Large Band Bending Research Articles

Novel CoFe2O4 / LaAlO3 nanocomposites: An impressive photocatalyst with p-n hetero-junction for improved H2 generation under visible exposure

The present work is devoted to the synthesis of perovskite LaAlO3 by Sol-Gel approach and its application for the photo-evolution of H2 in conjunction with cobalt ferrite CoFe2O4 prepared by nitrate route. The thermal analysis (TG/DSC) showed that the formation is completed at 600 °C. The X-ray diffraction (XRD) pattern is characteristic of a single phase, crystallizing in a rhombohedral symmetry with a crystallite size of 36 nm. The SEM micrographs revealed a homogeneous structure with an agglomeration of shaped grains (40–80 nm). The forbidden band (3.39 eV), calculated from diffuse reflectance data, is assigned to the ligand charge transfer O2−: 2p → Al3+: 3s orbital. As prepared, LaAlO3 is an n-type semiconductor as demonstrated from the capacitance - potential (C−2 - E) graph with an electron density of 9.4 × 1014 cm−3 due to oxygen under-stoichiometry. Attention was directed to photo-electrochemistry in connection with water reduction into hydrogen. With a negative conduction band potential (−0.11 VSCE), H2 generation can be synergized over the hetero-system by visible light. The photocatalytic capability of CoFe2O4 25%/LaAlO3 revealed a high H2 generation of 963 μmol g−1 in the alkaline electrolyte (NaOH, 0.1 M) with a catalyst dose of 1 mg mL−1, which is 1.3 times more than CoFe2O4 under similar conditions. Photoactivity is significantly improved by 60%, up to 2400 μmol g−1 in the presence of oxalate C2O42− as a hole scavenger in the hetero-junction, two hydrogen release tests were successfully recorded. The higher H2 production in the hetero-junction system is attributed to the lower recombination rate of electron/hole (e−/h+) in the material, due to the large band bending at the solid interfacial.

An Interface-cascading Silicon Photoanode with Strengthened Built-in Electric Field and Enriched Surface Oxygen Vacancies for Efficient Photoelectrochemical Water Splitting.

To promote interfacial charge transfer process and accelerate surface water oxidation reaction kinetics for photoelectrochemical (PEC) water splitting over n-type Silicon (n-Si) based photoanodes, herein, starting with surface stabilized n-Si/CoOx , a NiOx /NiFeOOH composite overlayer was coated by atomic layer deposition and spray coating to fabricate the multilayer structured n-Si/CoOx /NiOx /NiFeOOH photoanode. Encouragingly, the obtained n-Si/CoOx /NiOx /NiFeOOH photoanode exhibits much increased PEC activity for water splitting, with onset potential cathodically shifted to ~0.96 V vs. RHE and photocurrent density increased to 22.6 mA cm-2 at 1.23 V vs. RHE for OER, as compared to n-Si/CoOx , even significantly surpassing the counterpart n-Si/CoOx /NiOx /FeOOH and n-Si/CoOx /NiOx /NiOOH photoanodes. Photophysical and electrochemical characterizations evidence that the deposited CoOx /NiOx /NiFeOOH composite overlayer would create large band bending and strong built-in electric field at the introduced cascading interfaces, thereby producing a large photovoltage of 650 mV to efficiently accelerate charge transfer from the n-Si substrate to the electrolyte for water oxidation. Furthermore, the surface oxygen vacancy enriched NiFeOOH overlayer could effectively catalyze the water oxidation reaction by thermodynamically reducing the energy barrier of rate determining step for OER.

External catalyst-free InGaN photoelectrode for highly efficient energy conversion and H2 generation

GaN is a well-known material whose energy band edges can straddle the redox potentials deep in the visible and infrared wavelengths, thereby promising a drastically improved photon-to-current efficiency under applied bias. However, the material is still limited by the half-reactions of water splitting due to its high defect density, low light absorption, small reaction area, and large energy band bending. Here, our study provides a turn-key solution to all these issues. The synergistic effect of InGaN/GaN quantum pyramids on nanowires (QPs-NWs) directly addresses the performance degradation of the photocathodes (PCs). New InGaN QP structures on non-polar GaN nanowire show a unique tunable energy band (Eg: ∼2 eV to ∼1.36 eV) by quantum-sliding interface recombination effect. Without the use of external catalysts, the photoelectrochemical water splitting (PEC-WS) of QPs-NWs PC demonstrated enhanced performance with a current density of 34.36 mA cm−2 and a photon-to-current efficiency of 13.75 % under the −0.8 to 0 V applied biasing condition, which is much higher than in previous reports. The current density and the H2 production were measured to be ∼61.81 mA cm−2 and 11.5 mmol cm−2 for 10 h. The external catalyst-free electrode and the metal organic chemical vapor deposition (MOCVD) process will open a new platform for the commercialization of III-nitride based water splitting hydrogen technology.

