM analyses. TiO2-Co3O4-450 (the sample annealed at 450 °C) showed an enhanced photocurrent of 2.4 mA/cm2, which was 2.6 times larger than that of pristine TiO2. The improved photocurrent might be ascribed to the prepared p–n heterostructures (Co3O4 and TiO2), which promote electron–hole separation and charge transfer within the system and improve the photoelectrochemical performance. Moreover, the preparation of Co3O4 from the MOF carbonization process improved the electrical conductivity and significantly increased the number of exposed active sites and enhanced the photoresponse performance. The as-prepared ZIF-67 derived TiO2-Co3O4 based photoanodes demonstrate high PEC water oxidation, and the controlled carbonization method paves the way toward the synthesis of low-cost and efficient electrocatalysts. [ABSTRACT FROM AUTHOR]

SnS thin films were synthesized using the spray pyrolysis method and then annealed at 350, 400, and 450°C. According to the crystallographic analysis, the obtained SnS thin films crystallized in the polycrystalline orthorhombic system. The grains measured 47, 66, and 37 nm for the samples annealed at 350, 400, and 450°C, respectively. SEM and AFM images indicate that the samples’ surfaces were completely covered. Thus, the grains of SnS nanostructures have a granular-like shape and vary in size depending on the annealing temperatures. The transmittance measurement shows that annealing the sample at 400 °C extends and improves its absorption range to 600 nm. The resulting band gap energies were 1.60 eV, 1.30 eV, and 2.55 eV for annealing at 350 °C, 400 °C, and 450 °C, respectively. Hall Effect measurements reveal that annealing SnS films at 400 °C enhances their electrical properties. The values of carrier mobility, conductivity, and carrier concentration are 1.678 ×105 Cm2/Vs, 9.756 ×10-5 Ω-1 cm-1, and 3.168 ×1010Cm-3, respectively. Additionally, the photocurrent response validates that all samples annealed at 350, 400, and 450 °C have p-type conductivity, with values of 13, 28, and 2.5 µA/Cm2, respectively. The best conductivity, carrier mobility, and photocurrent values are obtained by annealing at 400 °C. Therefore, SnS thin films can be an interesting choice for absorber layer applications in photovoltaic systems. [ABSTRACT FROM AUTHOR]

A putative xanthorhodopsin-encoding gene, XR34, was found in the genome of the moderately halophilic gammaproteobacterium Salinivibrio socompensis S34, isolated from modern stromatolites found on the shore of Laguna Socompa (3570 m), Argentina Puna. XR-encoding genes were clustered together with genes encoding X-carotene, retinal (vitamin-A aldehyde), and carotenoid biosynthesis enzymes while the carotene ketolase gene critical for the salinixanthin antenna compound was absent. To identify its functional behavior, we herein overexpressed and characterized this intriguing microbial rhodopsin. Recombinant XR34 showed all the salient features of canonical microbial rhodopsin and covalently bound retinal as a functional chromophore with λmax = 561 nm (εmax ca. 60,000 M−1 cm−1). Two canonical counterions with pK values of around 6 and 3 were identified by pH titration of the recombinant protein. With a recovery time of approximately half an hour in the dark, XR34 shows light–dark adaptation shifting the absorption maximum from 551 to 561 nm. Laser-flash induced photochemistry at pH 9 (deprotonated primary counterion) identified a photocycle starting with a K-like intermediate, followed by an M-state (λmax ca. 400 nm, deprotonated Schiff base), and a final long wavelength-absorbing N- or O-like intermediate before returning to the parental 561 nm-state. Initiating the photocycle at pH 5 (protonated counterion) yields only bathochromic intermediates, due to the lacking capacity of the counterion to accept the Schiff base proton. Illumination of the membrane-embedded protein yielded a capacitive transport current. The presence of the M-intermediate under these conditions was demonstrated by a blue light-induced shunt process. [ABSTRACT FROM AUTHOR]

