Current Photoresponse Research Articles

The fabrication of ultra-wide bandgap GeO2 thin films by DC magnetron sputtering: The impacts of growth temperature and post-annealing process

Ultra-wide bandgap semiconductors (UWBSs), possessing the bandgap greater than 4 eV, have emerged as an advanced platform for optoelectronic device applications. The exploration of novel UWBSs becomes compelling research focus on the solar blind photodetectors (SBPDs). Here, we have deposited ultra-wide bandgap GeO2 films on c-plane sapphire substrates using direct-current (DC) magnetron sputtering method and investigated the effects of the growth and annealing temperatures on surface morphologies, crystal structure, oxygen vacancies, and bandgap energies of GeO2 films. The high quality GeO2 film with the hexagonal phase can be obtained at the growth temperature of 500 °C, which transforms to the mixture of hexagonal and tetragonal phases after annealing at 900 °C. By analyzing the energy loss spectra of O 1s peaks, GeO2 films exhibit the ultra-wide bandgap ranging from 5.78 to 5.90 eV, which is verified by optical transmittance measurements. Moreover, 200 nm SBPDs based on GeO2 films have been fabricated and an obvious improvement in the photoresponse current of the annealed device has been found due to the induced additional electrons by the hole capture of oxygen vacancies. Our findings on the development of ultra-wide bandgap GeO2 films pave a way towards the realization of robust and high-performance SBPDs.

SiW9Co3 @rGO composite-doping improved the crystallization and stability of a perovskite film for efficient photodetection.

The crystalline quality of perovskite films is a key factor that affects the performance of perovskite photovoltaic devices. Polyoxometalates can better match the energy levels of each layer in the devices through their own suitable energy level and band gap, and the good light absorption of POMs can also increase the mobility of photogenerated carriers in the devices. Moreover, POMs with Keggin-type structures can also improve the crystalline quality of perovskite films by eliminating defect sites, which can lead to better crystallization of perovskites with larger grains. In this study, we optimized the crystalline quality of a perovskite layer using the SiW9Co3@rGO composite prepared using POMs and graphene derivatives. XRD and SEM tests show that the crystallization degree of the perovskite layer was improved, the average grain size of which can reach up to 1222.92 nm, which is nearly four times higher than that of a blank perovskite. The photoresponse current of a SiW9Co3@rGO-doped photodetector can reach to 43.94 μA, which is about 226% higher than that of an undoped device. At the same time, the addition of the composite can improve the stability of photodetectors because of the special network structure of graphene. Photodetectors doped with SiW9Co3@rGO can still maintain more than 90% of their high performance for a month. This study proves that POM-based composites have good application prospects in the field of photovoltaic devices.

Investigation of Photoelectrocatalytic and Magnetic Properties of Sr2YbRu1-xTaxO6 (x = 0, 0.25, 0.5, 0.75, and 1).

We report the effect of substitution of Ru by Ta in Sr2YbRuO6 on its magnetic and photoelectrocatalytic properties. The powder X-ray diffraction data, was satisfactorily refined in the monoclinic space group, P21/n. The DC magnetization studies indicated that Sr2YbRuO6 shows antiferromagnetic interaction through Yb-O-Ru orbital ordering, with the highest Weiss temperature, among Sr2YbRu1-xTaxO6 (x = 0, 0.25, 0.5, and 0.75) which have values of -148, -125, -118, and -102 K, respectively. The difference in observed and theoretical magnetic moments was found to increase as x increases. It was also observed that with the increase of Ta concentration in Sr2YbRu1-xTaxO6, the band gap increased almost linearly, from 1.78(1) eV (x = 0) to 2.08(1) (x = 0.75), and thereafter a sharp increase 2.65(1) eV (x = 1) was observed, with the lowering of energy level of valence band, along with disruption in orbital ordering as x increases. The photoelectrocatalytic oxygen evolution reaction (OER) studies carried out on the series yield a maximum photocurrent density of 17 μA/cm2 and photoresponse current of 5.5 μA/cm2 at 0.8 V at an onset potential at 0.29 V vs Ag/AgCl for Sr2YbRuO6. The XPS analysis showed Ta and Ru to be in +5/+4 oxidation states, with the highest concentration of Ru4+ ion observed for Sr2YbRuO6. The presence of oxygen vacancies was confirmed by XPS as well as EPR studies.

