Photocurrent Time Research Articles

Quantification of alloy atomic composition sites in 2D ternary MoS2(1-x)Se2x and their role in persistent photoconductivity, enhanced photoresponse and photo-electrocatalysis

Engineering transition metal dichalcogenides-based semiconducting two-dimensional (2D) layered materials for photo(electro)chemical (PEC) hydrogen evolution reaction (HER) by water splitting is an enduring challenge. Here, alloy-assisted photoconductivity and photoresponse from CVD-grown MoS2(1-x)Se2x (MSSE) 2D ternary atomic layered alloy-based photodetector device is presented for the realization of PEC HER. The explicit role of ‘S–Se’ and ‘Se2’ atomic alloy sites including chalcogen-induced vacancy defects on the photoconductivity/photoresponse and PEC HER performance of MSSE 2D alloy is investigated. Alloy formation, atomic site-by-site ‘Se’ composition and atomic structure are characterized using Raman/Photoluminescence (PL) spectroscopy, high-angle annular dark field (HAADF)- scanning transmission electron microscopy (STEM) extensively and supported with Auger Electron Spectroscopy (AES) mapping. Further, the local density and concentration of S–Se, Se2 atomic sites and defects were quantitatively estimated using HAADF-STEM image analysis in correlation with AES and it is found between the range of ∼15–20 % in MSSE alloy. A 10-fold high photoresponsivity in the case of MSSE concerning as-grown MS having fast photocurrent growth time and the prolonged decay time originates from the ‘Se’ and this alloy assisted states to enhance the PEC performance of MSSE alloy. The enhanced PEC HER activity of MSSE alloy was identified in terms of overpotential and current density. In addition, increased density of states as a function of ‘Se’ alloying, shifts in a p-band centre and lowers ΔGH* according to density functional theory calculations, which makes MSSE alloy an efficient HER activity. Further, the PEC stability and presence of the ‘S–Se’ and ‘Se2’ alloying and their role towards HER have been correlated by the spectral line shape analysis of PL and Raman spectra from post-PEC HER catalysts. These experimental and theoretical findings establish the role of chalcogen, and transition metal-based 2D alloy, leading to the design of new PECs of engineered 2D atomic layer interfaces.

A novel ternary Ti-V-Bi oxide photoelectrocatalyst in advanced oxidation process

Photoelectrocatalytic pollutant degradation is one of the most promising advanced oxidation processes for wastewater treatment. However, its efficiency dramatically depends on the development of photoelectrocatalyst materials. Therefore, here, ternary Ti0.2-Vx-Bi(0.8−x)-oxides (x = 0.15, 0.3, 0.4, 0.5, and 0.65) were applied as the photoelectrocatalysts for pollutant degradation. The photoelectrocatalysts were synthesized by a dip-coating thermal decomposition (DCTD) method. The physical and optical characteristics of photoelectrocatalysts were analyzed by XRD, FE-SEM, EDS, PL, and DRS tests. The photo/electrochemical behavior of samples was studied by LSV, EIS, and chronoamperometry with and without visible light illumination. The activity of samples was investigated by photocatalytic, electrocatalytic, and photoelectrocatalytic treatment of methyl orange and rifampin solutions under visible light irradiation. The kinetics of photocatalytic, electrocatalytic, and photoelectrocatalytic degradation processes was investigated by the Langmuir-Hinshelwood (L-H) kinetic model. Moreover, the mineralization extent of rifampin was studied by COD test. The results pointed to the optimum composition of ternary Ti0.2V0.4Bi0.4-oxide, in terms of both photocurrent and degradation time, which could completely degrade methyl orange and rifampin solutions in less than 15 min at a current density of 5 mA/cm2 under visible light irradiation. The superior performance of Ti0.2V0.4Bi0.4-oxide was attributed to its smaller particle size (larger surface area), lower band gap (2.1 eV), the lower recombination rate of e-/h+ pairs, and lower charge transfer resistance than the other compositions. The high activity and stability of Ti0.2V0.4Bi0.4-oxide introduce it as an efficient photoelectrocatalyst for pollutant degradation by the advanced oxidation process (AOP).

