Some active metal oxides(Al_(2)O_(3),TiO_(2),and Cr_(2)O_(3))were selected as dopants to the Al_(2)O_(3)-based ceramic shells for investment casting of K417G superalloy.The effects of dopant types and contents(0,2,5,a...Some active metal oxides(Al_(2)O_(3),TiO_(2),and Cr_(2)O_(3))were selected as dopants to the Al_(2)O_(3)-based ceramic shells for investment casting of K417G superalloy.The effects of dopant types and contents(0,2,5,and 8 wt.%)on the wettability and interfacial reaction between the alloy and shell were investigated by a sessile-drop experiment.The results show that increasing the Al_(2)O_(3) doping contents(0−8 wt.%)reduces the porosity(21.74%−10.08%)and roughness(3.22−1.34μm)of the shell surface.The increase in Cr_(2)O_(3) dopant content(2−8 wt.%)further exacerbates the interfacial reaction,leading to an increase in the thickness of the reaction layer(2.6−3.1μm)and a decrease in the wetting angle(93.9°−91.0°).The addition of Al_(2)O_(3) and TiO_(2) dopants leads to the formation of Al_(2)TiO_(5) composite oxides in the reaction products,which effectively inhibits the interfacial reaction.The increase in TiO_(2) dopant contents(0−8 wt.%)further promotes the formation of Al_(2)TiO_(5),which decreases the thickness of the interfacial reaction layer(3.9−1.2μm)and increases the wetting angle(95.0°−103.8°).The introduced dopants enhance the packing density of the shell surface,while simultaneously suppress the diffusion of active metal elements from the alloy matrix to the interface.展开更多
Tetravalent tin(Sn^(4+))-based inorganic perovskite semiconductors like Cs_(2)SnI_(6)are expected to replace lead-based perovskite counterparts due to advantages such as structural stability and environmental friendli...Tetravalent tin(Sn^(4+))-based inorganic perovskite semiconductors like Cs_(2)SnI_(6)are expected to replace lead-based perovskite counterparts due to advantages such as structural stability and environmental friendliness.In this paper,we reported the dopant compensation effect in the component-dependent self-doped(111)-oriented Cs_(2)SnI_(6)thin films grown with pulsed laser deposition(PLD)at room temperature.The films were grown on(100)-SrTiO_(3)(STO)substrates at room temperature by PLD.Hall results of the Cs_(2)SnI_(6)films with different components realizing by controlling the ratio of SnI_(4)/CsI in the targets demonstrate a clear change of conductivity type from N-type to P-type,while the carrier concentration decreases from 1018 to 1013 and accordingly the film resistivity increases significantly from 3.8 to 2506Ωcm.The defect-relatedopticalfingerprints of Cs_(2)SnI_(6)films werealsoinvestigated withtemperature-dependent photoluminescence spectroscopy.At low temperatures of 10 K,the Cs_(2)SnI_(6)films exhibit donor-bound(D^(0)X)and donor-acceptor pair(DAP)emission,respectively,due to the self-doping effect.These re-sults indicate that controlling the composition of the PLD target is a powerful way to tune the electrical properties of Cs_(2)SnI_(6)films for possible applications in solar cells or X-ray detectors.展开更多
High temperature piezoelectric energy harvester(HTPEH)is an important solution to replace chemical battery to achieve independent power supply of HT wireless sensors.However,simultaneously excellent performances,inclu...High temperature piezoelectric energy harvester(HTPEH)is an important solution to replace chemical battery to achieve independent power supply of HT wireless sensors.However,simultaneously excellent performances,including high figure of merit(FOM),insulation resistivity(ρ)and depolarization temperature(Td)are indispensable but hard to achieve in lead-free piezoceramics,especially operating at 250°C has not been reported before.Herein,well-balanced performances are achieved in BiFeO3–BaTiO3 ceramics via innovative defect engineering with respect to delicate manganese doping.Due to the synergistic effect of enhancing electrostrictive coefficient by polarization configuration optimization,regulating iron ion oxidation state by high valence manganese ion and stabilizing domain orientation by defect dipole,comprehensive excellent electrical performances(Td=340°C,ρ250°C>10^(7)Ωcm and FOM_(250°C)=4905×10^(–15)m^(2)N^(−1))are realized at the solid solubility limit of manganese ions.The HT-PEHs assembled using the rationally designed piezoceramic can allow for fast charging of commercial electrolytic capacitor at 250°C with high energy conversion efficiency(η=11.43%).These characteristics demonstrate that defect engineering tailored BF-BT can satisfy high-end HT-PEHs requirements,paving a new way in developing selfpowered wireless sensors working in HT environments.展开更多
Doping plays a pivotal role in enhancing the performance of organic semiconductors(OSCs)for advanced optoelectronic and thermoelectric applications.In this study,we systematically investigated the doping performance a...Doping plays a pivotal role in enhancing the performance of organic semiconductors(OSCs)for advanced optoelectronic and thermoelectric applications.In this study,we systematically investigated the doping performance and applicability of the ionic dopant 4-isopropyl-4′-methyldiphenyliodonium tetrakis(penta-fluorophenyl-borate)(DPI-TPFB)as a p-dopant for OSCs.Using the p-type OSC PBBT-2T as a model system,we demonstrated that DPI-TPFB shows significant doping effect,as confirmed by ESR spectra,ultraviolet-visible-near-infrared(UV-vis-NIR)absorption,and work function analysis,and enhances the electronic conductivity of PBBT-2T films by over four orders of magnitude.Furthermore,DPI-TPFB exhibited broad doping applicability,effectively doping various p-type OSCs and even imparting p-type characteristics to the n-type OSC N2200,transforming its intrinsic n-type behavior into p-type.The application of DPI-TPFB-doped PBBT-2T films in organic thermoelectric devices(OTEs)was also explored,achieving a power factor of approximately 10μW·m^(-1)·K^(-2).These findings highlight the potential of DPI-TPFB as a versatile and efficient dopant for integration into organic optoelectronic and thermoelectric devices.展开更多
