Intensity-modulated Photocurrent Spectroscopy Research Articles

BiVO4 Photoanode with NiV2O6 Back Contact Interfacial Layer for Improved Hole-Diffusion Length and Photoelectrochemical Water Oxidation Activity.

The short hole diffusion length (HDL) and high interfacial recombination are among the main drawbacks of semiconductor-based solar energy systems. Surface passivation and introducing an interfacial layer are recognized for enhancing HDL and charge carrier separation. Herein, we introduced a facile recipe to design a pinholes-free BiVO4 photoanode with a NiV2O6 back contact interfacial (BCI) layer, marking a significant advancement in the HDL and photoelectrochemical activity. The fabricated BiVO4 photoanode with NiV2O6 BCI layer exhibits a 2-fold increase in the HDL compared to pristine BiVO4. Despite this improvement, we found that the front surface recombination still hinders the water oxidation process, as revealed by photoelectrochemical (PEC) studies employing Na2SO3 electron donors and by intensity-modulated photocurrent spectroscopy measurements. To address this limitation, the surface of the NiV2O6/BiVO4 photoanode was passivated with a cobalt phosphate electrocatalyst, resulting in a dramatic enhancement in the PEC performance. The optimized photoanode achieved a stable photocurrent density of 4.8 mA cm-2 at 1.23 VRHE, which is 12-fold higher than that of the pristine BiVO4 photoanode. Density Functional Theory (DFT) simulations revealed an abrupt electrostatic potential transition at the NiV2O6/BiVO4 interface with BiVO4 being more negative than NiV2O6. A strong built-in electric field is thus generated at the interface and drifts photogenerated electrons toward the NiV2O6 BCI layer and photogenerated holes toward the BiVO4 top layer. As a result, the back-surface recombination is minimized, and ultimately, the HDL is extended in agreement with the experimental findings.

Modulating Interfacial Charge Transfer Behavior through the Construction of a Hetero-Interface for Efficient Photoelectrochemical Water Splitting

Surface-coupled transition metal oxyhydroxide (TMOOH) on semiconductor (SC)-based photoanodes are effective strategies for improving photoelectrochemical (PEC) performance. However, there is a substantial difference between the current density and theoretical value due to the inevitable interfacial charge recombination of SC/TMOOH. Here, we employ BiVO4/FeNiOOH as a model, constructing the BiVO4/MnOx/CoOx/FeNiOOH integrated system by introducing a novel hetero-interface regulation unit, i.e., MnOx/CoOx. As expected, the optimized integrated system demonstrates a photocurrent density as high as 5.0 mA/cm2 at 1.23 V versus the reversible hydrogen electrode (RHE) under 1 sun AM 1.5G illumination, accompanied by 12-h stability. The detailed electrochemical analysis and intensity modulated photocurrent spectroscopy (IMPS) have confirmed that the high PEC performance mainly originates from the hetero-interface structure, which not only suppresses the interfacial charge recombination by accelerating the photogenerated hole transfer kinetics from BiVO4 to FeNiOOH but promotes the kinetics of surface oxygen evolution reaction (OER). Notably, these findings can also be extended to other structures (CeOx/CoOx), reflecting its universality. This finding has provided a new insight into the highly efficient solar energy conversion in the SC/TMOOH system.

Fabrication of TiO2 photoelectrodes doped with copper and zirconium to improve electron generation and flow in dye-sensitized solar cell

Dye-sensitized solar cell (DSSC) are devices that convert solar light into electricity using a semiconductor substance, e.g. TiO2. Although DSSC are environmentally friendly and economical, they exhibit a low energy conversion efficiency. In this study, to improve its energy conversion efficiency, a DSSC in which TiO2 was doped with transition metals (TMs) such as Cu and Zr was fabricated by a sol–gel method. Doping with TMs extended the light-absorption range of TiO2 to the visible-light region, generating more electrons and improving electrical conductivity. The successful doping of Cu, Zr in the fabricated photoelectrode was confirmed by X-ray diffraction (XRD) and FESEM–energy dispersive X-ray spectroscopy (EDS) analyses, and doping with Cu, Zr increased the dye adsorption amount and current density of DSSC. In addition, the electron-transfer resistance was confirmed to be reduced by electrochemical impedance spectroscopy (EIS) analysis, and the electron movement, speed, and lifetime were improved by Intensity-modulated photocurrent spectroscopy (IMPS) and intensity-modulated photovoltage spectroscopy (IMVS) analyses. The electrical properties of the Cu, Zr-doped TiO2 photoelectrodes were determined from the chemical capacitance and recombination resistance calculations, and the results revealed that the efficiency was improved by Cu, Zr doping. In conclusion, the Cu, Zr doping of the photoelectrode improved the electron generation and flow of TiO2, thereby increasing the energy conversion efficiency of the DSSC by up to 3.28%

