The successful applications of two-dimensional(2 D)transition metal dichalcogenides highly rely on rational regulation of their electronic properties.The nondestructive and controllable doping strategy is of great imp...The successful applications of two-dimensional(2 D)transition metal dichalcogenides highly rely on rational regulation of their electronic properties.The nondestructive and controllable doping strategy is of great importance to implement 2 D materials in electronic devices.Herein,we propose a straightforward and effective method to realize controllable n-type doping in WSe_(2)monolayer by electron beam irradiation.Electrical measurements and photoluminescence(PL)spectra verify the strong n-doping in electron beam-treated WSe_(2)monolayers.The n-type doping arises from the generation of Se vacancies and the doping degree is precisely controlled by irradiation fluences.Due to the n-dopinginduced narrowing of the Schottky barrier,the current of back-gated monolayer WSe_(2)is enhanced by an order of magnitude and a$8?increase in the electron filed-effect mobility is observed.Remarkably,it is a moderate method without significant reduction in electrical performance and severe damage to lattice structures even under ultra-high doses of irradiation.展开更多
To facilitate potential applications of tungsten diselenide （WSe2） in electronics, controllable doping is of great importance. As an industrially compatible technology, plasma treatment has been used to dope two-dim...To facilitate potential applications of tungsten diselenide （WSe2） in electronics, controllable doping is of great importance. As an industrially compatible technology, plasma treatment has been used to dope two-dimensional （2D） materials. However, owing to the strong etching effect in transition metal dichalcogenides （TMDCs）, it is difficult to controllably dope 2D WSe2 crystals by plasma. Herein, we develop a moderate ammonia plasma treatment method to prepare nitrogen-doped WSe2 with controlled nitrogen content. Interestingly, Raman, photoluminescence, X-ray photoelectron spectroscopy, and electrical Lts reveal abnormal n-doping behavior of nitrogen-doped WSe2, which is attributed to selenium anion vacancy introduced by hydrogen species in ammonia plasma. Nitrogen-doped WSe2 with abnormal n-doping behavior has potential applications in future TMDCs-based electronics.展开更多
Due to its ability to convert body heat into electricity,organic thermoelectric material is considered a promising and smart maintenance-free power source to charge wearable electronics.However,developing flexible n-t...Due to its ability to convert body heat into electricity,organic thermoelectric material is considered a promising and smart maintenance-free power source to charge wearable electronics.However,developing flexible n-type organic thermoelectric materials and wearable p/n junction thermoelectric devices remains challenging.In this work,two insulated polyamides(PA6 and PA66)that have been widely used as fiber materials are employed as novel dopants for converting p-type single-walled carbon nanotubes(SWCNTs)to n-type thermoelectric materials.Because of the electron transferability of the amide group,polyamide-doped SWCNTs exhibit excellent thermopower values as large as-56.0μV K^(-1) for PA66,and-54.5μV K^(-1) for PA6.Thermoelectric devices with five p/n junctions connected in series are fabricated.The testing device produces a thermoelectric voltage of 43.1 mV and generates 1.85μW thermoelectric power under temperature gradients of approximately 80 K.Furthermore,they display charming capability for temperature recognition and monitoring human activities as sensors.These promising results suggest that the flexible polyamide-doped SWCNT composites herein have high application potential as wearable thermoelectric electronics.展开更多
Solid electrolytes face challenges in solid-state sodium batteries(SSSBs)because of limited ionic conductivity,increased interfacial resistance,and sodium dendrite issues.In this study,we adopted a unique Sn4+doping s...Solid electrolytes face challenges in solid-state sodium batteries(SSSBs)because of limited ionic conductivity,increased interfacial resistance,and sodium dendrite issues.In this study,we adopted a unique Sn4+doping strategy for Na_(3.2)Zr_(2)Si_(2.2)P_(0.8)O_(12)(NZSP)that caused a partial structural transition from the monoclinic(C2/c)phase to the rhombohedral(R-3c)phase in Na_(3.2)Zr_(1.9)Sn_(0.1)Si_(2.2)P_(0.8)O_(12)(NZSnSP1).X-ray diffraction(XRD)patterns and high-resolution transmission electron microscopy analyses were used to confirm this transition,where rhombohedral NZSnSP1 showed an increase in the Na2-O bond length compared with monoclinic NZSnSP1,increasing its triangular bottleneck areas and noticeably enhancing Na+ionic conductivity,a higher Na transference number,and lower electronic conductivity.NZSnSP1 also showed exceptionally high compatibility with Na metal with an increased critical current density,as evidenced by symmetric cell tests.The SSSB,fabricated using Na_(0.9)Zn_(0.22)Fe_(0.3)Mn_(0.48)O_(2)(NZFMO),Na metal,and NZSnSP1 as the cathode,anode,and the solid electrolyte and separator,respectively,maintains 65.86%of retention in the reversible capacity over 300 cycles within a voltage range of 2.0-4.0 V at 25℃ at 0.1 C.The in-situ X-ray diffraction and X-ray absorption analyses of the P and Zr K-edges confirmed that NZSnSP1 remained highly stable before and after electrochemical cycling.This crystal structure modification strategy enables the synthesis of ideal solid electrolytes for practical SSSBs.展开更多
As a catalyst of the air cathode in zinc-air batteries,tungstic acid ferrous(FeWO_(4)),a nanoscale transition metal tungstate,shows a broad application prospect in the oxygen reduction reaction(ORR).While FeWO_(4)poss...As a catalyst of the air cathode in zinc-air batteries,tungstic acid ferrous(FeWO_(4)),a nanoscale transition metal tungstate,shows a broad application prospect in the oxygen reduction reaction(ORR).While FeWO_(4)possesses favorable electrochemical properties and thermodynamic stability,its intrinsic semiconductor characteristics result in a relatively slow electron transfer rate,limiting the ORR catalytic activity.In this work,the electronic structure of FeWO_(4)is significantly modulated by introducing phosphorus(P)atoms with abundant valence electrons.The P doping can adjust the electronic structure of FeWO_(4)and then optimize oxygen-containing intermediates'absorption/desorption efficiency to achieve improved ORR activity.Furthermore,the sodium chloride template is utilized to construct a porous carbon framework for anchoring phosphorus-doped iron tungstate(P-FeWO_(4)/PNC).The porous carbon skeleton provides numerous active sites for the absorption/desorption and redox reactions on the P-FeWO_(4)/PNC surface and serves as mass transport channels for reactants and intermediates.The P-FeWO_(4)/PNC demonstrates ORR performance(E1/2=0.86 V vs.RHE).Furthermore,the zinc-air batteries incorporating the P-FeWO_(4)/PNC composite demonstrate an increased peak power density(172.2 mW·cm^(-2)),high specific capacity(810.1 mAh·g^(-1)),and sustained long-term cycling stability lasting up to 240 h.This research not only contributes to the advancement of cost-effective tungsten-based non-precious metallic ORR catalysts,but also guides their utilization in zinc-air batteries.展开更多