The commercialization of polymer electrolyte membrane water splitting technology significantly depends on the oxygen/hydrogen evolution reaction(OER/HER)electrocatalysts;customarily catalyzed by platinum(Pt)and ruthen...The commercialization of polymer electrolyte membrane water splitting technology significantly depends on the oxygen/hydrogen evolution reaction(OER/HER)electrocatalysts;customarily catalyzed by platinum(Pt)and ruthenium/iridium oxides(RuO_(2)/IrO_(2)).In this work,we have devised a novel strategy to improve the catalytic activities towards OER and HER catalysis via the decoration of RuO_(2)with Pt.Pt dopants in ruthenium oxides(Pt-RuO_(2))create more oxygen vacancies inducing a weaker interaction between active site and oxygen reaction intermediates,evidenced by downshifted d band center and increment in e_(g)orbital filling of Ru atom;thereby,the acidic OER performance of Pt-RuO_(2)is enhanced by 3.5-fold than commercial RuO_(2)by mean of turnover frequency at 1.6 V vs.RHE.Moreover,Pt-RuO_(2)exhibits a similar HER performance to commercial Pt/C.The potential for overall water splitting is decreased by 0.18 V at100 mA/cm^(2);besides,an excellent stability is also recorded after the incorporation of Pt dopants.TheΔ_(ε_(d-p))value of Pt-RuO_(2)was 1.76 e V,which is lower than the counterpart of RuO_(2),suggesting easy electron transition between d and p orbitals,suppressing the over-oxidation of RuO_(2);thereby,a higher stability is achieved for Pt-RuO_(2).The invitation of Pt dopants to boost catalytic activity and stability has also been extended to IrO_(2).展开更多
Lithium salt-based hole transport layer(HTL)dopants commonly used in perovskite solar cells(PSCs)are known to negatively impact stability due to their intrinsic hygroscopic properties and ion migration.In this study,w...Lithium salt-based hole transport layer(HTL)dopants commonly used in perovskite solar cells(PSCs)are known to negatively impact stability due to their intrinsic hygroscopic properties and ion migration.In this study,we introduce an ammonium salt,p-methoxyphenylethylamine bis(trifluoromethyl)sulfoni mide(MPT),as a novel dual-function dopant for the HTL in PSCs.The chemical interaction between MPT and the widely used HTL material spiro-OMeTAD generates high concentrations of spiroOMeTAD^(+)radicals,effectively enhancing the doping of spiro-OMeTAD.Additionally,MPT reacts with the perovskite layer,forming a 2D perovskite structure at the perovskite/HTL interface,which passivates defects and suppresses interfacial ion migration.As a result,PSCs with MPT doping achieved a remarkable power conversion efficiency(PCE)of 25.52%for small-area devices(0.045 cm^(2))and 21.01%for mini-modules(16.8 cm^(2)).Moreover,the incorporation of MPT significantly enhances the moisture,light,and thermal stability of the PSCs by eliminating Li^(+)and suppressing I-migration.Notably,PSCs with MPT-doped PTAA retained 84%of their initial PCE after 1,300 h of aging at 60℃in a nitrogen-filled glovebox.Our work presents a unique doping strategy for the HTL in PSCs,offering a promising approach to simultaneously improve both the stability and efficiency of these devices.展开更多
To develop an efficient electrochemical CO_(2)reduction reaction(CO_(2)RR)for the production of C_(2)chemicals,improvements in the Cu catalyst are necessary.Doping is widely used for catalyst enhancement;however,only ...To develop an efficient electrochemical CO_(2)reduction reaction(CO_(2)RR)for the production of C_(2)chemicals,improvements in the Cu catalyst are necessary.Doping is widely used for catalyst enhancement;however,only a few elements have been examined.This study proposes guidelines for the selection of Cu catalyst dopants to promote ethylene production.It was hypothesized that the dopant chemical state highly influences the CO_(2)RR catalytic activity.In the case of dopants possessing a standard reduction potential within the CO_(2)RR potential region(e.g.,Mn and Ni),low Faradaic efficiency(FE)toward ethylene production was obtained owing to the presence of a metallic dopant(10.7%for Ni dopant).In contrast,a low standard reduction potential led to a stable high oxidation state for the dopant,yielding abundant Cu^(δ+)species with modified electronic structures and enhancing the CO_(2)RR catalytic activity for ethylene production(42.1%for Hf dopant).We expected that a dopant with a low standard reduction potential is difficult to reduce,which leads to a stable Cu-O-X bond and induces a stable Cu^(δ+)species.Our study provides insights into how to select dopant for various catalyst to enhance CO_(2)RR catalytic activity.展开更多
Selenium and zinc are used as anionic and cationic dopant elements to dope PbS nanostructures. The undoped and doped PbS nanostructures are grown using a thermal evaporation method. Scanning electron microscopy （SEM...Selenium and zinc are used as anionic and cationic dopant elements to dope PbS nanostructures. The undoped and doped PbS nanostructures are grown using a thermal evaporation method. Scanning electron microscopy （SEM） results show similar morphologies for the undoped and doped PbS nanostructures. X-ray diffraction （XRD） patterns of three sets of the nanostructures indicate that these nanostructures each have a PbS structure with a cubic phase. Evidence of dopant incorporation is demonstrated by X-ray photoelectron spectroscopy （XPS）. Raman spectra of the synthesized samples con- firm the XRD results and indicate five Raman active modes, which relate to the PbS cubic phase for all the nanostructures. Room temperature photoluminescence （PL） and UV-Vis spectrometers are used to study optical properties of the undoped and doped PbS nanostructures. Optical characterization shows that emission and absorption peaks are in the infrared （IR） region of the electromagnetic spectrum for all PbS nanostructures. In addition, the optical studies of the doped PbS nanos- tructures reveal that the band gap of the Se-doped PbS is smaller, and the band gap of the Zn-doped PbS is bigger than the band gap of the undoped PbS nanostructures.展开更多
