Heterojunction Nanostructures Research Articles

Study of Cu2O\\ZnO nanowires heterojunction designed by combining electrodeposition and atomic layer deposition

Cu2O\\ZnO nanowires (NWs) heterojunctions were successfully prepared by combining Atomic layer Deposition (ALD) and Electrochemical Deposition (ECD) processes. The crystallinity, morphology and photoconductivity properties of the Cu2O\\ZnO nanostructures have been investigated. The properties of the Cu2O absorber layer and the nanostructured heterojunction were studied in order to understand the mechanisms lying behind the low photoconductivity measured. It has been found that the interface state defects and the high resistivity of Cu2O film were limiting the photovoltaic properties of the prepared devices. The understanding presented in this work is expected to enable the optimization of solar cell devices based on Cu2O\\ZnO nanomaterials and improve their overall performance.

A novel ternary nanostructured carbonaceous-metal-semiconductor eRGO/NiO/α-Fe2O3 heterojunction photoanode with enhanced charge transfer properties for photoelectrochemical water splitting

A novel ternary hematite (α-Fe2O3)-based nanostructured photoanode with excellent photoelectrochemical (PEC) performance consisting of 2D-electrochemical reduced graphene oxide (eRGO) and nickel oxide (NiO) was successfully developed through electrodeposition synthesis method. Surface morphology studies showed that the flexible eRGO sheets provided intimate and coherent interfaces between α-Fe2O3, NiO, and eRGO that enhanced charge transfer properties and thus, lowering the recombination rate of photogenerated electron-hole pairs. The incorporation of eRGO and NiO has also endowed α-Fe2O3 nanostructured photoanode with a wider spectral absorption range, where the light absorption intensities in the visible light and near infrared regions were improved. Electrochemical impedance spectroscopy analysis further confirmed that the ternary eRGO/NiO/α-Fe2O3 nanostructured photoanode possessed the lowest charge transfer resistance among all as-synthesized photoanodes. This indicates that the combinatorial effects of eRGO and NiO could improve the electron mobility and prolong the recombination process of photogenerated charge carriers that result in enhanced PEC performance. In this instance, the eRGO sheets act as surface passivation layer and electron transporting bridge that increase the electrons transfer at the semiconductor/liquid junction. Whilst NiO serves as hole scavenger that also effectively hinders the recombination of photogenerated electron-hole pairs, and provides electron donor centres that accelerate the interfacial charge transfer. Finally, the hydrogen evolution rate from the ternary eRGO/NiO/α-Fe2O3 nanostructured photoanode was measured to be 92μmolh−1cm−2, which was about 3-fold higher than bare α-Fe2O3 nanostructured photoanode. It is expected that the fundamental understanding gained through this study is helpful for the rational design and construction of highly efficient ternary nanostructured heterojunction photoanodes for application in PEC water splitting.

Silicon nanowire array architecture for heterojunction electronics

Photosensitive nanostructured heterojunctions n-TiN/p-Si were fabricated by means of titanium nitride thin films deposition (n-type conductivity) by the DC reactive magnetron sputtering onto nano structured single crystal substrates of p-type Si (100). The temperature dependencies of the height of the potential barrier and series resistance of the n-TiN/p-Si heterojunctions were investigated. The dominant current transport mechanisms through the heterojunctions under investigation were determined at forward and reverse bias. The heterojunctions under investigation generate open-circuit voltage V oc = 0.8 V, short-circuit current I sc = 3.72 mA/cm2 and fill factor FF = 0.5 under illumination of 100 mW/cm2.

P-N depleted bulk BiOBr/α-Fe2O3 heterojunctions applied for unbiased solar water splitting.

P-N depleted bulk BiOBr/α-Fe2O3 heterojunction (DBH) nanostructures with the growth of (001) BiOBr facets were prepared via a simple hydrothermal method. BiOBr possesses an average thickness of around 50 nm and shows preferential exposure of the (001) facets. α-Fe2O3 nanoparticles, with an average diameter of 5 nm, are attached on the surface of BiOBr as 20-50 nm clusters with an intimate contact interface. Such DBH nanostructures show high hydrogen evolution, and 193 mmol g-1 of H2 is produced with DBH containing 1 wt% Pt, which is 6.3 times higher than that of α-Fe2O3 nanoparticles. The structural features of DBH are considered to be important to obtain attractive properties in photocatalytic water splitting.