N-type Mg_(3)Sb_(2)-based alloys have recently attracted considerable attention due to the high thermoelectric performance.However,the performance degradation occurs because of Mg loss at high temperature.Elemental Mg...N-type Mg_(3)Sb_(2)-based alloys have recently attracted considerable attention due to the high thermoelectric performance.However,the performance degradation occurs because of Mg loss at high temperature.Elemental Mg plays a significantly critical role in thermoelectric performance and thermal stability,where most studies on these compounds have thus far concentrated on the nominal Mg content which heavily depends on the fabrication methods,with few attentions devoted to the essential issue of actual Mg content,resulting in the unclear mechanism of improving their stability,severely limiting their practical applications in thermoelectric power generation.Here,we systematically analyzed the thermoelectric performance,thermal stability,and changed micro structures before and after in situ electronic thermoelectric performance measurement at 750 K,for n-type Mg_(3)Sb_(2)-based alloys with different Mg and Co content.It was found that elemental Mg and Co have a similar effect on adjusting the electron transport characteristic,and the peak values of power factor and ZT are up to 32.4μW cm^(-1)K^(-2)and 1.8,respectively.Thermal stability is more sensitive to the Mg content of material matrix than thermoelectric performance,and the effects of Mgpoor condition on thermal stability cannot be compensated via cationic Co doping.We also proved the route of Mg loss in experiments.By balancing Mg content and Co doping,the optimized sample showed good stability,in which it reduced only by 10%over 170 h of measurement at 750 K.Density functional theory calculation showed that the bonding strength of Co-Mg is stronger than MgMg,also explaining the enhanced thermal stability.展开更多
Mn^(2+)-doped CsPbCl_(3)(Mn^(2+):CsPbCl_(3)) nanocrystals(NCs) have attracted considerable attention due to their unique strong and broad orange-red emission band,presenting promising applications in the field of phot...Mn^(2+)-doped CsPbCl_(3)(Mn^(2+):CsPbCl_(3)) nanocrystals(NCs) have attracted considerable attention due to their unique strong and broad orange-red emission band,presenting promising applications in the field of photoelectric devices.However,pristine Mn^(2+):CsPbCl_(3)NCs commonly suffer from low photoluminescence quantum yield(PL QY) and stability issues.Herein,we introduced europium ions(Eu^(3+))into Mn^(2+):CsPbCl_(3)NCs via the thermal injection synthesis method to obtain high performance Eu^(3+)and Mn^(2+)codoped CsPbCl_(3)(Eu^(3+)/Mn^(2+):CsPbCl_(3)) NCs.The maximum PL QY of the resulting Eu^(3+)/Mn^(2+):CsPbCl_(3)NCs reaches up to 90.92%.It is found that the doping of Eu^(3+)ions significantly reduces the non-radiative recombination caused by high defect states,and improves the energy transfer efficiency from exciton to Mn^(2+),thereby boosting the PL performance.Moreover,doping Eu^(3+)ions notably improves the UV-light and water stability of Mn^(2+):CsPbCl_(3)NCs.We further demonstrate the application versatility of Eu^(3+)/Mn^(2+):CsPbCl_(3)NCs in white light emitting diodes(WLEDs) and optical anticounterfeiting applications.This work provides a valuable perspective for the attainment of high performance Mn^(2+):CsPbCl_(3)NCs and lays a foundation for the codoping of other lanthanide ions to adjust the luminescence properties of Mn^(2+):CsPbCl_(3)NCs.展开更多
The outstanding performance of O3-type NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)(NFM111)at both high and low temperatures coupled with its impressive specific capacity makes it an excellent cathode material for sodium-ion batte...The outstanding performance of O3-type NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)(NFM111)at both high and low temperatures coupled with its impressive specific capacity makes it an excellent cathode material for sodium-ion batteries.However,its poor cycling,owing to highpressure phase transitions,is one of its disadvantages.In this study,Cu/Ti was introduced into NFM111 cathode material using a solidphase method.Through both theoretically and experimentally,this study found that Cu doping provides a higher redox potential in NFM111,improving its reversible capacity and charge compensation process.The introduction of Ti would enhance the cycling stability of the material,smooth its charge and discharge curves,and suppress its high-voltage phase transitions.Accordingly,the NaNi_(0.27)Fe_(0.28)Mn_(0.33)Cu_(0.05)Ti_(0.06)O_(2)sample used in the study exhibited a remarkable rate performance of 142.97 mAh·g^(-1)at 0.1 C(2.0-4.2 V)and an excellent capacity retention of 72.81%after 300 cycles at 1C(1C=150 mA·g^(-1)).展开更多
This study focused on improving the cathode performance of Ba_(0.6)Sr_(0.4)Co_(0.85)Nb_(0.15)O_(3-δ)(BSCN)-based perovskite materials through molybdenum(Mo)doping.Pure BSCN and Mo-modified-BSCN—Ea_(0.6)Sr_(0.4)Co_(0...This study focused on improving the cathode performance of Ba_(0.6)Sr_(0.4)Co_(0.85)Nb_(0.15)O_(3-δ)(BSCN)-based perovskite materials through molybdenum(Mo)doping.Pure BSCN and Mo-modified-BSCN—Ea_(0.6)Sr_(0.4)Co_(0.85)Nb_(0.1)Mo_(0.05)O_(3-δ)(B S CNM_(0.05)),Ba_(0.6)Sr_(0.4)Co_(0.85)Nb_(0.05)Mo_(0.1)O_(3-δ)(BSCNM_(0.1)),and Ba_(0.6)Sr_(0.4)Co_(0.85)Mo_(0.15)O_(3-δ)(BSCM)—with Mo doping contents of 5mol%,10mol%,and15mol%,respectively,were successfully prepared using the sol-gel method.The effects of Mo doping on the crystal structure,conductivity,thermal expansion coefficient,oxygen reduction reaction(ORR)activity,and electrochemical performance were systematically evaluated using X-ray diffraction analysis,thermally induced characterization,electrochemical impedance spectroscopy,and single-cell performance tests.The results revealed that Mo doping could improve the conductivity of the materials,suppress their thermal expansion effects,and significantly improve the electrochemical performance.Surface chemical state analysis using X-ray photoelectron spectroscopy revealed that 5mol%Mo doping could facilitate a high adsorbed oxygen concentration leading to enhanced ORR activity in the materials.Density functional theory calculations confirmed that Mo doping promoted the ORR activity in the materials.At an operating temperature of 600℃,the BSCNM_(0.05)cathode material exhibited significantly enhanced electrochemical impedance characteristics,with a reduced area specific resistance of 0.048Ω·cm~2,which was lower than that of the undoped BSCN matrix material by 32.39%.At the same operating temperature,an anode-supported single cell using a BSCNM_(0.05)cathode achieved a peak power density of 1477 mW·cm^(-2),which was 30.71%,56.30%,and 171.50%higher than those of BSCN,BSCNM_(0.1),and B SCM,respectively.The improved ORR activity and electrochemical performance of BSCNM_(0.05)indicate that it can be used as a cathode material in low-temperature solid oxide fuel cells.展开更多
