BiVO4 Film Research Articles

The significant role of few sulfite replenishment in boosting electricity generation and organic wastewater degradation in photocatalytic fuel cell

The performance of electricity generation and organic wastewater degradation are two important indicators to evaluate photocatalytic fuel cell (PFC). However, data related to the impact of sulfite, especially few sulfite replenishment on PFC properties are scare. In this paper, a porous sheet-like BiVO4 photoanode was first prepared and then a self-biasing BiVO4-Au/BJS (BJS: buried junction silicon) PFC is constructed. The results show that the BiVO4 film exhibited an optimal water splitting photocurrent density of 1.15 mA cm−2 at 1.23 V vs. RHE. The PFC system can be operated without any external bias and showed high converting performance of organic into electricity. With the total addition of only 2 mM sulfite, a short-circuit current density of 0.61 mA cm−2, which is obviously higher than the BiVO4-Au/BJS system without sulfite, was obtained with maximum power output of 6.5 × 10−4 W cm−2 in 10 mg L−1 methyl orange. Furthermore, a removal ratio of 93.78% after 2 h was achieved with stable current output in the degradation process, compared with the removal ratio of 40.63% without sulfite. More importantly, TOC removal ratio also increased sharply from 30.2% to 85.4%. EPR test demonstrates that radicals including OH and SO4− cogenerated in system.

High‐Quality Coating of Conformal and Oriented Metal–Organic Framework Cocatalyst Layer for Efficient Photoelectrocatalysis

AbstractMetal–organic frameworks (MOFs) as cocatalyst for photoelectrochemical (PEC) water splitting is promising but still in its infancy due to the challenge to fabricate high‐quality MOFs coated photoelectrodes. Herein, a successive ionic layer adsorption and reaction (SILAR) method is used to fabricate high‐quality conformal and ultrathin MOFs overlayer with preferred orientation on nanoporous BiVO4 films. 20 molecular monolayers of Co‐MOF coated BiVO4 photoanodes exhibit 3.1‐folds of photocurrent density in comparison with pristine BiVO4. The onset potential shows a negative shift of 320 mV. To further demonstrate the extensibility of SILAR method, the alternative Co‐MOF and Ni‐MOF coated BiVO4 photoanodes deliver an enhanced photocurrent density of 2.97 mA cm−2. The PEC performance achieved rivals the reported results of BiVO4 and MOF hybrid photoanodes. The PEC improvements should be attributed to the high‐quality conformal and ultrathin MOFs overlayer, which can efficiently passivate the surface states of BiVO4, and accelerate the hole transfer through Co‐MOF layer. Three critical roles of Co‐MOF overlayer are elaborately revealed. In contrast, hydrothermally prepared BiVO4/Co‐MOF photoanodes possess inferior PEC performance, such as the photocurrent, and stability. This work clearly demonstrates SILAR method is a simple and efficient approach to realize conformal and ultrathin MOF coating with high‐quality.

BiVO4 Ceramic Photoanode with Enhanced Photoelectrochemical Stability.

Monoclinic bismuth vanadate (BiVO4) is an attractive material with which to fabricate photoanodes due to its suitable band structure and excellent photoelectrochemical (PEC) performance. However, the poor PEC stability originating from its severe photo-corrosion greatly restricts its practical applications. In this paper, pristine and Mo doped BiVO4 ceramics were prepared using the spark plasma sintering (SPS) method, and their photoelectrochemical properties as photoanodes were investigated. The as-prepared 1% Mo doped BiVO4 ceramic (Mo-BVO (C)) photoanode exhibited enhanced PEC stability compared to 1% Mo doped BiVO4 films on fluorine doped Tin Oxide (FTO) coated glass substrates (Mo-BVO). Mo-BVO (C) exhibited a photocurrent density of 0.54 mA/cm2 and remained stable for 10 h at 1.23 V vs. reversible hydrogen electrode (RHE), while the photocurrent density of the Mo-BVO decreased from 0.66 mA/cm2 to 0.11 mA/cm2 at 1.23 V vs. RHE in 4 h. The experimental results indicated that the enhanced PEC stability of the Mo-BVO (C) could be attributed to its higher crystallinity, which could effectively inhibit the dissociation of vanadium in BiVO4 during the PEC process. This work may illustrate a novel ceramic design for the improvement of the stability of BiVO4 photoanodes, and might provide a general strategy for the improvement of the PEC stability of metal oxide photoanodes.

