TiO_(2)Electron Transport Layer with p-n Homojunctions for Efficient and Stable Perovskite Solar Cells

Low-temperature processed electron transport layer(ETL)of TiO_(2)that is widely used in planar perovskite solar cells(PSCs)has inherent low carrier mobility,resulting in insufficient photogenerated elec-tron transport and thus recombination loss at buried interface.Herein,we demonstrate an effective strategy of laser embedding of p-n homojunctions in the TiO_(2)ETL to accelerate electron transport in PSCs,through localized build-in electric fields that enables boosted electron mobility by two orders of magnitude.Such embedding is found significantly helpful for not only the enhanced crystallization quality of TiO_(2)ETL,but the fabrication of perovskite films with larger-grain and the less-trap-states.The embedded p-n homojunction enables also the modulation of interfacial energy level between perovskite layers and ETLs,favoring for the reduced voltage deficit of PSCs.Benefiting from these merits,the formamidinium lead iodide(FAPbI_(3))PSCs employing such ETLs deliver a champion efficiency of 25.50%,along with much-improved device stability under harsh conditions,i.e.,maintain over 95%of their initial efficiency after operation at maximum power point under continuous heat and illumination for 500 h,as well as mixed-cation PSCs with a champion efficiency of 22.02%and over 3000 h of ambient storage under humidity stability of 40%.Present study offers new possibilities of regulating charge transport layers via p-n homojunction embedding for high performance optoelectronics.

Constructing low-cost Ni3C/twin-crystal Zn0.5Cd0.5S heterojunction/homojunction nanohybrids for efficient photocatalytic H2 evolution

The development of low-cost semiconductor photocatalysts for highly efficient and durable photocatalytic H2 evolution under visible light is very challenging.In this study,we combine low-cost metallic Ni3C cocatalysts with twin nanocrystal Zn0.5Cd0.5S(ZCS)solid solution homojunctions for an efficient visible-light-driven H2 production by a simple approach.As-synthesized Zn0.5Cd0.5S-1%Ni3C(ZCS-1)heterojunction/homojunction nanohybrid exhibited the highest photocatalytic H2-evolution rate of 783μmol h‒1 under visible light,which is 2.88 times higher than that of pristine twin nanocrystal ZCS solid solution.The apparent quantum efficiencies of ZCS and ZCS-1 are measured to be 6.13%and 19.25%at 420 nm,respectively.Specifically,the homojunctions between the zinc blende and wurtzite segments in twin nanocrystal ZCS solid solution can significantly improve the light absorption and separation of photogenerated electron-hole pairs.Furthermore,the heterojunction between ZCS and metallic Ni3C NP cocatalysts can efficiently trap excited electrons from ZCS solid solution and enhance the H2-evolution kinetics at the surface for improving catalytic activity.This study demonstrates a unique one-step strategy for constructing heterojunction/homojunction hybrid nanostructures for a more efficient photocatalytic H2 evolution compared to other noble metal photocatalytic systems.

Spatially Bandgap-Graded Mo S2（1-x）Se2x Homojunctions for Self-Powered Visible–Near-Infrared Phototransistors

Ternary transition metal dichalcogenide alloys with spatially graded bandgaps are an emerging class of two-dimensional materials with unique features,which opens up new potential for device applications.Here,visible–near-infrared and self-powered phototransistors based on spatially bandgap-graded MoS2(1−x)Se2x alloys,synthesized by a simple and controllable chemical solution deposition method,are reported.The graded bandgaps,arising from the spatial grading of Se composition and thickness within a single domain,are tuned from 1.83 to 1.73 eV,leading to the formation of a homojunction with a builtin electric field.Consequently,a strong and sensitive gate-modulated photovoltaic effect is demonstrated,enabling the homojunction phototransistors at zero bias to deliver a photoresponsivity of 311 mA W−1,a specific detectivity up to^10^11 Jones,and an on/off ratio up to^10^4.Remarkably,when illuminated by the lights ranging from 405 to 808 nm,the biased devices yield a champion photoresponsivity of 191.5 A W−1,a specific detectivity up to^1012 Jones,a photoconductive gain of 10^6–10^7,and a photoresponsive time in the order of^50 ms.These results provide a simple and competitive solution to the bandgap engineering of two-dimensional materials for device applications without the need for p–n junctions.

