There has been a continuous effort to improve the thermal stability of subnanometric platinum(Pt)cluster(<2 nm) catalyst because Pt cluster on CeO_(2) support can be mobile and aggregated into nanoparticle on heati...There has been a continuous effort to improve the thermal stability of subnanometric platinum(Pt)cluster(<2 nm) catalyst because Pt cluster on CeO_(2) support can be mobile and aggregated into nanoparticle on heating at elevated temperatures,yet this great challenge remains.In this study,a strategy is reported to improve the thermal stability of subnanometric Pt cluster by hydrothermal deposition method.Based on this method,zirconium(Zr) was precisely doped on surface of Ce_(0.95)Zr_(0.05)O_(2) by accurately controlling Pt subnanometric cluster size.The surface doping of Zr is favorable for forming the Zr-O-Ce site and activating surface lattice oxygen atoms,which results in strong electronic interactions to stabilize the Pt subnanometric cluster.After high-temperature aging treatment at 1000℃/4 h,the single atom Pt supported on CeO_(2) is aggregated into larger sized(>3 nm) nanoparticle.In contrast,the single atom Pt supported on Ce_(0.95)Zr_(0.0)5O_(2) displays less agglomeration into subnanometric cluster with size of(1.4±0.3) nm.Moreover,the CO oxide catalytic performance of Ce_(0.95)Zr_(0.0)5O_(2)-Pt is 26% and 31%higher than that of CeO_(2)-Pt and commercial Al_(2)O_(3)-Pt catalysts,respectively.The experimental and density functional theory(DFT) calculations indicate that the Zr-O-Ce site and Pt subnanometric cluster interface have more defect sites and active oxygen species than CeO_(2)-Pt interface,which activate the Mars van Krevelen(MvK) mechanism,facilitating the catalytic performance.展开更多
Ni-rich LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NCM)cathodes in layered oxide cathodes are attractive for high-energy lithium-ion batteries but suffer from rapid capacity fade and thermal instability at high charge voltages.I...Ni-rich LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NCM)cathodes in layered oxide cathodes are attractive for high-energy lithium-ion batteries but suffer from rapid capacity fade and thermal instability at high charge voltages.In this study,we propose an entropy-assisted multi-element doping strategy to mitigate these issues.Specifically,two routes are designed and compared:bulk-like localized high-entropy doping(BHE-NCM)and surface-distributed high-entropy-zone doping(SHE-NCM).The surface entropy-doped NCM cathode delivers enhanced electrochemical performance,including higher capacity retention under 4.5 V cycling and superior rate capability,compared to both bulk-like and pristine counterparts.Comprehensive material characterization reveals that surface-localized doping stabilizes the layered structure with reduced microcrack formation and creates a uniform dopant-rich surface region with improved thermal and electrochemical stability.Overall,entropy-assisted doping at the near surface zone effectively alleviates structural degradation and interface reactions in Ni-rich NCM,enabling improved cycling performance at high voltage.This work highlights the significance of surface entropy engineering as a promising strategy for designing high-voltage cathodes with improved safety and longevity.展开更多
The ceria-zirconia compound oxide-supported noble metal Pd(Pd@CZ)is widely used in three-way catalyst.Moreover,the surface structure of CZ plays an important role in catalytic activity of Pd.However,how to regulate th...The ceria-zirconia compound oxide-supported noble metal Pd(Pd@CZ)is widely used in three-way catalyst.Moreover,the surface structure of CZ plays an important role in catalytic activity of Pd.However,how to regulate the surface structure of CZ and clarify the structure–activity relationship is still a challenge.In this paper,a strategy is proposed to develop high activity Pd@CZ nanocatalysts by tuning Y doping sites in CZ.The precipitate-deposition method is developed to prepare the novel Ce_(0.485)Zr_(0.485)Y_(0.03)O_(2) composite with surface doping of Y(CZ-Y-S).In addition,the Pd@CZ-Y-S(Pd supported on CZ-Y-S)exhibits superior catalytic activity for HC,CO,and NO oxide,wherein,for CO and C_(3)H_(6) oxidation,the low-temperature activity of Pd@CZ-Y-S is still 20%higher than that of Pd@CZ-Y-B(Y bulk doping)and commercial Pd@CZ after 1000℃/4 h aging.The effect mechanism is further studied by density functional theory(DFT)calculation.Compared with Pd@CZ-Y-B,Pd@CZ-Y-S shows the lower CO oxide reaction energy barriers due to the weaker adsorption strength of O2.The Y surface doping strategy could provide valuable insights for the development of highly efficient Pd@CZ catalyst with extensive applications.展开更多
Na＋doped WO3 nanowire photocatalysts were prepared by using post-treatment（surface doping） and in situ（bulk doping） doping methods. Photocatalytic degradation of Methyl Blue was tested under visible light irradia...Na＋doped WO3 nanowire photocatalysts were prepared by using post-treatment（surface doping） and in situ（bulk doping） doping methods. Photocatalytic degradation of Methyl Blue was tested under visible light irradiation, the results showed that 1 wt.% Na＋bulk-doped WO3 performed better, with higher photoactivity than surface-doped WO3. Photoelectrochemical characterization revealed the differences in the photocatalytic process for surface doping and bulk doping. Uniform bulk doping could generate more electron–hole pairs, while minimizing the chance of electron–hole recombination. Some bulk properties such as the bandgap, Fermi level and band position could also be adjusted by bulk doping, but not by surface doping.展开更多
Manipulating emergent quantum phenomena is a key issue for understanding the underlying physics and contributing to possible applications.Here we study the evolution of insulating ground states of Ta_(2)Pu_(3)Te_(5) a...Manipulating emergent quantum phenomena is a key issue for understanding the underlying physics and contributing to possible applications.Here we study the evolution of insulating ground states of Ta_(2)Pu_(3)Te_(5) and Ta_(2)Ni_(3)Te_(5) under in-situ surface potassium deposition via angle-resolved photoemission spectroscopy.Our results confirm the excitonic insulator character of Ta_(2)d_(3)Te_(5).Upon surface doping,the size of its global gap decreases obviously.After a deposition time of more than 7 min,the potassium atoms induce a metal-insulator phase transition and make the system recover to a normal state.In contrast,our results show that the isostructural compound Ta_(2)Ni_(3)Te_(5) is a conventional insulator.The size of its global gap decreases upon surface doping,but persists positive throughout the doping process.Our results not only confirm the excitonic origin of the band gap in Ta_(2)Pd_(3)Te_(5),but also offer an effective method for designing functional quantum devices in the future.展开更多