Conductivity dopants with processing properties suitable for industrial applications are of importance to the organic electronics field. However, the number of commercially available organic molecular dopants is limit...Conductivity dopants with processing properties suitable for industrial applications are of importance to the organic electronics field. However, the number of commercially available organic molecular dopants is limited. The electron acceptor 2,3,5,6-tetrafluoro-7,7,8,8,-tetracyanoquinodimethane (F4-TCNQ) is the most utilized P-dopant;however, it has high volatility and a poor sticking coefficient, which makes it difficult to control doping levels and prevent vacuum system contamination. A design concept for P-type molecular dopants based on the TCNQ core which are substituted to improve processing properties without sacrificing the electronic properties necessary is presented. The correlation between the lowest unoccupied molecular orbital (LUMO) energy and the position of substitution as well as the choice of linker is evaluated. The position of substitution as well as the choice of linker has a significant effect on the electronic properties. However, the geometry of the substituted molecules was not significantly distorted from that of the parent F4-TCNQ, and the electron density was delocalized on the TCNQ core. We also put forward four possible molecular dopants with suitable energy levels.展开更多
Ti/Sb-SnO2 anodes were prepared by thermal decomposition to examine the influence of the amount of Sb dopant on the structure and electrocatalytic capability of the electrodes in the oxidation of 4-chlorophenol. The p...Ti/Sb-SnO2 anodes were prepared by thermal decomposition to examine the influence of the amount of Sb dopant on the structure and electrocatalytic capability of the electrodes in the oxidation of 4-chlorophenol. The physicochemical properties of the Sb-SnO2 coating were markedly influenced by different amounts of Sb dopant. The electrodes, which contained 5% Sb dopant in the coating, presented a much more homogenous surface and much smaller mud-cracks, compared with Ti/Sb-SnO2 electrodes containing 10% or 15% Sb dopant, which exibited larger mud cracks and pores on the surface. However, the main microstructure remained unchanged with the addition of the Sb dopant. No new crystal phase was observed by X-ray diffraction （XRD）. The electrochemical oxidation of 4-chlorophenol on the Ti/SnO2 electrode with 5% Sb dopant was inclined to electrochemical combustion; while for those containing more Sb dopant, intermediate species were accumulated. The electrodes with 5% Sb dopant showed the highest efficiency in the bulk electrolysis of 4-chlorophenol at a current density of 20 mA/cm^2 for 180 min; and the removal rates of 4-chlorophenol and COD were 51.0% and 48.9%, respectively.展开更多
In order to perform automated calculations of defect and dopant properties in semiconductors and insulators, we developed a software package, the Defect and Dopant ab-initio Simulation Package(DASP), which is composed...In order to perform automated calculations of defect and dopant properties in semiconductors and insulators, we developed a software package, the Defect and Dopant ab-initio Simulation Package(DASP), which is composed of four modules for calculating:(ⅰ) elemental chemical potentials,(ⅱ) defect(dopant) formation energies and charge-state transition levels,(ⅲ) defect and carrier densities and(ⅳ) carrier dynamics properties of high-density defects. DASP uses the materials genome database for quick determination of competing secondary phases when calculating the elemental chemical potential that stabilizes compound semiconductors. DASP calls the ab-initio software to perform the total energy, structural relaxation and electronic structure calculations of the defect supercells with different charge states, based on which the defect formation energies and charge-state transition levels are calculated. Then DASP can calculate the equilibrium densities of defects and electron and hole carriers as well as the Fermi level in semiconductors under different chemical potential conditions and growth/working temperature. For high-density defects, DASP can calculate the carrier dynamics properties such as the photoluminescence(PL) spectrum and carrier capture cross sections which can interpret the deep level transient spectroscopy(DLTS). Here we will show three application examples of DASP in studying the undoped GaN, C-doped GaN and quasi-one-dimensional SbSeI.展开更多
Nano-scale titanium oxide memristors exhibit complex conductive characteristics, which have already been proved by existing research. One possible reason for this is that more than one mechanism exists, and together t...Nano-scale titanium oxide memristors exhibit complex conductive characteristics, which have already been proved by existing research. One possible reason for this is that more than one mechanism exists, and together they codetermine the conductive behaviors of the memristor. In this paper, we first analyze the theoretical base and conductive process of a memristor, and then propose a compatible circuit model to discuss and simulate the coexistence of the dopant drift and tunnel barrier-based mechanisms. Simulation results are given and compared with the published experimental data to prove the possibility of the coexistence. This work provides a practical model and some suggestions for studying the conductive mechanisms of memristors.展开更多
Perovskite material is one of the promising classes of redox catalysts for hydrogen production through two-step ther-mochemical H20 splitting.Herein,an analogue of La1-xCaxMnO3 perovskite was systematically investigat...Perovskite material is one of the promising classes of redox catalysts for hydrogen production through two-step ther-mochemical H20 splitting.Herein,an analogue of La1-xCaxMnO3 perovskite was systematically investigated as a catalyst for thermochemical H2 evolution.The Ca doping level（x = 0.2,0.4,0.6,0.8）and re-oxidation temperature were com-prehensively optimized for the improvement of catalytic performance.According to our experimental results,La0.6-Ca0.4MnO3 perovskite displayed the highest yield of H2 at the re-oxidation temperature of 900℃ and the obtained H2 production was -10 times higher than that of the benchmark ceria catalyst under the same experimental condition.More importantly,Lao.6Ca0.4MnO3 perovskite catalyst exhibited impressive cyclic stability in repetitive O2 and H2 test.展开更多