Preparation of Cu2ZnSnS4@TiO2 nanotubes by pulsed electrodeposition for efficiently photoelectrocatalytic reduction of CO2 to ethanol

In this work, we reported a method of preparing Cu2ZnSnS4@TiO2 nanotubes (Cu2ZnSnS4/TiO2NTs) composite electrode by pulse electrodeposition and high-temperature vulcanization, which possesses high catalytic conversion efficiency for CO2 reduction and stable performance. In addition, the influence of pulse parameters on the morphology and photoelectrochemical properties of Cu2ZnSnS4/TiO2NTs composite electrode were studied in detail. The band gap of Cu2ZnSnS4/TiO2NTs is 1.39 eV, which is significantly reduced compared with TiO2NTs (3.27 eV). There are differences in the morphology, catalytic efficiency and product selectivity of the catalytic interface constructed by different pulse electrodeposition parameters. The photoresponse current of the composite electrode prepared by optimizing the parameters reaches −7 μA cm−2, and the ethanol yield is 7.0 μmol cm−2 after 5 h of photoelectrocatalytic reduction of CO2. No new phase was generated and the photocurrent density remained 33.2% of the original after the catalytic process, which indicated the Cu2ZnSnS4/TiO2NTs possess stable catalytic performance.

Picoampere Dark Current and Electro-Opto-Coupled Sub-to-Super-linear Response from Mott-Transition Enabled Infrared Photodetector for Near-Sensor Vision Processing.

Light-intensity selective superlinear photodetectors with ultralow dark current can provide an essential breakthrough for the development of high-performing near-sensor vision processing. However, the development of near-sensor vision processing is not only conceptually important for device operation (given that sensors naturally exhibit linear/sublinear responses), but also essential to get rid of the massive amount of data generated during object sensing and classification with noisy inputs. Therefore, achieving the giant superlinear photoresponse while maintaining the picoampere leakage current, irrespective of the measurement bias, is one of the most challenging tasks. Here, Mott material (vanadium dioxide) and silicon-based integrated infrared photodetectors are developed that show giant superlinear photoresponse (exponent >18) and ultralow dark current of 4.46pA. Specifically, the device demonstrates an electro-opto-coupled insulator-to-metal transition, which leads to outstanding photocurrent on/off ratio (>106 ), a high responsivity (>1mAW-1 ), and excellent detectivity (>1012 Jones), while maintaining response speed (τr =6µs and τf =10µs). Further, intensity-selective near-sensor processing is demonstrated and night vision pattern reorganization even with noisy inputs is exhibited. This research will pave the way for the creation of high-performance photodetectors with potential uses, such as in night vision, pattern recognition, and neuromorphic processing.

Z-scheme photocatalysis and photoelectrochemical platform with a Co3O4-CuO heterogeneous catalyst for the removal of water pollutants and generation of energy

Protection of the environment by increasing the use of renewable energy sources has become a global priority. The use of renewable resources to generate green energy and remove contaminants from water is an ongoing endeavor. Excellent dye degradation and water-splitting performances have been achieved using photocatalysis, a green technology, combined with the use of heterojunction nanocomposites fabricated with urchin-like and spherical morphologies (Co3O4:CuO). In this study, a one-pot solvothermal approach was used to fabricate a Co3O4–CuO heterojunction composite for use as a multifunctional substrate in dye degradation and photoelectrochemical (PEC) water splitting. For dye degradation, the weight percentage of CuO was adjusted against that of Co3O4; the fabricated CuO–Co3O4 (7.5 wt%) catalyst facilitated 82% degradation of azo dye within only 2 h. The improved catalyst was also used to degrade rhodamine B (76%), methylene blue (71%), and methyl orange (79%). Moreover, owing to its excellent photogenerated charge transfer kinetics and separation capability, the Co3O4–CuO photoelectrode exhibited a higher photocurrent density than the pristine materials in PEC water splitting. Linear sweep voltammetry under light illumination revealed that the photoresponse current of the multifunctional Co3O4–CuO composite was 6.05 mA/cm2 at a potential of 1.8 V (vs. Ag/AgCl), which is ∼2.01 and 3.1 times higher than those of pristine Co3O4 and CuO catalysts, respectively. The photocurrent response of the composite was 3.9 times higher than that under dark conditions. The substantial advantages offered by the fabricated composite over the pristine materials (Co3O4 and CuO), as well as its degradation and PEC water splitting capabilities, were attributed to the combined impact of numerous reactive sites, effective charge separation, increased light harvesting, and facile reactant transfer. Consequently, our research provides novel insights into the fabrication of unique binary nanocomposites with multiple applications and outstanding photocatalytic performance.