To address the capacity degradation,voltage fading,structural instability and adverse interface reactions in cathode materi-als of lithium-ion batteries(LIBs),numerous modification strategies have been developed,mainl...To address the capacity degradation,voltage fading,structural instability and adverse interface reactions in cathode materi-als of lithium-ion batteries(LIBs),numerous modification strategies have been developed,mainly including coating and doping.In particular,the important strategy of doping(surface doping and bulk doping)has been considered an effective strategy to modulate the crystal lattice structure of cathode materials.However,special insights into the mechanisms and effectiveness of the doping strategy,especially comparisons between surface doping and bulk doping in cathode materials,are still lacking.In this review,recent significant progress in surface doping and bulk doping strategies is demonstrated in detail by focusing on their inherent differences as well as effects on the structural stability,lithium-ion(Li-ion)diffusion and electrochemical properties of cathode materials from the following mechanistic insights:preventing the exposure of reactive Ni on the surface,stabilizing the Li slabs,mitigating the migration of transition metal(TM)ions,alleviating unde-sired structural transformations and adverse interface issues,enlarging the Li interslab spacing,forming three-dimensional(3D)Li-ion diffusion channels,and providing more active sites for the charge-transfer process.Moreover,insights into the correlation between the mechanisms of hybrid surface engineering strategies(doping and coating)and their influences on the electrochemical performance of cathode materials are provided by emphasizing the stabilization of the Li slabs,the enhancement of the surface chemical stability,and the alleviation of TM ion migration.Furthermore,the existing challenges and future perspectives in this promising field are indicated.展开更多
Inefficient charge separation and limited light absorption are two critical issues associated with high‐efficiency photocatalytic H2production using TiO2.Surface defects within a certain concentration range in photoc...Inefficient charge separation and limited light absorption are two critical issues associated with high‐efficiency photocatalytic H2production using TiO2.Surface defects within a certain concentration range in photocatalyst materials are beneficial for photocatalytic activity.In this study,surface defects(oxygen vacancies and metal cation replacement defects)were induced with a facile and effective approach by surface doping with low‐cost transition metals(Co,Ni,Cu,and Mn)on ultrafine TiO2.The obtained surface‐defective TiO2exhibited a3–4‐fold improved activity compared to that of the original ultrafine TiO2.In addition,a H2production rate of3.4μmol/h was obtained using visible light(λ>420nm)irradiation.The apparent quantum yield(AQY)at365nm reached36.9%over TiO2‐Cu,significantly more than the commercial P25TiO2.The enhancement of photocatalytic H2production activity can be attributed to improved rapid charge separation efficiency andexpanded light absorption window.This hydrothermal treatment with transition metal was proven to be a very facile and effective method for obtaining surface defects.展开更多
Doping is a critically important strategy to modulate the properties of organic semiconductors(OSCs) to improve their optoelectrical performances. Conventional bulk doping involves the incorporation of foreign molecul...Doping is a critically important strategy to modulate the properties of organic semiconductors(OSCs) to improve their optoelectrical performances. Conventional bulk doping involves the incorporation of foreign molecular species(i.e., dopants) into the lattice of the host OSCs, and thus disrupts the packing of the host OSCs and induces structural defects, which tends to reduce the mobility and(or) the on/off ratio in organic field-effect transistors(OFETs). In this article, we report a highly efficient and highly controllable surface doping strategy utilizing 2D molecular crystals(2DMCs) as dopants to boost the mobility and to modulate the threshold voltage of OFETs. The amount of dopants, i.e., the thickness of the 2DMCs, is controlled at monolayer precision, enabling fine tuning of the electrical properties of the OSCs at unprecedented accuracy. As a result, a prominent increase of the average mobility from 1.31 to 4.71 cm2 V-1 s-1 and a substantial reduction of the threshold voltage from -18.5 to -1.8 V are observed. Meanwhile, high on/off ratios of up to 108 are retained.展开更多
The implementation of ultrahigh-Ni cathodes in high-energy lithium-ion batteries(LIBs)is constrained by significant structural and interfacial degradation during cycling.In this study,doping-induced surface restructur...The implementation of ultrahigh-Ni cathodes in high-energy lithium-ion batteries(LIBs)is constrained by significant structural and interfacial degradation during cycling.In this study,doping-induced surface restructuring in ultrahigh-nickel cathode materials is rapidly facilitated through an ultrafast Joule heating method.Density functional theory(DFT)calculations,synchrotron X-ray absorption spectroscopy(XAS),and single-particle force test confirmed the establishment of a stable crystal framework and lattice oxygen,which mitigated H2-H3 phase transitions and improved structural reversibility.Additionally,the Sc doping process exhibits a pinning effect on the grain boundaries,as shown by scanning transmission electron microscopy(STEM),enhancing Li~+diffusion kinetics and decreasing mechanical strain during cycling.The in situ development of a cation-mixing layer at grain boundaries also creates a robust cathode/electrolyte interphase,effectively reducing interfacial parasitic reactions and transition metal dissolution,as validated by STEM and time-of-flight secondary ion mass spectrometry(TOF-SIMS).These synergistic modifications reduce particle cracking and surface/interface degradation,leading to enhanced rate capability,structural integrity,and thermal stability.Consequently,the optimized Sc-modified ultrahigh-Ni cathode(Sc-1)exhibits 93.99%capacity retention after 100 cycles at 1 C(25℃)and87.06%capacity retention after 100 cycles at 1 C(50℃),indicating excellent cycling and thermal stability.By presenting a one-step multifunctional modification approach,this research delivers an extensive analysis of the mechanisms governing the structure,microstructure,and interface properties of nickel-rich layered cathode materials(NCMs).These results underscore the potential of ultrahigh-Ni cathodes as viable candidates for advanced lithium-ion batteries(LIBs)in next-generation electric vehicles(EVs).展开更多
Surface charge transfer doping of graphene plays an important role in graphene-based electronics due to its simplicity,high doping efficiency,and easy-controllability.Here,we demonstrate the effective surface charge t...Surface charge transfer doping of graphene plays an important role in graphene-based electronics due to its simplicity,high doping efficiency,and easy-controllability.Here,we demonstrate the effective surface charge transfer hole doping of graphene by using a strong p-type molecular dopant hexacyanotrimethylene-cyclopropane (CN6-CP).The CN6-CP exhibits a very high intrinsic work function of 6.37 e V,which facilitates remarkable electron transfer from graphene to CN6-CP as revealed by in situ photoelectron spectroscopy investigations.Consequently,hole accumulation appears in the graphene layer at the direct contact with CN6-CP.As evidenced by Hall effect measurements,the areal hole density of graphene significantly increased from 8.3×10^(12)cm^(-2) to 2.21×10^(13)cm^(-2) upon 6 nm CN6-CP evaporation.The CN6-CP acceptor with strong p-doping effect has great implications for both graphene-based and organic electronics.展开更多
By using scanning tunneling microscopy,we investigated the electronic evolution of T_(d)-WTe_(2) via in-situ surface alkali K atoms deposition.The T_(d)-WTe_(2) surface is electron doped upon K deposition,and as the K...By using scanning tunneling microscopy,we investigated the electronic evolution of T_(d)-WTe_(2) via in-situ surface alkali K atoms deposition.The T_(d)-WTe_(2) surface is electron doped upon K deposition,and as the K coverage increases,two gaps are sequentially opened near Fermi energy,which probably indicates that two phase transitions concomitantly occur during electron doping.The two gaps both show a dome-like dependence on the K coverage.While the bigger gap shows no prominent dependence on the magnetic field,the smaller one can be well suppressed and thus possibly corresponds to the superconducting transition.This work indicates that T_(d)-WTe_(2) exhibits rich quantum states closely related to the carrier concentration.展开更多