Thickness-modulated in-plane Bi2O2Se homojunctions for ultrafast high-performance photodetectors

Bi2O2Se thin film could be one of the promising material candidates for the next-generation electronic and optoelectronic applications. However, the performance of Bi2O2Se thin film-based device is not fully explored in the photodetecting area. Considering the fact that the electrical properties such as carrier mobility, work function, and energy band structure of Bi2O2Se are thickness-dependent, the in-plane Bi2O2Se homojunctions consisting of layers with different thicknesses are successfully synthesized by the chemical vapor deposition(CVD) method across the terraces on the mica substrates,where terraces are created in the mica surface layer peeling off process. In this way, effective internal electrical fields are built up along the Bi2O2Se homojunctions, exhibiting diode-like rectification behavior with an on/off ratio of 102, what is more, thus obtained photodetectors possess highly sensitive and ultrafast features, with a maximum photoresponsivity of 2.5 A/W and a lifetime of 4.8 μs. Comparing with the Bi2O2Se uniform thin films, the photo-electric conversion efficiency is greatly improved for the in-plane homojunctions.

A Self-Powered Fast-Response Ultraviolet Detector of p–n Homojunction Assembled from Two ZnO-Based Nanowires

Nowadays, fabrication of micro/nano-scale electronic devices with bottom-up approach is paid much research attention. Here, we provide a novel micro/nano-assembling method, which is accurate and efficient, especially suitable for the fabrication of micro/nano-scale electronic devices. Using this method, a self-powered ZnO/Sb-doped ZnO nanowire p–n homojunction ultraviolet detector(UVD) was fabricated, and the detailed photoelectric properties were tested. At a reverse bias of -0.1 V under UV light illumination, the photoresponse sensitivity of the UVD was 26.5 and the rise/decay time of the UVD was as short as 30 ms. The micro/nano-assembling method has wide potential applications in the fabrication of specific micro/nano-scale electronic devices.

Coralline-like Ni_(2)P decorated novel tetrapod-bundle Cd_(0.9)Zn_(0.1)S ZB/WZ homojunctions for highly efficient visible-light photocatalytic hydrogen evolution

In this study,Ni_(2)P-Cd_(0.9)Zn_(0.1)S(NPCZS)composites were synthesized by coupling tetrapod bundle Cd_(0.9)Zn_(0.1)S(CZS)and coralline-like Ni_(2)P(NP)via a simple calcination method.CZS shows outstanding activity in photocatalytic hydrogen evolution(1.31 mmol h^(‒1)),owing to its unique morphology and heterophase homojunctions(ZB/WZ),which accelerate the separation and transfer of photogenerated charges.After coupling with NP,the photoactivity of NPCZS was enhanced,and the maximum hydrogen evolution rate of 1.88 mmol h^(‒1)was reached at a NP content of 12 wt%,which was 1.43 times higher than that of pure CZS.The experimental results of the photocatalytic activity,viz.photoluminescence spectra,surface photovoltage spectra,and electrochemical test showed that the enhanced photoactivity of NPCZS should be attributed to the synergistic effects of the novel tetrapod-bundle morphology,heterophase homojunctions,and decoration of the NP co-catalyst.Moreover,the as-prepared NPCZS composites exhibited excellent photostability and recyclability.Herein,we propose a possible mechanism for the enhanced photocatalytic activity.