A Comparative Analysis of Cavity Positions in Charge Plasma based Tunnel FET for Biosensor Application

This work reports a comparative analysis of different cavity positions in Charge Plasma-based Tunnel Field Effect Transistor (CP TFET) for Biosensor Application. In CP TFET, we have created a nanogap cavity at three different positions i.e. the Source, Gate, and Drain. The nanogap cavity formed at Source, Gate, and Drain is called Source Cavity, Gate Cavity, and Drain Cavity, respectively. The intrinsic properties of biomolecules, such as dielectric constant (K) and charge density (o̧), have been utilized to detect the biomolecules in the cavity. The source and drain region are formed by appropriate metal work functions using the charge plasma concept. The presence of biomolecules in the cavity increases the effective capacitance of the device. As a result, a high electric field generates under the cavity region. Consequently, due to large band bending, thinning of tunneling width occurred. Therefore, the increase in tunneling rate enhances the drive current of the device. The device physics has been analyzed using energy band variation, surface potential, electron tunneling rate, electric field, and transfer characteristics for different biomolecules. In addition, the Sensitivity of the device at different cavity positions has been investigated and compared in terms of ION, ION/IOFF, Vth, and SS. Furthermore, the sensitivity of the proposed device is compared with the existing literature and the possible fabrication process flow of the device has also been presented in this work.

High open-circuit voltage in single-crystalline n-type SnS/MoO3 photovoltaics

It has been recently reported that n-type single crystalline SnS exhibits a large band bending (∼1 eV) at the interface with MoO3, which is a large work function material. In this study, we applied this interface to solar cells for the first time and evaluated its photovoltaic properties. The highest VOC achieved was 437 mV. Although this value is the highest ever recorded for SnS solar cells, it was lower than the expected value of 700–800 mV. The highest power conversion efficiency (PCE) was 4.4%. Based on an analysis of the device parameters, we propose methods for improving the device performance, including VOC, the short-circuit current, and PCE. The carrier-collection length of the n-type SnS single crystals was estimated to be ∼200 nm based on the external quantum efficiency measurements. Therefore, this study demonstrates that the VOC of SnS solar cells can be improved by fabricating a junction with MoO3 thin films.

Enlightening the bimetallic effect of Au@Pd nanoparticles on Ni oxide nanostructures with enhanced catalytic activity

Bimetallic decoration of semiconductor electrodes typically improves catalytic and sensing performances because of a well-claimed synergistic effect. A microscopic and quantitative investigation of such an effect on energy bands of semiconductor can be really useful for further exploitation. Au, Pd and Au@Pd (core@shell) nanoparticles (10–20 nm in size) were synthesized through chemical reduction method and characterized with scanning and transmission microscopy, Rutherford backscattering spectrometry, cyclic voltammetry electrochemical impedance spectroscopy and Mott–Schottky analysis. The nanoparticles have been used to decorate Ni-based nanostructured electrodes with the aim to quantitatively investigate the effect of decoration with mono or bimetallic nanoparticles. Decorated electrodes show higher redox currents than bare ones and a shift in redox peaks (up to 0.3 V), which can be ascribed to a more efficient electron transport and improved catalytic properties. These effects were satisfactorily modeled (COMSOL) employing a nano Schottky junction at the nanoparticle–semiconductor interface, pointing out large energy band bending (up to 0.4 eV), space charge region and local electric field (up to {10}^{8}mathrm{ V }{mathrm{m}}^{-1}) in bimetallic decoration. Sensing test of glucose and H2O2 by decorated Ni oxide electrodes were performed to consolidate our model. The presence of bimetallic nanoparticles enhances enormously the electrochemical performances of the material in terms of sensitivity, catalytic activity, and electrical transport. The modification of energy band diagram in semiconductor is analyzed and discussed also in terms of electron transfer during redox reactions.