Pd-based catalysts are extensively employed to catalyze CO oxidative coupling to generate DMO,while the expensive price and high usage of Pd hinder its massive application in industrial production.Designing Pd-based c...Pd-based catalysts are extensively employed to catalyze CO oxidative coupling to generate DMO,while the expensive price and high usage of Pd hinder its massive application in industrial production.Designing Pd-based catalysts with high efficiency and low Pd usage as well as expounding the catalytic mechanisms are significant for the reaction.In this study,we theoretically predict that Pd stripe doping Co(111)surface exhibits excellent performance than pure Pd(111),Pd monolayer supporting on Co(111)and Pd single atom doping Co(111)surface,and clearly expound the catalytic mechanisms through the density functional theory(DFT)calculation and micro-reaction kinetic model analysis.It is obtained that the favorable reaction pathway is COOCH_(3)-COOCH_(3)coupling pathway over these four catalysts,while the rate-controlling step is COOCH_(3)+CO+OCH_(3)→2COOCH_(3)on Pd stripe doping Co(111)surface,which is different from the case(2COOCH_(3)→DMO)on pure Pd(111),Pd monolayer supporting on Co(111)and Pd single atom doping Co(111)surface.This study can contribute a certain reference value for developing Pd-based catalysts with high efficiency and low Pd usage for CO oxidative coupling to DMO.展开更多
The surface transfer doping model has been extensively adopted as a mechanism to account for the generation of hole accumulation layers below hydrogen-terminated diamond(H-diamond)surfaces.To achieve effective surface...The surface transfer doping model has been extensively adopted as a mechanism to account for the generation of hole accumulation layers below hydrogen-terminated diamond(H-diamond)surfaces.To achieve effective surface transfer doping,surface electron acceptor materials with high electron affinity(EA)are required to produce a high density of two-dimensional hole gas(2DHG)on the H-diamond subsurface.We have established ingenious theoretical models to demonstrate that even if these solid materials do not have a high EA value,they remain capable of absorbing electrons from the H-diamond surface by forming a negatively charged interface to act as a surface electron acceptor in the surface transfer doping model.Our calculations,particularly for the local density of states,provide compelling evidence that the effect of an interface with negative charges induces an upward band bending on the H-diamond side.Furthermore,the valence band maximum of the diamond atoms at the interface crosses the Fermi level,giving rise to strong surface transfer p-type doping.These results give a strong theoretical interpretation of the origin of 2DHG on H-diamond surfaces.The proposed guidelines contribute to further improvements in the performance of 2DHG H-diamond field effect transistors.展开更多
The development of optoelectronic technologies demands photodetectors with miniaturization,broadband operation,high sensitivity,and low power consumption.Although 2D van der Waals(vd W)heterostructures are promising c...The development of optoelectronic technologies demands photodetectors with miniaturization,broadband operation,high sensitivity,and low power consumption.Although 2D van der Waals(vd W)heterostructures are promising candidates due to their built-in electric fields,ultrafast photocarrier separation,and tunable bandgaps,defect states limit their performance.Therefore,the modulation of the optoelectronic properties in such heterostructures is imperative.Surface charge transfer doping(SCTD)has emerged as a promising strategy for non-destructive modulation of electronic and optoelectronic characteristics in two-dimensional materials.In this work,we demonstrate the construction of high-performance p-i-n vertical heterojunction photodetectors through SCTD of MoTe_(2)/ReS_(2)heterostructure using p-type F_(4)-TCNQ.Systematic characterization reveals that the interfacial doping process effectively amplifies the built-in electric field,enhancing photogenerated carrier separation efficiency.Compared to the pristine heterojunction device,the doped photodetector exhibits remarkable visible to nearinfrared(635-1064 nm)performance.Particularly under 1064 nm illumination at zero bias,the device achieves a responsivity of 2.86 A/W and specific detectivity of 1.41×10^(12)Jones.Notably,the external quantum efficiency reaches an exceptional value of 334%compared to the initial 11.5%,while maintaining ultrafast response characteristics with rise/fall times of 11.6/15.6μs.This work provides new insights into interface engineering through molecular doping for developing high-performance vd W optoelectronic devices.展开更多
Surface charge transfer doping(SCTD)is widely recognized as an effective and non-destructive method for modulating the electrical properties of atomically thin transition metal dichalcogenides(TMDs),capitalizing on th...Surface charge transfer doping(SCTD)is widely recognized as an effective and non-destructive method for modulating the electrical properties of atomically thin transition metal dichalcogenides(TMDs),capitalizing on their distinctive two-dimensional(2D)structure.Nevertheless,the challenges of achieving precise area-selective doping using conventional methods,such as dopant vaporization,have impeded the advancement of practical optoelectronic and electronic devices based on TMDs.Herein,we propose a simple and reliable area-selective SCTD strategy to facilitate transfer,doping,and encapsulation simultaneously during the polyvinyl alcohol(PVA)-assistant transfer process.The electrical performance of PVA-doped molybdenum disulfide(MoS_(2))field-effect transistor(FET)exhibited significant enhancement,with carrier concentrations reaching up to 1013 cm^(−2),on-state currents increasing to 10μA·μm^(−1),and on/off ratios attaining a remarkable value of 107.Optical photothermal infrared(O-PTIR)spectroscopy was employed to elaborate the intrinsic temperature-dependent doping mechanism.The functionalization of MoS_(2)FETs was successfully achieved by introducing a hexagonal boron nitride(hBN)capping layer to define the doping area,enabling the creation of a homojunction with a rectification ratio of 106,an inverter fabricated within a single channel,and a Schottky barrier as low as 30.17 meV at the Au/MoS_(2)interface.This area-selective SCTD strategy,enabled by the PVA-assisted transfer process,offers a reliable,efficient,and economical approach for tailoring the functionalities of TMD-based devices,demonstrating substantial potential for diverse electronic applications.展开更多
The channel lateral pocket or halo region of NMOSFET characterized by interface state R G current of a forward gated diode has been investigated numerically for the first time.The result of numerical analysis demons...The channel lateral pocket or halo region of NMOSFET characterized by interface state R G current of a forward gated diode has been investigated numerically for the first time.The result of numerical analysis demonstrates that the effective surface doping concentration and the interface state density of the pocket or halo region are interface states R G current peak position dependent and amplitude dependent,respectively.It can be expressed quantitatively according to the device physics knowledge,thus,the direct characterization of the interface state density and the effective surface doping concentration of the pocket or halo becomes very easy.展开更多