Gradient Si-and Ti-doped Fe_(2)O_(3) hierarchical homojunction photoanode for efficient solar water splitting:Effect of facile microwave-assisted growth of Si-FeOOH on Ti-FeOOH nanocorals

The construction of a homojunction is an effective approach for addressing issues such as slow charge separation and charge-transfer kinetics in photoanodes.In the present work,we designed a gradient Si-and Ti-doped Fe_(2)O_(3) homojunction photoanode to improve the photoelectrochemical(PEC)performance of a Ti-doped Fe_(2)O_(3) photoanode.Ti-FeOOH nanocorals were synthesized using a hydrothermal process,and Si-FeOOH was grown on Ti-FeOOH nanocorals using a rapid and facile microwaveassisted(MW)technique.By varying the MW irradiation time,the thickness of the Si/Ti:Fe_(2)O_(3) photoanode was adjusted and an optimized 3-Si/Ti:Fe_(2)O_(3) photoelectrode was achieved with a significantly enhanced photocurrent density(1.37 mA cm^(-2) at 1.23 V vs.RHE)and a cathodic shift of the onset potential(150 mV)compared with that of bare Ti-Fe_(2)O_(3).This enhanced PEC performance can be ascribed to homojunction formation and Si gradient doping.The Si dopant increased the donor concentration and the formation of a homojunction improved the intrinsic built-in electric field,thereby promoting charge separation and charge transfer.Furthermore,the as-formed homojunction passivated the surfacetrapping states,consequently improving the charge transfer efficiency(60%at 1.23 VRHE)at the photoanode/electrolyte interface.These findings could pave the way for the microwave-assisted fabrication of diverse efficient homojunction photoanodes for PEC water splitting applications.

Fabrication of Bi_2WO_6 quantum dots/ultrathin nanosheets 0D/2D homojunctions with enhanced photocatalytic activity under visible light irradiation

A novel visible light‐responsive homogeneous catalyst based on Bi2WO6 quantum dots(QDs‐BWO)/Bi2WO6 nanosheets(N‐BWO)was successfully fabricated through a simple hydrothermal method.A variety of techniques were employed to investigate the morphology,structure,and electronic properties of the samples.The photocatalytic performance of the QDs/N‐BWO materials was investigated by monitoring the degradation of 4‐chlorophenol and rhodamine B under visible light irradiation.The as‐fabricated QDs/N‐BWO materials showed higher photocatalytic activity than both QDs‐BWO and N‐BWO.The results reveal that the incorporation of the QDs improved the separation efficiency of electron‐hole pairs,leading to enhanced photocatalytic activity.Moreover,the results of quenching experiments show that·O2– species played a major role in the degradation process.This work provides an important reference for the fabrication of homogeneous catalysts with high performance in the degradation of different types of pollutants.

Dual-functional marigold-like Zn_(x)Cd_(1-x)S homojunction for selective glucose photoreforming with remarkable H_(2)coproduction

The global commitment to pivoting to sustainable energy and products calls for technology development to utilize solar energy for hydrogen(H_(2))and value-added chemicals production by biomass photoreforming.Herein,a novel dual-functional marigold-like Zn_(x)Cd_(1-x)S homojunction has been the production of lactic acid with high-yield and H_(2)with high-efficiency by selective glucose photoreforming.The optimized Zn_(0.3)Cd_(0.7)S exhibits outstanding H_(2)generation(13.64 mmol h^(-1)g^(-1)),glucose conversion(96.40%),and lactic acid yield(76.80%),over 272.80 and 19.21 times higher than that of bare ZnS(0.05 mmol h^(-1)g^(-1))and CdS(0.71 mmol h^(-1)g^(-1))in H_(2)generation,respectively.The marigold-like morphology provides abundant active sites and sufficient substrates accessibility for the photocatalyst,while the specific role of the homojunction formed by hexagonal wurtzite(WZ)and cubic zinc blende(ZB)in photoreforming biomass has been demonstrated by density functional theory(DFT)calculations.Glucose is converted to lactic acid on the WZ surface of Zn_(0.3)Cd_(0.7)S via the photoactive species·O_(2)^(-),while the H_(2)is evolved from protons(H^(+))in H_(2)O on the ZB surface of Zn_(0.3)Cd_(0.7)S.This work paves a promising road for the production of sustainable energy and products by integrating photocatalysis and biorefine.