Schottky barrier effect on plasmon-induced charge transfer.

Plasmon-induced charge transfer causes electron-hole spatial separation at the metal-semiconductor interface, which plays a key role in photocatalytic and photovoltaic applications. The Schottky barrier formed at the metal-semiconductor interface can modify the hot carrier dynamics. Taking the Ag-TiO2 system as an example, we have investigated plasmon-induced charge transfer at the Schottky junction using quantum mechanical simulations. We find that the Schottky barrier induced by n-type doping enhances the electron transfer and that induced by p-type doping enhances the hole transfer, which is attributed to the shift of the Fermi energy and the band bending of the Schottky junction at the interface. The Schottky barrier also modifies the layer distribution of hot carriers. In particular, for the system with a large band bending, there exists electron-hole spatial separation inside the TiO2 substrate. Our results reveal the mechanism and dynamics of charge transfer at the Schottky junction, and pave the way for manipulating plasmon-assisted photocatalytic and photovoltaic applications.

Ohmic contacts of the two-dimensional Ca2N/MoS2 donor-acceptor heterostructure.

In the current stage, conventional silicon-based devices are suffering from the scaling limits and the Fermi level pinning effect. Therefore, looking for low-resistance metal contacts for semiconductors has become one of the most important topics, and two-dimensional (2D) metal/semiconductor contacts turn out to be highly interesting. Alternatively, the Schottky barrier and the tunneling barrier impede their practical applications. In this work, we propose a new strategy for reducing the contact potential barrier by constructing a donor-acceptor heterostructure, that is, Ca2N/MoS2 with Ca2N being a 2D electrene material with a significantly small work function and a rather high carrier concentration. The quasi-bond interaction of the heterostructure avoids the formation of a Fermi level pinning effect and gives rise to high tunneling probability. An excellent n-type Ohmic contact form between Ca2N and MoS2 monolayers, with a 100% tunneling probability and a perfect linear I-V curve, and large lateral band bending also demonstrates the good performance of the contact. We verify a fascinating phenomenon that Ca2N can trigger the phase transition of MoS2 from 2H to 1T'. In addition, we also identify that Ohmic contacts can be formed between Ca2N and other 2D transition metal dichalcogenides (TMDCs), including WS2, MoSe2, WSe2, and MoTe2.

Low voltage AC electroluminescence in silicon MOS capacitors

Low power silicon based light source and detector are attractive for on-chip photonic circuits given their ease of process integration. However, conventional silicon light emitting diodes emit photons with energies near the band edge where the corresponding silicon photodetectors lack responsivity. On the other hand, previously reported hot carrier electroluminescent silicon devices utilizing a reverse biased diode require high operating voltages. Here, we investigate hot carrier electroluminescence in silicon metal–oxide–semiconductor capacitors operating under transient voltage conditions. During each voltage transient, large energy band bending is created at the edge of the source contact, much larger than what is achievable at a steady state. As a result, electrons and holes are injected efficiently from a single source contact into the silicon channel at the corresponding voltage transient, where they subsequently undergo impact ionization and phonon-assisted interband recombination. Notably, we show low voltage operation down to 2.8 V by using a 20 nm thick high-κ gate dielectric. We show further voltage scaling is possible by reducing the gate dielectric thickness, thus presenting a low voltage platform for silicon optoelectronic integrated circuits.

Hematite surfaces: Band bending and local electronic states

Hematite is a promising material for photoelectrochemical water splitting applications and understanding the complete mechanism of water oxidation reaction close to its surfaces is of great importance. Herein, we present a theoretical investigation of the electronic states of nonstoichiometric hematite(0001) films in the presence of absorbed H on the surfaces, as well as Ti doping. The calculations, performed at the $\text{DFT}+U$ level, indicate that iron can appear in different oxidation states, from ${\mathrm{Fe}}^{2+}$ to ${\mathrm{Fe}}^{4+}$ and ${\mathrm{Fe}}^{5+}$ in the vicinity of impurities or surfaces. The electron and hole distributions in hematite slabs could control the bending and local state of valence and conduction bands. The projected density of states in different atomic positions shows an upward band bending close to the surfaces, which varies with the number of absorbed H or with Ti doping. In the dark, the width of the depletion layer is computed as less than 12 \AA{} for neutral slabs, while adding excess electrons expands it to involve more atomic layers, depending on the number of absorbed H on the surface. In the neutral slabs in the presence of H, we obtain an upward band bending of 0.18, 0.42, and 0.24 eV by increasing the number of H from one to three on each side, respectively. The evolution of bands in neutral slabs, with/without Ti doping, occurs in a few layers in nearby the surface and also Fe with an oxidation state rather than ${\mathrm{Fe}}^{3+}$. According to our results, doping Ti creates a polaron and locally affects the band structure. In the charged surface with excess electrons, a metallic behavior is observed on the surface and a large band bending in the middle layers. This work shows that a substantial upward bending of the bands in hematite can exist even at neutral surfaces in contact with a vacuum.