Research plan was proposed for systematic observation with scientific way in the solar cell field of photogalvanics. It was analysis of experimental work under the solar energy output. The study of photogalvanic was done for solar energy conversion and storage by using of dye as Coomassie Brilliant Blue (CBB), reductant as Isopropyl alcohol (IA), and surfactant as Sodium Lauryl Sulphate (SLS). For this purpose, a specially designed H shaped photogalvanic system was used under investigation for innovative results. Different scientific instruments were used for methodology set up i.e., pH meter (digital), microammeter, and 200 Wt. W bulb (As light source), multi-meter, two electrodes (one was calomel and another was Pt), carbon pot 450 k, resistance key. Findings: The photogalvanic cells were studied using different parameters via photo potential, photocurrent, conversion efficiency, fill factor and cell performance. The above values are as follows: 533.0 mV, 201.0 mA, 0.8796%, 0.3066 and 114.0 minutes. These cells were studied for the good results in solar energy field. Novelty: The observed results are very good over previously obtained results with respect to Coomassie brilliant blue, reductant as Isopropyl alcohol, and surfactant as sodium lauryl sulphate system. [ABSTRACT FROM AUTHOR]

Searching for novel two-dimensional (2D) materials with excellent properties is of great importance for the design of next generation nano-devices. Based on first-principles calculations, we propose an unexplored 2D monolayer PdTeI2 material, which can be prepared from its bulk crystal by exfoliation method. Our calculations show that monolayer PdTeI2 has excellent dynamical and thermal stability. The appropriate bandgap of 0.82 eV endows monolayer PdTeI2 with superior optical absorption capacity in the infrared and visible regions. Remarkably, the in-plane electron mobility of monolayer PdTeI2 is as high as 104cm2v-1s-1, which is much larger than those of most previously reported 2D materials. Based on the combination of density functional theory and non-equilibrium Green’s function formalism, a large photocurrent of 40 a02/photon for photon energy of 1.0 eV is obtained under a small bias voltage in PdTeI2-based two-electrode optoelectronic devices, indicating the outstanding photoresponse characteristic of monolayer PdTeI2 in the infrared region. The large photocurrent, along with the high electron mobility and strong optical absorption make monolayer PdTeI2 a candidate material for future applications in novel optoelectronics and microelectronic devices, such as infrared photodetectors.

WO3/Cu composite film electrodes were synthesized by hydrothermal combined electrodeposition method. Characterization of samples was conducted by SEM, XRD and XPS, which showed WO3/Cu composite films had been synthesized. The diffusion coefficient, reversibility, response time, coloration efficiency and transmission rate of the samples were obtained by electrochemical and spectral measurements. The photocurrent and photoelectric catalysis degradation efficiency of the samples were obtained by photocurrent and photoelectric catalysis measurements. The WO3/Cu composite films improve electrochromic performance, photocurrent and photoelectric catalytic activity compared with pure WO3 nanoblocks, and the WO3/Cu composite film obtained by depositing Cu nanoparticles at 50 s shows the highest electrochromic performance, photocurrent and photoelectric catalytic activity. Meanwhile, the direct photocatalytic and electric catalytic activity of the composite film are also discussed. The combined effects of the lower band gap and the Schottky junction lead to significant enhancement in the electrochromic and photoelectrochemical properties of the WO3/Cu composite film. In this study, WO3/Cu composite film electrodes were prepared. Compared with single WO3 film, the combined effects of the lower band gap and the Schottky junction lead to significant enhancement in the electrochromic and photoelectrochemical properties of the WO3/Cu composite film. [ABSTRACT FROM AUTHOR]

This paper describes the establishment of free-standing rolled graphene oxide (roll-GO) and polypyrrole (Ppy) using a modified Hummer method and oxidative polymerization. Then, a photodetector was created by removing a thin film of the free-standing rolled graphene oxide from a filter paper and attaching it to a tape. The chemical structure of the roll-GO was confirmed using XRD and FTIR analysis, while SEM and TEM showed that it was rolled in nature. The material had a small bandgap of 2.4 eV and a high current density in light conditions. The photodetector responded well to monochromatic light, with Jph values changing from 0.027 to 0.019 mA/cm2 as the light wavelengths decreased from 340 to 730 nm. The photoresponsivity (R) and detectivity (D) values were high, at 340 nm (0.27 mA/W and 6.0 × 107 Jones, respectively) and at 730 nm (0.19 and 4.25 × 107 Jones, respectively). The addition of Ppy improved these parameters, with the Ppy/roll-GO/tape photoelectrode showing excellent R and D values of 0.33 mA/W and 7.34 × 107 Jones, respectively. Furthermore, the production of a photocurrent at V = 0 indicated that the Ppy/roll-GO layer could be used for solar cell applications. Overall, the results suggest that the prepared free-standing Ppy/roll-GO/tape photodetector has high potential for use in the optical region between 340 and 730 nm and may be suitable for industrial applications. [ABSTRACT FROM AUTHOR]

