Solution-processed oxide semiconductors have been considered as a potential alternative to vacuum-based ones in printable electronics.However,despite spincoated InZnO(IZO)thin-film transistors(TFTs)have shown a relati...Solution-processed oxide semiconductors have been considered as a potential alternative to vacuum-based ones in printable electronics.However,despite spincoated InZnO(IZO)thin-film transistors(TFTs)have shown a relatively high mobil-ity,the lack of carrier suppressor and the high sensitivity to oxygen and water molecules in ambient air make them potentially suffer issues of poor stability.In this work,Al is used as the third cation doping element to study the effects on the electrical,optoelectronic,and physical properties of IZO TFTs.A hydrophobic self-assembled monolayer called octadecyltrimethoxysilane is introduced as the surface passivation layer,aiming to reduce the effects from air and understand the importance of top surface conditions in solution-processed,ultra-thin oxide TFTs.Owing to the reduced trap states within the film and at the top surface enabled by the doping and passivation,the optimized TFTs show an increased current on/off ratio,a reduced drain current hysteresis,and a significantly enhanced bias stress stability,compared with the untreated ones.By combining with high-capacitance AlO_(x),TFTs with a low operating voltage of 1.5 V,a current on/off ratio of>10^(4) and a mobility of 4.6 cm^(2)/(V·s)are demonstrated,suggesting the promising features for future low-cost,low-power electronics.展开更多
Cobalt-free cathode materials are attractive for their high capacity and low cost,yet they still encounter issues with structural and surface instability.AlPO_(4),in particular,has garnered attention as an effective s...Cobalt-free cathode materials are attractive for their high capacity and low cost,yet they still encounter issues with structural and surface instability.AlPO_(4),in particular,has garnered attention as an effective stabilizer for bulk and surface.However,the impact of interfacial reactions and elemental interdiffusion between AlPO_(4) and LiNi_(0.95)Mn_(0.05)O_(2) upon sintering on the bulk and surface remains elusive.In this study,we demonstrate that during the heat treatment process,AlPO_(4) decomposes,resulting in Al doping into the bulk of the cathode through elemental interdiffusion.Simultaneously,PO_(4)^(3-)reacts with the surface Li of material to form a Li_3PO_(4) coating,inducing lithium deficiency,thereby increasing Li/Ni mixing.The suitable Li/Ni mixing,previously overlooked in AlPO_(4) modification,plays a pivotal role in stabilizing the bulk and surface,exceeding the synergy of Al doping and Li_3PO_(4) coating.The presence of Ni^(2+)ions in the lithium layers contributes to the stabilization of the delithiated structure via a structural pillar effect.Moreover,suitable Li/Ni mixing can stabilize the lattice oxygen and electrode-electrolyte interface by increasing oxygen removal energy and reducing the overlap between the Ni^(3+/4+)e_g and O^(2-)2p orbitals.These findings offer new perspectives for the design of stable cobalt-free cathode materials.展开更多
The poor structural stability and capacity retention of the high-voltage spinel-type LiNi_(0.5)Mn_(1.5)O_(4)(LNMO)limits their further application.Herein,Al and Co were doped in LNMO materials for a more stable struct...The poor structural stability and capacity retention of the high-voltage spinel-type LiNi_(0.5)Mn_(1.5)O_(4)(LNMO)limits their further application.Herein,Al and Co were doped in LNMO materials for a more stable structure and capacity.The LNMO,LiNi_(0.45)Al_(0.05)Mn_(1.5)O_(4)(LNAMO)and LiNi_(0.45)Co_(0.05)Mn_(1.5)O_(4)(LNCMO)were synthesized by calcination at 900℃ for 8 h,which was called as solid-phase method and applied universally in industry.XRD,FT-IR and CV test results showed the synthesized samples have cation disordering Fd-3m space group structures.Moreover,the incorporation of Al and Co increased the cation disordering of LNMO,thereby increasing the transfer rate of Li+.The SEM results showed that the doped samples performed more regular and ortho-octahedral.The EDS elemental analysis confirmed the uniform distribution of each metal element in the samples.Moreover,the doped samples showed better electrochemical properties than undoped LNMO.The LNAMO and LNCMO samples were discharged with specific capacities of 116.3 mA·h·g^(-1)and 122.8 mA·h·g^(-1)at 1 C charge/discharge rate with good capacity retention of 95.8% and 94.8% after 200 cycles at room temperature,respectively.The capacity fading phenomenon of the doped samples at 50℃ and 1 C rate was significantly improved.Further,cations doping also enhanced the rate performance,especially for the LNCMO,the discharge specific capacity of 117.9 mA·h·g^(-1)can be obtained at a rate of 5 C.展开更多