Boosting ultralong chemiluminescence for the self-powered time-resolved immunosensor

The construction of an immunosensor based on ultralong chemiluminescence is challenged due to the shortage of highly efficient initiator for long and stable catalysis. Herein, the heterogeneous Au/Pt@CuO/Cu2O catalyst was used to investigate the structure-activity relationship, while Au/Pt significantly promotes the activity of CuO/Cu2O to catalyze H2O2 and thus produces ·OH and O2•- radicals in highly alkaline solutions, resulting in the strong and long chemiluminescence in the reaction with luminol (10 mL, more than 4 min with 1 μg catalyst). By using the Au/Pt@CuO/Cu2O as the label in the immunoassay, the strong and long chemiluminescence could initiate the photocurrent of the photoelectrochemical (PEC) substrate, and the luminescence time could influence the photocurrent extinction time, thus a self-powered time-resolved PEC immunosensor was developed to detect furosemide, showing a linear relationship between the extinction time and the logarithm of concentrations from 10−3 to 1 μg/L. This work not only experimentally verifies that the Pt–O–Cu bond in heterogeneous catalysts breaks the pH limitation of the Fenton reaction, but also realizes the chemiluminescence for self-powered time-resolved immunosensor, thereby expanding the portable applicability of chemiluminescence in food safety inspection, health monitoring, and biomedical detection without external light source.

Toward smart flexible self-powered near-UV photodetector of amorphous Ga2O3 nanosheet

Recently, the thin amorphous Ga2O3 nanosheet attracts enormous interest in dielectric and passivation materials, but it is still lack of the study about its photodetection performance. In this work, the amorphous Ga2O3 nanosheet is peeled off from the Ga solid-melt surface. Its amorphous characteristic is verified by selected area electron diffraction and X-ray diffraction. Owing to the limited absorption ability and abundant defect states, the amorphous Ga2O3 nanosheet photodetector shows a low photocurrent and slow response time even at a bias voltage. For improving the photodetection performance, PbI2 nanosheet is selected to be grown on the surface of amorphous Ga2O3 nanosheet. Owing to the built-in electric field at the interface, the Ga2O3/PbI2 heterojunction photodetector can work at a bias voltage of 0 V, along with a larger photocurrent of 1.6 nA and faster response times of about 2 ms (rise time) and 3 ms (decay time). When configured into the flexible photodetector, it also displays excellent self-powered photoresponse characteristic and excellent mechanical flexibility. This work paves the way for the development of high-performance flexible optoelectronic devices.

Large area planar UV–Visible photodetectors using wide bandgap WO3−δ films

A simple synthesis technique of semiconducting monoclinic phase tungsten oxide (WO3−δ) films is demonstrated. In this article, we report the effect of oxidation temperature on oxygen vacancy gradient of WO3 films and their photo sensing properties. The WO3−δ films were grown on Si/SiO2 substrates by argon ion-beam sputtering of a high purity W (tungsten) target followed by thermal oxidization in the tubular furnace at three different oxidation temperatures at 500, 600 and 700 °C with controlled oxygen gas pressure. Detailed crystal structure, microscopic and spectroscopic characterizations reveal that the oxidation at temperature 700 °C produces reasonably good crystalline quality of the film exhibiting UV–Visible photo sensing properties. The effect of oxidation temperature towards an enhancement in crystallinity which in turn gives rise to sharp Raman peak is discussed. The fabricated device exhibits a very low dark current of 7.5 × 10 −8 A at ±0.5 V bias for WO3−δ films oxidized at 700 °C. The photodetection measurements show linear current-voltage (I–V) behaviour with light-to-dark current (ILight/IDark) ratio ∼102 at 365 nm illumination (∼0.82 mW cm−2) at 2 V applied bias. The responsivity (Rλ), specific detectivity (D*) and external quantum efficiency (EQE) were found to be ∼0.12 AW−1, ∼2.1 × 1010 Jones (cm Hz1/2 W−1) and 40%, respectively, at 365 nm illumination (∼0.82 mW cm−2) with an applied bias of 2 V for the films oxidized at 700 °C. While upon visible light illuminations, the Rλ, D* and EQE were calculated to be ∼0.78 AW−1, ∼1.4 × 1011 Jones and 174%, respectively, upon 555 nm illumination (∼0.21 mW cm−2), with 2 V applied bias. A faster photocurrent relaxation time was observed from the films oxidized at 700 °C. The ultraviolet photoelectron spectroscopy study shows a surface band gap of 3.7 eV with absolutely no density of states in the near Fermi-level, validating fully stoichiometric surface. The effects of oxidation temperatures causing the large bandgap are discussed in terms of the device performances.