Synthesis and thermoelectric properties of defect-containing PbSe–PbTe heterojunction nanostructures

Defect-containing and defect-free PbSe–PbTe heterogeneous (HNSs) nanostructures are synthesized. The strain distribution and defects in the interface of PbSe–PbTe HNSs affect the thermoelectric parameters of PbSe–PbTe HNSs.

Enhanced photoelectrochemical response of plasmonic Au embedded BiVO4/Fe2O3 heterojunction.

The effect of embedding Au nanoparticles (NPs) in a BiVO4/Fe2O3 heterojunction for photoelectrochemical water splitting is studied here for the first time. The present nanostructured heterojunction offers three major advantages over pristine BiVO4 and Fe2O3: (i) the formation of a heterojunction between BiVO4 and Fe2O3 enhances the charge carrier separation and transfer, (ii) the layer of Fe2O3 provides protection to BiVO4 from photocorrosion and, (iii) the Au NPs possessing surface plasmon resonance (SPR) enhance the photoelectrochemical response by transferring energy to metal oxides by hot electron transfer (HET) and plasmon resonant energy transfer (PRET). The present study reveals that the heterojunction ITO/BiVO4/Fe2O3 (with 32% v/v Au solution in both layers) gives the best performance and mitigates the limitations of both pristine Fe2O3 and BiVO4. A thirteen-fold increment in applied bias photon-to-current conversion efficiency (ABPE) was observed at 1.24 V vs. RHE under the condition of 1 Sun illumination. Monochromatic incident photon-to-current conversion efficiency (IPCE) measurements indicated that an Au embedded heterojunction is more effective in harvesting visible light in comparison to a heterojunction without Au NPs.

Silicon nanowire array architecture for heterojunction electronics

Photosensitive nanostructured heterojunctions n-TiN/p-Si were fabricated by means of titanium nitride thin films deposition (n-type conductivity) by the DC reactive magnetron sputtering onto nanostructured single crystal substrates of p-type Si (100). The temperature dependencies of the height of the potential barrier and series resistance of the n-TiN/p-Si heterojunctions were investigated. The dominant current transport mechanisms through the heterojunctions under investigation were determined at forward and reverse bias. The heterojunctions under investigation generate open-circuit voltage Voc=0.8 V, short-circuit current Isc=3.72 mA/cm2 and fill factor FF=0.5 under illumination of 100 mW/сm2. DOI: 10.21883/FTP.2017.04.44354.8407

Electrochemistry with Impact

ChemElectroChem is in its third year and is now established as one of the top electrochemistry journals worldwide. The journal has received its first (partial) impact factor of 3.506 from Thomson Reuters's Web of Knowledge, which is an excellent result. The ten most cited articles published so far are listed in Table 1. Authors Title Vol. Page Nos. X. Zhou, Y.-G. Guo Highly Disordered Carbon as a Superior Anode Material for Room-Temperature Sodium-Ion Batteries 1 83–86 Q. Wang , J. Xu, X. Wang, B. Liu, X. Hou, G. Yu, P. Wang, D. Chen, G. Shen Core–Shell CuCo2O4@MnO2 Nanowires on Carbon Fabrics as High-Performance Materials for Flexible, All-Solid-State, Electrochemical Capacitors 1 559–564 C. Costentin, J.-M. Savéant Multielectron, Multistep Molecular Catalysis of Electrochemical Reactions: Benchmarking of Homogeneous Catalysts 1 1226–1236 X. Hou, X. Wang, B. Liu, Q. Wang, Z. Wang, D. Chen, G. Shen SnO2@TiO2 Heterojunction Nanostructures for Lithium-Ion Batteries and Self-Powered UV Photodetectors with Improved Performances 1 108–115 I. Valov Redox-Based Resistive Switching Memories (ReRAMs): Electrochemical Systems at the Atomic Scale 1 26–36 H. Kim, K.-Y. Park, M.-Y. Cho, M.-H. Kim, J. Hong, S.-K. Jung, K. C. Roh, K. Kang High-Performance Hybrid Supercapacitor Based on Graphene-Wrapped Li4Ti5O12 and Activated Carbon 1 125–130 A. Chiappone, F. Bella, J. R. Nair, G. Meligrana, R. Bongiovanni, C. Gerbaldi Structure–Performance Correlation of Nanocellulose-Based Polymer Electrolytes for Efficient Quasi-solid DSSCs 1 1350–1358 R. Frydendal, E. A. Paoli, B. P. Knudsen, B. Wickman, P. Malacrida, I. E. L. Stephens, I. Chorkendorff Benchmarking the Stability of Oxygen Evolution Reaction Catalysts: The Importance of Monitoring Mass Losses 1 2075–2081 U. B. Nasini, V. G. Bairi, S. K. Ramasahayam, S. E. Bourdo, T. Viswanathan, A. U. Shaikh Oxygen Reduction Reaction Studies of Phosphorus and Nitrogen Co-Doped Mesoporous Carbon Synthesized via Microwave Technique 1 573–579 N. Yabuuchi, Y. Matsuura, T. Ishikawa, S. Kuze, J.-Y. Son, Y.-T. Cui, H. Oji, S. Komaba Phosphorus Electrodes in Sodium Cells: Small Volume Expansion by Sodiation and the Surface-Stabilization Mechanism in Aprotic Solvent 1 580–589 Of course, ChemElectroChem would not be successful without the support from you, our readers, authors and reviewers, as well as our society partners. So, many thanks to all of you. Here is to a successful 2017!