In recent years,the research on superconductivity in one-dimensional(1D)materials has been attracting increasing attention due to its potential applications in low-dimensional nanodevices.However,the critical temperat...In recent years,the research on superconductivity in one-dimensional(1D)materials has been attracting increasing attention due to its potential applications in low-dimensional nanodevices.However,the critical temperature(T_(c))of 1D superconductors is low.In this work,we theoretically investigate the possible high T_(c) superconductivity of(5,5)carbon nanotube(CNT).The pristine(5,5)CNT is a Dirac semimetal and can be modulated into a semiconductor by full hydrogenation.Interestingly,by further hole doping,it can be regulated into a metallic state with the sp3-hybridized𝜎electrons metalized,and a giant Kohn anomaly appears in the optical phonons.The two factors together enhance the electron–phonon coupling,and lead to high-T_(c) superconductivity.When the hole doping concentration of hydrogenated-(5,5)CNT is 2.5 hole/cell,the calculated T_(c) is 82.3 K,exceeding the boiling point of liquid nitrogen.Therefore,the predicted hole-doped hydrogenated-(5,5)CNT provides a new platform for 1D high-T_(c) superconductivity and may have potential applications in 1D nanodevices.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
Peroxymonosulfate(PMS)-based advanced oxidation processes(AOPs)are an effective way to remove emerging contaminants(ECs)from water.The catalytic process involving PMS is hindered by the suboptimal electron trans-fer e...Peroxymonosulfate(PMS)-based advanced oxidation processes(AOPs)are an effective way to remove emerging contaminants(ECs)from water.The catalytic process involving PMS is hindered by the suboptimal electron trans-fer efficiency of current catalysts,the further application of AOPs technology is limited.Here,it is proposed that the interfacial electric field can be controlled by bor(B)-doped FeNC catalysts,which shows significant advantages in the efficient generation,release and participation of reactive oxygen species(ROS)in the reaction.The super exchange interaction between Fe sites and N and B sites is realized through the directional transfer of electrons in the interfacial electric field,which ensures the high efficiency and stability of the PMS catalytic process.B doping increases the d orbitals distribution at Fermi level,which facilitates enhanced electron transition activity,thereby promoting the effective generation of (1)^O_(2).At the same time,orbital hybridization causes the center of the d band to move to a lower energy level,which not only contributes to the desorption process of (1)^O_(2),but also accelerates its release.In addition,B-doping also improved the adsorption capacity of organic pollutants and shortened the migration distance of ROS,thereby significantly improving the degradation efficiency of ECs.The B-doping strategy outlined offers a novel approach to the development of FeNC catalysts,it lays a theoretical foundation and offers technical insights for the integration of PMS/AOPs technology in the ECs management.展开更多
Two-dimensional(2D)transition metal dichalcogenides(TMDs)are considered to be promising building blocks for the next generation electronic and optoelectronic devices.Various doping schemes and work function engineerin...Two-dimensional(2D)transition metal dichalcogenides(TMDs)are considered to be promising building blocks for the next generation electronic and optoelectronic devices.Various doping schemes and work function engineering techniques have been explored to overcome the intrinsic performance limits of 2D TMDs.However,a reliable and long-time air stable doping scheme is still lacking in this field.In this work,we utilize keV ion beams of H2+to irradiate layered WSe2 crystals and obtain efficient n-type doping effect for all irradiated crystals within a fluence of 1×1014 protons·cm−2(1e14).Moreover,the irradiated WSe2 remains an n-type semiconductor even after it is exposed to ambient conditions for a year.Localized ion irradiation with a focused beam can directly pattern on the sample to make high performance homogenous p-n junction diodes.Raman and photoluminescence(PL)spectra demonstrate that the WSe2 crystal lattice stays intact after irradiation within 1e14.We attribute the reliable electrondoping to the significant increase in Se vacancies after the proton irradiation,which is confirmed by our scanning transmission electron microscope(STEM)results.Our work demonstrates a reliable and long-term air stable n-type doping scheme to realize high-performance electronic TMD devices,which is also suitable for further integration with other 2D devices.展开更多
Recent theoretical predictions and experimental findings on the transport properties of n-type SnTe have triggered extensive researches on this simple binary compound,despite the realization of n-type SnTe being a gre...Recent theoretical predictions and experimental findings on the transport properties of n-type SnTe have triggered extensive researches on this simple binary compound,despite the realization of n-type SnTe being a great challenge.Herein,Cl as a donor dopant can effectively regulate the position of Fermi level in Sn_(0.6)Pb_(0.4)Te matrix and successfully achieve the n-type transport behavior in SnTe.An outstanding power factor of~14.7μW·cm^(-1)·K^(-2) at 300 K was obtained for Cl-doped Sn_(0.6)Pb_(0.4)Te sample.By combining the experimental analysis with theoretical calculations,the transport properties of n-type SnTe thermoelectrics doped with different halogen dopants(Cl,Br,and I)were then systematically investigated and estimated.The results demonstrated that Br and I had better doping efficiencies compared with Cl,which contributed to the well-optimized carrier concentrations of~1.03×10^(19)and~1.11×10^(19)cm^(-3)at 300 K,respectively.The improved n-type carrier concentrations effectively lead to the significant enhancement on the thermoelectric performance of n-type SnTe.Our study further promoted the experimental progress and deep interpretation of the transport features in n-type SnTe thermoelectrics.The present results could also be crucial for the development of n-type counterparts for SnTe-based thermoelectric devices.展开更多