In this work, hydrothermal technique and precursor materials obtained from the wastes of filtration unit of gas pressure reduction station were used to create ZnO-Fe2O3 nanocomposite. FT-IR, FE-SEM, XRD and TEM analyzes were used to investigate the properties of the produced nanocomposite. XRD analysis showed the structure of ZnO and Fe2O3 without impurities. The crystal size of ZnO-Fe2O3 nanocomposite was determined to be about 53 nm. FE-SEM images showed a nanocomposite pattern with an approximate diameter of 50 nm. Finally, visual decomposition of anionic and cationic dyes under visible light was used to study the photocatalytic activity of ZnO-Fe2O3 nanocomposite. By exposing a metal halide lamp to light and darkness for 60 minutes and 150 minutes, respectively, it was possible to study the photocatalytic activity of the synthesized nanocomposite in removing anionic and cationic dyes from aqueous medium. In the photocatalytic degradation of anionic and cationic dyes, the following factors were considered as essential variables: pH, initial dye concentration, nanocomposite content and exposure time. In this study, the degradation percentage of anionic and cationic dyes of ZnO-Fe2O3 nanocomposite with a ratio of 0.75:1 was 99.89 and 99.9%, respectively. The amount of band gap was calculated by Tack plot method and electrical conductivity was calculated using electrochemical impedance spectroscopy, which reduced the band gap. And the resistance increases. Due to the acceleration of charge transfer at the heterogeneous junction surface and the suppression of electron/hole pairs from recombination, the ZnO-Fe2O3 nanocomposite significantly increased the visible light current response.

In recent years, clean energy technologies that meet ever-increasing energy demands without the risk of environmental contamination has been a major interest. One approach is the utilization of plant leaves, which release redox-active NADPH as a result of photosynthesis, to generate photocurrent. In this work, we show for the first time that photocurrent can be harvested directly from the fruit of a cherry tree when associated with a bio-electrochemical cell. Furthermore, we apply electrochemical and spectroscopic methods to show that NADH in the fruit plays a major role in electric current production.

WO3 nanosheet films were prepared on the conductive glass substrate. WO3/BiVO4 composite film samples with different thicknesses were successfully synthesized on WO3 nanosheet films by changing the number of spin coating of BiVO4. X-ray diffraction and scanning electron microscopy were used to characterize samples. WO3/BiVO4 composite film samples were tested for absorption spectrum, photocurrent, photoelectrocatalysis and alternating current impedance. The results show that the photocurrent density and photocatalytic degradation efficiency of the WO3/BiVO4 composite film sample are improved compared with pure WO3 nanosheet films, and it has better photoelectrochemical property. Meanwhile, WO3/BiVO4 composite film sample with twice spin coating of BiVO4 has the highest photocurrent density (1.79 mA/cm2) and photoelectric degradation efficiency (about 60.5%), which is increased by 27.4% than the photocurrent density of pure WO3films (1.30 mA/cm2), the photoelectric degradation efficiency is also 26.3% higher than pure WO3 films (approximately 47.9%), and has the most excellent photoelectrochemical property.

Integration of semiconducting transition metal dichalcogenides (TMDs) into functional optoelectronic circuitries requires an understanding of the charge transfer across the interface between the TMD and the contacting material. Here, we use spatially resolved photocurrent microscopy to demonstrate electronic uniformity at the epitaxial graphene/molybdenum disulfide (EG/MoS2) interface. A 10× larger photocurrent is extracted at the EG/MoS2 interface when compared to the metal (Ti/Au)/MoS2 interface. This is supported by semi-local density functional theory (DFT), which predicts the Schottky barrier at the EG/MoS2 interface to be ∼2× lower than that at Ti/MoS2. We provide a direct visualization of a 2D material Schottky barrier through combination of angle-resolved photoemission spectroscopy with spatial resolution selected to be ∼300 nm (nano-ARPES) and DFT calculations. A bending of ∼500 meV over a length scale of ∼2-3 μm in the valence band maximum of MoS2 is observed via nano-ARPES. We explicate a correlation between experimental demonstration and theoretical predictions of barriers at graphene/TMD interfaces. Spatially resolved photocurrent mapping allows for directly visualizing the uniformity of built-in electric fields at heterostructure interfaces, providing a guide for microscopic engineering of charge transport across heterointerfaces. This simple probe-based technique also speaks directly to the 2D synthesis community to elucidate electronic uniformity at domain boundaries alongside morphological uniformity over large areas.