Conformally coated BiVO4 nanodots on porosity-controlled WO3 nanorods as highly efficient type II heterojunction photoanodes for water oxidation

Bismuth vanadate (BiVO4) has become a hot topic for solar hydrogen generation by water oxidation due to its appropriate band edges, and narrow band gap. However, the actual conversion efficiency achieved with BiVO4-based photoanodes is considerably less than the theoretical values because of drawbacks such as poor electron transportation and slow kinetics of oxygen evolution. In these respects, formation of nanostructured heterojunctions is considered to have a marked effect in terms of improving the photoactivities of BiVO4 photoanodes since it is possible to enhance the charge transfer at the interface and increase light absorption significantly. Herein, we report the synthesis and photoelectrochemical (PEC) properties of various BiVO4-based heterojunction anodes based on stoichiometric BiVO4 by pulsed electrodeposition. We show that WO3 is the optimum bottom layer for a type II band system with BiVO4 among various metal oxides. It is revealed that the photocurrent density of bare WO3 nanorods can be changed drastically by controlling the porosity and aspect ratio and thus BiVO4/WO3 heterojunction anodes show as similar tendency to bare WO3 nanorods. Under the optimum conditions, a BiVO4/WO3 heterojunction anode can lead to a high photocurrent density of 4.55mA/cm2 and an incident photon to current conversion efficiency of 80% at 1.23V versus a reversible hydrogen electrode without additional catalyst. Cross-sectional transmission electron microscopy shows that dot-like BiVO4 is well decorated on the entire surface of WO3 nanorods. This systematic study provides a viewpoint on the crucial role of the active area of the bottom layer for high-performance BiVO4-based type II heterojunction photoanodes, and the proposed concept is applicable to various photoelectrode systems.

Fabrication of 3D flower-like black N-TiO2-x@MoS2 for unprecedented-high visible-light-driven photocatalytic performance

As is well-known, it is a great challenge that the smooth TiO2 nanospheres are coated by MoS2 nanosheets to form the core-shell nanostructure owing to their poor interaction. Herein, we report 3D black N-TiO2-x@MoS2 core-shell nanostructures synthesized by a mild and effective strategy combined with a typical hydrothermal reaction and an in situ solid-state chemical reduction method followed by 350°C calcination under an argon atmosphere. The prepared samples are characterized in detail by X-ray diffraction, Raman, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The results suggest that the 3D N-TiO2-x@MoS2 photocatalyst is successfully doped with N and Ti3+, and simultaneously coupling with MoS2 to form the core-shell heterojunction nanostructure. The N and Ti3+ co-doped and hybrid heterostructures can effectively utilize visible-light and solar energy to degrade methyl orange and produce hydrogen. The degradation rate of methyl orange and the hydrogen production rate are as high as 91.8% and 1.882mmolh−1g−1. To the best of our knowledge, this work is the first instance of combining MoS2 with N and Ti3+ co-doped TiO2, and the proposed photocatalytic mechanism will provide a new perspective for high activity photocatalyst in future.