P-Type DSSCs by sensitizing a benzofuran[b]-fused BODIPY with cyanoacrylic acid

We found that a benzofuran[b]-fused 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) with cyanoacrylic acid (1) served as a photosensitizer for p-type dye-sensitized solar cells (DSSCs). The photovoltaic parameters (short circuit current density = 3.57 mA cm2, open circuit voltage = 0.12 V, fill factor = 0.33, and power conversion efficiency = 0.14%) were obtained with a 1-loaded NiO photocathode under AM 1.5 conditions. The incident photon-to-current efficiency spectrum showed excellent photo-harvesting capability, with a significant band at approximately 600 nm. Time-dependent density functional theory (TD-DFT)/DFT calculations indicated that electron distributions of both the HOMO and LUMO levels spread over the benzofuran-fused BODIPY core, mainly owing to π-π* transition. It is noteworthy that 1 served as a photosensitizer for p-type DSSC, despite almost no push-pull sensitizers. The hole transport and recombination processes were investigated by using intensity-modulated photocurrent spectroscopy and intensity-modulated photovoltage spectroscopy. This study demonstrates that the local excitation (LE) character of dye is significantly workable for p-type sensitization, which may contribute to surpass recombination.

Comparing Charge Dynamics in Organo-Inorganic Halide Perovskite: Solid-State versus Solid-Liquid Junctions

In this study, we explore the dynamics of a perovskite-electrolyte photoelectrochemical cell, pivotal for advancing electrolyte-gated field effect transistors, water-splitting photoelectrochemical and photocatalytic cells, supercapacitors, and CO2 capture and reduction technologies. The instability of hybrid perovskite materials in aqueous electrolytes presents a significant challenge, yet recent breakthroughs have been achieved in stabilizing organo-inorganic halide perovskite films. This stabilization is facilitated by employing liquid electrolytes, specifically those formed by dissolving tetrabutylammoniumperchlorate in dichloromethane. A critical aspect of this research is the comparative analysis of charge and ion kinetics at the perovskite/liquid electrolyte interface versus the perovskite/solid charge transport layer interface. Employing Intensity Modulated Photocurrent Spectroscopy (IMPS), Open-Circuit Voltage Decay (OCVD), and Capacitance-Frequency (C-F) methods, the study scrutinizes charge dynamics in both perovskite/electrolyte and perovskite/solid interfaces. Furthermore, the investigation extends to contrasting the properties of solid–liquid and solid-state junctions, focusing on mobile ions, electric field impacts, and electron-hole transport. The research also examines variations in recombination resistance and ionic double layer charging in perovskite-based devices, aiming to elucidate the operational mechanisms and kinetic complexities at the hybrid perovskite/electrolyte interface.

Intensity-Modulated Photocurrent Spectroscopy Measurements of High-Efficiency Perovskite Solar Cells.

Frequency domain characterization has long served as an important method for the examination of diverse kinetic processes that occur in solar cells. In this study, we investigated the dynamic response of high-efficiency perovskite solar cells utilizing ultra-low-intensity-modulated photocurrent spectroscopy. Distinctive intensity-modulated photocurrent spectroscopy (IMPS) attributes were detected only as a result of this low-intensity modulation, and their evolution under light and voltage bias was investigated in detail. We generally observed only two arcs in the Q-plane plots and attributed the smaller, low-frequency arc to trap-dominated charge transport in the device. Light and voltage bias-dependent measurements confirm this attribution. An equivalent circuit model was used to better understand the features and trends of these measurements and to validate our physical interpretation of the results. Additionally, we tracked the IMPS response of one of the cells over time and showed that slow degradation impacts the size and attributes of the low-frequency arc. Finally, we found that changes in the IMPS response correlate closely with the current versus voltage characteristics of the devices.

Probing Intra-Gap States Mediated Charge Dynamics of Rh-Doped Rutile TiO2 Photocatalyst by Light-Modulated Photocurrent Spectroscopies.