The p-type TiCoSb-based half-Heuslers are widely studied due to the good electrical transport properties after hole doping,while the pristine TiCoSb is intrinsically n-type.It is thus desired to obtain a comparable n-...The p-type TiCoSb-based half-Heuslers are widely studied due to the good electrical transport properties after hole doping,while the pristine TiCoSb is intrinsically n-type.It is thus desired to obtain a comparable n-type counterpart through optimization of electron concentration.In this work,n-type Ti_(0.9-x)HfxTa_(0.1)CoSb half-Heuslers were fabricated by arc melting,ball milling,and spark plasma sintering.An optimized carrier concentration,together with a decreased lattice thermal conductivity,was obtained by Ta doping at the Ti site,leading to a peak figure of merit(ZT)of 0.7 at 973 K in Ti_(0.9)Ta_(0.1)-CoSb.By further alloying Hf at the Ti site,the lattice thermal conductivity was significantly reduced without deteriorating the power factor.As a result,a peak ZT of 0.9 at 973 K and an average ZT of 0.54 in the temperature range of 300-973 K were achieved in Ti_(0.6)Hf_(0.3)Ti_(0.1)CoSb.This work demonstrates that n-type TiCoSb-based halfHeuslers are promising thermoelectric materials.展开更多
Sol--gol method was employed to synthesize Mg doped ZnO films on Si substrates. The annealing temperature-dependent structure and optical property of the produced samples were studied. An interesting result observed i...Sol--gol method was employed to synthesize Mg doped ZnO films on Si substrates. The annealing temperature-dependent structure and optical property of the produced samples were studied. An interesting result observed is that increasing Mg concentration in the studied samples induces the full width at half maximum （FWHM） of their near-band-edge （NBE） emission decrease and the defect related emission of the corresponding sample suppresses drastically. The possible mechanism of the observed result is discussed.展开更多
Nitrogen-doped single-walled carbon nanotubes （CNx-SWNTs） with tunable dopant concentrations were synthesized by chemical vapor deposition （CVD）, and their structure and elemental composition were characterized by...Nitrogen-doped single-walled carbon nanotubes （CNx-SWNTs） with tunable dopant concentrations were synthesized by chemical vapor deposition （CVD）, and their structure and elemental composition were characterized by using transmission electron microscopy （TEM） in combination with electron energy loss spectroscopy （EELS）. By comparing the Raman spectra of pristine and doped nanotubes, we observed the doping-induced Raman G band phonon stiffening and 2D band phonon softening, both of which reflect doping-induced renormalization of the electron and phonon energies in the nan- otubes and behave as expected in accord with the n-type doping effect. On the basis of first principles calculations of the distribution of delocalized carrier density in both the pristine and doped nanotubes, we show how the n-type doping occurs when nitrogen heteroatoms are substitutionally incorporated into the honeycomb tube-shell carbon lattice.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
While heteroatom doping serves as a powerful strategy for devising novel polycyclic aromatic hydrocarbons(PAHs), the further fine-tuning of optoelectronic properties via the precisely altering of doping patterns remai...While heteroatom doping serves as a powerful strategy for devising novel polycyclic aromatic hydrocarbons(PAHs), the further fine-tuning of optoelectronic properties via the precisely altering of doping patterns remains a challenge. Herein, by changing the doping positions of heteroatoms in a diindenopyrene skeleton, we report two isomeric boron, sulfur-embedded PAHs, named Anti-B_(2)S_(2) and Syn-B_(2)S_(2), as electron transporting semiconductors. Detailed structure-property relationship studies revealed that the varied heteroatom positions not only change their physicochemical properties, but also largely affect their solid-state packing modes and Lewis base-triggered photophysical responses. With their low-lying frontier molecular orbital levels, n-type characteristics with electron mobilities up to 1.5 × 10^(-3)cm^(2)V^(-1)s^(-1)were achieved in solution-processed organic field-effect transistors. Our work revealed the critical role of controlling heteroatom doping patterns for designing advanced PAHs.展开更多
Monometallic doping has proved its superiority in improving either permselectivity or H_(2) permeability of organosilica membranes for H_(2)/CO_(2) separation,but it is still challenging to break the trade-off effect....Monometallic doping has proved its superiority in improving either permselectivity or H_(2) permeability of organosilica membranes for H_(2)/CO_(2) separation,but it is still challenging to break the trade-off effect.Herein,we report a series of Pd-Nb bimetallic doped 1,2-bis(triethoxysilyl)ethane(Pd-Nb-BTESE,PNB)membranes with different metal doping routes for simultaneously improving H_(2) permeance and H_(2)/CO_(2) permselectivity by the synergetic effects of Pd and Nb.The doped Pd can exist in the BTESE network as nanoparticles while the doped Nb is incorporated into BTESE network forming Nb-O-Si covalent bonds.The metal doping routes significantly influence the microstructure of PNB networks and gas separation performance of the PNB membranes.We found that the PNB membrane with Pd doping priority(PNB-Pd)exhibited the highest surface area and pore volume,comparing with Nb doping priority(PNB-Nb)or Pd-Nb simultaneous doping(PNB-PdNb).The PNB-Pd membrane could not only exhibit an excellent H_(2) permeance of~10^(−6) mol·m^(−2)·s^(−1)·Pa^(−1) but also a high H_(2)/CO_(2) permselectivity of 17.2.Our findings may provide novel insights into preparation of bimetallic doped organosilica membranes with excellent H_(2)/CO_(2) separation performance.展开更多
基金supported by the KRDPC(No.2019YFA0308000)National Natural Science Foundation of China(Nos.61927808and 91963130)。
文摘The successful applications of two-dimensional(2 D)transition metal dichalcogenides highly rely on rational regulation of their electronic properties.The nondestructive and controllable doping strategy is of great importance to implement 2 D materials in electronic devices.Herein,we propose a straightforward and effective method to realize controllable n-type doping in WSe_(2)monolayer by electron beam irradiation.Electrical measurements and photoluminescence(PL)spectra verify the strong n-doping in electron beam-treated WSe_(2)monolayers.The n-type doping arises from the generation of Se vacancies and the doping degree is precisely controlled by irradiation fluences.Due to the n-dopinginduced narrowing of the Schottky barrier,the current of back-gated monolayer WSe_(2)is enhanced by an order of magnitude and a$8?increase in the electron filed-effect mobility is observed.Remarkably,it is a moderate method without significant reduction in electrical performance and severe damage to lattice structures even under ultra-high doses of irradiation.