C/BCN core/shell nanotube films with improved thermoelectric properties

A proof-of-concept of the enhancement in thermoelectric properties using C/BCN core/shell nanotube heterojunctions has been reported. We demonstrated a scalable two-step reaction route to produce C/BCN core/shell nanotubes with bulk quantities. Systematic X-ray photoelectron spectroscopy (XPS) and atomic-scale high-resolution transmission electron microscope electron energy loss spectroscopy (HRTEM-EELS) characterizations indicate that the synthetic heterostructures with CNT core and BCN shell can be prepared by the developed method. Thermoelectric property measurements revealed that moderate BCN shell effectively improves the Seebeck coefficient, leading to a 6.4-fold increase in thermoelectric power factor of 0.64 μW/mK2. Our study provides a fundamental understanding for the rational design of nanostructured heterojunctions for improved thermoelectric properties of carbon-based materials.

High-resolution noncontact AFM and Kelvin probe force microscopy investigations of self-assembled photovoltaic donor-acceptor dyads.

Self-assembled donor–acceptor dyads are used as model nanostructured heterojunctions for local investigations by noncontact atomic force microscopy (nc-AFM) and Kelvin probe force microscopy (KPFM). With the aim to probe the photo-induced charge carrier generation, thin films deposited on transparent indium tin oxide substrates are investigated in dark conditions and upon illumination. The topographic and contact potential difference (CPD) images taken under dark conditions are analysed in view of the results of complementary transmission electron microscopy (TEM) experiments. After in situ annealing, it is shown that the dyads with longer donor blocks essentially lead to standing acceptor–donor lamellae, where the acceptor and donor groups are π-stacked in an edge-on configuration. The existence of strong CPD and surface photo-voltage (SPV) contrasts shows that structural variations occur within the bulk of the edge-on stacks. SPV images with a very high lateral resolution are achieved, which allows for the resolution of local photo-charging contrasts at the scale of single edge-on lamella. This work paves the way for local investigations of the optoelectronic properties of donor–acceptor supramolecular architectures down to the elementary building block level.

Graphitic Carbon Nitride (g-C3N4)-Based Photocatalysts for Artificial Photosynthesis and Environmental Remediation: Are We a Step Closer To Achieving Sustainability?

As a fascinating conjugated polymer, graphitic carbon nitride (g-C3N4) has become a new research hotspot and drawn broad interdisciplinary attention as a metal-free and visible-light-responsive photocatalyst in the arena of solar energy conversion and environmental remediation. This is due to its appealing electronic band structure, high physicochemical stability, and "earth-abundant" nature. This critical review summarizes a panorama of the latest progress related to the design and construction of pristine g-C3N4 and g-C3N4-based nanocomposites, including (1) nanoarchitecture design of bare g-C3N4, such as hard and soft templating approaches, supramolecular preorganization assembly, exfoliation, and template-free synthesis routes, (2) functionalization of g-C3N4 at an atomic level (elemental doping) and molecular level (copolymerization), and (3) modification of g-C3N4 with well-matched energy levels of another semiconductor or a metal as a cocatalyst to form heterojunction nanostructures. The construction and characteristics of each classification of the heterojunction system will be critically reviewed, namely metal-g-C3N4, semiconductor-g-C3N4, isotype g-C3N4/g-C3N4, graphitic carbon-g-C3N4, conducting polymer-g-C3N4, sensitizer-g-C3N4, and multicomponent heterojunctions. The band structures, electronic properties, optical absorption, and interfacial charge transfer of g-C3N4-based heterostructured nanohybrids will also be theoretically discussed based on the first-principles density functional theory (DFT) calculations to provide insightful outlooks on the charge carrier dynamics. Apart from that, the advancement of the versatile photoredox applications toward artificial photosynthesis (water splitting and photofixation of CO2), environmental decontamination, and bacteria disinfection will be presented in detail. Last but not least, this comprehensive review will conclude with a summary and some invigorating perspectives on the challenges and future directions at the forefront of this research platform. It is anticipated that this review can stimulate a new research doorway to facilitate the next generation of g-C3N4-based photocatalysts with ameliorated performances by harnessing the outstanding structural, electronic, and optical properties for the development of a sustainable future without environmental detriment.

A solar light driven dual photoelectrode photocatalytic fuel cell (PFC) for simultaneous wastewater treatment and electricity generation

In this paper, a novel dual heterojunction Photocatalytic Fuel Cell (PFC) system based on BiVO4/TiO2 nanotubes/FTO photoanode and ZnO/CuO nanowires/FTO photocathode has been designed. Compared with the electrodes in PFCs reported in earlier literatures, the proposed heterojunction not only enhances the visible light absorption but also offers a higher photoconversion efficiency. In addition, the nanostructured heterojunction owns a large surface area that ensures a large amount of active sites for organics degradation. The performance of the PFC base on the dual photoelectrodes was also studied herein. The results indicated that the PFC in ths paper exhibits a superior performance and its JVmax reached 0.116mwcm−2, which is higher than that in most of reported PFCs with a Pt-free photocathode. When hazardous organic compounds such as methyl orange, Congo red and methylene blue were decomposed, the degradation rates obtained is to be 76%, 83%, and 90% respectively after 80 mins reaction. The proposed heterojunction photoelectrodes provided great potential for cost-effective and high-efficiency organic pollutants degradation and electricity generation in a PFC system.