The work considers "transverse" and "longitudinal" photoconductivity modes, regarding the direction of radiation, photoconductivity in semiconductor detectors of CdZnTe. Mathematical calculations were made from the representation of the internal area of the detector in the form of radiation absorption sites. The results of the calculations are compared with experimentally measured photocurrent of the detector with a cross section of 2 × 2 mm CdZnTe from the direction of its radiation by X-ray. From the ratio of photocurrents in the range of X-ray radiation energies 35–72 keV for these two cases, a linear coefficient of X-ray absorption by the CdZnTe detector is determined. [ABSTRACT FROM AUTHOR]

Terahertz generation from atoms driven by two color linearly polarized (LP) and circularly polarized (CP) laser fields have been well investigated. In this work, based on the photocurrent model, we investigate theoretically the intensity and polarization characteristics of terahertz waves radiated by the bi-elliptical polarized two-color laser fields with orthogonal or parallel major axes. We show that polarization-controlled, including circularly polarized terahertz waves with sufficient intensity comparable to that of co-rotating CP or parallel LP laser field, can be generated by using a longer-wavelength few-cycle bi-elliptical field. Our simulations also show that THz energy and ellipticity can be dramatically improved with dual-color elliptical field with tiny or large ellipticity, compared with that with two-color orthogonal LP field and counter-rotating CP laser field, respectively. Bi-elliptical polarized laser field provides a huge parameter space allowing for far-reaching control of THz emission.

In this paper, we calculated current–voltage characteristic curves (IV curves), Conductivity, real space charge distribution, transmission spectrum, photocurrent, and thermal current of the borophene-black phosphorus heterostructure. Our results show that the zigzag device has excellent photocurrent characteristics. The direction of photocurrent can be adjusted by changing the wavelength of incident light and adding gate voltage. The armchair device has excellent IV curve characteristics and good linear characteristics at low voltage. The armchair device also has good thermoelectric current properties. The position distribution of covalent bonds formed between atoms in this heterostructure is revealed by the real space charge distribution. Our results are significant for applying borophene-black phosphorus heterostructure in electric transport devices.

In this work, graphitic carbon nitride doped by chlorine was prepared by a two-stage procedure for the first time. At the first stage, melamine was hydrothermally treated with glucose; at the second stage, the resulting precursor was calcined in a mixture with ammonium chloride. The obtained samples were studied using a set of physicochemical methods, such as X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), diffuse reflectance spectroscopy, and photoelectrochemical methods. All of the synthesized photocatalysts were tested in the reaction of photocatalytic hydrogen production from basic solutions of triethanolamine. The highest rates of hydrogen evolution and short-circuit current densities were obtained with a photocatalyst prepared by the calcination of a mixture consisting of 30% ammonium chloride and 70% melamine. The catalytic activity of this sample was 1332 μmol h–1 g–1, and it was higher than the catalytic activity of carbon nitride prepared by the calcination of melamine without pretreatment by a factor of 22. [ABSTRACT FROM AUTHOR]

• Al/BaTi 1-2x Fe x Nb x O 3 /Ag is an excellent bulk ferroelectric photovoltaic device configuration. • Increment of aliovalent Fe3+ and Nb5+ ionic substitutions reduces the bandgap of 0.075BFNT ceramics to ∼2.55 eV and broadens the visible spectrum absorption. • The photocurrent density of Al/0.075BFNT/Ag photovoltaic cell is about ∼ 2.2 times higher than that of pure BT. • A high photovoltaic power of ∼ 12 μW/cm2 was achieved. The generation of above bandgap photovoltage using bulk ferroelectric materials has become a subject of great interest, however, their photocurrent density is limited by a broad bandgap and poor conductivity. To overcome this limitation, we replaced aliovalent metal ions (Fe3+ and Nb5+) at the B-site of robust ferroelectric BaTiO 3 and fabricated an Al/BaTi 1-2x Fe x Nb x O 3 /Ag photovoltaic device. Both the experimental and the theoretical studies showed that bandgap was lowered to ∼2.55 eV and hence absorption of wide energy range of the solar spectrum was attained. An apt top electrode, reduced bandgap and domain size resulted in greater photocurrent density of 1.46 μA/cm2 and photovoltage of 8.31 V for Al/0.075BFNT/Ag solar cell in unpoled condition. This research suggest that reduced band gap, mixed structural phases and nano-sized domains suffices greatest PV power output while the large polarization and poling are not necessary prerequisites. [ABSTRACT FROM AUTHOR]