Two-Step Process of a Crystal Facet-Modulated BiVO4 Photoanode for Efficiency Improvement in Photoelectrochemical Hydrogen Evolution.

The photoactivity of nanoporous bismuth vanadate (BiVO4, BVO) photoanodes that were fabricated by a two-step process (electrodeposition and then thermal conversion) in photoelectrochemical (PEC) hydrogen (H2) evolution can be enhanced about 1.44-fold by improving the constitutive ratio of (111̅), (061), and (242̅) crystal facets. The PEC characterization was carried out to investigate the factors altering the performance, which revealed that the crystal facet modulation could improve the photoactivity of the BVO photoanodes. In addition, the orientation-controlled BVO thin-film electrodes are introduced as evidence that the present crystal facet modulation is the positive effect for BVO photoanodes in PEC. The investigation of energy band structures and interfacial charge carrier dynamics of the BVO photoanodes reveals that the crystal facet modulation could result in a shorter lifetime of charge carrier recombination and larger band bending at the interface between BVO and electrolytes. This outcome could improve the charge separation and charge transfer efficiencies of BVO photoanodes, promoting the efficiency of PEC H2 evolution. Moreover, this crystal facet modulation can combine with co-catalyst decoration to further improve the solar-to-hydrogen efficiency of BVO photoanodes in PEC. This study presents a potential strategy to promote the PEC activity by crystal facet modulation and important insights into the interfacial charge transfer properties of semiconductor photoelectrodes for the application in solar fuel generation.

Effect of defect-rich Co-CeOx OER cocatalyst on the photocarrier dynamics and electronic structure of Sb-doped TiO2 nanorods photoanode

This work demonstrates the in-depth mechanism of enhanced photoelectrochemical (PEC) water oxidation of Sb-doped rutile TiO2 nanorods (NRs) photoanode coupled with oxygen vacancy defect-rich Co-doped CeOx (Co-CeOx) oxygen evolution reaction (OER) cocatalyst. The defect-rich Co-CeOx cocatalyst modification improves the conductivity, light absorption, charge transfer efficiency, and surface photovoltage generation of the Co-CeOx/Sb-TiO2 hybrid NRs photoanode. The Co-CeOx cocatalyst also serves as the surface passivating overlayer for the Sb-TiO2 photoanode, which suppresses the surface states mediated recombination of electron-hole pairs in the NRs. The PEC studies further indicate that Co-CeOx cocatalyst induces remarkably large band bending at the semiconductor/electrolyte interface and shortens the carrier diffusion length and depletion layer width, facilitating the rapid separation and transportation of the photocarriers for the surface PEC reactions. The experimental and theoretical studies confirm that the Co-doping in CeOx cocatalyst enhances the surface oxygen vacancy defects, which provides active catalytic sites for OH− adsorption and charge transportation for enhanced OER kinetics. The density functional theory (DFT) calculations demonstrate a higher conductivity of the Co-CeOx cocatalyst, advantageous for rapid charge transfer capability during PEC reactions. The synergy between all these merits helps the optimized Co-CeOx/Sb-TiO2 photoanode to deliver a maximum photocurrent density of 1.41 mA cm−2 at 1.23 V vs. reversible hydrogen electrode (VRHE) and an ultra-low turn on potential (Von) of 0.1 VRHE under AM 1.5G solar illumination compared to the Sb-TiO2 NRs (0.96 mA cm−2 at 1.23 VRHE and Von = 0.42 VRHE). This work demonstrates the design of an efficient defect-rich cocatalyst modified photoanode for solar energy harvesting.