The intra-gap states that are introduced into a semiconducting photocatalyst via dopants and other defects have significant implications on the transport dynamics of photoexcited electrons and holes during an aqueous light-driven reaction. In this work, mechanistic understanding of Rh-doped rutile, a promising photocatalyst for hydrogen production from water, is gained by systematic assessment combining intensity-modulated photocurrent spectroscopy with sub-gap excitations and alternating-current photocurrent spectroscopy. These operando techniques not only help in discovering a new electronic transport path in Rh-rutile via surface Rh4+ species and elucidating complex interaction between electrolyte molecules and semiconductors, but also underscore the potential of utilizing multiple sub-gap excitations synergistically. This combination offers a powerful tool for acquiring insight into photo-physical and photo-chemical behaviors of photo(electro)catalysts with intra-gap states.

InGaN based Schottky barrier solar cell: Study of the temperature dependence of electrical characteristics

The indium gallium nitride (InGaN) semiconductor alloy shows great promise for high-efficiency thin-film solar cells due to its intrinsic characteristics. However, there are major challenges in the development of high-quality p-doped and indium-rich InGaN layers to fabricate a pn or pin solar cell. This study focuses on the development of an alternative structure, not requiring p-doping, with a Schottky contact on n-type InGaN. The InGaN absorber was grown by metalorganic chemical vapor deposition and its structural, morphological and optical properties studied. Structural analysis by X-ray diffraction showed the growth of single crystal layers without phase separation. Indium compositions which vary up to around 8.3 % were confirmed by transmission measurements. The formation of V-shaped pits was observed with increased indium composition at lower growth temperatures. Schottky diodes based on InGaN with platinum metallic contacts were fabricated and their current–voltage characteristics studied in detail as a function of temperature. This analysis of the conduction mechanisms in Schottky/InGaN devices permitted in particular the extraction of the diode parameters as a function of the temperature showing a high rectification with an ideality factor of 1.15 with reverse saturation current of 6.7×10−9A at room temperature for an indium composition of 5.52 %. In addition, the analysis revealed the presence of a dual Gaussian distribution of barrier heights in a specific temperature range. Finally, the incident photon-to-electron conversion efficiency (IPCE) of the fabricated InGaN Schottky solar cells, measured using intensity-modulated photocurrent spectroscopy, reached a peak value of 51 %, which is among the highest published values for InGaN based solar cells.

Exploring the role of Ti3C2TxMXene in photoelectrochemical water splitting over solution-processed BiVO4 photoanode

Transition metal carbides, nitrides, or carbonitrides known as MXenes commonly improve the efficiency of photo(electro)catalysts, but their role is still not fully explored. Herein, we developed a novel and facile solution-processing method to fabricate BiVO4 and Ti3C2Tx-modified BiVO4 (Ti3C2Tx/BiVO4) photoanodes to explore the role of Ti3C2Tx MXene in photoelectrochemical water splitting. The charge transfer and recombination kinetics were studied by transient open-circuit potential, transient photocurrent, photoelectrochemical impedance spectroscopy, and intensity-modulated photocurrent spectroscopy. It was demonstrated that Ti3C2Tx forms a Schottky-like junction at the BiVO4/Ti3C2Tx interface and that it acts as a hole transport/storage layer. The Ti3C2Tx layer creates a built-in electric field at the surface that increases the band bending and space charge layer width, eventually enhancing the charge separation efficiency. Modification of Ti3C2Tx/BiVO4 with a water oxidation catalyst such as cobalt phosphate (Co-Pi) was essential to deliver the maximum photocurrent. For instance, the Co-Pi/Ti3C2Tx/BiVO4 photoanode delivered 4.72 mA/cm−2 at 1.23 VRHE, which is 2- and 11-fold higher than those of Ti3C2Tx/BiVO4 and pristine BiVO4 photoanodes, respectively. This study provides a practical protocol for fabricating Ti3C2Tx/BiVO4 and reveals the role of MXene in photoelectrochemical water splitting.