The dependence of the terahertz（THz） yield radiated from gases on the intensity of driving laser field is theoretically investigated by using photocurrent model. The simulation shows that when the laser is weak, the THz yield increases rapidly with the increase of laser intensity, regardless of monochromatic laser pulse or two-color laser field. When the gas ionization approaches or reaches saturation, the THz yield has the oscillating change with further increasing laser intensity. Higher laser intensities, which cause the gas to fully ionize, further increase the THz radiation intensity compared to the weaker intensity usually used. These results can be well explained by analyzing the number of electrons released at each ionization event and the symmetry of their trajectories. [ABSTRACT FROM AUTHOR]

In this special work, two types of material, which are undoped and Mn doped TiO2 thin films, have been produced by spin coating technique, and then their structural, morphological and optical properties have been measured at different Mn doping rates. Four different doping ratios, undoped, 1, 3 and 5% Mn doped TiO2 have been both experimentally and theoretically investigated and some significant enhancements have been reported. The results of X-ray diffraction (XRD) such as dislocation density, strain, and crystallite size have indicated that undoped, 1, 3 and 5% Mn doped TiO2 thin films had the phase of anatase at 450 °C. It has been observed that the peak intensity of 3% Mn doped TiO2 films has decreased compared to undoped and 1% Mn doped TiO2 while the peak intensity has increased for 5% Mn doped TiO2. The refractive indices and dielectric coefficients of the undoped and Mn doped TiO2 thin films have also been calculated. The undoped and Mn doped TiO2/p-Si heterojunction diodes has exhibited photosensitive behaviour in the illuminated environment. 1% Mn doped TiO2/p-Si heterojunction diode indicated the highest photocurrent. The electrical parameters of all diodes have been calculated and compared to the conventional J–V and Norde methods. Additionally, 1% Mn doped TiO2/p-Si heterojunction diode has been modelled by using the SCAPS-1D program, and Jph values have also been calculated based on the shallow donor density (ND). The experimental and theoretical Jph values of this diode were found to be compatible with each other. [ABSTRACT FROM AUTHOR]

The position of embedded plasmon nanoparticle is a key factor affecting the performance of perovskite solar cells (PSCs). It is crucial to unveil whether and how do the randomly distributed Ag nanoparticles within the active layer improve the optical efficiency of PSC. In this work, a comparative study between the optical properties of PSCs by embedding randomly distributed Ag nanospheres and nanocubes within the absorption layer is numerically performed by the finite element method. It demonstrates that the obtained maximum photocurrent reaches 23.5 mA/cm2 and 23.6 mA/cm2, which gets 22.7% and 23.3% improvement relative to that of planar reference, respectively. Their optimal filling factor F is also predicted, which is discussed in terms of the synergistic effects of the localized surface plasmon resonance (LSPR) and the occupancy competition between the nanoparticle and perovskite. The photocurrent improvement of the concerned PSCs embedded with Ag@TiO2 core–shell NPs is also discussed. The present work is believed to be highly useful for the future development and application of PSCs to boost their optical efficiencies, especially for PSC embedded with randomly distributed plasmon nanoparticles. [ABSTRACT FROM AUTHOR]

In this paper, the Mixed CNTs (mixture of SWCNTs and MWCNTs) with rGO and C60 are prepared, and their optoelectronic properties are investigated by using them in the active layer. The device has configuration FTO/rGO: Mixed CNTs:C60/BCP/Al. The UV–Vis spectrum is used to investigate the optical activity of Mixed CNTs with rGO and C60 in terms of absorption. Raman spectrum suggests the formation of all the carbon-based nanocomposites in the active layer. The field emission scanning electron microscopy analysis reflected a smooth and uniform morphology; however, the uneven surfaces of Mixed CNTs observed in the micrograph indicate better carbon-based materials dispersion. The I–V characteristic determines the optoelectronic parameters such as ideality factor and reverse saturation current, responsivity, and detectivity. The value of reverse saturation current shows a higher value in illumination conditions than in dark conditions. The transport properties of the device are studied by impedance analysis, which suggests a better device performance. [ABSTRACT FROM AUTHOR]