Li-based selenized Cu2ZnSnS4 surface: Possible route to overcoming voc-deficit of kesterite solar cells

Usually, open-circuit voltage (Voc) of thin film solar cells significantly depends on the band bending at the front interface of an absorber/buffer. The failed band bending at a Cu2ZnSnS4/CdS (CZTS/CdS) interface severely hinders the increase in Voc due to the excessively high concentration of holes at the CZTS side. Alleviating the strong p-type or converting it to weak n-type at the CZTS surface is a credible idea to overcome the Voc− deficit. First-principles calculations show that the Li-based selenized CZTS surface presents the desired property with excellent advantages: (i) The greatly improved defects and band offset suppress carrier nonradiative recombination and facilitate electrons transmission, respectively. (ii) Its intrinsic weak n-type characteristic effectively promotes the large band bending at the interface.

Unoccupied electronic states of 2D Si on Ag--Si(111)

Optimizing substrate characterization to grow 2D Si layers on surfaces is a major issue toward the development of synthesis techniques of the promising silicene. We have used inverse photoemission spectroscopy (IPES) to study the electronic band structure of an ordered 2D Si layer on the -Ag/Si(111) surface (-Ag). Exploiting the large upwards band bending of the -Ag substrate, we could investigate the evolution of the unoccupied surface and interface states in most of the Si band gap. In particular, the k ∥-dispersion of the -Ag free-electron-like S 1 surface state measured by IPES, is reported for the first time. Upon deposition of ∼1 ML Si on -Ag maintained at ∼200 °C, the interface undergoes a metal-insulator transition with the complete disappearance of the S 1 state. The latter is replaced by a higher-lying state U 0 with a minimum at 1.0 eV above E F. The origin of this new state is discussed in terms of various Si 2D structures including silicene.

Enhancement of photoresponse in Bi2Se3/graphene heterostructures by effective electron–hole separation through internal band bending

Topological insulators (TIs) have been investigated as attractive candidates for the channels and contact metals of high-performance photodetectors over a broad spectral range. To achieve excellent photoresponse performances, several suggestions regarding material selection, various heterostructures, and proper device structure have been proposed. Here, we investigated the photoresponse of Bi2Se3/graphene heterostructures in lateral photodetectors. Graphene, with similar lattice symmetry, can improve the crystallinity of grown Bi2Se3 films, as well as induce large internal band bending with Bi2Se3, thereby causing electron–hole (e–h) separation. By comparing the photoresponses in vertical Bi2Se3 stack structures grown on various substrates, we conclude that the significantly improved photoresponse in the Bi2Se3/graphene stack structure results from graphene-induced internal band bending. Moreover, by investigating the thickness dependence of the Bi2Se3/graphene heterostructures on photoresponse, the maximum photoresponse is determined to be the result of an enhanced e–h separation caused by internal band bending and limiting of the optical penetration depth. As a well-matched stack structure based on band bending and the crystal growth system, TI/graphene heterostructures with stable and excellent photoresponse abilities can be considered as attractive candidates to attain outstanding performances for optoelectronic applications.

Manipulating metal-oxygen local atomic structures in single-junctional p-Si/WO3 photocathodes for efficient solar hydrogen generation

Self-passivation in aqueous solution and sluggish surface reaction kinetics significantly limit the photoelectrochemical (PEC) performances of silicon-based photoelectrodes. Herein, a WO3 thin layer is deposited on the p-Si substrate by pulsed laser deposition (PLD), acting as a photocathode for PEC hydrogen generation. Compared to bare p-Si, the single-junctional p-Si/WO3 photoelectrodes exhibit excellent and stable PEC performances with significantly increased cathodic photocurrent density and exceptional anodic shift in onset potential for water reduction. It is revealed that the WO3 layer could reduce the charge transfer resistance across the electrode/electrolyte interface by eliminating the effect of Fermi level pinning on the surface of p-Si. More importantly, by varying the oxygen pressures during PLD, the collaborative modulation of W-O bond covalency and WO6 octahedral structure symmetry contributes to the promoted charge carrier transport and separation. Meanwhile, a large band bending at the p-Si/WO3 junction, induced by the optimized O vacancy contents in WO3, could provide a photovoltage as high as ∼ 500 mV to efficiently drive charge transfer to overcome the water reduction overpotential. Synergistically, by manipulating W-O local atomic structures in the deposited WO3 layer, a great improvement in PEC performance could be achieved over the single-junctional p-Si/WO3 photocathodes for solar hydrogen generation.