In this work,Eu^(3+)doped SrTiO_(3)powders were synthesized by sol-gel method and the influences of Eu^(3+)dopants on the crystalline structure,micro structure mo rphology,electronic band-gap and photocatalytic perfor...In this work,Eu^(3+)doped SrTiO_(3)powders were synthesized by sol-gel method and the influences of Eu^(3+)dopants on the crystalline structure,micro structure mo rphology,electronic band-gap and photocatalytic performance for degradation of o rganic pollutant were investigated in detail.Research results reveal that the incorporated Eu^(3+)ions in SrTiO_(3)lattice are preferable to substitute the Sr^(2+)-Ti^(4+)ions pair by two Eu^(3+)ions.The presence of Eu^(3+)ions plays a significant role for the microstructure morphology of the S rTiO_(3)powders,leading to the formation of smaller size nanoparticles with a higher specific surface area.The light absorption capability of the resulting materials is improved owing to the narrowing of the band-gap induced by Eu^(3+)dopants.As a result,the enhanced photocatalytic activity application for photodegradation of Rhodamine B solution is demonstrated for the SrTiO_(3)powders doped with Eu^(3+)ions.展开更多
X-ray drive asymmetry is one of the main seeds of low-mode implosion asymmetry that blocks further improvement of the nuclear per-formance of“high-foot”experiments on the National Ignition Facility[Miller et al.,Nuc...X-ray drive asymmetry is one of the main seeds of low-mode implosion asymmetry that blocks further improvement of the nuclear per-formance of“high-foot”experiments on the National Ignition Facility[Miller et al.,Nucl.Fusion 44,S228(2004)].More particularly,the P2 asymmetry of Au's M-band flux can also severely influence the implosion performance of ignition capsules[Li et al.,Phys.Plasmas 23,072705(2016)].Here we study the smoothing effect of mid-and/or high-Z dopants in ablator on Au's M-band flux asymmetries,by modeling and comparing the implosion processes of a Ge-doped ignition capsule and a Si-doped one driven by X-ray sources with P2 M-band flux asymmetry.As the results,(1)mid-or high-Z dopants absorb hard X-rays(M-band flux)and re-emit isotropically,which helps to smooth the asymmetric M-band flux arriving at the ablation front,therefore reducing the P2 asymmetries of the imploding shell and hot spot;(2)the smoothing effect of Ge-dopant is more remarkable than Si-dopant because its opacity in Au's M-band is higher than the latter's;and(3)placing the doped layer at a larger radius in ablator is more efficient.Applying this effect may not be a main measure to reduce the low-mode implosion asymmetry,but might be of significance in some critical situations such as inertial confinement fusion(ICF)experiments very near the performance cliffs of asymmetric X-ray drives.展开更多
A series of Yb：Nd：LiNbO3 crystals tridoped with various concentrations of Zr4＋（1 mol.%, 2 mol.% and 4 mol.%） were grown by the Czochralski technique from the congruent melt. The X-ray powder diffraction, UV-Vis-N...A series of Yb：Nd：LiNbO3 crystals tridoped with various concentrations of Zr4＋（1 mol.%, 2 mol.% and 4 mol.%） were grown by the Czochralski technique from the congruent melt. The X-ray powder diffraction, UV-Vis-NIR absorption spectra and IR transmittance spectra were measured to analyze the crystal composition and defect structure. The Zr4＋, Yb3＋ and Nd3＋ ions in LiNbO3 crystal had two effects： volume compensation effect and ion valence state compensation effect. The Zr O2 doping threshold concentration was nearly 2.0 mol.%. The fluorescence emissions of Nd3＋ ions and Yb3＋ ions were observed under 808 nm excitation. The intensity of fluorescence emissions enhanced with the increasing of the Zr4＋ doping concentrations. The Zr：Yb：Nd：LiNbO3 crystals with 4 mol.% doping concentration of Zr4＋ ion revealed strong emission around 1 μm, which is of great significance for laser materials.展开更多
The Ni(OH) 2 film electrodes doped respectively with alkali-earth metal aluminum, lead, partial transition metal and some rare-earth metal(altogether 17 kinds of metals) ions were prepared by cathode electrodeposition...The Ni(OH) 2 film electrodes doped respectively with alkali-earth metal aluminum, lead, partial transition metal and some rare-earth metal(altogether 17 kinds of metals) ions were prepared by cathode electrodeposition. The electrode reaction reversibility, the difficult extent of oxygen evolution, the proton diffusion coefficient, the discharge potential of middle value and the active material utilization of the Ni(OH) 2 film electrode were compared with those of the ones doped with the metal ions by means of cyclic voltammetry, potential step and constant current charge-discharge experiments. It was found that Ca 2+ , Co 2+ , Cd 2+ , Al 3+ etc. have obviously positive effect.展开更多
Non-graphitized carbon(NGC)has been extensively utilized as carbonaceous anode in sodium-ion batteries(SIBs).However,more optimization to achieve competitive capacity and stability is still challenging for SIBs.In the...Non-graphitized carbon(NGC)has been extensively utilized as carbonaceous anode in sodium-ion batteries(SIBs).However,more optimization to achieve competitive capacity and stability is still challenging for SIBs.In the study,the dopant strategy is utilized to construct nitrogen/sulfur-doped non-graphitized carbon(N-NGC or S-NGC)shell decorated on three-dimensional graphene foam(GF)as a self-support electrode.The highly disordered microstructures of heteroatom doped carbons are produced by applying a low-temperature pyrolysis treatment to precursors containing nitrogen and sulfur.The DFT calculations of Na-ion adsorption energies at diverse heteroatom sites show marginal-S,pyrrolic N and pyridinic N with more intensive Na-ion adsorption ability than middle-S,C=O and pristine carbon.The N-NGC with dominant small graphitic regions delivers adsorption ability to Na-ion,while the S-NGC with significant single carbon lattice stripes demonstrates redox reaction with Na-ion.Evidently,in comparison with only adsorption-driven slope regions at high potential for N-NGC,the redox reaction-generated potentialplateau enables non-graphitized S-NGC superior discharge/charge capacity and cycle-stability in the slope region.This work could provide deep insight into the rational design of non-graphitized carbon with rich microstructure and composition.展开更多
The influence of technological process parameters (aiming angle and implantation energy) on the distributions of dopant concentrations in a silicon substrate is investigated by computer modeling.