CoFe prussian blue decorated BiVO4 as novel photoanode for continuous photocathodic protection of 304 stainless steel

The development of efficient photocathodic protection system requires highly active and robust light-absorbing electrodes for promoting the electron transfer from the light-absorber to the protected metal. Herein, we present an extremely active and stable CoFe prussian blue (CoFe-PB) modified BiVO4 film prepared by sequentially dipping the BiVO4 film in K3[Fe(CN)6] and CoCl2 solution, which can realize the long-term protection of 304 stainless steel under simulated solar illumination. Particularly, the photocathodic protection process can be operated in a scavenger-free environment. Our mechanism studies reveal that the CoFe-PB overlayer acts as the hole storage layer which can effective extract the photo-generated holes from the BiVO4 photoanode, and meanwhile works as an efficient catalyst that overcome the slow water oxidation barrier at the electrode/liquid interface, and thus greatly increase the electron lifetime, thereby enhancing the photocathodic protection capability. Our work provides a rather simple and effective design strategy for constructing semiconductor/electrocatalysts system for the underlying photogenerated cathodic protection application.

Geometric Optimization of Bismuth Vanadate Core-Shell Nanowire Photoanodes using Atomic Layer Deposition.

In this study, systematic geometric tuning of core-shell nanowire (NW) architectures is used to decouple the contributions from light absorption, charge separation, and charge transfer kinetics in photoelectrochemical water oxidation. Core-shell-shell NW arrays were fabricated using a combination of hydrothermal synthesis of ZnO and atomic layer deposition (ALD) of SnO2 and BiVO4. The length and spacing of the NW scaffold, as well as the BiVO4 film thickness, were systematically tuned to optimize the photoelectrochemical performance. A photocurrent of 4.4 mA/cm2 was measured at 1.23 V vs RHE for sulfite oxidation and 4.0 mA/cm2 at 1.80 V vs RHE for water oxidation without a cocatalyst, which are the highest values reported to date for an ALD-deposited photoanode. Electromagnetic simulations demonstrate that spatial heterogeneity in light absorption along the core-shell NW length has a critical role in determining internal quantum efficiency. The mechanistic understandings in this study highlight the benefits of systematically optimizing electrode geometry at the nanoscale when designing photoelectrodes.

Role of Gd in Enhancing the Charge Carrier Mobility of Spray–Deposited BiVO4 Photoanodes

The emergence of BiVO4 as one of the most promising photoanodes for solar water splitting is largely driven by the success in dopant introduction and optimization to improve its photoelectrochemical performance. To this end, although less commonly used, several trivalent ions (e.g., In3+, Gd3+) that substitute Bi3+ have also been demonstrated to be effective dopants, which can increase the photocurrent of BiVO4 photoanodes. However, the main factor behind such improvement is still unclear as various explanations were proposed in the literature. Herein, Gd3+ is introduced to substitute Bi3+ in spray‐deposited BiVO4 films, which enables up to a ∼2‐fold photocurrent increase. Further analysis suggests that Gd‐doping enhances the carrier separation in BiVO4 and does not affect the catalytic and optical properties. Indeed, time‐resolved microwave conductivity measurements reveal that the carrier mobility of BiVO4 is increased by 50% with the introduction of Gd, while the carrier lifetime is unaffected. This mobility increase is rationalized to be a result of a higher degree of monoclinic lattice distortion in Gd‐doped BiVO4, as evident from the X‐ray diffraction and Raman spectroscopy data. Overall, these findings provide important insights into the nature and the underlying role of Gd in improving the performance of BiVO4.

Electrodeposition of BiVO4 with needle-like flower architecture for high performance photoelectrochemical splitting of water