WO_(3) homojunction photoanode:Integrating the advantages of WO_(3) different facets for efficient water oxidation

The manipulation of the surface property of WO_(3) photoanode is the main breakthrough direction to improve its solar water oxidation performance both in thermodynamics and kinetics.Here,we report a WO_(3)(002)/m-WO_(3) homojunction film that is composed of an upper WO_(3) layer with predominant(002)facet(WO_(3)(002))and a lower WO_(3) layer with multi-crystal facets(m-WO_(3))as a photoanode for solar water oxidation.Due to the synergistic effect of WO_(3)(002)layer and m-WO_(3) layer,better water oxidation activity and stability are achieved on the WO_(3)(002)/m-WO_(3) homojunction film relative to the m-WO_(3) and WO_(3)(002)film.Specifically,the improved water oxidation performance on the WO_(3)(002)/m-WO_(3) homojunction film is attributed to the followings.In thermodynamics,the band position differences between WO_(3)(002)layer and m-WO_(3) layer lead to the formation of WO_(3)(002)/m-WO_(3) homojunction,which has positive function of improving their charge separation and transfer.In kinetics,the upper WO_(3)(002)layer of the WO_(3)(002)/m-WO_(3) film has superior activity in the adsorption and activation of water molecules,water oxidation on this homojunction film photoanode is inclined to follow the four-holes pathway,and the corrosion of photoanode from the H_(2)O_(2) intermediate is restrained.The present work provides a new strategy to modify the WO_(3) photoanodes for thermodynamically and kinetically efficient water oxidation.

Large unsaturated magnetoresistance of 2D magnetic semiconductor Fe-SnS_(2) homojunction

A magnetic semiconductor whose electronic charge and spin can be regulated together will be an important compon-ent of future spintronic devices.Here,we construct a two-dimensional(2D)Fe doped SnS_(2)(Fe-SnS_(2))homogeneous junction and investigate its electromagnetic transport feature.The Fe-SnS_(2) homojunction device showed large positive and unsatur-ated magnetoresistance(MR)of 1800%in the parallel magnetic field and 600%in the vertical magnetic field,indicating an obvi-ous anisotropic MR feature.In contrast,The MR of Fe-SnS_(2) homojunction is much larger than the pure diamagnetic SnS_(2) and most 2D materials.The application of a gate voltage can regulate the MR effect of Fe-SnS_(2) homojunction devices.Moreover,the stability of Fe-SnS_(2) in air has great application potential.Our Fe-SnS_(2) homojunction has a significant potential in future mag-netic memory applications.

Effect of homojunction structure in boosting sodium-ion storage: The case of MoO_(2)

High-efficiency sodium-ion batteries(SIBs) are in great demand for energy storage applications,which are dominated by the Na+storage performance of electrode materials.Here,a one-pot solvothermal method is developed to construct amorphous/crystalline MoO_(2)(a/c-MoO_(2)) homojunction for boosting Na+storage.Theoretical simulations signify that electrons redistribute at the homogenous interface of a/c-MoO_(2),resulting in an inbuilt driving force to easily adsorb charge carriers and promote the electron/ion transfer ability.Relying on its crystallographic superiorities,the a/c-MoO_(2)homojunction with high Na adsorbability(-1.61 eV) and low Na diffusion energy barrier(0.519 eV) achieves higher capacity(307 mA h g^(-1)at 0.1 A/g),better rate capability and cycling stability than either a-MoO_(2)or c-MoO_(2)counterpart.Combining in-situ X-ray diffraction(XRD) and ex-situ X-ray photoelectron spectroscopy(XPS)techniques,the ’adsorption-insertion-conversion’ mechanism is well established for Na+storage of MoO_(2).Our work opens new opportunities to optimize electrode materials via crystallographic engineering for efficient Na+storage,and helps to better understand the effects of homojunction structure in enhanced electrochemical performance.