文摘To facilitate potential applications of tungsten diselenide （WSe2） in electronics, controllable doping is of great importance. As an industrially compatible technology, plasma treatment has been used to dope two-dimensional （2D） materials. However, owing to the strong etching effect in transition metal dichalcogenides （TMDCs）, it is difficult to controllably dope 2D WSe2 crystals by plasma. Herein, we develop a moderate ammonia plasma treatment method to prepare nitrogen-doped WSe2 with controlled nitrogen content. Interestingly, Raman, photoluminescence, X-ray photoelectron spectroscopy, and electrical Lts reveal abnormal n-doping behavior of nitrogen-doped WSe2, which is attributed to selenium anion vacancy introduced by hydrogen species in ammonia plasma. Nitrogen-doped WSe2 with abnormal n-doping behavior has potential applications in future TMDCs-based electronics.
基金supported by the National Natural Science Foundation of China(Project no.51973120)the Natural Science Foun-dation of Guangdong Province(No.2019A1515010613)+1 种基金the Shenzhen Science and Technology Research Grant(Nos.JCYJ20170818093417096 and JCYJ20180305125649693)the Shenzhen Science and Technology Program(No.20220809111527001).
文摘Due to its ability to convert body heat into electricity,organic thermoelectric material is considered a promising and smart maintenance-free power source to charge wearable electronics.However,developing flexible n-type organic thermoelectric materials and wearable p/n junction thermoelectric devices remains challenging.In this work,two insulated polyamides(PA6 and PA66)that have been widely used as fiber materials are employed as novel dopants for converting p-type single-walled carbon nanotubes(SWCNTs)to n-type thermoelectric materials.Because of the electron transferability of the amide group,polyamide-doped SWCNTs exhibit excellent thermopower values as large as-56.0μV K^(-1) for PA66,and-54.5μV K^(-1) for PA6.Thermoelectric devices with five p/n junctions connected in series are fabricated.The testing device produces a thermoelectric voltage of 43.1 mV and generates 1.85μW thermoelectric power under temperature gradients of approximately 80 K.Furthermore,they display charming capability for temperature recognition and monitoring human activities as sensors.These promising results suggest that the flexible polyamide-doped SWCNT composites herein have high application potential as wearable thermoelectric electronics.
基金supported by the National Research Foundation of Korea(RS-2024-00404414)the National Research Council of Science&Technology(NST,No.GTL24011-000)funded by the Ministry of Science and ICTsupported by the KIST Institutional Program(Project No.2E33270).
文摘Solid electrolytes face challenges in solid-state sodium batteries(SSSBs)because of limited ionic conductivity,increased interfacial resistance,and sodium dendrite issues.In this study,we adopted a unique Sn4+doping strategy for Na_(3.2)Zr_(2)Si_(2.2)P_(0.8)O_(12)(NZSP)that caused a partial structural transition from the monoclinic(C2/c)phase to the rhombohedral(R-3c)phase in Na_(3.2)Zr_(1.9)Sn_(0.1)Si_(2.2)P_(0.8)O_(12)(NZSnSP1).X-ray diffraction(XRD)patterns and high-resolution transmission electron microscopy analyses were used to confirm this transition,where rhombohedral NZSnSP1 showed an increase in the Na2-O bond length compared with monoclinic NZSnSP1,increasing its triangular bottleneck areas and noticeably enhancing Na+ionic conductivity,a higher Na transference number,and lower electronic conductivity.NZSnSP1 also showed exceptionally high compatibility with Na metal with an increased critical current density,as evidenced by symmetric cell tests.The SSSB,fabricated using Na_(0.9)Zn_(0.22)Fe_(0.3)Mn_(0.48)O_(2)(NZFMO),Na metal,and NZSnSP1 as the cathode,anode,and the solid electrolyte and separator,respectively,maintains 65.86%of retention in the reversible capacity over 300 cycles within a voltage range of 2.0-4.0 V at 25℃ at 0.1 C.The in-situ X-ray diffraction and X-ray absorption analyses of the P and Zr K-edges confirmed that NZSnSP1 remained highly stable before and after electrochemical cycling.This crystal structure modification strategy enables the synthesis of ideal solid electrolytes for practical SSSBs.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.22178148 and 22278193)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘As a catalyst of the air cathode in zinc-air batteries,tungstic acid ferrous(FeWO_(4)),a nanoscale transition metal tungstate,shows a broad application prospect in the oxygen reduction reaction(ORR).While FeWO_(4)possesses favorable electrochemical properties and thermodynamic stability,its intrinsic semiconductor characteristics result in a relatively slow electron transfer rate,limiting the ORR catalytic activity.In this work,the electronic structure of FeWO_(4)is significantly modulated by introducing phosphorus(P)atoms with abundant valence electrons.The P doping can adjust the electronic structure of FeWO_(4)and then optimize oxygen-containing intermediates'absorption/desorption efficiency to achieve improved ORR activity.Furthermore,the sodium chloride template is utilized to construct a porous carbon framework for anchoring phosphorus-doped iron tungstate(P-FeWO_(4)/PNC).The porous carbon skeleton provides numerous active sites for the absorption/desorption and redox reactions on the P-FeWO_(4)/PNC surface and serves as mass transport channels for reactants and intermediates.The P-FeWO_(4)/PNC demonstrates ORR performance(E1/2=0.86 V vs.RHE).Furthermore,the zinc-air batteries incorporating the P-FeWO_(4)/PNC composite demonstrate an increased peak power density(172.2 mW·cm^(-2)),high specific capacity(810.1 mAh·g^(-1)),and sustained long-term cycling stability lasting up to 240 h.This research not only contributes to the advancement of cost-effective tungsten-based non-precious metallic ORR catalysts,but also guides their utilization in zinc-air batteries.