Hierarchical core/shell ZnO/NiO nanoheterojunctions synthesized by ultrasonic spray pyrolysis and their gas-sensing performance

ZnO nanorod arrays decorated with NiO nanosheets on FTO substrates were prepared via a simple ultrasonic spray pyrolysis process combined with chemical bath method. The synthesized samples were characterized and analyzed by scanning electron microscopy and X-ray diffraction. The hierarchical and porous morphologies of ZnO/NiO core–shell nanoheterojunctions could be controlled by changing the growth time of NiO sheets. The “oriented attachment” and “self-assembly” crystal growth mechanisms were proposed to explain the formation of the ZnO/NiO nanostructures. Sensors based on the ZnO/NiO heterojunction nanostructure were fabricated and investigated for their ethanol-sensing properties. The result indicated that response was about 180% toward 100 ppm ethanol at an operating temperature of 200 °C. The growth approach in this work offers a new technique for the design and synthesis of transition metal oxide hierarchical nanoarrays which are promising for gas sensing applications.

Particle-on-Film Gap Plasmons on Antireflective ZnO Nanocone Arrays for Molecular-Level Surface-Enhanced Raman Scattering Sensors.

When semiconducting nanostructures are combined with noble metals, the surface plasmons of the noble metals, in addition to the charge transfer interactions between the semiconductors and noble metals, can be utilized to provide strong surface plasmon effects. Here, we suggest a particle-film plasmonic system in conjunction with tapered ZnO nanowire arrays for ultrasensitive SERS chemical sensors. In this design, the gap plasmons between the metal nanoparticles and the metal films provide significantly improved surface-enhanced Raman spectroscopy (SERS) effects compared to those of interparticle surface plasmons. Furthermore, 3D tapered metal nanostructures with particle-film plasmonic systems enable efficient light trapping and waveguiding effects. To study the effects of various morphologies of ZnO nanostructures on the light trapping and thus the SERS enhancements, we compare the performance of three different ZnO morphologies: ZnO nanocones (NCs), nanonails (NNs), and nanorods (NRs). Finally, we demonstrate that our SERS chemical sensors enable a molecular level of detection capability of benzenethiol (100 zeptomole), rhodamine 6G (10 attomole), and adenine (10 attomole) molecules. This work presents a new design platform based on the 3D antireflective metal/semiconductor heterojunction nanostructures, which will play a critical role in the study of plasmonics and SERS chemical sensors.

Broadband All-Polymer Phototransistors with Nanostructured Bulk Heterojunction Layers of NIR-Sensing n-Type and Visible Light-Sensing p-Type Polymers.

We report ‘broadband light-sensing’ all-polymer phototransistors with the nanostructured bulk heterojunction (BHJ) layers of visible (VIS) light-sensing electron-donating (p-type) polymer and near infrared (NIR) light-sensing electron-accepting (n-type) polymer. Poly[{2,5-bis-(2-ethylhexyl)-3,6-bis-(thien-2-yl)-pyrrolo[3,4-c]pyrrole-1,4-diyl}-co-{2,2′-(2,1,3-benzothiadiazole)]-5,5′-diyl}] (PEHTPPD-BT), which is synthesized via Suzuki coupling and employed as the n-type polymer, shows strong optical absorption in the NIR region (up to 1100 nm) in the presence of weak absorption in the VIS range (400 ~ 600 nm). To strengthen the VIS absorption, poly(3-hexylthiophene) (P3HT) is introduced as the p-type polymer. All-polymer phototransistors with the BHJ (P3HT:PEHTPPD-BT) layers, featuring a peculiar nano-domain morphology, exhibit typical p-type transistor characteristics and efficiently detect broadband (VIS ~ NIR) lights. The maximum corrected responsivity (without contribution of dark current) reaches up to 85 ~ 88% (VIS) and 26 ~ 40% (NIR) of theoretical responsivity. The charge separation process between P3HT and PEHTPPD-BT components in the highest occupied molecular orbital is proposed as a major working mechanism for the effective NIR sensing.