Photoelectrochemical (PEC) water splitting is a green and sustainable approach capable of driving mass hydrogen production in the future. To realize this vision, development of a well-performing photoelectrode is highly demanded. In this comprehensive study, electrodeposition technique was applied for fabricating BiVO4 films by regulating the deposition time from 1 min until 9 min. Interestingly, the morphology, crystallinity, chemical structure, and optical properties of BiVO4 films depend strongly on the deposition time. It is found that BiVO4 layer deposited for 7 min with a cross-section thickness of around 321.1–326.5 nm showed the optimum performance, whereby the photocurrent reached up to ~0.32 mA/cm−2 at 1.23 V vs. RHE. The deposited BiVO4 represents tiny and long petals, similar to “needle” nanostructures, which is embedded closely into compact agglomerates. Such morphology enables the BiVO4 films to perform efficiently as photoanode in PEC cells. Besides, high crystallinity is detected from the sharp peaks of XRD and Raman analysis, as well as good light absorption capability that are the main contributors to the enhancement of PEC performance. In addition to the facile fabrication offered by electrodeposition method, the non-toxic attributes and the impressive PEC performance of the optimum BiVO4 layer could serve as an interesting option for other applications such as gas sensors, solar cells, degradation of pollutants and photocatalytic water splitting.

An Inorganic–Organic Hybrid Polymer Cocatalyst for Photoelectrochemical Water Oxidation with Dual Functions of Accelerating Kinetics and Improving Charge Transfer

Oxygen evolution cocatalysts (OECs) play important roles in improving the efficiency of photocatalysts in solar water splitting. Inorganic–organic hybrid polymers (IOHPs), which have good electroly...

Effect of Radio-Frequency Power on the Composition of BiVO4 Thin-Film Photoanodes Sputtered from a Single Target

BiVO4 films were fabricated by radio frequency (RF) sputtering from a single target. The deposited BiVO4 films were found to be rich in Bi, and the reason for the Bi-richness was investigated. It was inferred from the Monte Carlo simulation that, during sputtering, the transfer process of target atoms through argon gas played a major role in this phenomenon. The transfer process resulted in an imbalanced ratio of Bi and V, arising from the difference in atom mass and interaction radius. The high RF power was found to be effective in adjusting the Bi/V ratio, influencing the sputtering yield. This type of preferential sputtering was maintained by the diffusion of target atoms from the bulk to the surface. BiVO4 films with monoclinic scheelite crystal structures were obtained at high RF power values and found to exhibit photocatalytic performances beneficial for photoanodic applications.

Sb2S3 surface modification for improved photoelectrochemical water splitting performance of BiVO4 photoanode

A fabrication of Sb2S3 layer as surface modification on pyramidal BiVO4 film is realized to improve photoelectrochemical (PEC) performance of BiVO4 photoanode. The Sb2S3-modified BiVO4 film exhibits an increased photocurrent density of 1.1 mA / cm2 at 1.23 V versus reversible hydrogen electrode and a negative shift of onset potential. Further, the negative shift of flat band potential demonstrates that the role of Sb2S3 surface modification is to suppress surface recombination, and thus increased surface separation and hole transfer efficiency are also achieved for the Sb2S3-modified BiVO4 photoanode. Accordingly, the Sb2S3 surface modification enhances surface water oxidation kinetics for the BiVO4 photoanode, resulting in improved PEC performance. These findings inspire further application of Sb2S3 into a PEC water splitting system.

Characterization and Photo-Induced Electrocatalytic Evaluation for BiVO4 Films Obtained by the SILAR Process

Characterization and Photo-Induced Electrocatalytic Evaluation for BiVO4 Films Obtained by the SILAR Process

In Situ Induced Crystalline-Amorphous Heterophase Junction by K+ to Improve Photoelectrochemical Water Oxidation of BiVO4.

Solar water splitting is one of the most efficient technologies to produce H2, which is a clean and renewable energy carrier. Photoanodes for water oxidation play the determining roles in solar water splitting, while its photoelectrochemical (PEC) performance is severely limited by the hole injection efficiency at the interface of semiconductor/electrolyte. To address this problem, in this research, by employing BiVO4 as the model semiconductor for photoanodes, we develop a novel, facile, and efficient method, which simply applies K cations in the preparation process of BiVO4 photoanodes, to in situ induce a crystalline-amorphous heterophase junction by the formation of an amorphous BiVO4 layer (a-BiVO4) on the surface of the crystalline BiVO4 (c-BiVO4) film for PEC water oxidation. The K cation is the key to stimulate the formation of the heterophase, but not incorporated in the final photoelectrodes. Without sacrificing the light absorption, the in situ formed a-BiVO4 layer accelerates the kinetics of the hole transfer at the photoanode/electrolyte interface, leading to the significantly increased efficiency of the surface hole injection to water molecules. Consequently, the BiVO4 photoanode with the crystalline-amorphous heterophase junction (a-BiVO4/c-BiVO4) exhibits almost twice the photocurrent density at 1.23 V (vs reversible hydrogen electrode) for water oxidation than the bare c-BiVO4 ones. Such advantages from the crystalline-amorphous heterophase junction are still effective even when the a-BiVO4/c-BiVO4 is coated by the cocatalyst of FeOOH, reflecting its broad applications in PEC devices. We believe this study can supply an efficient and simple protocol to enhance the PEC water oxidation performance of photoanodes, and provide a new strategy for the potential large-scale application of the solar energy-conversion related devices.