Homojunction structure amorphous oxide thin film transistors with ultra-high mobility

Amorphous oxide semiconductors(AOS)have unique advantages in transparent and flexible thin film transistors(TFTs)applications,compared to low-temperature polycrystalline-Si(LTPS).However,intrinsic AOS TFTs are difficult to obtain field-effect mobility(μFE)higher than LTPS(100 cm^(2)/(V·s)).Here,we design ZnAlSnO(ZATO)homojunction structure TFTs to obtainμFE=113.8 cm^(2)/(V·s).The device demonstrates optimized comprehensive electrical properties with an off-current of about1.5×10^(-11)A,a threshold voltage of–1.71 V,and a subthreshold swing of 0.372 V/dec.There are two kinds of gradient coupled in the homojunction active layer,which are micro-crystallization and carrier suppressor concentration gradient distribution so that the device can reduce off-current and shift the threshold voltage positively while maintaining high field-effect mobility.Our research in the homojunction active layer points to a promising direction for obtaining excellent-performance AOS TFTs.

High mobility ultrathin ZnO p–n homojunction modulated by Zn_(0.85)Mg_(0.15)O quantum barriers

The adding of ZnMgO asymmetric double barriers(ADB)in p-ZnO2(Li,N)/n-ZnO homojunction affects the p-n junction device performance prominently.Two different homojunctions are fabricated on Si(100)substrates by pulsed laser deposition;one is the traditional p-ZnO2(Li,N)/n-ZnO homojunction with different thicknesses named as S_(1)(250 nm)and S2(500 nm),the other is the one with ADB embedded in the n-layer named as Q(265 nm).From the photoluminescence spectra,defect luminescence present in the S-series devices is effectively limited in the Q device.The current-voltage curve of the Q device shows Zener-diode rectification property because the two-dimensional electron gas tunnels through the narrow ZnMgO barrier under a reverse bias,thus decreasing the working p-n homojunction thickness from 500 nm to 265 nm.The ADB-modified homojunction shows higher carrier mobility in the Q device.The electroluminescence of the ZnO homojunction is improved in Q compared to S_(2),because the holes in p-type ZnO(Li,N)can cross the wide ZnMgO barrier under a forward bias voltage into the ZnO quantum well.Therefore,electron-hole recombination occurs in the narrow bandgap of n-type ZnO,creating an ultraviolet light-emitting diode using the ZnO homojunction.

Band alignment in SiC-based one-dimensional van der Waals homojunctions

The density functional theory method is utilized to verify the electronic structures of SiC nanotubes(SiCNTs) and SiC nanoribbons(SiCNRs) one-dimensional(1D) van der Waals homojunctions(vdWh) under an applied axial strain and an external electric field. According to the calculated results, the SiCNTs/SiCNRs 1D vdWhs are direct semiconductors with a type-II band alignment and robust electronic structures with different diameters or widths. Furthermore,the SiCNTs/SiCNRs 1D vdWhs are direct semiconductors with a type-I band alignment, respectively, in a range of[-0.3,-0.1] V/A and [0.1, 0.3] V/A and change into metal when the electric field intensity is equal to or higher than0.4 V/A. Interestingly, the SiCNTs/SiCNRs 1D vdWhs have robust electronic structures under axial strain. These findings demonstrate theoretically that the SiCNTs/SiCNRs 1D vdWhs can be employed in nanoelectronics devices.