Doping electrochemically inert elements in Li-rich layered oxide cathodes usually stabilizes the structure to improve electrochemical performance at the expense of available capacity.Here,we use an element segregation...Doping electrochemically inert elements in Li-rich layered oxide cathodes usually stabilizes the structure to improve electrochemical performance at the expense of available capacity.Here,we use an element segregation principle to realize a uniform surface doping without capacity sacrifice.On the basis of Hume-Rothery rule,element yttrium is chosen as a candidate dopant to spontaneously segregate at particle surface due to mismatched ionic size.Combined with X-ray photoelectron spectroscopy and electron energy loss spectroscopy mapping,yttrium is demonstrated uniformly distributed on particle surface.More importantly,a significant alleviation of oxygen release after surface doping is detected by operando differential electrochemical mass spectrometry.As a result,the modified sample exhibits improved reversibility of oxygen redox with 82.1%coulombic efficiency and excellent cycle performances with 84.15%capacity retention after 140 cycles.Postmortem analysis by transmission electron microscopy,Raman spectroscopy and X-ray diffraction reveal that the modified sample maintains the layered structure without a significant structure transformation after long cycles.This work provides an effective strategy with a series of elements to meet the industrial application.展开更多
Doping of semiconductors,i.e.,accurately modulating the charge carrier type and concentration in a controllable manner,is a key technology foundation for modern electronics and optoelectronics.However,the conventional...Doping of semiconductors,i.e.,accurately modulating the charge carrier type and concentration in a controllable manner,is a key technology foundation for modern electronics and optoelectronics.However,the conventional doping technologies widely utilized in silicon industry,such as ion implantation and thermal diffusion,always fail when applied to two-dimensional(2D)materials with atomically-thin nature.Surface charge transfer doping(SCTD)is emerging as an effective and non-destructive doping technique to provide reliable doping capability for 2D materials,in particular 2D semiconductors.Herein,we summarize the recent advances and developments on the SCTD of 2D semiconductors and its application in electronic and optoelectronic devices.The underlying mechanism of STCD processes on 2D semiconductors is briefly introduced.Its impact on tuning the fundamental properties of various 2D systems is highlighted.We particularly emphasize on the SCTD-enabled high-performance 2D functional devices.Finally,the challenges and opportunities for the future development of SCTD are discussed.展开更多
Tuning the photoresponse of monolayer MoS_(2) could extend its potential application in many fields,however,it is still a challenge.In this study,CsPbBr_(3) nanoparticles were prepared and spin-coated on the surface o...Tuning the photoresponse of monolayer MoS_(2) could extend its potential application in many fields,however,it is still a challenge.In this study,CsPbBr_(3) nanoparticles were prepared and spin-coated on the surface of monolayer MoS_(2) to fabricate hybrid CsPbBr_(3)/MoS_(2) photodetectors.By combing the photoelectrical property of the CsPbBr_(3),the synergistic effect has been systematically studied from its carrier mobility,photoresponse and detectivity.It was found that nanofilm-coating of CsPbBr_(3)would impede the photoelectric performance due to the electron-hole recombination facilitated by the defects at the interface of C PbBr_(3) and MoS_(2) films.While the nanoparticles decorating was observed to significantly improve the conductivity of the monolayer Mo S_(2),which also increased the on/off ratio of the MoS_(2) transistor from 8.2×10~3 to 4.4×10^(4),and enhanced the carrier mobility from 0.090 cm^(2)V^(-1)s^(-1)to 0.202 cm^(2)V^(-1)s^(-1),ascribing to a mixed electron recombination-injection process.Furthermore,the CsPbBr_(3) nanofilm would decrease the responsivity to 136 and 178 A/W under the light wavelength of 400 and 500 nm,respectively,while decorating CsPbBr_(3) nanoparticles improve the photoresponse to 948 and 883 A/W with the detectivity at the level of 10^(11)Jones.This work may provide an easy and cost-efficient way to tune the photoresponse of MoS_(2) photodetectors.展开更多
Na-based layered iron-manganese oxide Na_(0.67)Fe_(0.5)Mn_(0.5)O_(2) containing only low-cost elements is a promising cathode for Na-ion batteries used in large-scale energy storage systems.However,the poor cycle stab...Na-based layered iron-manganese oxide Na_(0.67)Fe_(0.5)Mn_(0.5)O_(2) containing only low-cost elements is a promising cathode for Na-ion batteries used in large-scale energy storage systems.However,the poor cycle stability restricts its practical application.The capacity decay of Na_(0.67)Fe_(0.6)Mn_(0.5)O_(2) mainly originates from the irreversible anionic redox reaction charge compensation due to the high-level hybridization between oxygen and iron.Herein,we rationally design a surface Ti doping strategy to tune the anionic redox reaction activity of Na_(0.67)Fe_(0.5)Mn_(0.5)O_(2) and improve its Na-storage properties.The doped Ti ions not only enlarge the Na migration spacing layer but also improve the structure stability thanks to the strong Ti-O bond.More importantly,the d0-shell electronic structure of Ti^(4+) can suppress the charge transfer from the oxidized anions to cations,thus reducing the anionic redox reaction activity and enhancing the reversibility of charge compensation.The modified Na_(0.67)Fe_(0.5)Mn_(0.5)O_(2) cathode shows a reversible capacity of 198 mA h g^(-1) and an increased capacity retention from 15% to 73% after about1 month of cycling.Meanwhile,a superior Na-ion diffusion kinetics and rate capability are also observed.This work advances the commercialization process of Na-based layered iron-manganese oxide cathodes;on the other hand,the proposed modification strategy paves the way for the design of high-performance electrode materials relying on anionic redox reactions.展开更多
基金supported by National Natural Science Foundation of China (52204376)Youth Foundation of Hebei Province (E2022103007)+1 种基金Open Project of Yunnan Precious Metals Laboratory Co.(YPML-20240502059)Young Elite Scientists Sponsorship Program by CAST (2021QNRC001)。
文摘There has been a continuous effort to improve the thermal stability of subnanometric platinum(Pt)cluster(<2 nm) catalyst because Pt cluster on CeO_(2) support can be mobile and aggregated into nanoparticle on heating at elevated temperatures,yet this great challenge remains.In this study,a strategy is reported to improve the thermal stability of subnanometric Pt cluster by hydrothermal deposition method.Based on this method,zirconium(Zr) was precisely doped on surface of Ce_(0.95)Zr_(0.05)O_(2) by accurately controlling Pt subnanometric cluster size.The surface doping of Zr is favorable for forming the Zr-O-Ce site and activating surface lattice oxygen atoms,which results in strong electronic interactions to stabilize the Pt subnanometric cluster.After high-temperature aging treatment at 1000℃/4 h,the single atom Pt supported on CeO_(2) is aggregated into larger sized(>3 nm) nanoparticle.In contrast,the single atom Pt supported on Ce_(0.95)Zr_(0.0)5O_(2) displays less agglomeration into subnanometric cluster with size of(1.4±0.3) nm.Moreover,the CO oxide catalytic performance of Ce_(0.95)Zr_(0.0)5O_(2)-Pt is 26% and 31%higher than that of CeO_(2)-Pt and commercial Al_(2)O_(3)-Pt catalysts,respectively.The experimental and density functional theory(DFT) calculations indicate that the Zr-O-Ce site and Pt subnanometric cluster interface have more defect sites and active oxygen species than CeO_(2)-Pt interface,which activate the Mars van Krevelen(MvK) mechanism,facilitating the catalytic performance.