A new method to increase the luminance and quantum efficiency of polymer light emitting diodes with a lower threshold voltage has been reported.The threshold voltagef luminajice and quantum efficiency have been signif...A new method to increase the luminance and quantum efficiency of polymer light emitting diodes with a lower threshold voltage has been reported.The threshold voltagef luminajice and quantum efficiency have been significantly improved by doping certain dopants with a lower highest occupied molecular orbital(HOMO)level into the hole transporting layer.A high performance device has been achieved by addition of the perylene and tri ph enylamin e as a dopant into poly(N-vinylcarbazole).The luminance and quantum efficiency increase by 2-3 times in comparison with the undoped device,reaching 10000cd/m^(2) in luminance and 0.58%in quantum efficiency,while threshold voltage is reduced to one half va/ue.The energy diagram has been obtained by measuring the HOMO levels and band gap values.Based on this,the carriers injection and balance between electrons and holes as well as the action of dopant are discussed.展开更多
基金supported by the National Natural Science Foundation of China (No. 52374292)China Baowu Low Carbon Metallurgy Innovation Foundation, China (No. BWLCF202309)the Natural Science Foundation of Changsha City, China (No. KQ2208271)。
文摘Some active metal oxides(Al_(2)O_(3),TiO_(2),and Cr_(2)O_(3))were selected as dopants to the Al_(2)O_(3)-based ceramic shells for investment casting of K417G superalloy.The effects of dopant types and contents(0,2,5,and 8 wt.%)on the wettability and interfacial reaction between the alloy and shell were investigated by a sessile-drop experiment.The results show that increasing the Al_(2)O_(3) doping contents(0−8 wt.%)reduces the porosity(21.74%−10.08%)and roughness(3.22−1.34μm)of the shell surface.The increase in Cr_(2)O_(3) dopant content(2−8 wt.%)further exacerbates the interfacial reaction,leading to an increase in the thickness of the reaction layer(2.6−3.1μm)and a decrease in the wetting angle(93.9°−91.0°).The addition of Al_(2)O_(3) and TiO_(2) dopants leads to the formation of Al_(2)TiO_(5) composite oxides in the reaction products,which effectively inhibits the interfacial reaction.The increase in TiO_(2) dopant contents(0−8 wt.%)further promotes the formation of Al_(2)TiO_(5),which decreases the thickness of the interfacial reaction layer(3.9−1.2μm)and increases the wetting angle(95.0°−103.8°).The introduced dopants enhance the packing density of the shell surface,while simultaneously suppress the diffusion of active metal elements from the alloy matrix to the interface.
基金financially supported by the National Key Re-search and Development Program of China(No.2022YFC3700801)the Key R&D Program of Shandong Province,China(No.2024SFGC0102),the Jinan Bureau of Education(No.JNSX2023015)the Jinan Bureau of Science and Technology(No.202333042).
文摘Tetravalent tin(Sn^(4+))-based inorganic perovskite semiconductors like Cs_(2)SnI_(6)are expected to replace lead-based perovskite counterparts due to advantages such as structural stability and environmental friendliness.In this paper,we reported the dopant compensation effect in the component-dependent self-doped(111)-oriented Cs_(2)SnI_(6)thin films grown with pulsed laser deposition(PLD)at room temperature.The films were grown on(100)-SrTiO_(3)(STO)substrates at room temperature by PLD.Hall results of the Cs_(2)SnI_(6)films with different components realizing by controlling the ratio of SnI_(4)/CsI in the targets demonstrate a clear change of conductivity type from N-type to P-type,while the carrier concentration decreases from 1018 to 1013 and accordingly the film resistivity increases significantly from 3.8 to 2506Ωcm.The defect-relatedopticalfingerprints of Cs_(2)SnI_(6)films werealsoinvestigated withtemperature-dependent photoluminescence spectroscopy.At low temperatures of 10 K,the Cs_(2)SnI_(6)films exhibit donor-bound(D^(0)X)and donor-acceptor pair(DAP)emission,respectively,due to the self-doping effect.These re-sults indicate that controlling the composition of the PLD target is a powerful way to tune the electrical properties of Cs_(2)SnI_(6)films for possible applications in solar cells or X-ray detectors.
基金supported by the National Natural Science Foundation of China(Grant Nos.52272103 and 52072010)Beijing Natural Science Foundation(Grant Nos.2242029 and JL23004).
文摘High temperature piezoelectric energy harvester(HTPEH)is an important solution to replace chemical battery to achieve independent power supply of HT wireless sensors.However,simultaneously excellent performances,including high figure of merit(FOM),insulation resistivity(ρ)and depolarization temperature(Td)are indispensable but hard to achieve in lead-free piezoceramics,especially operating at 250°C has not been reported before.Herein,well-balanced performances are achieved in BiFeO3–BaTiO3 ceramics via innovative defect engineering with respect to delicate manganese doping.Due to the synergistic effect of enhancing electrostrictive coefficient by polarization configuration optimization,regulating iron ion oxidation state by high valence manganese ion and stabilizing domain orientation by defect dipole,comprehensive excellent electrical performances(Td=340°C,ρ250°C>10^(7)Ωcm and FOM_(250°C)=4905×10^(–15)m^(2)N^(−1))are realized at the solid solubility limit of manganese ions.The HT-PEHs assembled using the rationally designed piezoceramic can allow for fast charging of commercial electrolytic capacitor at 250°C with high energy conversion efficiency(η=11.43%).These characteristics demonstrate that defect engineering tailored BF-BT can satisfy high-end HT-PEHs requirements,paving a new way in developing selfpowered wireless sensors working in HT environments.
基金supported by the Fundamental Research Program of Shanxi Province(Nos.202303021212159 and 202303021222190)the National Natural Science Foundation of China(No.62222403)+2 种基金the Higher Education Institutions Science and Technology Innovation Program of Shanxi Province(No.2023L160)the Scientific Research Fund of Hunan Provincial Education Department(No.23B0842)the Natural Science Foundation of Shanxi Normal University(Nos.JCYJ2024017 and JCYJ2023015)。
文摘Doping plays a pivotal role in enhancing the performance of organic semiconductors(OSCs)for advanced optoelectronic and thermoelectric applications.In this study,we systematically investigated the doping performance and applicability of the ionic dopant 4-isopropyl-4′-methyldiphenyliodonium tetrakis(penta-fluorophenyl-borate)(DPI-TPFB)as a p-dopant for OSCs.Using the p-type OSC PBBT-2T as a model system,we demonstrated that DPI-TPFB shows significant doping effect,as confirmed by ESR spectra,ultraviolet-visible-near-infrared(UV-vis-NIR)absorption,and work function analysis,and enhances the electronic conductivity of PBBT-2T films by over four orders of magnitude.Furthermore,DPI-TPFB exhibited broad doping applicability,effectively doping various p-type OSCs and even imparting p-type characteristics to the n-type OSC N2200,transforming its intrinsic n-type behavior into p-type.The application of DPI-TPFB-doped PBBT-2T films in organic thermoelectric devices(OTEs)was also explored,achieving a power factor of approximately 10μW·m^(-1)·K^(-2).These findings highlight the potential of DPI-TPFB as a versatile and efficient dopant for integration into organic optoelectronic and thermoelectric devices.