Nail-like α-SnWO4 Array Film with Increased Reactive Facets for Photoelectrochemical Water Splitting

α-SnWO4 is a good candidate for photoelectrochemical (PEC) water splitting due to its suitable band position that straddles the H+/H2 and O2/H2O redox potentials. However, its poor charge transfer ability results in unsatisfactory PEC performance. From the view of material design, a nail-like α-SnWO4 array film was constructed by a hydrothermal method assisted by halogen ions, and the corresponding physical and PEC properties are discussed. Density functional theory (DFT) calculations were also performed to help understand the effect of halogen ions (Cl–, F–) on the growth and exposure facet of α-SnWO4 and the underlying mechanism of PEC performance. The existence of F– decreases the surface energy of the {100} and {001} facets, directions along which the film has better charge transfer, and the {001} facet has a lower barrier in the PEC water oxidation reaction. The α-SnWO4 film photoanode after facet regulation presents better charge transfer ability, and the oxygen evolution rate is 0.16 μmol cm–2 h–1. In addition, a 1.9-fold photoresponse current is obtained during unbiased PEC water splitting.

Performance enhancement of an organic photodetector enabled by NPB modified hole transport layer

Transport layers are extremely important for organic photodetectors (OPDs) due to their effective role in improving the charge selectivity at the contacts, thus leading to high photoresponse and low dark current. The quintessential hole transport layer (HTL), e.g. MoO3, is suffering from the work function instability caused by the preparation process and the evolution in external environment. In this paper, we introduce an N,N′-bis-(1-naphthyl)-N,N′-diphenyl-1,1′-biphenyl-4,4′-diamine (NPB) interfacial layer to modify MoO3 HTL. At an optimized NPB thickness of 20 nm, the photocurrent (J p) density of the device increases by 19%, thus the responsivity and external quantum efficiency are raised to 0.44 A W−1 and 75% at 725 nm. Besides, owing to the suppressed dark current, the optimized device showcases an enhanced specific detectivity of over 1011 Jones in the range of 460–750 nm (under negative bias). This achievement is assigned to the improvement in transport and collection efficiency of holes. The study provides a feasible method of HTL modification to improve the performance of OPDs.

Optimized performances in InGaN/GaN quantum-well membrane based vertical optoelectronics by the Piezo-phototronic effect

In this work, by conducting selective electrochemical (EC) etching of the sapphire based nitrides epitaxial film, freestanding InGaN/GaN quantum-wells (QWs) membrane was firstly and specifically prepared. InGaN/GaN QWs based device with vertical geometry were then fabricated using the membranes, which can work either as a light-emitting diode (LED) or as a photodetector (PD). The emission intensity and polarization characteristics of vertical devices are optimized by introducing the Piezo-phototronic effect under external straining. Under a tensile strain of 2.04%, the relative electroluminescence (EL) intensity of the LED is increased by 183%, which is ascribed to the enhancement of carriers recombination arisen from the external-strain-induced Piezo-phototronic effect. And the polarization ratio of the emission light is increased or decreased by 135% and 56% under the tensile or compressive strain of 2.04%. For the PD working mode, the polarization ratio of photoresponse current is increased by 107% under the condition of 2.04% tensile strain, while it is reduced by 81% under compressive strain. The modulated polarization characteristics in the vertical devices were attributed to the adjustment in anisotropic optoelectronic properties of InGaN/GaN QWs. This work provides a novel method to fabricate vertical nitride optoelectronics and also presents a unique strategy to their optoelectronic performances.

Unraveling Electron-deficient Setaria-viridis-like Co3O4@MnO2 heterostructure with superior photoelectrocatalytic efficiency for water remediation

Photoelectrocatalytic (PEC) degradation efficiency of refractory organic pollutants depends strongly on the characteristics of photoanode semiconductors. Therefore, choosing a photoanode semiconductor material to enhance the PEC efficiency is a critical problem. Here, we assemble a unique Co3O4@(δ-)MnO2 setaria-viridis-like heterostructure employing a two-step hydrothermal method. To maximize PEC degradation efficiency, coupling Co3O4 with an appropriate amount of MnO2 achieves Co3O4@MnO2-0.05, resulting in high oxygen evolution potential, fast carrier transfer, low resistance, electron-deficient surface, and high photo-response current. Those properties endow Co3O4@MnO2-0.05 as a promising candidate for practice application of dye degradation, with a degradation rate of ∼ 94.8 % and long-term durability (∼12000 s) under 1.0 mol·L−1 H2SO4 condition at a current density of 250 mA·cm−2 for blue KN-R degradation. Remarkably, the superior PEC degradation efficiency of Co3O4@MnO2-0.05 outperformed that of Co3O4-based and MnO2-based catalysts due to the dominant role of •O2− and h+ radical during degradation experiments.