基金supported by the Australian Research Council via Discovery Projects(Nos.DP200103315,DP200103332 and DP230100685)Linkage Projects(No.LP220200920)+1 种基金support from the IONTOF M6 ToF-SIMS(funded by ARC LIEF,LE190100053)the Kratos Axis Ultra XPS(ARC LIEF,LE120100026)。
文摘Ni-rich LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)(NCM)cathodes in layered oxide cathodes are attractive for high-energy lithium-ion batteries but suffer from rapid capacity fade and thermal instability at high charge voltages.In this study,we propose an entropy-assisted multi-element doping strategy to mitigate these issues.Specifically,two routes are designed and compared:bulk-like localized high-entropy doping(BHE-NCM)and surface-distributed high-entropy-zone doping(SHE-NCM).The surface entropy-doped NCM cathode delivers enhanced electrochemical performance,including higher capacity retention under 4.5 V cycling and superior rate capability,compared to both bulk-like and pristine counterparts.Comprehensive material characterization reveals that surface-localized doping stabilizes the layered structure with reduced microcrack formation and creates a uniform dopant-rich surface region with improved thermal and electrochemical stability.Overall,entropy-assisted doping at the near surface zone effectively alleviates structural degradation and interface reactions in Ni-rich NCM,enabling improved cycling performance at high voltage.This work highlights the significance of surface entropy engineering as a promising strategy for designing high-voltage cathodes with improved safety and longevity.
基金This study was financially supported by the National Natural Science Foundation of China(No.52204376)Youth Foundation of Hebei Province(No.E2022103007)+2 种基金Young Elite Scientists Sponsorship Program by CAST 2021QNRC001High Tech Zone Science and Technology Project of Yanjiao(No.YJXM211211)Youth Fund Project of GRINM(No.G12620223129035).
文摘The ceria-zirconia compound oxide-supported noble metal Pd(Pd@CZ)is widely used in three-way catalyst.Moreover,the surface structure of CZ plays an important role in catalytic activity of Pd.However,how to regulate the surface structure of CZ and clarify the structure–activity relationship is still a challenge.In this paper,a strategy is proposed to develop high activity Pd@CZ nanocatalysts by tuning Y doping sites in CZ.The precipitate-deposition method is developed to prepare the novel Ce_(0.485)Zr_(0.485)Y_(0.03)O_(2) composite with surface doping of Y(CZ-Y-S).In addition,the Pd@CZ-Y-S(Pd supported on CZ-Y-S)exhibits superior catalytic activity for HC,CO,and NO oxide,wherein,for CO and C_(3)H_(6) oxidation,the low-temperature activity of Pd@CZ-Y-S is still 20%higher than that of Pd@CZ-Y-B(Y bulk doping)and commercial Pd@CZ after 1000℃/4 h aging.The effect mechanism is further studied by density functional theory(DFT)calculation.Compared with Pd@CZ-Y-B,Pd@CZ-Y-S shows the lower CO oxide reaction energy barriers due to the weaker adsorption strength of O2.The Y surface doping strategy could provide valuable insights for the development of highly efficient Pd@CZ catalyst with extensive applications.
基金supported by the Project of Shandong Province Higher Educational Science and Technology Program (No. J12LA09)the Applied Basic Research Project of the Ministry of Transport in China (No. 2013319817050)+1 种基金the National Natural Science Foundation of China (No. 21407098)the Promotive research fund for excellent young and middle-aged scientists of Shandong Province (No. BS2014HZ012)
文摘Na＋doped WO3 nanowire photocatalysts were prepared by using post-treatment（surface doping） and in situ（bulk doping） doping methods. Photocatalytic degradation of Methyl Blue was tested under visible light irradiation, the results showed that 1 wt.% Na＋bulk-doped WO3 performed better, with higher photoactivity than surface-doped WO3. Photoelectrochemical characterization revealed the differences in the photocatalytic process for surface doping and bulk doping. Uniform bulk doping could generate more electron–hole pairs, while minimizing the chance of electron–hole recombination. Some bulk properties such as the bandgap, Fermi level and band position could also be adjusted by bulk doping, but not by surface doping.
基金Project supported by the Ministry of Science and Technology of China (Grant No. 2022YFA1403800)the National Natural Science Foundation of China (Grant Nos. U2032204,12188101, and U22A6005)+2 种基金the Chinese Academy of Sciences (Grant No. XDB33000000)the Synergetic Extreme Condition User Facility (SECUF)the Center for Materials Genome。
文摘Manipulating emergent quantum phenomena is a key issue for understanding the underlying physics and contributing to possible applications.Here we study the evolution of insulating ground states of Ta_(2)Pu_(3)Te_(5) and Ta_(2)Ni_(3)Te_(5) under in-situ surface potassium deposition via angle-resolved photoemission spectroscopy.Our results confirm the excitonic insulator character of Ta_(2)d_(3)Te_(5).Upon surface doping,the size of its global gap decreases obviously.After a deposition time of more than 7 min,the potassium atoms induce a metal-insulator phase transition and make the system recover to a normal state.In contrast,our results show that the isostructural compound Ta_(2)Ni_(3)Te_(5) is a conventional insulator.The size of its global gap decreases upon surface doping,but persists positive throughout the doping process.Our results not only confirm the excitonic origin of the band gap in Ta_(2)Pd_(3)Te_(5),but also offer an effective method for designing functional quantum devices in the future.
基金the National Natural Science Foundation of China(52072298 and 51802261)the Local Special Service Program Funded by Education Department of Shaanxi Provincial Government(19JC031)+2 种基金the Natural Science Foundation of Shaanxi(2020JC-41,2021TD-15)the Xi’an Science and Technology Project of China(2019219714SYS012CG034)the Project 2019JLP-04 supported by the Joint Foundation of Shaanxi.