基金supported by the National Natural Science Foundation of China(No.22209126)the Opening Project of Key Laboratory of Optoelectronic Chemical Materials and Devices,Ministry of Education,Jianghan University(No.JDGD-202314)。
文摘The commercialization of polymer electrolyte membrane water splitting technology significantly depends on the oxygen/hydrogen evolution reaction(OER/HER)electrocatalysts;customarily catalyzed by platinum(Pt)and ruthenium/iridium oxides(RuO_(2)/IrO_(2)).In this work,we have devised a novel strategy to improve the catalytic activities towards OER and HER catalysis via the decoration of RuO_(2)with Pt.Pt dopants in ruthenium oxides(Pt-RuO_(2))create more oxygen vacancies inducing a weaker interaction between active site and oxygen reaction intermediates,evidenced by downshifted d band center and increment in e_(g)orbital filling of Ru atom;thereby,the acidic OER performance of Pt-RuO_(2)is enhanced by 3.5-fold than commercial RuO_(2)by mean of turnover frequency at 1.6 V vs.RHE.Moreover,Pt-RuO_(2)exhibits a similar HER performance to commercial Pt/C.The potential for overall water splitting is decreased by 0.18 V at100 mA/cm^(2);besides,an excellent stability is also recorded after the incorporation of Pt dopants.TheΔ_(ε_(d-p))value of Pt-RuO_(2)was 1.76 e V,which is lower than the counterpart of RuO_(2),suggesting easy electron transition between d and p orbitals,suppressing the over-oxidation of RuO_(2);thereby,a higher stability is achieved for Pt-RuO_(2).The invitation of Pt dopants to boost catalytic activity and stability has also been extended to IrO_(2).
基金supported by the National Natural Science Foundation of China(52172238,52102304,51902264)Open Project of Shaanxi Laboratory of Aerospace Power(2021SXSYS-01-03)the Fundamental Research Funds for the Central Universities(3102019JC0005)。
文摘Lithium salt-based hole transport layer(HTL)dopants commonly used in perovskite solar cells(PSCs)are known to negatively impact stability due to their intrinsic hygroscopic properties and ion migration.In this study,we introduce an ammonium salt,p-methoxyphenylethylamine bis(trifluoromethyl)sulfoni mide(MPT),as a novel dual-function dopant for the HTL in PSCs.The chemical interaction between MPT and the widely used HTL material spiro-OMeTAD generates high concentrations of spiroOMeTAD^(+)radicals,effectively enhancing the doping of spiro-OMeTAD.Additionally,MPT reacts with the perovskite layer,forming a 2D perovskite structure at the perovskite/HTL interface,which passivates defects and suppresses interfacial ion migration.As a result,PSCs with MPT doping achieved a remarkable power conversion efficiency(PCE)of 25.52%for small-area devices(0.045 cm^(2))and 21.01%for mini-modules(16.8 cm^(2)).Moreover,the incorporation of MPT significantly enhances the moisture,light,and thermal stability of the PSCs by eliminating Li^(+)and suppressing I-migration.Notably,PSCs with MPT-doped PTAA retained 84%of their initial PCE after 1,300 h of aging at 60℃in a nitrogen-filled glovebox.Our work presents a unique doping strategy for the HTL in PSCs,offering a promising approach to simultaneously improve both the stability and efficiency of these devices.
基金supported by Research Project for‘Carbon Upcycling Project for Platform Chemicals’of the National Research Foundation(NRF)funded by the Ministry of Science and ICT,Republic of Korea(grant number:2022M3J3A1050053)supported by the National Research Council of Science&Technology(NST)grant by the Korean government(MSIT)(No.CAP21011-100)+1 种基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(RS-2023-00302697)institutional program grants from the Korea Institute of Science and Technology。
文摘To develop an efficient electrochemical CO_(2)reduction reaction(CO_(2)RR)for the production of C_(2)chemicals,improvements in the Cu catalyst are necessary.Doping is widely used for catalyst enhancement;however,only a few elements have been examined.This study proposes guidelines for the selection of Cu catalyst dopants to promote ethylene production.It was hypothesized that the dopant chemical state highly influences the CO_(2)RR catalytic activity.In the case of dopants possessing a standard reduction potential within the CO_(2)RR potential region(e.g.,Mn and Ni),low Faradaic efficiency(FE)toward ethylene production was obtained owing to the presence of a metallic dopant(10.7%for Ni dopant).In contrast,a low standard reduction potential led to a stable high oxidation state for the dopant,yielding abundant Cu^(δ+)species with modified electronic structures and enhancing the CO_(2)RR catalytic activity for ethylene production(42.1%for Hf dopant).We expected that a dopant with a low standard reduction potential is difficult to reduce,which leads to a stable Cu-O-X bond and induces a stable Cu^(δ+)species.Our study provides insights into how to select dopant for various catalyst to enhance CO_(2)RR catalytic activity.
基金the Iranian National Science Foundation (INSF) for a research grant support the Islamic Azad University(I.A.U.), Masjed-Soleiman and Ahwaz Branches, respectively, for their financial support of this research workthe financial support from the Ministry of Higher Education of Malaysia for the High Impact Research Grant (UM.C/1/HIR/MOHE/SC/21)
文摘Selenium and zinc are used as anionic and cationic dopant elements to dope PbS nanostructures. The undoped and doped PbS nanostructures are grown using a thermal evaporation method. Scanning electron microscopy （SEM） results show similar morphologies for the undoped and doped PbS nanostructures. X-ray diffraction （XRD） patterns of three sets of the nanostructures indicate that these nanostructures each have a PbS structure with a cubic phase. Evidence of dopant incorporation is demonstrated by X-ray photoelectron spectroscopy （XPS）. Raman spectra of the synthesized samples con- firm the XRD results and indicate five Raman active modes, which relate to the PbS cubic phase for all the nanostructures. Room temperature photoluminescence （PL） and UV-Vis spectrometers are used to study optical properties of the undoped and doped PbS nanostructures. Optical characterization shows that emission and absorption peaks are in the infrared （IR） region of the electromagnetic spectrum for all PbS nanostructures. In addition, the optical studies of the doped PbS nanos- tructures reveal that the band gap of the Se-doped PbS is smaller, and the band gap of the Zn-doped PbS is bigger than the band gap of the undoped PbS nanostructures.