Unraveling the impact of tetravalent and pentavalent ions on the charge dynamics of hematite photoelectrodes for solar water splitting

This study focuses on understanding the impact of tetravalent (Hf4+) and pentavalent (Nb5+) ions in hematite photoelectrodes using a two-step synthesis approach. Structural, morphological, and compositional analyses confirms that Nb5+ is segregated over the hematite crystal surface while Hf4+ is allocated over the crystal surface and between the fluorine-doped tin oxide substrate (FTO)-hematite interface. Our results indicate that the modifier insertion led to substantial improvements in overall efficiency and photoelectrochemical (PEC) performance. However, it creates additional surface states, as evidenced by shifts in the anodic onset potential (Vonset) observed in the linear sweep voltammetry curves. For Nb-modified photoelectrodes, Vonset shift of ∼20 mV with respect to hematite was observed and confirmed by intensity modulated photocurrent spectroscopy (IMPS). For Hf-modified hematite, this Vonset shift is more pronounced (∼30 mV). When combined with NiFeOx, Nb5+ acted synergistically showing a 4-fold efficiency increase compared to hematite and ∼70 mV cathodic shift in the Vonset. Otherwise, NiFeOx showed no significant impact in the Hf4+ modified hematite photoelectrodes, suggesting that Hf4+ role lies in enhancing electron collection at the FTO-hematite interface. This study not only sheds light on the charge dynamics of modified hematite photoelectrodes but also provides strategies for boosting the PEC devices efficiency.

Experimental and theoretical studies on improving the efficiency of ZnO-based dye-sensitized solar cells using single-layer anti-reflective coating

The effect of a single-layer anti-reflective coating (ARC) on ZnO-based dye-sensitized solar cells (DSSCs) is theoretically predicted and verified by experimental fabrication. By the transfer matrix method (TMM), the absorption of the DSSC with and without the single-layer ARC is calculated and the improvement in short-circuit current density (∆ Jsc%) is estimated. The optimized thickness of the ARC required to obtain maximum improvement in the short-circuit current density (∆ Jsc%) is determined. By employing ARC with the calculated optimized thickness, the fabrication of spin-coated ZnO-based DSSCs is carried out. The structural and optical parameters are studied using XRD analysis and UV absorption spectra. The efficiency of the DSSC with and without the ARC is measured by intensity-modulated photocurrent and photovoltage spectroscopy. The theoretically predicted efficiency of the DSSC with and without ARC agrees well with the experimental values that provide insights about improving the electrical performance of the DSSC by the ARC.

Anodic Oxidation of Tungsten under Illumination-Multi-Method Characterization and Modeling at the Molecular Level.

Tungsten oxide has received considerable attention as photo-anode in photo-assisted water splitting due to its considerable advantages such as significant light absorption in the visible region, good catalytic properties, and stability in acidic and oxidative conditions. The present paper is a first step in a detailed study of the mechanism of porous WO3 growth via anodic oxidation. In-situ electrochemical impedance spectroscopy (EIS) and intensity modulated photocurrent spectroscopy (IMPS) during oxidation of W illuminated with UV and visible light are employed to study the ionic and electronic processes in slightly acidic sulfate-fluoride electrolytes and a range of potentials 4-10 V. The respective responses are discussed in terms of the influence of fluoride addition on ionic and electronic process rates. A kinetic model is proposed and parameterized via regression of experimental data to the EIS and IMPS transfer functions.

Sn-Doped Hematite Films as Photoanodes for Photoelectrochemical Alcohol Oxidation

Here, the modification of semiconductor thin film hematite photoanode by doping with Sn ions is reported. Undoped and Sn-doped hematite films are fabricated by the electrochemical deposition of FeOOH from aqueous alkaline electrolyte, followed by calcination in air. The photoanodes were tested in photoelectrocatalytic oxidation of water, methanol, ethylene glycol, and glycerol. It is shown that modification by tin dramatically increased the activity of hematite in the photoelectrochemical oxidation of alcohols upon visible light irradiation. The photoelectrocatalytic activity of Sn-modified hematite increased in the sequence of: H2O < MeOH < C2H2(OH)2 < C3H5(OH)3. The quantum yield of photocurrent in the oxidation of alcohols reached 10%. The relatively low photocurrent yield was ascribed to the recombination of photoexcited holes within the hematite layer and on surface states located at the hematite/electrolyte interface. Intensity-modulated photocurrent spectroscopy (IMPS) was used to quantify the recombination losses of holes via surface states. The IMPS results suggested that the hole acceptor in the electrolyte (alcohol) influences photocurrent both by changing the charge transfer rate in the photoelectrooxidation process and by the efficient suppression of the surface recombination of generated holes. Thin-film Sn-modified hematite photoanodes are promising instruments for the photoelectrochemical degradation of organic pollutants.