Light-Motivated SnO2 /TiO2 Heterojunctions Enabling the Breakthrough in Energy Density for Lithium-Ion Batteries.

Powering lithium-ion batteries (LIBs) by light-irradiation will bring a paradigm shift in energy-storage technologies. Herein, a photoaccelerated rechargeable LIB employing SnO2 /TiO2 heterojunction nanoarrays as a multifunctional anode is developed. The electron-hole pairs generated by the Lix TiO2 (x≥ 0) under light irradiation synergistically enhance the lithiation kinetics and electrochemical reversibility of both SnO2 and TiO2 . Specifically, the electrons can quickly pour into the SnO2 and the generated Sn due to the more positive conduction band potentials (vs TiO2 ), and mean while the holes also promote the intercalation of Li+ into TiO2 by reaching charge balance. A remarkable increase in areal specific capacity is therefore achieved from 1.91 to 3.47 mAh cm-2 at 5mA cm-2 . More impressively, there is no capacity loss even through 100 cycles, which is the best report for photorechargeable LIBs to date, owing to the strong and stable photoresponse current. This finding exhibits a feasible pathway to break the limitation in the energy density of LIBs by the efficient conversion and storage of solar energy.

Flexible Photocatalytic Electrode Using Graphene, Non‐noble Metal, and Organic Semiconductors for Hydrogen Evolution Reaction

Two kinds of visible light‐responsible organic semiconductors (epindolidione [EPI] and fluorinated EPI [2F‐EPI]) are synthesized. The solar hydrogen evolution photocatalytic electrode properties of the organic semiconductors are investigated and the heterostructure effect caused by manipulating the order of the deposition of 2F‐EPI and EPI is found, which increased the photoresponse current by reducing the carrier recombination of photoexcited electrons and holes. In addition, it is found that the deposition of Ni metal on the organic semiconductors further enhanced the photoresponse current and increased the durability of the organic semiconductor photocatalyst. Finally, a flexible photocatalytic electrode using graphene, organic semiconductors, and non‐noble metal cocatalyst for solar hydrogen generation is prepared. A transparent flexible electric conductive film is prepared by transfer of a graphene sheet on the polymer film. The graphene electrode is coated by two kinds of organic semiconductors layer by layer to reduce recombination of photoexcited electrons and holes. Ni metal particles are deposited on the surface of the organic semiconductor layer as a cocatalyst to improve the photocatalytic property and durability of organic semiconductors. A clear photoresponse current (about 4 μA cm−2) of the flexible photocatalytic electrode under the simulated solar light (AM 1.5 G, 100 mW cm−2) is observed.

Enhanced photovoltaic performance of dye-sensitized solar cells-based Carica papaya leaf and black cherry fruit co-sensitizers

Natural dye sensitizers are attractive as an alternative to expensive and rare organic sensitizers in dye-sensitized solar cells. The partial absorption of solar spectrum by solar cell-based natural dye negates its usefulness as the power conversion efficiency (PCE) is poor. Co-sensitization of two or more natural dyes with variant absorption spectra could be a feasible solution. Herein, Carica papaya leaf (P) and black cherry (B) fruit dye extracts were prepared and used as co-sensitizers at different volume concentration ratios (B:P=1:3, B:P=1:1 and B:P=3:1). The optical performance analysis shows that the light-harvesting ability of the device optimized after the co-sensitization at B:P=3:1 significantly improved. The DSSCs-based B and P show PCEs of 0.25% and 0.29%, respectively. The DSSC-based B:P=3:1 shows the highest PCE of 0.56%. Further investigation using cyclic voltammetry (CV) shows that DSSC-based B:P=3:1 has the smallest electron-injection barrier (ΔEe) among all the fabricated DSSCs while DSSC-based B has the highest ΔEe. Also, electrochemical impedance spectroscopy (EIS) reveals that the DSSC-based B:P=3:1 has the least charge flow resistance, thereby reducing charge recombination in the device. Meanwhile, the radius of the DSSCs-based B arc is the largest depicting presence of high charge flow resistance thereby increasing charge recombination in the device. The co-sensitizer, (B:P=3:1), compensates for absorption defects of single dye ((B or P) and improves the photo-response current. Also, it suppresses the charge recombination in the device and improves the PCE of the device.