文摘Conductivity dopants with processing properties suitable for industrial applications are of importance to the organic electronics field. However, the number of commercially available organic molecular dopants is limited. The electron acceptor 2,3,5,6-tetrafluoro-7,7,8,8,-tetracyanoquinodimethane (F4-TCNQ) is the most utilized P-dopant;however, it has high volatility and a poor sticking coefficient, which makes it difficult to control doping levels and prevent vacuum system contamination. A design concept for P-type molecular dopants based on the TCNQ core which are substituted to improve processing properties without sacrificing the electronic properties necessary is presented. The correlation between the lowest unoccupied molecular orbital (LUMO) energy and the position of substitution as well as the choice of linker is evaluated. The position of substitution as well as the choice of linker has a significant effect on the electronic properties. However, the geometry of the substituted molecules was not significantly distorted from that of the parent F4-TCNQ, and the electron density was delocalized on the TCNQ core. We also put forward four possible molecular dopants with suitable energy levels.
基金Project supported by the Institute of Environmental Engineering,Peking University and China Postdoctoral Science Foundation(No.2005037032)
文摘Ti/Sb-SnO2 anodes were prepared by thermal decomposition to examine the influence of the amount of Sb dopant on the structure and electrocatalytic capability of the electrodes in the oxidation of 4-chlorophenol. The physicochemical properties of the Sb-SnO2 coating were markedly influenced by different amounts of Sb dopant. The electrodes, which contained 5% Sb dopant in the coating, presented a much more homogenous surface and much smaller mud-cracks, compared with Ti/Sb-SnO2 electrodes containing 10% or 15% Sb dopant, which exibited larger mud cracks and pores on the surface. However, the main microstructure remained unchanged with the addition of the Sb dopant. No new crystal phase was observed by X-ray diffraction （XRD）. The electrochemical oxidation of 4-chlorophenol on the Ti/SnO2 electrode with 5% Sb dopant was inclined to electrochemical combustion; while for those containing more Sb dopant, intermediate species were accumulated. The electrodes with 5% Sb dopant showed the highest efficiency in the bulk electrolysis of 4-chlorophenol at a current density of 20 mA/cm^2 for 180 min; and the removal rates of 4-chlorophenol and COD were 51.0% and 48.9%, respectively.
基金supported by the joint project between Hongzhiwei Technology (Shanghai) Co., Ltd. and Fudan University。
文摘In order to perform automated calculations of defect and dopant properties in semiconductors and insulators, we developed a software package, the Defect and Dopant ab-initio Simulation Package(DASP), which is composed of four modules for calculating:(ⅰ) elemental chemical potentials,(ⅱ) defect(dopant) formation energies and charge-state transition levels,(ⅲ) defect and carrier densities and(ⅳ) carrier dynamics properties of high-density defects. DASP uses the materials genome database for quick determination of competing secondary phases when calculating the elemental chemical potential that stabilizes compound semiconductors. DASP calls the ab-initio software to perform the total energy, structural relaxation and electronic structure calculations of the defect supercells with different charge states, based on which the defect formation energies and charge-state transition levels are calculated. Then DASP can calculate the equilibrium densities of defects and electron and hole carriers as well as the Fermi level in semiconductors under different chemical potential conditions and growth/working temperature. For high-density defects, DASP can calculate the carrier dynamics properties such as the photoluminescence(PL) spectrum and carrier capture cross sections which can interpret the deep level transient spectroscopy(DLTS). Here we will show three application examples of DASP in studying the undoped GaN, C-doped GaN and quasi-one-dimensional SbSeI.
基金supported by the National Natural Science Foundation of China(Grant No.61171017)
文摘Nano-scale titanium oxide memristors exhibit complex conductive characteristics, which have already been proved by existing research. One possible reason for this is that more than one mechanism exists, and together they codetermine the conductive behaviors of the memristor. In this paper, we first analyze the theoretical base and conductive process of a memristor, and then propose a compatible circuit model to discuss and simulate the coexistence of the dopant drift and tunnel barrier-based mechanisms. Simulation results are given and compared with the published experimental data to prove the possibility of the coexistence. This work provides a practical model and some suggestions for studying the conductive mechanisms of memristors.
基金financially supported by Australian Research Council(ARC)the National Natural Science Foundation of China(Grant Nos.51372248 and 51432009)
文摘Perovskite material is one of the promising classes of redox catalysts for hydrogen production through two-step ther-mochemical H20 splitting.Herein,an analogue of La1-xCaxMnO3 perovskite was systematically investigated as a catalyst for thermochemical H2 evolution.The Ca doping level（x = 0.2,0.4,0.6,0.8）and re-oxidation temperature were com-prehensively optimized for the improvement of catalytic performance.According to our experimental results,La0.6-Ca0.4MnO3 perovskite displayed the highest yield of H2 at the re-oxidation temperature of 900℃ and the obtained H2 production was -10 times higher than that of the benchmark ceria catalyst under the same experimental condition.More importantly,Lao.6Ca0.4MnO3 perovskite catalyst exhibited impressive cyclic stability in repetitive O2 and H2 test.
基金Project supported by the National Natural Science Foundation of China(51777138)Natural Science Foundation of Tianjin City(18JCZDJC99700,18JCYBJC87400,18JCQNJC73900)Scientific Developing Foundation of Tianjin Education Commission(2018KJ130)。
文摘In this work,Eu^(3+)doped SrTiO_(3)powders were synthesized by sol-gel method and the influences of Eu^(3+)dopants on the crystalline structure,micro structure mo rphology,electronic band-gap and photocatalytic performance for degradation of o rganic pollutant were investigated in detail.Research results reveal that the incorporated Eu^(3+)ions in SrTiO_(3)lattice are preferable to substitute the Sr^(2+)-Ti^(4+)ions pair by two Eu^(3+)ions.The presence of Eu^(3+)ions plays a significant role for the microstructure morphology of the S rTiO_(3)powders,leading to the formation of smaller size nanoparticles with a higher specific surface area.The light absorption capability of the resulting materials is improved owing to the narrowing of the band-gap induced by Eu^(3+)dopants.As a result,the enhanced photocatalytic activity application for photodegradation of Rhodamine B solution is demonstrated for the SrTiO_(3)powders doped with Eu^(3+)ions.