基金financially supported by Shandong Provincial Natural Science Foundation(No.ZR2023QE028)Dalian National Laboratory for Clean Energy(DNL),CAS,DNL Cooperation Fund,CAS(No.DNL202021)+1 种基金the National Key Research and Development Program of China(No.2024YFB3813800)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.Y202041)
文摘N-type Mg_(3)Sb_(2)-based alloys have recently attracted considerable attention due to the high thermoelectric performance.However,the performance degradation occurs because of Mg loss at high temperature.Elemental Mg plays a significantly critical role in thermoelectric performance and thermal stability,where most studies on these compounds have thus far concentrated on the nominal Mg content which heavily depends on the fabrication methods,with few attentions devoted to the essential issue of actual Mg content,resulting in the unclear mechanism of improving their stability,severely limiting their practical applications in thermoelectric power generation.Here,we systematically analyzed the thermoelectric performance,thermal stability,and changed micro structures before and after in situ electronic thermoelectric performance measurement at 750 K,for n-type Mg_(3)Sb_(2)-based alloys with different Mg and Co content.It was found that elemental Mg and Co have a similar effect on adjusting the electron transport characteristic,and the peak values of power factor and ZT are up to 32.4μW cm^(-1)K^(-2)and 1.8,respectively.Thermal stability is more sensitive to the Mg content of material matrix than thermoelectric performance,and the effects of Mgpoor condition on thermal stability cannot be compensated via cationic Co doping.We also proved the route of Mg loss in experiments.By balancing Mg content and Co doping,the optimized sample showed good stability,in which it reduced only by 10%over 170 h of measurement at 750 K.Density functional theory calculation showed that the bonding strength of Co-Mg is stronger than MgMg,also explaining the enhanced thermal stability.
基金Project supported by the National Natural Science Foundation of China (12174075)the Scientific and Technological Bases and Talents of Guangxi (Guike AD21220016)+1 种基金Guangxi Science and Technology Major Project(AA23073018)the special fund for Guangxi Bagui Scholars。
文摘Mn^(2+)-doped CsPbCl_(3)(Mn^(2+):CsPbCl_(3)) nanocrystals(NCs) have attracted considerable attention due to their unique strong and broad orange-red emission band,presenting promising applications in the field of photoelectric devices.However,pristine Mn^(2+):CsPbCl_(3)NCs commonly suffer from low photoluminescence quantum yield(PL QY) and stability issues.Herein,we introduced europium ions(Eu^(3+))into Mn^(2+):CsPbCl_(3)NCs via the thermal injection synthesis method to obtain high performance Eu^(3+)and Mn^(2+)codoped CsPbCl_(3)(Eu^(3+)/Mn^(2+):CsPbCl_(3)) NCs.The maximum PL QY of the resulting Eu^(3+)/Mn^(2+):CsPbCl_(3)NCs reaches up to 90.92%.It is found that the doping of Eu^(3+)ions significantly reduces the non-radiative recombination caused by high defect states,and improves the energy transfer efficiency from exciton to Mn^(2+),thereby boosting the PL performance.Moreover,doping Eu^(3+)ions notably improves the UV-light and water stability of Mn^(2+):CsPbCl_(3)NCs.We further demonstrate the application versatility of Eu^(3+)/Mn^(2+):CsPbCl_(3)NCs in white light emitting diodes(WLEDs) and optical anticounterfeiting applications.This work provides a valuable perspective for the attainment of high performance Mn^(2+):CsPbCl_(3)NCs and lays a foundation for the codoping of other lanthanide ions to adjust the luminescence properties of Mn^(2+):CsPbCl_(3)NCs.
基金supported by the Low-Cost Long-Life Batteries program,China(No.WL-24-08-01)the National Natural Science Foundation of China(No.22279007)。
文摘The outstanding performance of O3-type NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)(NFM111)at both high and low temperatures coupled with its impressive specific capacity makes it an excellent cathode material for sodium-ion batteries.However,its poor cycling,owing to highpressure phase transitions,is one of its disadvantages.In this study,Cu/Ti was introduced into NFM111 cathode material using a solidphase method.Through both theoretically and experimentally,this study found that Cu doping provides a higher redox potential in NFM111,improving its reversible capacity and charge compensation process.The introduction of Ti would enhance the cycling stability of the material,smooth its charge and discharge curves,and suppress its high-voltage phase transitions.Accordingly,the NaNi_(0.27)Fe_(0.28)Mn_(0.33)Cu_(0.05)Ti_(0.06)O_(2)sample used in the study exhibited a remarkable rate performance of 142.97 mAh·g^(-1)at 0.1 C(2.0-4.2 V)and an excellent capacity retention of 72.81%after 300 cycles at 1C(1C=150 mA·g^(-1)).
基金financially supported by the National Natural Science Foundation of China(No.22309067)the Open Project Program of the State Key Laboratory of Materials-Oriented Chemical Engineering,China(No.KL21-05)the Marine Equipment and Technology Institute,Jiangsu University of Science and Technology,China(No.XTCX202404)。
文摘This study focused on improving the cathode performance of Ba_(0.6)Sr_(0.4)Co_(0.85)Nb_(0.15)O_(3-δ)(BSCN)-based perovskite materials through molybdenum(Mo)doping.Pure BSCN and Mo-modified-BSCN—Ea_(0.6)Sr_(0.4)Co_(0.85)Nb_(0.1)Mo_(0.05)O_(3-δ)(B S CNM_(0.05)),Ba_(0.6)Sr_(0.4)Co_(0.85)Nb_(0.05)Mo_(0.1)O_(3-δ)(BSCNM_(0.1)),and Ba_(0.6)Sr_(0.4)Co_(0.85)Mo_(0.15)O_(3-δ)(BSCM)—with Mo doping contents of 5mol%,10mol%,and15mol%,respectively,were successfully prepared using the sol-gel method.The effects of Mo doping on the crystal structure,conductivity,thermal expansion coefficient,oxygen reduction reaction(ORR)activity,and electrochemical performance were systematically evaluated using X-ray diffraction analysis,thermally induced characterization,electrochemical impedance spectroscopy,and single-cell performance tests.The results revealed that Mo doping could improve the conductivity of the materials,suppress their thermal expansion effects,and significantly improve the electrochemical performance.Surface chemical state analysis using X-ray photoelectron spectroscopy revealed that 5mol%Mo doping could facilitate a high adsorbed oxygen concentration leading to enhanced ORR activity in the materials.Density functional theory calculations confirmed that Mo doping promoted the ORR activity in the materials.At an operating temperature of 600℃,the BSCNM_(0.05)cathode material exhibited significantly enhanced electrochemical impedance characteristics,with a reduced area specific resistance of 0.048Ω·cm~2,which was lower than that of the undoped BSCN matrix material by 32.39%.At the same operating temperature,an anode-supported single cell using a BSCNM_(0.05)cathode achieved a peak power density of 1477 mW·cm^(-2),which was 30.71%,56.30%,and 171.50%higher than those of BSCN,BSCNM_(0.1),and B SCM,respectively.The improved ORR activity and electrochemical performance of BSCNM_(0.05)indicate that it can be used as a cathode material in low-temperature solid oxide fuel cells.