Facile one-step deposition of ZnO-graphene nanosheets hybrid photoanodes for enhanced photoelectrochemical water splitting

ZnO-graphene nanosheets photoanodes were deposited at room temperature by a one-step kinetic spray process on a titanium sheet from micro-sized ZnO and graphite powders. ZnO-graphene nanosheet hybrid photoanodes with varying graphite contents were utilized for studying photoelectrochemical (PEC) water splitting. The Raman spectra revealed the direct transformation of micro-sized graphite powder to graphene nanosheets in all hybrid photoanodes after the deposition process, without any post-treatment. Surface morphology analysis revealed the fragmentation of the micro-sized flake morphology to morphology composed of mixed nanorods and nanosheets. The optical properties of the ZnO-graphene nanocomposites were investigated by the diffuse reflectance and photoluminescence (PL) emission spectroscopy, which revealed the decrease of the optical band gap and quenching of PL intensity. The hybrid photoanode with 50 wt% graphite content revealed the smallest bandgap of 2.6 eV and the lowest emission intensity compared with other hybrid photoanodes, which demonstrated the inhibition of photogenerated charge carrier recombination rate as well as an improvement in the visible-light-harvesting. The PEC results exhibited an improvement of the photocurrent with the incorporation of graphene nanosheets due to the improved photogenerated charge transfer kinetics and separation. The hybrid photoanode with 50 wt% graphite content revealed the highest photo-response current of 4.82 mAˑcm−2 corresponds to photoconversion efficiency of 3.25% @1.23 V vs. RHE.

Graphene-nanowalls/silicon hybrid heterojunction photodetectors

We study and fabricate graphene nanowalls/silicon hybrid heterojunction photoconductive detector to provide process technology of the device and theoretical foundation for the purpose of preparation of high-performance photodetectors. The graphene nanowalls (GNWs) film is patterned by double-layered photoresist-based photolithography and reactive ion etching (RIE) process to achieve high quality GNWs channel and fabricate three different GNWs/Si heterojunction photoconductive detectors with n-doped, intrinsic and p-doped silicon substrates (n-Si, i-Si, p-Si), respectively. The GNWs film not only acts as a photoconductive channel for carrier transport, but also constructs a Schottky heterojunction with the silicon to participate in the separation and transport of photogenerated carriers. Since the injection of holes needs to pass through the Schottky junction region, the height of the Schottky barrier determines the injection ability of photogenerated carriers, which directly affects the photoconductive gain of the GNWs and silicon. In addition, under low bias VDS, the GNWs/n-Si photoresponse current is maximum and the GNWs/p-Si photoresponse current is minimum. The photoresponse is attributed to the barrier heights of the GNWs/n-Si, GNWs/i-Si, and GNWs/p-Si with values of 0.73 eV, 0.69 eV, and 0.63 eV, respectively. The higher the barrier, the more the number of photogenerated carriers injected into the GNWs will be, and the photoresponse current is large as well.

Enhanced performance of flexible ultraviolet photodetectors based on carbon nitride quantum dot/ZnO nanowire nanocomposites

While the ZnO based ultraviolet (UV) photodetectors are generally restrained by the slow response and the weak photosensitivity, present work develops a facile method to fabricate flexible UV photodetectors with high device performance based on graphitic carbon nitride (g-C3N4) quantum dot/ZnO nanowire nanocomposites. The sensors are prepared by spin-coating method followed by annealing on flexible substrates, which exhibit remarkable responsivity of 355 mA W−1 under UV irradiation, a 1000% improvement over ZnO nanowire sensors (35.4 mA W−1). Both on/off ratio and photoresponse current are significantly improved by introducing g-C3N4 quantum dots compared with pure ZnO nanowire sensors. Current report provides a new choice for UV material system to efficiently improve sensor performance, and it could be easily scaled up for large scale applications.