Temperature induced thermochromism of m-BiVO4 thin films prepared by sol-gel spin coating technique

Now-a-days, thermochromic materials have gained the interest of scientific community because of their diverse applications. Bismuth vanadate (BiVO4) is a promising candidate for thermochromic application. In the present work, we report on the thermochromism of m-BiVO4 films prepared by a modified citrate-route of simple sol-gel spin coating method, for the first time. X-ray diffraction (XRD) study witnesses the formation of monoclinic structure of BiVO4 films. From the Raman study, the symmetric (Ag) and the anti-symmetric (Bg) of V-O stretching and bending modes of BiVO4 are confirmed. The highest transmittance of 95% is obtained in the near-infrared region. The Urbach energy, steepness parameter and strength of electron-phonon interactions are extracted from the optical data and correlated with other measurements. The films possess the petal-like morphology throughout the substrate. The temperature induced reversible colour change of the films (from yellow to reddish-orange) clearly demonstrates the thermochromic behaviour of BiVO4 films. This may be due to the annealing temperature induced variation in structural distortion of BiVO4 from monoclinic to tetragonal phase.

Improvement Strategies for Photoelectrochemical Water Splitting at n-Type Oxide Semiconductors: A Case Study of WO3–Based Systems

The attraction of n-type metal oxide (MO) semiconductors for photoelectrochemical water splitting lies in their inherent stability, specifically against oxidation. Hence, n-type MO photoelectrodes are suitable for solar water splitting systems, especially in tandem configurations. The semiconducting MO must absorb sunlight efficiently, the valence and conduction band edges must be situated at appropriate energies, and the electrochemical reaction must have favorable kinetics in order to be able to compete with charge separation, transport and recombination kinetics in the MO photoelectrode.Many n-type MO photoelectrodes have been evaluated for photo-oxidation of water in the past 10 years, including Fe2O3, WO3, BiVO4, CuWO4, TiO2, etc. In order to improve the efficiency of each material, the specific causes for the lower than desired efficiency need to be elucidated. Based on these insights, strategies need to be designed to improve performance. However, it is not straightforward to determine the precise loss mechanisms and generally non-steady state methods need to be applied. Intensity-modulated photocurrent spectroscopy (IMPS) is a powerful technique to study the carrier dynamics in a photoelectrochemical cell: the photocurrent admittance corresponds to the frequency-dependent external quantum efficiency, and time constants for charge separation, charge transfer and surface recombination may be determined, depending on the kinetic model can may be applied to the specific system [1].We report on the results from IMPS studies of the charge transfer and recombination dynamics in two systems, where strategies have been applied in order to increase the conversion efficiency of WO3 nanomaterials [2-4]: (i) a WO3 nanowire array was either partially or completely converted to CuWO4 using a surface treatment; then, the array was covered with a thin BiVO4 film [3]; (ii) a planar, compact WO3 / BiVO4 heterojunction systems was compared with the nanorod array WO3 / BiVO4 heterojunction, with and without a hole scavenger. The results indicate the importance of the balance of the variety of kinetics parameters that determine performance. The best results were obtained for the WO3 nanoarray / BiVO4 heterojunction system, reaching a water oxidation photocurrent of about 2 mA cm-2 at sufficiently positive potentials [4].This work was performed with the help of Dr. Antonio Zapien within the NANOMXCN initiative to foment scientific collaboration between Mexico and China. The authors gratefully acknowledge funding from CONACYT, SENER, and CICY through the Renewable Energy Laboratory of South East Mexico (LENERSE; Project 254667; SP-4). References “Photoelectrochemical Water Splitting at Semiconductor Electrodes: Fundamental Problems and New Perspectives”. L. M. Peter and K. G. Upul Wijayantha, ChemPhysChem, 15, 1983–1995 (2014). “Charge Transfer and Recombination Kinetics at WO3 for Photoelectrochemical Water Oxidation”. Manuel Rodríguez-Pérez, Ingrid Rodríguez-Gutiérrez, Alberto Vega-Poot, Rodrigo García-Rodríguez, Geonel Rodríguez-Gattorno, Gerko Oskam. Electrochim. Acta, 258, 900-908 (2017).“Photoelectrochemical Water Oxidation at FTO|WO3@CuWO4 and FTO|WO3@CuWO4|BiVO4 Heterojunction Systems: An IMPS Analysis”. Ingrid Rodríguez-Gutiérrez, Essossimna Djatoubai, Manuel Rodríguez-Pérez, Jinzhan Su, Geonel Rodríguez-Gattorno, Lionel Vayssieres and Gerko Oskam. Electrochim. Acta, 308, 317-327 (2019).“An intensity-modulated photocurrent spectroscopy study of the charge carrier dynamics of WO3/BiVO4 heterojunction systems”. Ingrid Rodríguez-Gutiérrez, Essossimna Djatoubai, Jinzhan Su, Alberto Vega-Poot, Geonel Rodríguez-Gattorno, Flavio L. Souza, Gerko Oskam. Sol. Energ. Mater. Sol. Cells, 208, 110378 (11 pag.) (2020).