基金supported by the National Natural Science Foundation of China (Grant Nos.12074213 and 11574108)the Major Basic Program of Natural Science Foundation of Shandong Province (Grant No.ZR2021ZD01)the Natural Science Foundation of Shandong Province (Grant No.ZR2023MA082)。
文摘In recent years,the research on superconductivity in one-dimensional(1D)materials has been attracting increasing attention due to its potential applications in low-dimensional nanodevices.However,the critical temperature(T_(c))of 1D superconductors is low.In this work,we theoretically investigate the possible high T_(c) superconductivity of(5,5)carbon nanotube(CNT).The pristine(5,5)CNT is a Dirac semimetal and can be modulated into a semiconductor by full hydrogenation.Interestingly,by further hole doping,it can be regulated into a metallic state with the sp3-hybridized𝜎electrons metalized,and a giant Kohn anomaly appears in the optical phonons.The two factors together enhance the electron–phonon coupling,and lead to high-T_(c) superconductivity.When the hole doping concentration of hydrogenated-(5,5)CNT is 2.5 hole/cell,the calculated T_(c) is 82.3 K,exceeding the boiling point of liquid nitrogen.Therefore,the predicted hole-doped hydrogenated-(5,5)CNT provides a new platform for 1D high-T_(c) superconductivity and may have potential applications in 1D nanodevices.
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supported by the National Natural Science Foundation of China(No.22278156)the Guangdong Special Support Program Project(No.2021JC060580)+1 种基金the Young Elite Scientists Sponsorship Program by CAST-Doctoral Student Special Plan,the China Scholarship Council Program(No.202406150148)the Natural Science Foundation of Guangdong Province(No.2023A1515011186).
文摘Peroxymonosulfate(PMS)-based advanced oxidation processes(AOPs)are an effective way to remove emerging contaminants(ECs)from water.The catalytic process involving PMS is hindered by the suboptimal electron trans-fer efficiency of current catalysts,the further application of AOPs technology is limited.Here,it is proposed that the interfacial electric field can be controlled by bor(B)-doped FeNC catalysts,which shows significant advantages in the efficient generation,release and participation of reactive oxygen species(ROS)in the reaction.The super exchange interaction between Fe sites and N and B sites is realized through the directional transfer of electrons in the interfacial electric field,which ensures the high efficiency and stability of the PMS catalytic process.B doping increases the d orbitals distribution at Fermi level,which facilitates enhanced electron transition activity,thereby promoting the effective generation of (1)^O_(2).At the same time,orbital hybridization causes the center of the d band to move to a lower energy level,which not only contributes to the desorption process of (1)^O_(2),but also accelerates its release.In addition,B-doping also improved the adsorption capacity of organic pollutants and shortened the migration distance of ROS,thereby significantly improving the degradation efficiency of ECs.The B-doping strategy outlined offers a novel approach to the development of FeNC catalysts,it lays a theoretical foundation and offers technical insights for the integration of PMS/AOPs technology in the ECs management.
基金The authors acknowledge financial support from NRF CRP on Oxide Electronics on Silicon Beyond Moore(NRF-CRP15-2015-01)the National Natural Science Foundation of China(Nos.U2032147,21872100,and 62004128)+2 种基金Singapore MOE Grant T2EP50220-0001,MOE AcRF Tier 1 Startup grant R-284-000-179-133the Science and Engineering Research Council of A*STAR(Agency for Science,Technology and Research)Singapore,under Grant No.A20G9b0135the Fundamental Research Foundation of Shenzhen(No.JCYJ20190808152607389).
文摘Two-dimensional(2D)transition metal dichalcogenides(TMDs)are considered to be promising building blocks for the next generation electronic and optoelectronic devices.Various doping schemes and work function engineering techniques have been explored to overcome the intrinsic performance limits of 2D TMDs.However,a reliable and long-time air stable doping scheme is still lacking in this field.In this work,we utilize keV ion beams of H2+to irradiate layered WSe2 crystals and obtain efficient n-type doping effect for all irradiated crystals within a fluence of 1×1014 protons·cm−2(1e14).Moreover,the irradiated WSe2 remains an n-type semiconductor even after it is exposed to ambient conditions for a year.Localized ion irradiation with a focused beam can directly pattern on the sample to make high performance homogenous p-n junction diodes.Raman and photoluminescence(PL)spectra demonstrate that the WSe2 crystal lattice stays intact after irradiation within 1e14.We attribute the reliable electrondoping to the significant increase in Se vacancies after the proton irradiation,which is confirmed by our scanning transmission electron microscope(STEM)results.Our work demonstrates a reliable and long-term air stable n-type doping scheme to realize high-performance electronic TMD devices,which is also suitable for further integration with other 2D devices.
基金supported by the National Natural Science Foundation of China(No.52002042)the National Postdoctoral Program for Innovative Talents(No.BX20200028)+3 种基金the National Key Research and Development Program of China(No.2018YFA0702100)China Postdoctoral Science Foundation(No.2021M690280)the Natural Science Foundation of Chongqing,China(No.cstc2019jcyj-msxmX0554)the support from the National Science Fund for Distinguished Young Scholars(No.51925101)。
文摘Recent theoretical predictions and experimental findings on the transport properties of n-type SnTe have triggered extensive researches on this simple binary compound,despite the realization of n-type SnTe being a great challenge.Herein,Cl as a donor dopant can effectively regulate the position of Fermi level in Sn_(0.6)Pb_(0.4)Te matrix and successfully achieve the n-type transport behavior in SnTe.An outstanding power factor of~14.7μW·cm^(-1)·K^(-2) at 300 K was obtained for Cl-doped Sn_(0.6)Pb_(0.4)Te sample.By combining the experimental analysis with theoretical calculations,the transport properties of n-type SnTe thermoelectrics doped with different halogen dopants(Cl,Br,and I)were then systematically investigated and estimated.The results demonstrated that Br and I had better doping efficiencies compared with Cl,which contributed to the well-optimized carrier concentrations of~1.03×10^(19)and~1.11×10^(19)cm^(-3)at 300 K,respectively.The improved n-type carrier concentrations effectively lead to the significant enhancement on the thermoelectric performance of n-type SnTe.Our study further promoted the experimental progress and deep interpretation of the transport features in n-type SnTe thermoelectrics.The present results could also be crucial for the development of n-type counterparts for SnTe-based thermoelectric devices.