基金This work is partly supported by the National Natural Science Foundation of China under Grant Nos.11575034,11275031,11475033the Fundamental Research Program of CAEP(Contract No.2013A0102002).
文摘X-ray drive asymmetry is one of the main seeds of low-mode implosion asymmetry that blocks further improvement of the nuclear per-formance of“high-foot”experiments on the National Ignition Facility[Miller et al.,Nucl.Fusion 44,S228(2004)].More particularly,the P2 asymmetry of Au's M-band flux can also severely influence the implosion performance of ignition capsules[Li et al.,Phys.Plasmas 23,072705(2016)].Here we study the smoothing effect of mid-and/or high-Z dopants in ablator on Au's M-band flux asymmetries,by modeling and comparing the implosion processes of a Ge-doped ignition capsule and a Si-doped one driven by X-ray sources with P2 M-band flux asymmetry.As the results,(1)mid-or high-Z dopants absorb hard X-rays(M-band flux)and re-emit isotropically,which helps to smooth the asymmetric M-band flux arriving at the ablation front,therefore reducing the P2 asymmetries of the imploding shell and hot spot;(2)the smoothing effect of Ge-dopant is more remarkable than Si-dopant because its opacity in Au's M-band is higher than the latter's;and(3)placing the doped layer at a larger radius in ablator is more efficient.Applying this effect may not be a main measure to reduce the low-mode implosion asymmetry,but might be of significance in some critical situations such as inertial confinement fusion(ICF)experiments very near the performance cliffs of asymmetric X-ray drives.
基金supported by the Youth Science Fund of Heilongjiang Province of China(QC2015061)
文摘A series of Yb：Nd：LiNbO3 crystals tridoped with various concentrations of Zr4＋（1 mol.%, 2 mol.% and 4 mol.%） were grown by the Czochralski technique from the congruent melt. The X-ray powder diffraction, UV-Vis-NIR absorption spectra and IR transmittance spectra were measured to analyze the crystal composition and defect structure. The Zr4＋, Yb3＋ and Nd3＋ ions in LiNbO3 crystal had two effects： volume compensation effect and ion valence state compensation effect. The Zr O2 doping threshold concentration was nearly 2.0 mol.%. The fluorescence emissions of Nd3＋ ions and Yb3＋ ions were observed under 808 nm excitation. The intensity of fluorescence emissions enhanced with the increasing of the Zr4＋ doping concentrations. The Zr：Yb：Nd：LiNbO3 crystals with 4 mol.% doping concentration of Zr4＋ ion revealed strong emission around 1 μm, which is of great significance for laser materials.
基金Supported by the Science Foundation of Jilin Province( No.980 5 6 2
文摘The Ni(OH) 2 film electrodes doped respectively with alkali-earth metal aluminum, lead, partial transition metal and some rare-earth metal(altogether 17 kinds of metals) ions were prepared by cathode electrodeposition. The electrode reaction reversibility, the difficult extent of oxygen evolution, the proton diffusion coefficient, the discharge potential of middle value and the active material utilization of the Ni(OH) 2 film electrode were compared with those of the ones doped with the metal ions by means of cyclic voltammetry, potential step and constant current charge-discharge experiments. It was found that Ca 2+ , Co 2+ , Cd 2+ , Al 3+ etc. have obviously positive effect.
基金supported by the National Natural Science Foundation of China(52272296,51502092)the Fundamental Research Funds for the Central Universities(JKD01211601,1222201718002)+1 种基金the National Overseas High-Level Talent Youth Program in Chinathe Eastern Scholar Project of Shanghai。
文摘Non-graphitized carbon(NGC)has been extensively utilized as carbonaceous anode in sodium-ion batteries(SIBs).However,more optimization to achieve competitive capacity and stability is still challenging for SIBs.In the study,the dopant strategy is utilized to construct nitrogen/sulfur-doped non-graphitized carbon(N-NGC or S-NGC)shell decorated on three-dimensional graphene foam(GF)as a self-support electrode.The highly disordered microstructures of heteroatom doped carbons are produced by applying a low-temperature pyrolysis treatment to precursors containing nitrogen and sulfur.The DFT calculations of Na-ion adsorption energies at diverse heteroatom sites show marginal-S,pyrrolic N and pyridinic N with more intensive Na-ion adsorption ability than middle-S,C=O and pristine carbon.The N-NGC with dominant small graphitic regions delivers adsorption ability to Na-ion,while the S-NGC with significant single carbon lattice stripes demonstrates redox reaction with Na-ion.Evidently,in comparison with only adsorption-driven slope regions at high potential for N-NGC,the redox reaction-generated potentialplateau enables non-graphitized S-NGC superior discharge/charge capacity and cycle-stability in the slope region.This work could provide deep insight into the rational design of non-graphitized carbon with rich microstructure and composition.
文摘The influence of technological process parameters (aiming angle and implantation energy) on the distributions of dopant concentrations in a silicon substrate is investigated by computer modeling.
基金Supported by the National Natural Science Foundation of China.
文摘A new method to increase the luminance and quantum efficiency of polymer light emitting diodes with a lower threshold voltage has been reported.The threshold voltagef luminajice and quantum efficiency have been significantly improved by doping certain dopants with a lower highest occupied molecular orbital(HOMO)level into the hole transporting layer.A high performance device has been achieved by addition of the perylene and tri ph enylamin e as a dopant into poly(N-vinylcarbazole).The luminance and quantum efficiency increase by 2-3 times in comparison with the undoped device,reaching 10000cd/m^(2) in luminance and 0.58%in quantum efficiency,while threshold voltage is reduced to one half va/ue.The energy diagram has been obtained by measuring the HOMO levels and band gap values.Based on this,the carriers injection and balance between electrons and holes as well as the action of dopant are discussed.