Graphite-bridged indirect Z-scheme system TiO2–C–BiVO4 film with enhanced photoelectrocatalytic activity towards serial bisphenols

Due to the increase in the occurrence of bisphenols (BPs) in the environments, it is urgent to develop efficient and ecofriendly methods for their removal. A novel, indirect Z-scheme TiO2–C–BiVO4 film was prepared by a sol-gel method combined with hydrothermal carbonization. The doped graphite carbon was generated in situ from glucose, which acted as an electron-transfer bridge for the Z-scheme system to enhance the heterojunction tightness between TiO2 and BiVO4. This resulted in an increasing separation efficiency of photogenerated electrons and holes and a stronger redox ability of the TiO2–C–BiVO4 film for the degradation and detoxification of BPs. The degradation efficiency of BPs was over 95% in 240 min, except for that of 4,4′-sulphonyldiphenol (BPS) due to the presence of the OSO group, and all of the BPs were nearly completely mineralized when the reaction time reached 360 min. Consequently, the inhibition ratio towards Vibrio fischeri decreased significantly along with the loss and mineralization of aromatic intermediates during photoelectrocatalytic degradation. 2,2-bis(4-Hydroxyphenyl) butane (BPB), 4,4’-(1-phenylethylidene)-bisphenol (BPAP), and (4,4′-hexafluoroisopropylidene) diphenol (BPAF), with relatively high toxicity levels and lipophilicity and as toxic product precursors, require attention in terms of environmental safety. Overall, this work provides a promising and environmentally friendly way to remove BPs from water.

Cu3Mo2O9/BiVO4 Heterojunction Films with Integrated Thermodynamic and Kinetic Advantages for Solar Water Oxidation

The development of BiVO4-based heterojunction photoanodes with thermodynamic and kinetic advantages is one of the breakthrough directions to fulfill the potential of BiVO4 for solar water splitting. Here, we designed and investigated a Cu3Mo2O9/BiVO4 heterojunction film photoanode that consisted of p-type Cu3Mo2O9 nanoparticles and an n-type BiVO4 film for water oxidation. Compared to the BiVO4 film, the resultant Cu3Mo2O9/BiVO4 heterojunction film shows better activity and stability during water oxidation owing to the synergistic effect of the p–n heterojunction and Cu3Mo2O9 cocatalysis. Specifically, the formed p–n heterojunctions of Cu3Mo2O9/BiVO4 are thermodynamically favorable to the separation and transfer of photoexcited holes–electrons, which result in a higher activity of the Cu3Mo2O9/BiVO4 photoanode for water oxidation. Meanwhile, the Cu3Mo2O9 electrocatalysis could be initiated by the photoexcited holes of BiVO4, which can enhance the water oxidation kinetics and stability of the Cu3Mo2O9/BiVO4 film photoanode. Our study provides a reference to design BiVO4-based heterojunction photoanodes with integrated advantages in thermodynamics and kinetics for water splitting.