Organic-inorganic p-type PEDOT:PSS/CuO/MoS2 photocathode with in-built antipodal photogenerated holes and electrons transfer pathways for efficient solar-driven photoelectrochemical water splitting

Organic PEDOT:PSS thin film and n-type MoS2 flakes were incorporated on CuO photocathode as the underlying layer and surface co-catalysts, respectively, establishing a rationally-designed novel integrated structure of PEDOT:PSS/CuO/MoS2. The organic-inorganic interface of PEDOT:PSS/CuO effectively shuttles photogenerated holes towards the FTO/PEDOT:PSS junction. Furthermore, the surface MoS2 co-catalysts form a p-n junction with CuO, which accelerates the transport of photogenerated electrons towards the photocathode/electrolyte junction, in addition to providing more reactive sites for the H2 evolution reaction. These synergistically formed antipodal charge transfer pathways have led to improved charge separation, rapid interfacial charge transfer kinetics and impeded electron-hole recombination in the PEDOT:PSS/CuO/MoS2 photocathode, which can achieve a photocurrent density of – 2.26 mA/cm2 at −0.6 V vs Ag/AgCl (2.1 times higher than that of the bare CuO photocathode). Analytical characterisations, electrochemical impedance spectroscopy (EIS) and intensity-modulated photocurrent spectroscopy (IMPS), also provide supporting evidence for its dramatically enhanced PEC water splitting performance.

Photoelectrocatalytic Activity of ZnO-Modified Hematite Films in the Reaction of Alcohol Degradation.

Thin-film nanocrystalline hematite electrodes were fabricated by electrochemical deposition and loaded with electrodeposited zinc oxide in various amounts. Under visible light illumination, these electrodes demonstrate high activity in the photoelectrochemical degradation of methanol, ethylene glycol and, in particular, glycerol. Results of intensity-modulated photocurrent spectroscopy show that the photoelectrocatalysis efficiency is explained by the suppression of the electron-hole pair recombination and an increase in the rate of photo-induced charge transfer. Thus, zinc oxide can be considered an effective modifying additive for hematite photoanodes.

Interfacial engineering of hematite photoanodes toward high water splitting performance

Efficient and scalable photoelectrochemical water splitting electrode designs are a challenge. This study focuses on hafnium-modified hematite (X%Hf-HEM) photoanodes, prepared via spin-coating polymeric precursor solutions with varying Hf4+/Fe3+ (mol) ratios (1.0%, 3.0%, 4.0%, and 5.0%) onto fluorine-doped tin oxide substrates. Structural, morphological, and compositional analyses confirm pure hematite phases in all X%Hf-HEM samples. Increasing Hf4+ content correlated with reduced grain size, thickness, and surface roughness due to Hf4+ segregation at grain boundaries during thermal treatment. Hafnium segregation at hematite grain boundaries and hematite|fluorine-doped tin oxide interfaces is confirmed using scanning transmission electron microscopy coupled with energy dispersive spectroscopy. Notably, the 4%Hf-HEM photoanode exhibits exceptional efficiency enhancement, outperforming HEM efficiency by 4.5 times. Gas chromatography results highlight O2 and H2 evolution rates of 14.49 ± 0.09 μmol/cm2/h and 8.1 ± 0.5 μmol/cm2/h, respectively, for 4%Hf-HEM, with a H2/O2 ratio close to 2:1. The charge dynamics investigated from intensity-modulated photocurrent spectroscopy evidence the main Hf4+ effect of improving charge separation, achieving greater efficiency for 4%Hf-HEM. Shifts in valence band maximum from ultraviolet photoelectron spectroscopy measurements indicate surface state presence, supported by ηtransfer trends calculated from intensity-modulated photocurrent spectroscopy. This research presents a scalable, cost-effective approach to multiinterface photoanode development, holding promise for innovative photoelectrochemical water splitting technologies.

Fast Photoresponse from Hybrid Monolayer MoS2/Organic Photodetector

As a direct‐bandgap transition semiconductor with high carrier mobility, monolayer (ML) transition metal dichalcogenides (TMDCs) have attracted significant attention as a promising class of material for photodetection. It is reported that these layers exhibit a persistent photoconductance (PPC) effect, which is assigned to long‐lasting hole capture by deep traps. Therefore, TMDCs‐based photodetectors show a high photoresponse but also a slow response. Herein, intensity‐modulated photocurrent spectroscopy (IMPS) with steady‐state background illumination is performed to investigate the photoresponse dynamics in a hybrid photodetector based on ML MoS2 covered with an ultrathin layer of phthalocyanine (H2Pc) molecules. The results demonstrate that adding the H2Pc layer speeds up the photoresponse of the neat ML‐MoS2 photodetector by almost two orders of magnitude without deteriorating its responsivity. The origin of these improvements is revealed by applying the Hornbeck–Haynes model to the photocarrier dynamics in the IMPS experiment. It is shown that the improved response speed of the hybrid device arises mostly from a faster detrapping of holes in the presence of the H2Pc layer, while the trap densities remain rather unchanged. Meanwhile, the additional absorption of photons in the H2Pc layer contributes to photocarrier generation, resulting in an enlarged responsivity of the hybrid device.