A photo-sensitizer made of graphene-based material (2-D) is used in concert with EDTA in photoelectrochemical solar cells to increase efficiency and storage capacity of solar energy in order to make a solar cell economically feasible. Photopotential and photocurrent are created at 1142mV and 960 μA, respectively. Photoelectrochemical cell have achieved a maximum power of 228.40 μW, a fill factor of 0.17, and a conversion efficiency of 4.38%. The cell storage capacity allows for a half power (t1/2) level to be maintained for 1300 minutes. The electrical output of the photoelectrochemical cell has been observed to be influenced by a number of different factors. [ABSTRACT FROM AUTHOR]

We report the light-dependent AC transport properties of an ITO/ZnO/rGO/Au heterostructure from impedance spectroscopy measurements carried out at room temperature in the frequency range of 20 Hz to 50 MHz under dark light, white light, and red laser light with variable intensities. It has been observed that impedance is decreased with an increase in illuminating light intensities. The equivalent circuits have been considered for fitting the experimental ac responses that permit the isolation of exact resistance–capacitance (RC) contributions which can be attributed to the interface region. The diameter of the semicircles in Nyquist plots were found to decrease with the increase in illuminated light intensities, indicating transfer of charge carriers at the ITO/ZnO and ZnO/rGO interfaces. Here, interface resistances and capacitances were found to decrease and increase, respectively, with increases in incident light intensities. I–V measurements of our device have been performed under dark and red laser illumination condition. From the I–V measurements of our device, a photocurrent has been found to be directly proportional to the incident photon energy, and resistive switching behavior was also prominent at a high biasing voltage under illuminated conditions. We have also shown that electrical hysteresis in our device depends on the biasing voltage along with the incident light intensity. We believe such observations of our fabricated device seem to be promising for light energy-dependent photodetectors for multipurpose use. [ABSTRACT FROM AUTHOR]

van der Waals heterostructures (vdWHs) based on two-dimensional (2D) materials without the crystal lattice matching constraint have great potential for high-performance optoelectronic devices. Herein, a WS2/InSe vdWH photodiode is proposed and fabricated by precisely stacking InSe and WS2 flakes through an all-dry transfer method. The WS2/InSe vdWH forms an n—n heterojunction with strong built-in electric field due to their intrinsic n-type semiconductor characteristics and energy-band alignments with a large Fermi level offset between WS2 and InSe. As a result, the device displays excellent photovoltaic behavior with a large open voltage of 0.47 V and a short-circuit current of 11.7 nA under 520 nm light illumination. Significantly, a fast rising/decay time of 63/76 µs, a large light on/off ratio of 105, a responsivity of 61 mA/W, a high detectivity of 2.5 × 1011 Jones, and a broadband photoresponse ranging from ultraviolet to near-infrared (325–980 nm) are achieved at zero bias. This study provides a strategy for developing high-performance self-powered broadband photodetectors based on 2D materials. [ABSTRACT FROM AUTHOR]

The growing need to process a diverse range of data has ignited effort in developing new multifunctional logic gate devices. In this article, we report a new form of all‐in‐one logic gate system that exploits the photoresponsivity of a self‐powered multifunctional BiFeO3 (BFO) sensor material. The BFO sensor can not only detect both light intensity and temperature, but it can also execute three common logic gates of "AND", "OR", and "NOT" by converting optical and thermal inputs into electrical output. The diverse functionality of the BFO logic gate sensor array utilizes the unique light‐and temperature‐controlled energy band structure and carrier behavior of the BFO material. To demonstrate the potential, a 3 × 3 logic gate sensor matrix is developed, which successfully detected light and temperature distributions, and accurately produced the three basic logic gate operations. This work provides a new route to construct highly integrated multifunctional electronic devices for the advancement of large sensing, communication, and computing operations. [ABSTRACT FROM AUTHOR]