文摘To address the capacity degradation,voltage fading,structural instability and adverse interface reactions in cathode materi-als of lithium-ion batteries(LIBs),numerous modification strategies have been developed,mainly including coating and doping.In particular,the important strategy of doping(surface doping and bulk doping)has been considered an effective strategy to modulate the crystal lattice structure of cathode materials.However,special insights into the mechanisms and effectiveness of the doping strategy,especially comparisons between surface doping and bulk doping in cathode materials,are still lacking.In this review,recent significant progress in surface doping and bulk doping strategies is demonstrated in detail by focusing on their inherent differences as well as effects on the structural stability,lithium-ion(Li-ion)diffusion and electrochemical properties of cathode materials from the following mechanistic insights:preventing the exposure of reactive Ni on the surface,stabilizing the Li slabs,mitigating the migration of transition metal(TM)ions,alleviating unde-sired structural transformations and adverse interface issues,enlarging the Li interslab spacing,forming three-dimensional(3D)Li-ion diffusion channels,and providing more active sites for the charge-transfer process.Moreover,insights into the correlation between the mechanisms of hybrid surface engineering strategies(doping and coating)and their influences on the electrochemical performance of cathode materials are provided by emphasizing the stabilization of the Li slabs,the enhancement of the surface chemical stability,and the alleviation of TM ion migration.Furthermore,the existing challenges and future perspectives in this promising field are indicated.
基金supported by the Double First‐rate Subject‐Food Science and Engineering Program of Hebei Province (2018SPGCA18)Young Tip‐top Talents Plan of Universities and Colleges in Hebei Province of China (BJ2017026)the Specific Foundation for Doctor in Hebei Agriculture University of China (ZD201709)~~
文摘Inefficient charge separation and limited light absorption are two critical issues associated with high‐efficiency photocatalytic H2production using TiO2.Surface defects within a certain concentration range in photocatalyst materials are beneficial for photocatalytic activity.In this study,surface defects(oxygen vacancies and metal cation replacement defects)were induced with a facile and effective approach by surface doping with low‐cost transition metals(Co,Ni,Cu,and Mn)on ultrafine TiO2.The obtained surface‐defective TiO2exhibited a3–4‐fold improved activity compared to that of the original ultrafine TiO2.In addition,a H2production rate of3.4μmol/h was obtained using visible light(λ>420nm)irradiation.The apparent quantum yield(AQY)at365nm reached36.9%over TiO2‐Cu,significantly more than the commercial P25TiO2.The enhancement of photocatalytic H2production activity can be attributed to improved rapid charge separation efficiency andexpanded light absorption window.This hydrothermal treatment with transition metal was proven to be a very facile and effective method for obtaining surface defects.
基金supported by the National Natural Science Foundation of China (51873148, 61674116, 51633006)the Ministry of Science and Technology of China (2016YFA0202302)the Natural Science Foundation of Tianjin City (18JC-YBJC18400)。
文摘Doping is a critically important strategy to modulate the properties of organic semiconductors(OSCs) to improve their optoelectrical performances. Conventional bulk doping involves the incorporation of foreign molecular species(i.e., dopants) into the lattice of the host OSCs, and thus disrupts the packing of the host OSCs and induces structural defects, which tends to reduce the mobility and(or) the on/off ratio in organic field-effect transistors(OFETs). In this article, we report a highly efficient and highly controllable surface doping strategy utilizing 2D molecular crystals(2DMCs) as dopants to boost the mobility and to modulate the threshold voltage of OFETs. The amount of dopants, i.e., the thickness of the 2DMCs, is controlled at monolayer precision, enabling fine tuning of the electrical properties of the OSCs at unprecedented accuracy. As a result, a prominent increase of the average mobility from 1.31 to 4.71 cm2 V-1 s-1 and a substantial reduction of the threshold voltage from -18.5 to -1.8 V are observed. Meanwhile, high on/off ratios of up to 108 are retained.
基金supported by the National Key R&D Program of China(2022YFB3803501)the National Natural Science Foundation of China(22179008,22209156)+5 种基金support from the Beijing Nova Program(20230484241)support from the China Postdoctoral Science Foundation(2024M754084)the Postdoctoral Fellowship Program of CPSF(GZB20230931)support from beamline BL08U1A of Shanghai Synchrotron Radiation Facility(2024-SSRF-PT-506950)beamline 1W1B of the Beijing Synchrotron Radiation Facility(2021-BEPC-PT-006276)support from Initial Energy Science&Technology Co.,Ltd(IEST)。
文摘The implementation of ultrahigh-Ni cathodes in high-energy lithium-ion batteries(LIBs)is constrained by significant structural and interfacial degradation during cycling.In this study,doping-induced surface restructuring in ultrahigh-nickel cathode materials is rapidly facilitated through an ultrafast Joule heating method.Density functional theory(DFT)calculations,synchrotron X-ray absorption spectroscopy(XAS),and single-particle force test confirmed the establishment of a stable crystal framework and lattice oxygen,which mitigated H2-H3 phase transitions and improved structural reversibility.Additionally,the Sc doping process exhibits a pinning effect on the grain boundaries,as shown by scanning transmission electron microscopy(STEM),enhancing Li~+diffusion kinetics and decreasing mechanical strain during cycling.The in situ development of a cation-mixing layer at grain boundaries also creates a robust cathode/electrolyte interphase,effectively reducing interfacial parasitic reactions and transition metal dissolution,as validated by STEM and time-of-flight secondary ion mass spectrometry(TOF-SIMS).These synergistic modifications reduce particle cracking and surface/interface degradation,leading to enhanced rate capability,structural integrity,and thermal stability.Consequently,the optimized Sc-modified ultrahigh-Ni cathode(Sc-1)exhibits 93.99%capacity retention after 100 cycles at 1 C(25℃)and87.06%capacity retention after 100 cycles at 1 C(50℃),indicating excellent cycling and thermal stability.By presenting a one-step multifunctional modification approach,this research delivers an extensive analysis of the mechanisms governing the structure,microstructure,and interface properties of nickel-rich layered cathode materials(NCMs).These results underscore the potential of ultrahigh-Ni cathodes as viable candidates for advanced lithium-ion batteries(LIBs)in next-generation electric vehicles(EVs).
基金financially supported by the National Key Research and Development Program of China(No.2017YFA0204700)the National Natural Science Foundation of China(Nos.21805285,22175186 and 21803008)。
文摘Surface charge transfer doping of graphene plays an important role in graphene-based electronics due to its simplicity,high doping efficiency,and easy-controllability.Here,we demonstrate the effective surface charge transfer hole doping of graphene by using a strong p-type molecular dopant hexacyanotrimethylene-cyclopropane (CN6-CP).The CN6-CP exhibits a very high intrinsic work function of 6.37 e V,which facilitates remarkable electron transfer from graphene to CN6-CP as revealed by in situ photoelectron spectroscopy investigations.Consequently,hole accumulation appears in the graphene layer at the direct contact with CN6-CP.As evidenced by Hall effect measurements,the areal hole density of graphene significantly increased from 8.3×10^(12)cm^(-2) to 2.21×10^(13)cm^(-2) upon 6 nm CN6-CP evaporation.The CN6-CP acceptor with strong p-doping effect has great implications for both graphene-based and organic electronics.