Evolution of surface properties of titanium oxide thin films

Titanium oxide thin films were deposited by rf magnetron sputtering of Ti metallic target in flow-controlled O2 + Ar atmosphere. Comprehensive investigations of crystallographic structure, phase composition, morphology and optical properties were performed by means of X-ray diffraction, X-ray reflectivity (XRR), scanning electron microscopy, optical spectrophotometry, and X-ray photoemission spectroscopy. It was found that as the O2/(O2 + Ar) flow ratio increased, the microstructure of thin films changed from TiO, Ti2O3, to rutile TiO2, rutile-anatase mixture and, finally, to pure anatase. Special emphasis was given to soft X-ray absorption spectroscopy in surface-sensitive total electron yield mode, which provided simultaneous information on electronic occupancy and local atomic structure. Studies of titanium L23 edge revealed systematic changes in crystal field strength, increasing upon rutile formation and decreasing when anatase became the dominant phase in sputtered films. Diffuse reflectance and XRR were employed to investigate the light scattering effects related to the surface roughness. The highest value (5.3 nm) of XRR roughness was observed for pure rutile sample. Performance of films as photoanodes in photoelectrochemical cells was assessed by photocurrent vs potential and time measurements. Results revealed that crystallized, stoichiometric films containing a mixture of anatase and rutile were promising photoanode materials for green hydrogen generation.

Revealing the Variation of Photodetectivity in MAPbI3 and MAPb(I0.88Br0.12)3 Single Crystal Based Photodetectors Under Electrical Poling-Induced Polarization

The use of electrical poling to induce polarization potential has been found to increase the photocurrent (Ilight) in hybrid perovskite-based devices; however, the origin of this process has not been fully understood. Here, we study the effect of electrical poling on the photodetection properties of self-powered photodetectors (PDs) based on halide perovskites in two different phase structures (i.e., tetragonal and cubic). Specifically, extensive investigations are performed on the MAPbI3 (tetragonal) and MAPb(I0.88Br0.12)3 (cubic) single crystals (SCs). Our characterization results revealed that the Ilight has increased by 2-fold during forward poling and decreased during reverse poling in both PDs. The improved Ilight is caused by polarization induced ion migration, which builds remanent potential due to ion accumulation near metal electrodes. The effect of this polarization was found to be greater in MAPbI3 PD as compared to MAPb(I0.88Br0.12)3 PD, which influences the interface band bending and reduces Schottky barrier height (SBH). This study highlights that the modification of SBH, which describes the potential energy barrier for electrons formed at a metal–semiconductor junction, can tune the photocurrent and response time of PDs.

High-performance CuO nanowire printed devices for visible light sensing and switching characteristics

CuO nanowires (NWs) were synthesized by thermal oxidation of Cu wire in a muffle furnace. The furnace was set to 600 ˚C for 24 h to obtain a high aspect ratio NWs (400–700), with good crystallinity and negligible impurities. Further, CuO NWs were transferred to the silicon substrate to form a two-terminal, single nanowire device using contact printing. The fabricated devices exhibit good photocurrent, response, and recovery time (<50 ms). Also, the printed devices were analyzed at various bias voltages to explore the switching characteristics.

Aligned CuO nanowire array for a high performance visible light photodetector

Recently, copper oxide (CuO) has drawn much attention as a promising material in visible light photodetection with its advantages in ease of nanofabrication. CuO allows a variety of nanostructures to be explored to enhance the optoelectrical performance such as photogenerated carriers scattering and bandgap engineering. However, previous researches neglect in-depth analysis of CuO’s light interaction effects, restrictively using random orientation such as randomly arranged nanowires, single nanowires, and dispersed nanoparticles. Here, we demonstrate an ultra-high performance CuO visible light photodetector utilizing perfectly-aligned nanowire array structures. CuO nanowires with 300 nm-width critical dimension suppressed carrier transport in the dark state and enhanced the conversion of photons to carriers; additionally, the aligned arrangement of the nanowires with designed geometry improved the light absorption by means of the constructive interference effect. The proposed nanostructures provide advantages in terms of dark current, photocurrent, and response time, showing unprecedentedly high (state-of-the-art) optoelectronic performance, including high values of sensitivity (S = 172.21%), photo-responsivity (R = 16.03 A/W, λ = 535 nm), photo-detectivity (D* = 7.78 × 1011 Jones), rise/decay time (τr/τd = 0.31 s/1.21 s).