S-scheme regulated Ni_(2)P-NiS/twinned Mn_(0.5)Cd_(0.5)S hetero-homojunctions for efficient photocatalytic H_(2)evolution

Effective bulk phase and surface charge separation is critical for charge utilization during the photo-catalytic energy conversion process.In this work,the ternary Ni_(2)P-NiS/twinned Mn_(0.5)Cd_(0.5)S(T-MCS)nanohybrids were successfully constructed via combining Ni_(2)P-NiS with T-MCS solid solution for visible light photocatalytic H_(2)evolution.T-MCS is composed of zinc blende Mn_(0.5)Cd_(0.5)S(ZB-MCS)and wurtzite Mn_(0.5)Cd_(0.5)S(WZ-MCS)and those two alternatively arranged crystal phases endow T-MCS with excellent bulk phase charge separation performance for the slight energy level difference between ZB-MCS and WZ-MCS.S-scheme carriers transfer route between NiS and T-MCS can accelerate the interfacial charge separation and retain the active electrons and holes,meanwhile,co-catalyst Ni_(2)P as electron receiver and proton reduction center can further optimize the H_(2)evolution reaction kinetics based on the surface Schottky barrier effect.The above-formed homo-heterojunctions can establish multiple charge transfer channels in the bulk phase of T-MCS and interface of T-MCS and Ni_(2)P-NiS.Under the synergistic effect of twinned homojunction,S-scheme heterojunction,and Schottky barrier,the ternary Ni_(2)P-NiS/T-MCS com-posite manifested an H_(2)production rate of 122.5 mmol h^(-1)g^(-1),which was 1.33,1.24,and 2.58 times higher than those of the NiS/T-MCS(92.4 mmol h^(-1)g^(-1)),Ni_(2)P/T-MCS(98.4 mmol h^(-1)g^(-1)),and T-MCS(47.5 mmol h^(-1)g^(-1)),respectively.This work demonstrates a promising strategy to develop efficient sul-fides photocatalyst toward targeted solar-driven H_(2)evolution through homo-heterojunction engineering.

Built-in electric field induced S-scheme g-C_(3)N_(4)homojunction for efficient photocatalytic hydrogen evolution:Interfacial engineering and morphology control

S-scheme possesses superior redox capabilities compared with the II-scheme,providing an effective method to solve the innate defects of g-C_(3)N_(4)(CN).In this study,S-doped g-C_(3)N_(4)/g-C_(3)N_(4)(SCN-tm/CN)S-scheme homojunction was constructed by rationally integrating morphology control with interfacial engineering to enhance the photocatalytic hydrogen evolution performance.In-situ Kelvin probe force microscopy(KPFM)confirms the transport of photo-generated electrons from CN to SCN.Density functional theory(DFT)calculations reveal that the generation of a built-in electric field between SCN and CN enables the carrier separation to be more efficient and effective.Femtosecond transient absorption spectrum(fs-TAS)indicates prolonged lifetimes of SCN-tm/CN_(3)(τ1:9.7,τ2:110,andτ3:1343.5 ps)in comparison to those of CN(τ1:4.86,τ2:55.2,andτ3:927 ps),signifying that the construction of homojunction promotes the separation and transport of electron hole pairs,thus favoring the photocatalytic process.Under visible light irradiation,the optimized SCN-tm/CN_(3)exhibits excellent photocatalytic activity with the hydrogen evolution rate of 5407.3μmol·g^(−1)·h^(−1),which is 20.4 times higher than that of CN(265.7μmol·g^(−1)·h^(−1)).Moreover,the homojunction also displays an apparent quantum efficiency of 26.8%at 435 nm as well as ultra-long and ultra-stable cycle ability.This work offers a new strategy to construct highly efficient photocatalysts based on the metal-free conjugated polymeric CN for realizing solar energy conversion.