基金financially supported by the National Natural Science Foundation of China(Grants Nos.11790311,92165205,51902152,11874210,and 11774149)the National Key R&D Program of China(Grants No.2021YFA1400403)。
文摘By using scanning tunneling microscopy,we investigated the electronic evolution of T_(d)-WTe_(2) via in-situ surface alkali K atoms deposition.The T_(d)-WTe_(2) surface is electron doped upon K deposition,and as the K coverage increases,two gaps are sequentially opened near Fermi energy,which probably indicates that two phase transitions concomitantly occur during electron doping.The two gaps both show a dome-like dependence on the K coverage.While the bigger gap shows no prominent dependence on the magnetic field,the smaller one can be well suppressed and thus possibly corresponds to the superconducting transition.This work indicates that T_(d)-WTe_(2) exhibits rich quantum states closely related to the carrier concentration.
基金financially supported by the National Key Research and Development Program of China(2021YFA1502804)the Regional Innovation and Development Joint Fund of the National Natural Science Foundation of China(U22A20430)+3 种基金the Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering(2022SX-FR001)the Natural Science Foundation of Shanxi Province(202203021212201)the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxithe Foundation of Taiyuan University of Technology(2022QN138)
文摘Pd-based catalysts are extensively employed to catalyze CO oxidative coupling to generate DMO,while the expensive price and high usage of Pd hinder its massive application in industrial production.Designing Pd-based catalysts with high efficiency and low Pd usage as well as expounding the catalytic mechanisms are significant for the reaction.In this study,we theoretically predict that Pd stripe doping Co(111)surface exhibits excellent performance than pure Pd(111),Pd monolayer supporting on Co(111)and Pd single atom doping Co(111)surface,and clearly expound the catalytic mechanisms through the density functional theory(DFT)calculation and micro-reaction kinetic model analysis.It is obtained that the favorable reaction pathway is COOCH_(3)-COOCH_(3)coupling pathway over these four catalysts,while the rate-controlling step is COOCH_(3)+CO+OCH_(3)→2COOCH_(3)on Pd stripe doping Co(111)surface,which is different from the case(2COOCH_(3)→DMO)on pure Pd(111),Pd monolayer supporting on Co(111)and Pd single atom doping Co(111)surface.This study can contribute a certain reference value for developing Pd-based catalysts with high efficiency and low Pd usage for CO oxidative coupling to DMO.
基金supported by the National Nat-ural Science Foundation of China(Nos.62174122,U2241244,and 52302046)Major Program(JD)of Hubei Province(No.2023BAA008)+2 种基金the Fundamental Research Funds for the Central Universities(Nos.2042023kf0116 and 2042023kf1041)the Guangdong Basic and Applied Basic Research Foundation(Nos.2024A1515011764 and 2024A1515010383)the Open Fund of Hubei Key Laboratory of Electronic Manufacturing and Packaging Integration(Wuhan University)(No.EMPI2023016).
文摘The surface transfer doping model has been extensively adopted as a mechanism to account for the generation of hole accumulation layers below hydrogen-terminated diamond(H-diamond)surfaces.To achieve effective surface transfer doping,surface electron acceptor materials with high electron affinity(EA)are required to produce a high density of two-dimensional hole gas(2DHG)on the H-diamond subsurface.We have established ingenious theoretical models to demonstrate that even if these solid materials do not have a high EA value,they remain capable of absorbing electrons from the H-diamond surface by forming a negatively charged interface to act as a surface electron acceptor in the surface transfer doping model.Our calculations,particularly for the local density of states,provide compelling evidence that the effect of an interface with negative charges induces an upward band bending on the H-diamond side.Furthermore,the valence band maximum of the diamond atoms at the interface crosses the Fermi level,giving rise to strong surface transfer p-type doping.These results give a strong theoretical interpretation of the origin of 2DHG on H-diamond surfaces.The proposed guidelines contribute to further improvements in the performance of 2DHG H-diamond field effect transistors.
基金financial support from 2024 Domestic Visiting Scholar Program for Teachers'Professional Development in Universities(Grant No.FX2024022)National Natural Science Foundation of China(Grant No.61904043)。
文摘The development of optoelectronic technologies demands photodetectors with miniaturization,broadband operation,high sensitivity,and low power consumption.Although 2D van der Waals(vd W)heterostructures are promising candidates due to their built-in electric fields,ultrafast photocarrier separation,and tunable bandgaps,defect states limit their performance.Therefore,the modulation of the optoelectronic properties in such heterostructures is imperative.Surface charge transfer doping(SCTD)has emerged as a promising strategy for non-destructive modulation of electronic and optoelectronic characteristics in two-dimensional materials.In this work,we demonstrate the construction of high-performance p-i-n vertical heterojunction photodetectors through SCTD of MoTe_(2)/ReS_(2)heterostructure using p-type F_(4)-TCNQ.Systematic characterization reveals that the interfacial doping process effectively amplifies the built-in electric field,enhancing photogenerated carrier separation efficiency.Compared to the pristine heterojunction device,the doped photodetector exhibits remarkable visible to nearinfrared(635-1064 nm)performance.Particularly under 1064 nm illumination at zero bias,the device achieves a responsivity of 2.86 A/W and specific detectivity of 1.41×10^(12)Jones.Notably,the external quantum efficiency reaches an exceptional value of 334%compared to the initial 11.5%,while maintaining ultrafast response characteristics with rise/fall times of 11.6/15.6μs.This work provides new insights into interface engineering through molecular doping for developing high-performance vd W optoelectronic devices.
基金support from the National Natural Science Foundation of China(Nos.62104017 and 62074015)Beijing Institute of Technology Research Fund Program for Young Scholars.
文摘Surface charge transfer doping(SCTD)is widely recognized as an effective and non-destructive method for modulating the electrical properties of atomically thin transition metal dichalcogenides(TMDs),capitalizing on their distinctive two-dimensional(2D)structure.Nevertheless,the challenges of achieving precise area-selective doping using conventional methods,such as dopant vaporization,have impeded the advancement of practical optoelectronic and electronic devices based on TMDs.Herein,we propose a simple and reliable area-selective SCTD strategy to facilitate transfer,doping,and encapsulation simultaneously during the polyvinyl alcohol(PVA)-assistant transfer process.The electrical performance of PVA-doped molybdenum disulfide(MoS_(2))field-effect transistor(FET)exhibited significant enhancement,with carrier concentrations reaching up to 1013 cm^(−2),on-state currents increasing to 10μA·μm^(−1),and on/off ratios attaining a remarkable value of 107.Optical photothermal infrared(O-PTIR)spectroscopy was employed to elaborate the intrinsic temperature-dependent doping mechanism.The functionalization of MoS_(2)FETs was successfully achieved by introducing a hexagonal boron nitride(hBN)capping layer to define the doping area,enabling the creation of a homojunction with a rectification ratio of 106,an inverter fabricated within a single channel,and a Schottky barrier as low as 30.17 meV at the Au/MoS_(2)interface.This area-selective SCTD strategy,enabled by the PVA-assisted transfer process,offers a reliable,efficient,and economical approach for tailoring the functionalities of TMD-based devices,demonstrating substantial potential for diverse electronic applications.