基金financially supported by the National Natural Science Foundation of China(Nos.51971081 and 11674078)the Natural Science Foundation for Distinguished Young Scholars of Guangdong Province of China(No.202031515020023)Shenzhen Science and Technology Innovation Plan(No.KQJSCX20180328165435202)。
文摘The p-type TiCoSb-based half-Heuslers are widely studied due to the good electrical transport properties after hole doping,while the pristine TiCoSb is intrinsically n-type.It is thus desired to obtain a comparable n-type counterpart through optimization of electron concentration.In this work,n-type Ti_(0.9-x)HfxTa_(0.1)CoSb half-Heuslers were fabricated by arc melting,ball milling,and spark plasma sintering.An optimized carrier concentration,together with a decreased lattice thermal conductivity,was obtained by Ta doping at the Ti site,leading to a peak figure of merit(ZT)of 0.7 at 973 K in Ti_(0.9)Ta_(0.1)-CoSb.By further alloying Hf at the Ti site,the lattice thermal conductivity was significantly reduced without deteriorating the power factor.As a result,a peak ZT of 0.9 at 973 K and an average ZT of 0.54 in the temperature range of 300-973 K were achieved in Ti_(0.6)Hf_(0.3)Ti_(0.1)CoSb.This work demonstrates that n-type TiCoSb-based halfHeuslers are promising thermoelectric materials.
文摘Sol--gol method was employed to synthesize Mg doped ZnO films on Si substrates. The annealing temperature-dependent structure and optical property of the produced samples were studied. An interesting result observed is that increasing Mg concentration in the studied samples induces the full width at half maximum （FWHM） of their near-band-edge （NBE） emission decrease and the defect related emission of the corresponding sample suppresses drastically. The possible mechanism of the observed result is discussed.
基金supported by the National Natural Science Foundation of China(Grant Nos.11004230,51172273,11290161,and 11027402)the National Key Basic Research Program of China(Grant Nos.2012CB933003 and 2013CB932603)the Innovative Project of the Chinese Academy of Sciences(GrantNo.KJCX2-YW-W35)
文摘Nitrogen-doped single-walled carbon nanotubes （CNx-SWNTs） with tunable dopant concentrations were synthesized by chemical vapor deposition （CVD）, and their structure and elemental composition were characterized by using transmission electron microscopy （TEM） in combination with electron energy loss spectroscopy （EELS）. By comparing the Raman spectra of pristine and doped nanotubes, we observed the doping-induced Raman G band phonon stiffening and 2D band phonon softening, both of which reflect doping-induced renormalization of the electron and phonon energies in the nan- otubes and behave as expected in accord with the n-type doping effect. On the basis of first principles calculations of the distribution of delocalized carrier density in both the pristine and doped nanotubes, we show how the n-type doping occurs when nitrogen heteroatoms are substitutionally incorporated into the honeycomb tube-shell carbon lattice.
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the National Natural Science Foundation of China (Nos.22375059, 22005133, 51922039 and52273174)Shenzhen Science and Technology Program (No.RCJC20200714114434015)+1 种基金Science and Technology Innovation Program of Hunan Province (No.2020RC5033)National Key Research and Development Program of China (No.2020YFC1807302) for financial support。
文摘While heteroatom doping serves as a powerful strategy for devising novel polycyclic aromatic hydrocarbons(PAHs), the further fine-tuning of optoelectronic properties via the precisely altering of doping patterns remains a challenge. Herein, by changing the doping positions of heteroatoms in a diindenopyrene skeleton, we report two isomeric boron, sulfur-embedded PAHs, named Anti-B_(2)S_(2) and Syn-B_(2)S_(2), as electron transporting semiconductors. Detailed structure-property relationship studies revealed that the varied heteroatom positions not only change their physicochemical properties, but also largely affect their solid-state packing modes and Lewis base-triggered photophysical responses. With their low-lying frontier molecular orbital levels, n-type characteristics with electron mobilities up to 1.5 × 10^(-3)cm^(2)V^(-1)s^(-1)were achieved in solution-processed organic field-effect transistors. Our work revealed the critical role of controlling heteroatom doping patterns for designing advanced PAHs.
基金supported by the National Natural Science Foundation of China(21490581)China Petroleum&Chemical Corporation(317008-6)Guangxi Innovation Driven Development Foundation(AA17204092).
文摘Monometallic doping has proved its superiority in improving either permselectivity or H_(2) permeability of organosilica membranes for H_(2)/CO_(2) separation,but it is still challenging to break the trade-off effect.Herein,we report a series of Pd-Nb bimetallic doped 1,2-bis(triethoxysilyl)ethane(Pd-Nb-BTESE,PNB)membranes with different metal doping routes for simultaneously improving H_(2) permeance and H_(2)/CO_(2) permselectivity by the synergetic effects of Pd and Nb.The doped Pd can exist in the BTESE network as nanoparticles while the doped Nb is incorporated into BTESE network forming Nb-O-Si covalent bonds.The metal doping routes significantly influence the microstructure of PNB networks and gas separation performance of the PNB membranes.We found that the PNB membrane with Pd doping priority(PNB-Pd)exhibited the highest surface area and pore volume,comparing with Nb doping priority(PNB-Nb)or Pd-Nb simultaneous doping(PNB-PdNb).The PNB-Pd membrane could not only exhibit an excellent H_(2) permeance of~10^(−6) mol·m^(−2)·s^(−1)·Pa^(−1) but also a high H_(2)/CO_(2) permselectivity of 17.2.Our findings may provide novel insights into preparation of bimetallic doped organosilica membranes with excellent H_(2)/CO_(2) separation performance.