Coupling behaviors of large lattice mismatch interfaces between hexagonal ZnO and cubic (001)MgO

The combination of materials with large lattice mismatch due to different phase structures plays a significant role on designing devices. Precise control of heteroepitaxial thin films is still a big challenge because of the ambiguous understanding of the interfacial coupling behaviors. Here, by combing of molecular beam epitaxy and X-ray reflection diffraction techniques, as well as the density function theory method, we investigate the mechanisms of large mismatch interface coupling behaviors by taking ZnO film heteroepitaxial on cubic MgO(001) substrate. The X-ray reflection diffraction pole figures show a two- and four-fold rotations for the c- and m-plane ZnO films respectively. The density function theory calculations show the interface energy of c-plane ZnO is larger than that of the m-plane, and the interface azimuthal registry is determined by the interaction energy between epitaxy layers and substrates. Moreover, the evolution of the density of states crossover the interfaces shows a large band bending at the polar interface due to the internal spontaneous field.

Dramatically improved electron transport performance by a deep triangular potential well in organic field-effect transistors

Overcoming the intrinsic properties of organic molecules to achieve high device performance, particularly for electron transport, is a challenge in the field of organic semiconductor device physics. Energy-band engineering in modern inorganic electronics has been introduced in organic electronics. Here, we utilized Al2O3 and PbO metal-oxide layers as dielectric modification layers and fabricated high-quality organic heterojunction films with large band bending and sharp interfaces. The large band bending indicated a deeper triangular potential well, which can confine more electrons and form a high carrier density organic two-dimensional electron gas. A sharp heterojunction interface can reduce interface carrier transport scattering and crystal lattice defects and can retain uniform interfacial electronic structures. These two features of organic heterojunctions are the key factors to realize energy-band engineering in organic electronics. By using these heterojunction films as active layers in organic field-effect transistors, the transistors exhibited a high electron mobility of approximately 8 cm2 V−1 s−1. Therefore, we demonstrated the feasibility and solutions of energy-band engineering in organic electronics, and provided a novel strategy to improve device performance.

Junction energetics engineering using Ni/NiOx core-shell nanoparticle coating for efficient photoelectrochemical water splitting

We report a sparse Ni/NiOx core-shell nanoparticle coating on an n-GaN photoanode that yields a high photocurrent by engineering junction energetics. A conventional thin film coating of high work function NiOx induces a large band bending that helps generate high photovoltage. However, the high work function causes a Fermi level downshift and compromises photopotential. The discrete core-shell nanoparticle coating balances these two effects. The Ni core creates localized large band bending to produce a high photovoltage. Meanwhile, the reduced coating surface area decreases Fermi level downshift. The resulting higher photopotential together with the catalytic NiOx shell enables a photocurrent 50% higher than NiOx thin film coating and multiple times higher than Ni nanoparticle or film coating. The localized large band bending also forms a potential well to deplete holes from semiconductor, thereby providing full surface protection against corrosion. This core-shell nanoparticle coating demonstrates a new junction energetics engineering paradigm useful for photoelectrode optimization.

Cascading Interfaces Enable n-Si Photoanodes for Efficient and Stable Solar Water Oxidation.

Interfaces with multifunctions for promoted solid/solid interfacial charge-transfer dynamics and accelerated solid/electrolyte interfacial water redox reaction kinetics are determinative for the photoelectrodes achieving high performances for photoelectrochemical (PEC) water splitting. In this work, well-designed cascading interfaces are introduced in the n-Si photoanode, which is effectively protected by an atomic layer-deposited CoO x thin layer for stabilizing the n-Si photoanode and then coated with an earth-abundant NiCuO x layer for catalyzing the water oxidation reaction. Furthermore, the formed n-Si/CoO x/NiCuO x triple junction could generate a large band bending to provide a considerable photovoltage for promoting the photoinduced charge-transfer and separation processes at the n-Si/CoO x/NiCuO x cascading interfaces. Moreover, at the NiCuO x/electrolyte interface, an in situ electrochemically formed NiCu(OH) x/NiOOH active layer facilitates the water oxidation reaction kinetics. This study demonstrates an alternative approach to stabilize and catalyze n-Si-based photoanodes with cascading interfaces for efficient solar water oxidation.