A Light-Driven Integrated Bio-Capacitor with Single Nano-Channel Modulation

Bioelectronics, an emerging discipline formed by the biology and electronic information disciplines, has maintained a state of rapid development since its birth. Amongst the various functional bioelectronics materials, bacteriorhodopsin (bR), with its directional proton pump function and favorable structural stability properties, has drawn wide attention. The main contents of the paper are as follows: Inspired by the capacitive properties of natural protoplast cell membranes, a new bio-capacitor based on bR and artificial nanochannels was constructed. As a point of innovation, microfluidic chips were integrated into our device as an ion transport channel, which made the bio-capacitor more stable. Meanwhile, a single nanopore structure was integrated to improve the accuracy of the device structure. Experiments observed that the size of the nanopore affected the ion transmission rate. Consequently, by making the single nanopore’s size change, the photocurrent duration time (PDT) of bR was effectively regulated. By using this specific phenomenon, the original transient photocurrent was successfully transformed into a square-like wave.

Anions mediated amino-type Cd-MOFs catalysts for efficient photocatalytic hydrogen evolution

Photocatalytic water splitting can be used to directly transfer solar energy into chemical energy with highly efficiency. Metal-organic frameworks (MOFs) materials are well known on the advantages of high design flexibility and metal center functionalization. In this study, a series of Cd-centered MOFs were successfully fabricated by a simple solvent evaporation method based on the different anion mediated pyridyl leucine derivatives. Single-crystal X-Ray diffraction showed the isostructural 3D chiral coordination networks of three Cd-MOFs with helical chains connected by the adjacent carboxylate groups. Within the helical coordination chains, the formate (For) and acetate (OAc) anions adopted chelate modes in Cd-LFor and Cd-LOAc, whereas the chloride worked as a monodetate ligand in Cd-LCl. Powder X-ray diffraction (PXRD), Thermogravimetric analysis, UV–vis spectra, Photocurrent-time test (I-t) and Mott-Schottky (MS) curves were carried out to characterize and analysis these Cd-MOFs. All the samples exhibit photocatalytic activity for hydrogen generation in aqueous solution of Na2S/Na2SO3 upon irradiation at full light. The photocurrent time test showed that Cd-LCl showed a higher photocurrent intensity than those of Cd-LFor and Cd-LOAc, which proved the lower electron-hole recombination and correspondingly higher hydrogen production photocatalysis active. The highest H2 production rate reached 17242 ​μmol ​g−1 ​h−1 for Cd-LCl. In the photocatalytic reaction, the hydrogen production rate was stable without significant decrease, indicating that the material had no significant deactivation and had good photocatalytic activity.

Zero-Process-Change SiGe Heterojunction Avalanche Photodiode for High-Speed, High-Gain Detection Near the Silicon Band Edge

A novel design for a silicon-integrated avalanche photodiode (APD) capable of high internal gain (>16,000) is presented. The APD was fabricated in an unmodified, commercial high-volume, high-performance (300 GHz f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> /f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> MAX</sub> ) silicon-germanium (SiGe) BiCMOS technology. The APD's high gain is partially attributed to the enhanced lateral carrier mobility of its strained SiGe anode, and the low sheet resistance of its cathode contact. These design aspects lower parasitic resistance and improve junction electric field uniformity, increasing maximum gain. For applications not requiring maximum device speed, a time-resolved overall responsivity of 4.2 A/W is demonstrated, with a photocurrent pulse fall time (90%/10%) of 46 ns at 1066 nm. Alternatively, for applications requiring faster speed, the device can be biased to 0.16 A/W with a fall time of 2.5 ns, or 0.07 A/W with a fall time of 0.8 ns.

56‐1: Enhancing Response Time of Quantum‐Dot‐Based TFT Photosensor with Self‐Assembled Monolayer

Quantum‐dot‐based a‐IGZO phototransistor has become one of the promising devices for image sensor application due to its bandgap tunability and solution‐process compatibility. However, the QD phototransistor with a‐IGZO, which contains a large amount of charge traps on the surface, exhibited slow photoresponse (τdecay &gt;10 s). In this work, the photocurrent and decay time were significantly enhanced by 2.2 times and 73%, respectively, by introducing a self‐assembled monolayer (SAM), which effectively passivates the traps at the QD/a‐IGZO interface.