Detailed characterization of good-quality SnS thin films obtained by chemical solution deposition at different reaction temperatures

A process for the chemical deposition of good-quality SnS thin films is presented. This process consists of a careful substrate sensitization; the placement of the substrate in a particular angle in the reaction solution; and the use of an aqueous reaction solution composed of stannous chloride, ethanol, triethanolamine, thioacetamide, and ammonium hydroxide. This process enables the deposition of good-quality SnS thin films that are homogenous and strongly adhered to the substrate, even at a temperature of 70 °C. The effect of reaction temperature (40, 45, 50, 55, 60, 65, and 70 °C) on the properties of the SnS thin films was studied by means of X-ray diffraction (including a Rietveld analysis), scanning electron microscopy, X-ray photoelectron spectroscopy, optical spectroscopy, and current photo-response. Rietveld analysis shows the presence of two tin sulfide orthorhombic phases (α-SnS and β-SnS) and a platelet-like microstructure with less than 20% of the total volume oriented in the (111) plane. Surface morphology confirms that grains have platey-like habits. It is found that with increasing reaction temperature the thin films increase in thickness, become more crystalline, and the conductivity photo-response improves, making the prepared SnS thin films suitable for optoelectronic applications.

Highly Polarized and Fast Photoresponse of Black Phosphorus‐InSe Vertical p–n Heterojunctions

AbstractThe van der Waals heterojunctions of 2D materials offer tremendous opportunities in designing and investigating multifunctional and high‐performance electronic and optoelectronic devices. In this study, a vertical p–n diode is constructed by vertically stacking p‐type few‐layer black phosphorus (BP) on n‐type few‐layer indium selenide (InSe). The photodetector based on the heterojunction displays a broadband and gate‐modulated photoresponse under illumination. More importantly, by taking advantage of the strong linear dichroism of BP, the device demonstrates a highly polarization‐sensitive photocurrent with an anisotropy ratio as high as 0.83. Additionally, the device can function in a zero‐bias photovoltaic mode, enabling a fast photoresponse and low dark current. The external quantum efficiency can reach ≈3%, which is impressive for BP‐based devices. The results pave the way for the implementation of p‐BP/n‐InSe heterostructure as a promising candidate for future multifunctional optoelectronics and, especially, polarization‐sensitive applications.

Graphite carbon nitride nanosheets decorated with ZIF-8 nanoparticles: Effects of the preparation method and their special hybrid structures on the photocatalytic performance

A highly efficient ZIF-8/g-C3N4 photocatalyst was prepared by a facile ultrasonic in-situ method. The structure-property relationship of ZIF-8/g-C3N4 composite was analysed by various characterization techniques. The comprehensive study illustrated that ZIF-8 served as an adsorbent to capture the substrates in the contaminated solution and increased the contact possibilities of the active species and substrates. The formation of ZIF-8/g-C3N4 hybrids helped to significantly enhance visible light absorption and facilitate charge transfer and separation of the photogenerated electron-hole pairs, eventually improving the photocatalytic efficiency. Meanwhile, compared with ZIF-8/g-C3N4 composites obtained by incipient wetness impregnation method, ultrasonic in-situ synthesis contributed to hindering the aggregation of g-C3N4 nanosheets and simultaneously promoting ZIF-8 well dispersed on the surface of g-C3N4 nanosheets. The synergistic effect of preparation method and special hybrid structure was studied in-depth and could significantly enhanced photocatalytic activity and stability for the degradation of organic pollutants (such as tetracycline, rhodamine B and methyl orange) under visible light irradiation. The reaction rate constant K values of optimal ratio sample for degradation of TC, RhB and MO were 0.039 min−1, 0.034 min−1 and 0.012 min−1, respectively 1.69, 3.96 and 4.10 times as big as that of pure g-C3N4. Meanwhile, the photoresponse current of optimal ratio sample was 3.3 μA/cm2, around 4.73 times as big as that of the pure g-C3N4. A reasonable photocatalytic mechanism was proposed by the photoelectrochemical experiments and the controlled experiments using radical scavengers.

Facile fabrication of In:Ge/Cu nano-octahedra film for improving photoelectrochemical properties

The novel In:Ge/Cu nano-octahedra photoelectric film, a kind of metal-semiconductor-metal (MSM) like structures, was prepared from by a facile two-step electrodeposition process, which In:Ge and Cu nano-octahedra were successively deposited on the indium tin oxide (ITO) substrates from aqueous solution. With the modification of Cu nano-octahedral, the photoresponse and photoactive current of the In:Ge films has significantly improved 88 flods under illuminations (wavelength range: 365, 532 and 805 nm). Notably, the In:Ge/Cu nano-octahedra films exhibit excellent photoelectrochemical properties in wide wavelength range from the UV to near-infrared. This novel photoelectric film shows great potential applications in optoelectronic devices and photodetectors, and the facilely synthesis route can provide an enlightening insight for the fabrication of photoelectric devices and high-performance energy conversion systems.