Thin-Film Nanocrystalline Zinc Oxide Photoanode Modified with CdO in Photoelectrocatalytic Degradation of Alcohols

Thin-film nanocrystalline zinc oxide electrodes were fabricated by electrochemical deposition of ZnO on FTO-coated glass slides. ZnO electrodes were promoted by CdO coating on top of ZnO in amounts corresponding to 0.8, 0.1, and 0.05 C cm−2 in electric units. Modification of ZnO by a small amount of CdO, corresponding to 0.05 C cm−2, shifts the photoactivity of the composite photoanode into the visible part of the solar spectrum. It is shown that the ZnO/(0.05C)CdO/FTO electrode demonstrates high efficiency in photoelectrochemical degradation of methanol, ethylene glycol, and glycerol when irradiated by a simulated sunlight. According to intensity-modulated photocurrent spectroscopy (IMPS), the effect is due to suppression of the electron–hole pairs recombination and increase in the rate of photo-induced charge transfer. Therefore, thin-film photoanodes based on zinc oxide modified by CdO can be used for photoelectrochemical degradation of byproducts of biofuel production glycerol, and of other alcohols.

Nb/TiO2 oxides: A study of synthesis and electron transport mechanism as an ETL in a solar device

Efficient solar devices to energy conversion are the key to a sustainable future. TiO2 dye solar cells are systems that present limited energy conversion efficiency due to recombination reactions. An alternative to reduce the back-electron recombination is the insertion of new oxides in electron transport material, such as Nb. However, what are the changes in electron lifetime and collection time caused by Nb insertion in TiO2 photoanodes? This work aims to analyze TiO2 dye solar devices with different Nb proportions synthesized by an easy and low-cost particle preparation methodology, Pechini. The techniques performed were X-ray Diffraction (XRD), Scanning Electronic Microscopy (SEM), and X-ray fluorescence to particle characterization. To the electrochemical analysis of the cells, j-V curves, Electrochemical Impedance Spectroscopy (EIS), charge extraction, Intensity Modulated Photovoltage Spectroscopy (IMVS), and Intensity-Modulated Photocurrent Spectroscopy (IMPS) were performed. The results showed a mix of anatase and rutile phase to TiO2 with Nb insertion and at the 5% of Nb proportion has been able to generate a cell with better electrochemical parameters (PCE = 5.43 %; j = 6.34 mA cm−2). The creation of energy substates below the conduction band has been able to increase the collection time (0.1748 s) and electron lifetime (0.15514 s) when compared to the cell with bare TiO2, suppressing the back-electron recombination but also difficulting the collection reaction.

Photoanode with enhanced performance achieved by a novel charge modulation strategy without sacrificial agents

Although the catalytic effect can be enhanced by using sacrificial agents, it still faces numerous difficulties in large-scale production applications. Investigating the improvement of photocatalytic efficiency without sacrificial agents is therefore crucial. This study proposes a cost-effective and efficient photochemical modification system that utilizes a seed layer of BiVO4 to improve photoelectrochemical (PEC) performance, the result shows that the photocurrent density of BiVO4 with a seed layer thickness of 312 nm was improved by 40% to 0.99 mA cm−2 at 1.23 VRHE without any sacrificial agent. Meanwhile, Electrochemical impedance spectroscopy (EIS) and intensity modulated photocurrent spectroscopy (IMPS) demonstrated that the introduction of the seed layer effectively prevents the recombination of electron-hole pairs and improves the charge transfer efficiency, leading to a “slow” decrease in the current density of the composite photoanode (from 32% to 9.8%) in combination with the linear sweep voltammetry (LSV) results. We exhibit the scanning photoelectrochemical microscopy (SPECM) method to in-situ quantitatively study the hole transfer kinetics with different seed layer thicknesses using the feedback model and find those photoelectrodes with a thickness of 312 nm has the highest kinetic rate constant of 0.62 × 10−2 cm s−1 which is approximately 5 times higher than that of the pristine photoelectrode (0.11 × 10−2 cm s−1).