Construction of a novel electron transfer pathway by modifying ZnIn2S4 with α-MnO2 and Ag for promoting solar H2 generation

Using photocatalysts to split water by solar energy for sustainable H2 generation has aroused researchers' wide concern. In this study, we chose α-MnO2 as the electron storage and transfer medium, and introduced the surface plasma resonance effect of Ag into the composite material to successfully prepare novel ternary Ag/α-MnO2/ZnIn2S4 (Ag/α-MnO2/ZIS) photocatalysts. Various technologies such as photoluminescence (PL), Photocurrent-Time (PC), Linear sweep voltammetry (LSV), Mott–Schottky measurement (M–S) and electrochemical impedance spectra (EIS) were used to characterize the ternary Ag/α-MnO2/ZnIn2S4 photocatalysts. Noteworthy, due to the synergistic effect of the three materials, the composite catalysts have the characteristics of excellent optical properties, more active sites, greater carrier density, and stronger carrier separation and transfer ability. This structural design can remarkably improve photocatalytic performance driven by visible light. As expected, the Ag/α-MnO2/ZnIn2S4 photocatalysts exhibit excellent photocatalytic activity with a maximum H2-production rate of 3.65 mmol g-1 h−1, and it is about 14.9 times higher than that of pure ZnIn2S4. Furthermore, the ternary Ag/α-MnO2/ZnIn2S4 photocatalysts show recycle ability and good stability, and a photogenerated electron transfer mechanism has been put forward and detailly analyzed. The work offers a novel strategy to design highly active visible light photocatalysts for clean energy.

Fractal Generalization of the Scher–Montroll Model for Anomalous Transit-Time Dispersion in Disordered Solids

The Scher–Montroll model successfully describes subdiffusive photocurrents in homogeneously disordered semiconductors. The present paper generalizes this model to the case of fractal spatial disorder (self-similar random distribution of localized states) under the conditions of the time-of-flight experiment. Within the fractal model, we calculate charge carrier densities and transient current for different cases, solving the corresponding fractional-order equations of dispersive transport. Photocurrent response after injection of non-equilibrium carriers by the short laser pulse is expressed via fractional stable distributions. For the simplest case of one-sided instantaneous jumps (tunneling) between neighboring localized states, the dispersive transport equation contains fractional Riemann–Liouville derivatives on time and longitudinal coordinate. We discuss the role of back-scattering, spatial correlations induced by quenching of disorder, and spatiotemporal non-locality produced by the fractal trap distribution and the finite velocity of motion between localized states. We derive expressions for the photocurrent and transit time that allow us to determine the fractal dimension of the distribution of traps and the dispersion parameter from the time-of-flight measurements.

Revealing Electrical-Poling-Induced Polarization Potential in Hybrid Perovskite Photodetectors.

Despite recent rapid advances in metal halide perovskites for use in optoelectronics, the fundamental understanding of the electrical-poling-induced ion migration, accounting for many unusual attributes and thus performance in perovskite-based devices, remain comparatively elusive. Herein, the electrical-poling-promoted polarization potential is reported for rendering hybrid organic-inorganic perovskite photodetectors with high photocurrent and fast response time, displaying a tenfold enhancement in the photocurrent and a twofold decrease in the response time after an external electric field poling. First, a robust meniscus-assisted solution-printing strategy is employed to facilitate the oriented perovskite crystals over a large area. Subsequently, the electrical poling invokes the ion migration within perovskite crystals, thus inducing a polarization potential, as substantiated by the surface potential change assessed by Kelvin probe force microscopy. Such electrical-poling-induced polarization potential is responsible for the markedly enhanced photocurrent and largely shortened response time. This work presents new insights into the electrical-poling-triggered ion migration and, in turn, polarization potential as well as into the implication of the latter for optoelectronic devices with greater performance. As such, the utilization of ion-migration-produced polarization potential may represent an important endeavor toward a wide range of high-performance perovskite-based photodetectors, solar cells, transistors, scintillators, etc.