Lightweight and flexible electronics have recently emerged at the forefront of optoelectronic applications. In this regard, graphene electrodes enable opportunities for new photodiode devices. In this paper, we formulated and tested graphene ink using the standard inkjet printing technique. It was shown that the maximum conductivity of ink was achieved for 14 print passes of the graphene layer. Moreover, we deposited Molybdenum Disulfide (MoS2) ink in the same pattern and used it as an active layer. We put MoS2 ink on an Indium-Tin-Oxide (ITO) glass substrate and then deposited graphene ink as a top electrode to fabricate an ITO/MoS2/graphene device. The fabricated device showed good rectification behavior and high ON/OFF switching behavior with a max photocurrent of 15 µA at +2 V. The technique thus paves the way for low-cost, low-temperature processing of electronics and one-step fabrication. [ABSTRACT FROM AUTHOR]

Ultra-rapid microwave-assisted hydrothermal synthesis was performed, zinc oxide nanoparticles were fabricated and doped with gallium. Different times (5, 15, and 30 min) and concentrations of doped Ga (1, 3, and 6%) were used to improve their characteristic properties. In addition, the relation between time/dopant was analyzed. The samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, and UV–Vis diffuse reflectance spectroscopy. Photoluminescence (PL) to verify number of defects. SEM analysis showed the formation of nanorods morphology even with a short synthesis time. The X-ray diffractograms and Raman spectra suggest the successful insertion of Ga into the ZnO lattice. The crystallite size obtained by doping was between 36 and 50 nm. The lattice parameters determined by the Rietveld refinement confirmed the formation of a wurtzite hexagonal structure. The band gap range found was 3.12–3.22 eV, which increases the potential of ZnO for optical applications. The presence of defects as result of doping was confirmed by PL. The microstructural changes of the material are enhanced by doping, which causes the photocurrent to increase from 0,002 to 0.012 mA/cm2 in doped ZnO. The synthesis time and Ga doping facilitated the production of ZnO nanoparticles with improved properties. [ABSTRACT FROM AUTHOR]

In the context of innovative education, experiments on the synthesis of Prussian blue films and investigation of their photoelectric properties are proposed to introduce the results of scientific research into comprehensive university experiments. The Prussian blue film was prepared on the surface of ITO-conductive glass by simple electrochemical polymerization methods, and the physical and chemical properties of Prussian blue film were studied by scanning electron microscopy, X-ray diffraction, cyclic voltammetry, and UV-Vis absorption spectroscopy, among other methods. Based on the experimental skills already acquired by the university students in chemistry experiments, we designed and built an in situ UV-Vis spectroscopy electrochemical and photocurrent test platform in combination with the existing comprehensive electrochemical experiments. Through specific experiments and by understanding the principle of mutual transformation of Prussian blue and Prussian white, the electrochromic phenomenon and photocurrent generation of Prussian blue were further understood; this stimulated students’ interest in photoelectrochemical experiments and helped them expand their scientific divergent thinking and improve their experimental skills. [ABSTRACT FROM AUTHOR]

Zero dimensional antimony(III) halides have captured more and more attention as broadband emitters. Herein, Using photochemically active ruthenium complexes as templates, two new antimony(III) halide based hybrids have been prepared and structurally determined, i.e., [Ru(bipy)3](Sb2Cl6O) (1) and [Ru(phen)3](SbI5) (2). Both the (Sb2Cl6O)2- and (SbI5)2-are rare examples of antimony halides, in which Sb centers are in square pyramidal environments with stereochemically active lone pairs. The (Sb2Cl6O)2- ion bearing secondary Sb···Cl interactions are further stabilized by C-H···Cl hydrogen bonds to give a quasi-3D network. The (SbI5)2- anions are anchored in the 1D[Ru(phen)3]n2n+ chains based on strong π···π stacking interactions among phenanthroline ligands, which are the reason for the formation of its square pyramid geometry.1 exhibits bright red luminescence but 2produces weak blue emission. This trend might be assigned to the larger conjugated system of phenanthroline in 2, which is dominant by ruling out the contribution of antimony(III) halide. Besides, reversible thermochromism can be found in 1. Furthermore, good electrical chemical and photocurrent performance can be detected. The photoluminescence modulation by controlling the conjugated degree of organic ligands is an efficient strategy for the precise preparation of new luminescent materials. Two antimony(III) halide-based hybrids template byruthenium complexes have been prepared, whose rare (Sb2Cl6O)2- and (SbI5)2- anions are stereo chemically active. Different luminescent performances (bright red and weak blue) might be assigned to the larger conjugated system of phenanthroline. Besides, reversible thermochromism and good photocurrent performance can be found. [ABSTRACT FROM AUTHOR]