Non-fullerene electron acceptors for use in organic solar cells.

ConspectusThe active layer in a solution processed organic photovoltaic device comprises a light absorbing electron donor semiconductor, typically a polymer, and an electron accepting fullerene acceptor. Although there has been huge effort targeted to optimize the absorbing, energetic, and transport properties of the donor material, fullerenes remain as the exclusive electron acceptor in all high performance devices. Very recently, some new non-fullerene acceptors have been demonstrated to outperform fullerenes in comparative devices. This Account describes this progress, discussing molecular design considerations and the structure–property relationships that are emerging.The motivation to replace fullerene acceptors stems from their synthetic inflexibility, leading to constraints in manipulating frontier energy levels, as well as poor absorption in the solar spectrum range, and an inherent tendency to undergo postfabrication crystallization, resulting in device instability. New acceptors have to address these limitations, providing tunable absorption with high extinction coefficients, thus contributing to device photocurrent. The ability to vary and optimize the lowest unoccupied molecular orbital (LUMO) energy level for a specific donor polymer is also an important requirement, ensuring minimal energy loss on electron transfer and as high an internal voltage as possible. Initially perylene diimide acceptors were evaluated as promising acceptor materials. These electron deficient aromatic molecules can exhibit good electron transport, facilitated by close packed herringbone crystal motifs, and their energy levels can be synthetically tuned. The principal drawback of this class of materials, their tendency to crystallize on too large a length scale for an optimal heterojunction nanostructure, has been shown to be overcome through introduction of conformation twisting through steric effects. This has been primarily achieved by coupling two units together, forming dimers with a large intramolecular twist, which suppresses both nucleation and crystal growth. The generic design concept of rotationally symmetrical aromatic small molecules with extended π orbital delocalization, including polyaromatic hydrocarbons, phthalocyanines, etc., has also provided some excellent small molecule acceptors. In most cases, additional electron withdrawing functionality, such as imide or ester groups, can be incorporated to stabilize the LUMO and improve properties. New calamitic acceptors have been developed, where molecular orbital hybridization of electron rich and poor segments can be judiciously employed to precisely control energy levels. Conformation and intermolecular associations can be controlled by peripheral functionalization leading to optimization of crystallization length scales. In particular, the use of rhodanine end groups, coupled electronically through short bridged aromatic chains, has been a successful strategy, with promising device efficiencies attributed to high lying LUMO energy levels and subsequently large open circuit voltages.

One-pot facile synthesis of branched Ag-ZnO heterojunction nanostructure as highly efficient photocatalytic catalyst

In this paper, the branched Ag-ZnO heterojunction nanostructure and the branched ZnO were synthesized successfully by a facile, green and one-pot hydrothermal method. Such branched heterojunction and the comparing branched pure ZnO were characterized by X-ray diffraction, field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), energy-dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), photoluminescence spectroscopy (PL) and UV–vis diffuse reflectance spectra (DRS). The photocatalytic degradation of RhB aqueous solution and acetaldehyde (CH3CHO) gas results both showed that the branched Ag-ZnO heterojunction possessed the enhanced photocatalytic properties in comparison to the branched ZnO and Ag-ZnO counterparts due to its special interface structures and fast separation of its photogenerated charge carriers. This method is simple, feasible and can provide an important clue for synthesis and application of other branched metal/semiconductor heterojunction nanostructures.

Solar Fuel Generation By 1D ZnO /QDs Heterostructures

Nowadays, with the crisis of the fossil fuels’ depletion and the pollution from these fuels’ combustion, there is a huge demand for clean and sustainable energy source, which makes solar energy extremely appealing. Using a photoelectrochemical cell (PEC) with the semiconductor as a photoanode, the solar energy could be absorbed, converted and stored in hydrogen via water splitting. One-dimensional (1D) nanostructured semiconductors, as a photoanode, are promising with their advantage in photon absorption and charge transport. The solar fuel efficiency could be increased using the hybridized Quantum Dots-1D nanostructure heterojunction. Herein we report the fabrication of QDs/ZnO 1D heterostructure for solar fuel generation. Such band alignment not only extends the light harvesting up to near infrared region, but also forces the forward transfer of the charge carriers, which improves the charge separation and suppresses the charge recombination, and thus ensures the high efficiency. Such 1D nanostructures provide great opportunities for the realization of the solar cell commercialization.