Selenium‐Based Solar Cell with Conjugated Polymers as Both Electron and Hole Transport Layers to Realize High Water Tolerance as well as Good Long‐Term and Thermal Stability

Solar cells with varied absorbers, ranging from crystalline silicon to perovskite materials, are very vulnerable to water. Expensive and complicated encapsulation is needed to protect the devices. Thus, it is highly desirable to achieve encapsulation‐free solar cells with high water tolerance. Herein, encapsulation‐free selenium (Se)‐based solar cells (SSCs) with hydrophobic polymers as electron and hole transport layers are presented and can successfully tolerate the aqueous conditions. Moreover, it is found that the photocurrent–time curve under the aqueous/ambient environment can be smoothly fitted into the first‐order exponential models. The photocurrent of water‐soaking SSCs can recover to its original value after drying in the air, which proves the great water tolerance of fabricated SSCs. Furthermore, the SSCs also show good long‐term and thermal stability. The viability of encapsulation‐free SSCs under a harsh environment provides opportunities to further explore the interactions among light, water, and solar cells as well as make large‐scale industrialization applications of SSCs much easier.

The Micro-Scaled Characterization of Natural Terrestrial Ferromanganese Coatings and Their Semiconducting Properties

Different types of ferromanganese coatings were collected from the Chinese mainland to study their mineralogical characteristics and semiconducting properties. Measurements, including by optical microscope, scanning electron microscope, energy dispersive X-ray spectroscopy, micro-Raman spectrometer and transmission electron microscope, were employed to study their morphology, mineral assemblage, element abundance and distribution patterns. Soil Fe coatings are mainly composed of Al-rich hematite and clays. Soil Fe/Mn coatings can be divided into an outer belt rich in birnessite and an inner belt rich in hematite, goethite, ilmenite and magnetite. Goethite is the only component of rock Fe coatings. Rock Fe/Mn coatings mainly consist of birnessite and hematite, and alternating Fe/Mn-rich layers and Fe/Mn-poor layers can be observed. Powders were scraped off from the topmost part of ferromanganese coatings to conduct laboratory photochemical experiments. The photocurrent–time behavior indicates that natural coating electrodes exhibit an immediate increase in photocurrent intensity when exposed to light irradiation. Natural coatings can photo-catalytically degrade 14.3%–58.4% of methyl orange in 10 h. Under light irradiation, the photocurrent enhancement and organic degradation efficiency of the rock Fe/Mn coating, which has a close intergrowth structure of Fe and Mn components, is most significant. This phenomenon is attributed to the formation of semiconductor heterojunctions, which can promote the separation of electrons and holes. Terrestrial ferromanganese coatings are common in natural settings and rich in semiconducting Fe/Mn oxide minerals. Under solar light irradiation, these coatings can catalyze important photochemical processes and will thus have an impact on the surrounding environment.

Growth and UV detector of serrated GaN nanowires by chemical vapor deposition

Serrated GaN nanowires were synthesized on sapphire substrate by chemical vapor deposition. Copper nanowires were synthesized by liquid-phase reduction method. The surface morphology of GaN and copper nanowires was observed by scanning electron microscopy. An UV detector based on GaN nanowires was prepared with copper nanowires as electrode. The results show that the device is a photoconductive detector. The detector has different response under different wavelength light illumination and has the maximum response under 365nm ultraviolet light. Photocurrent–time characteristics show the detector has good stability over time.

Graphitic carbon nitride bedecked with CuO/ZnO hetero-interface microflower towards high photocatalytic performance

Abstract The micron-size flower-like metal oxide of copper/zinc decorated graphitic carbon nitride (g–C3N4–CuO/ZnO) composite was successfully synthesized by solvent mixing assisted with the sonication method. The structural, functional groups, morphology, particle size, optical properties of synthesized g–C3N4–CuO/ZnO composites were analyzed using various techniques such as XRD, XPS, FTIR, SEM, TEM, UV–Vis, photoluminescence (PL), and photocurrent–time (PT) measurements. Further, the photocatalytic capacity of the synthesized composite was examined by the evolution of hydrogen production through the water-splitting using visible light and the study of methylene blue dye (MB) degradation under solar irradiation. The g–C3N4–CuO/ZnO composites showed the enhanced photocatalytic activity as compared to the pure bulk form of g-C3N4, DMSO-g-C3N4, and CuO/ZnO. Also, it showed an increment of photocatalytic activity in the treatment of pollutants as well as increased production of hydrogen gas under visible light. These enhanced photocatalytic activities could be attributed to the combined effect between g-C3N4 and CuO/ZnO crystalline phases. The maximum quantum efficiency and degradation of the MB dye by g–C3N4–CuO/ZnO composite were 5.5% and 99%, respectively. The mechanism of enhanced photocatalytic activity of the g–C3N4–CuO/ZnO composite was also discussed in this work.