文摘The channel lateral pocket or halo region of NMOSFET characterized by interface state R G current of a forward gated diode has been investigated numerically for the first time.The result of numerical analysis demonstrates that the effective surface doping concentration and the interface state density of the pocket or halo region are interface states R G current peak position dependent and amplitude dependent,respectively.It can be expressed quantitatively according to the device physics knowledge,thus,the direct characterization of the interface state density and the effective surface doping concentration of the pocket or halo becomes very easy.
基金This work was financially supported by S&T Innovation 2025 Major Special Programme of Ningbo(Grant No.2018B10081)"Lingyan"Research and Development Plan of Zhejiang Province(Grant No.2022C01071)+2 种基金the National Natural Science Foundation of China(Grant No.21773279)the Natural Science Foundation of Ningbo(Grant Nos.202003N4030,202003N4347)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2022299).
文摘Doping electrochemically inert elements in Li-rich layered oxide cathodes usually stabilizes the structure to improve electrochemical performance at the expense of available capacity.Here,we use an element segregation principle to realize a uniform surface doping without capacity sacrifice.On the basis of Hume-Rothery rule,element yttrium is chosen as a candidate dopant to spontaneously segregate at particle surface due to mismatched ionic size.Combined with X-ray photoelectron spectroscopy and electron energy loss spectroscopy mapping,yttrium is demonstrated uniformly distributed on particle surface.More importantly,a significant alleviation of oxygen release after surface doping is detected by operando differential electrochemical mass spectrometry.As a result,the modified sample exhibits improved reversibility of oxygen redox with 82.1%coulombic efficiency and excellent cycle performances with 84.15%capacity retention after 140 cycles.Postmortem analysis by transmission electron microscopy,Raman spectroscopy and X-ray diffraction reveal that the modified sample maintains the layered structure without a significant structure transformation after long cycles.This work provides an effective strategy with a series of elements to meet the industrial application.
基金the financial support from Natural Science Foundation of Jiangsu Province(No.BK20170005)the National Natural Science Foundation of China(No.21872100)+1 种基金Singapore MOE Grants MOE2019-T2-1-002 and R143-000-A43-114,Fundamental Research Foundation of Shenzhen(Nos.JCYJ20190808152607389 and JCYJ20170817100405375)Shenzhen Peacock Plan(No.KQTD2016053112042971).
文摘Doping of semiconductors,i.e.,accurately modulating the charge carrier type and concentration in a controllable manner,is a key technology foundation for modern electronics and optoelectronics.However,the conventional doping technologies widely utilized in silicon industry,such as ion implantation and thermal diffusion,always fail when applied to two-dimensional(2D)materials with atomically-thin nature.Surface charge transfer doping(SCTD)is emerging as an effective and non-destructive doping technique to provide reliable doping capability for 2D materials,in particular 2D semiconductors.Herein,we summarize the recent advances and developments on the SCTD of 2D semiconductors and its application in electronic and optoelectronic devices.The underlying mechanism of STCD processes on 2D semiconductors is briefly introduced.Its impact on tuning the fundamental properties of various 2D systems is highlighted.We particularly emphasize on the SCTD-enabled high-performance 2D functional devices.Finally,the challenges and opportunities for the future development of SCTD are discussed.
基金financially supported by the National Natural Science Foundation of China (Nos. 52002254, 52272160)Sichuan Science and Technology Foundation (Nos. 2020YJ0262, 2021YFH0127, 2022YFH0083, 2022YFSY0045)+2 种基金the Chunhui plan of Ministry of Education, Fundamental Research Funds for the Central Universities, China (No. YJ201893)the Open-Foundation of Key Laboratory of Laser Device Technology, China North Industries Group Corporation Limited (No. KLLDT202104)Supported by the fund of the State Key Laboratory of Solidification Processing in NWPU (No. SKLSP202210)。
文摘Tuning the photoresponse of monolayer MoS_(2) could extend its potential application in many fields,however,it is still a challenge.In this study,CsPbBr_(3) nanoparticles were prepared and spin-coated on the surface of monolayer MoS_(2) to fabricate hybrid CsPbBr_(3)/MoS_(2) photodetectors.By combing the photoelectrical property of the CsPbBr_(3),the synergistic effect has been systematically studied from its carrier mobility,photoresponse and detectivity.It was found that nanofilm-coating of CsPbBr_(3)would impede the photoelectric performance due to the electron-hole recombination facilitated by the defects at the interface of C PbBr_(3) and MoS_(2) films.While the nanoparticles decorating was observed to significantly improve the conductivity of the monolayer Mo S_(2),which also increased the on/off ratio of the MoS_(2) transistor from 8.2×10~3 to 4.4×10^(4),and enhanced the carrier mobility from 0.090 cm^(2)V^(-1)s^(-1)to 0.202 cm^(2)V^(-1)s^(-1),ascribing to a mixed electron recombination-injection process.Furthermore,the CsPbBr_(3) nanofilm would decrease the responsivity to 136 and 178 A/W under the light wavelength of 400 and 500 nm,respectively,while decorating CsPbBr_(3) nanoparticles improve the photoresponse to 948 and 883 A/W with the detectivity at the level of 10^(11)Jones.This work may provide an easy and cost-efficient way to tune the photoresponse of MoS_(2) photodetectors.
基金supported by the National Natural Science Foundation of China (Grant No. 12105197)the Science Center of the National Science Foundation of China (Grant No. 52088101)+1 种基金the Fundamental Research Funds for the Central Universitiesthe Scientific Instrument Developing Project of the Chinese Academy of Sciences (Grant ZDKYYQ20170001)。
文摘Na-based layered iron-manganese oxide Na_(0.67)Fe_(0.5)Mn_(0.5)O_(2) containing only low-cost elements is a promising cathode for Na-ion batteries used in large-scale energy storage systems.However,the poor cycle stability restricts its practical application.The capacity decay of Na_(0.67)Fe_(0.6)Mn_(0.5)O_(2) mainly originates from the irreversible anionic redox reaction charge compensation due to the high-level hybridization between oxygen and iron.Herein,we rationally design a surface Ti doping strategy to tune the anionic redox reaction activity of Na_(0.67)Fe_(0.5)Mn_(0.5)O_(2) and improve its Na-storage properties.The doped Ti ions not only enlarge the Na migration spacing layer but also improve the structure stability thanks to the strong Ti-O bond.More importantly,the d0-shell electronic structure of Ti^(4+) can suppress the charge transfer from the oxidized anions to cations,thus reducing the anionic redox reaction activity and enhancing the reversibility of charge compensation.The modified Na_(0.67)Fe_(0.5)Mn_(0.5)O_(2) cathode shows a reversible capacity of 198 mA h g^(-1) and an increased capacity retention from 15% to 73% after about1 month of cycling.Meanwhile,a superior Na-ion diffusion kinetics and rate capability are also observed.This work advances the commercialization process of Na-based layered iron-manganese oxide cathodes;on the other hand,the proposed modification strategy paves the way for the design of high-performance electrode materials relying on anionic redox reactions.