Modified synthesis of BiVO4 and effect of doping (Mo or W) on its photoelectrochemical performance for water splitting

The photoelectrochemical (PEC) water splitting approach is an interesting concept due to abundant solar energy source and economical viability. However, it is challenging to realize the theoretical potential of photoactive materials mainly because of intricate interactions between sunlight, semiconductors and liquid solutions. BiVO4 is one such promising material because of its favorable valence and conduction band position with a bandgap of ∼2.4 eV. In this work, thin films of BiVO4 (2 cm X 2 cm surface area) have been prepared through modified synthesis route by using robust USP technique. Further, BiVO4 doped with Mo or W elements of different atomic concentrations (3, 5, 7 and 9 at.%) have been prepared. The results indicate that doping of Mo and W in BiVO4 shown ∼2.5 times of higher photocurrent density as compared to pristine BiVO4. Poor electron–hole separation yield is one of the main limiting factors for BiVO4. The purpose of Mo or W-doping in this study is to increase the electron–hole separation yield which is resulted by improving the electron transport properties. Mo or W played a role of donor dopants by compensating cation vacancies or electrons, which contribute to increase in conductivity. Both structural and performance characterization of electrodes have been carried out to corroborate with the results. Increase in charge carrier density and decrease in charge transfer resistance unfolds the reason behind increase in photoelectrochemical performance.

Comprehensive Study of the Growth Mechanism and Photoelectrochemical Activity of a BiVO4/Bi2S3 Nanowire Composite.

A BiVO4/Bi2S3 composite comprising Bi2S3 nanowires on top of a BiVO4 film was prepared via hydrothermal reaction. Because additional Bi3+ ions were not delivered during the reaction, BiVO4 served as the Bi3+ ion source for the development of Bi2S3. A detailed growth mechanism of the nanowire was elucidated by an analysis of the concentration gradient of Bi3+ and S2- ions during the reaction. The in situ growth was followed by the etching of BiVO4 to Bi3+ and VO43- ions and regrowth to Bi2S3, which resulted in the rapid evolution of nanowires on the BiVO4 substrate. The fabricated BiVO4/Bi2S3NW composite exhibited an improved photoelectrochemical activity compared to other Bi2S3 samples. The improved efficiency was mainly attributed to both improved charge separation and effective adhesion obtained by the in situ growth.

In-situ synthesis of BiVO4 film by OH− assisted VO3− releasing and its efficient visible light photocatalytic property

A fish bone-like BiVO4 film was successfully prepared in-situ on metal Bi substrate via a facile one-step hydrothermal method. The obtained BiVO4 film exhibits excellent tetracycline photodegradation efficiency, reaching 89.7% in 240 min under visible light irradiation. Its quantum yield (6.3 × 10−5 molecules photon−1) and kinetic reaction rate (7.80 μmol g−1 h−1) are better than most reported immobilized Bi-based systems. Finally, the formation mechanism was investigated, which suggests that OH− plays a vital role in forming BiVO4 film by affecting the release of VO3−. The results of this study provide available means in the in-situ preparation of Bi-based photocatalyst film.

Modification of BiVO4 with partially covered α-Fe2O3 spindles serving as hole-transport channels for significantly improved photoelectrochemical performance

Here, we constructed a BiVO4/Fe2O3 heterostructure using a simple solution dry-out method, in which MIL-53(Fe) was used as the precursor of Fe2O3. After the calcining treatment, MIL-53(Fe) polyhedrons were transformed to Fe2O3 spindles. A firm combination between BiVO4 and Fe2O3 would be achieved. Since the dimension of Fe2O3 spindles was larger than the thickness of BiVO4 films, a unique BiVO4 photoanode modified with partially covered Fe2O3 (PC-Fe2O3) spindles was produced, in which Fe2O3 constituted the hole-transport channels. Under light illumination, both the photo-excited electrons and the holes would transfer from BiVO4 to Fe2O3. The electrons migrated to the counterpart to induce the reduction reaction while the holes took part in the oxidation reaction on the exposed part of Fe2O3. As a result, the unique BiVO4/PC-Fe2O3 heterostructure exhibited higher PEC performance than other BiVO4/Fe2O3 nanocomposites reported in previous literatures. This work provides a novel strategy to address the intrinsic drawbacks of type-I heterostructures.