A Novel Dual‑Channel Carbon Nitride Homojunction with Nanofibrous Carbon for Significantly Boosting Photocatalytic Hydrogen Peroxide Production

Photocatalytic H_(2)O_(2)synthesis(PHS)via graphite carbon nitride(g-C_(3)N_(4))is a low-carbon and environmentally friendly approach,which has garnered tremendous attention.However,as for the pristine g-C_(3)N_(4),the PHS is severely constrained by the slow transfer and rapid recombination of photogenerated carriers.Herein,we introduced cellulose-derived carbon nanofib-ers(CF)into the homojunction of g-C_(3)N_(4)nanotubes(MCN)and g-C_(3)N_(4)nanosheets(SCN).A series of photocatalytic results demonstrate that the embedding of cellulose-derived carbon for MCN/SCN/CF composite catalyst significantly improved the photocatalytic H_(2)O_(2)generation(136.9μmol·L^(-1)·h^(-1))with 5-holds higher than that of individual MCN(27.5μmol·L^(-1)·h^(-1))without any sacrificial agent.This enhancement can be attributed to the combined effects of the two-step one-electron oxy-gen reduction reaction(ORR)on conduction band(CB)side and the water oxidation reaction(WOR)on valence band(VB)side.A comprehensive characterization of the mechanism indicates that CF enhances the absorption of light,promotes the separation and migration of photogenerated carriers,and regulates the position of the valence and conduction bands with an effective dual-channel ORR pathway for photo-synthesis of H_(2)O_(2).This work provides valuable insights into utilizing biomass-based materials for significantly boosting photocatalytic H_(2)O_(2)production.

Tunning the bandgap of MnO_(2)homojunction by building active high-index facet to achieve rapid electron transfer for enhanced photocatalytic sterilization

Photocatalysis has been a research hotspot in recent years,and the design and modification of photocat-alysts have been the key points.Common methods for designing photocatalysts,including constructing heterojunctions and homojunctions,have been developed on the basis of heterojunctions.In this study,two homojunctions of manganese dioxide(MnO_(2)),including a high-index crystal plane homojunction and a general homojunction,are prepared using a stepwise hydrothermal method.Using a capping agent,the high-index crystal surface of the MnO_(2)is exposed.It is found that the electron transport efficiency be-tween the two components of the homojunction with high-index planes is higher and the adsorption capacity of the oxygen is stronger,which leads to higher photocatalytic efficiency.In addition,the newly designed high-index homojunction is used for the treatment of bacterial infections,and it kills Staphy-lococcus aureus(S.aureus)and Escherichia coli(E.coli)at rates of 99.95%±0.04%and 99.31%±0.25%,respectively.It also has excellent therapeutic effects on mouse wounds,which implies superb practical application value.This work provides a new strategy for the improved design of homojunctions and the application of photocatalytic materials.

Synergistic effect of homojunction and Ohmic junctions in CdS boosting spatial charge separation for U(VI)photoreduction

Photo-excited holes usually migrate to the surface of the catalyst and rapidly recombine with electrons,reducing the photocatalytic reduction efficiency of uranium(VI)(U(VI))in radioactive wastewater.Consequently,we employed a straightforward synthesis technique to meticulously shape and manipulate the morphology of CdS to precisely construct CdS-Ni dandelion-like composites with different aspect ratios.Briefly,the introduction of crystal facet homojunction with Ohmic contacts in this unique morphology siqnificantly improves the photocatalytic efficiency.Temperature-dependent photoluminescence spectroscopy(TD-PL)verifies that the composite material positively effects on the dissociation of excitons.Within 30 min,CdS(002)/(102)/Ni-4 removed 98% of the uranium content in solution and showed a rather high apparent rate constant(0.114 min^(−1)),which was 4.8 times higher than that of CdS nanospheres(NSs)(0.024 min^(−1))and 3.7 times higher than that of CdS nanorods(NRs)(0.031 min^(−1)).This is much higher the most reported photocatalysts for U(VI)reduction.Even after 5 consecutive cycles,the photocatalytic efficiency only decreased by 7%.This offers a fresh perspective on constructing a new perspective for building a green,efficient,and multi mechanism collaborative catalytic system to remediate environmental pollution.