LaTaON_(2)is an attractive visible-light-active photocatalyst for water splitting due to its broad visible light absorption as far as 650 nm and proper band edge positions.Notwithstanding these promising properties,La...LaTaON_(2)is an attractive visible-light-active photocatalyst for water splitting due to its broad visible light absorption as far as 650 nm and proper band edge positions.Notwithstanding these promising properties,LaTaON_(2)generally exhibits poor photocatalytic activity because of its high defect concentration that severely hinders charge separation.Here,LaTaON_(2)has been modified by doping Al into the Ta sublattice,i.e.,LaTa_(1−x)Al_(x)O_(1+y)N_(2−y)(0≤x≤0.20).Al doping not only inhibits the defect concentration and increases surface hydrophilicity but also maintains the desired visible light absorption of LaTaON_(2).These important modifications substantially ameliorate the charge separation conditions within LaTaON_(2)and are responsible for a much enhanced photocatalytic performance for water redox reactions under visible light illumination.Under optimal conditions,the Al-doped LaTaON_(2)delivers an apparent quantum efficiency of 1.17%at 420±20 nm for water oxidation into O_(2),outperforming most LaTaON_(2)-based photocatalysts.These findings highlight Al as a useful dopant to open up the photocatalytic potential of metal oxynitrides whose activity is often undermined by a high defect concentration.展开更多
A uniform Al-doped LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2) cathode material was prepared using a coprecipitation method to take advantage of the positive effect of Al on regenerated NCM(Ni,Co,Mn)cathode materials and ameliora...A uniform Al-doped LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2) cathode material was prepared using a coprecipitation method to take advantage of the positive effect of Al on regenerated NCM(Ni,Co,Mn)cathode materials and ameliorate cumbersome and high-cost impurity removal processes during lithium-ion battery recycling.When the Al^(3+) content in the leachate was 1 at.%with respect to the total amount of transition metals(Ni,Co,and Mn),the produced Al-doped NCM cathode material increased concentrations of lattice oxygen and Ni^(2+).The initial specific capacity at 0.1C was 167.4 mA·h/g,with a capacity retention of 79.1%after 400 cycles at 1C.Further,this Al-doped sample showed improved rate performance and a smaller electrochemical impedance.These findings provide a reference for developing industrial processes to resynthesize cathode materials with improved electrochemical performance by incorporating Al^(3+) impurities produced during lithium-ion battery recycling.展开更多
LiNi0.78 Co0.2 Al0.02O2 cathode materials were prepared with a novel co-precipitation method followed by heat-treating. The properties of the materials were characterized. XRD patterns showed that no secondary phase a...LiNi0.78 Co0.2 Al0.02O2 cathode materials were prepared with a novel co-precipitation method followed by heat-treating. The properties of the materials were characterized. XRD patterns showed that no secondary phase appeared and the hexagonal lattice parameter c of LiNi0.rsCoo.2AI^0202 was larger than that of LiNi0.8Co0.2O2. The SEM images indicated that the powders of the material were submicron size. The results of the ICP-AES analysis proved that elemental compositions of the material were similar to those of the targeted one. Cyclic voltammetry (3.0- 4. 2 V) illustrated that the new material had good lithium-ion intercalation/de-intercalation performance. The results of galvanostatic cycling showed that the initial specific discharge capacity of the prepared material was 181.4 mAh/g, and the specific discharge capacity was 177.3 mAh/g after 100 cycles (0. 2C, 3.0 - 4. 2 V, vs. Li^+/Li) with the capacity retention ratio of 97.7%.展开更多
The relation among electronic structure, chemical bond and property of Ti3SiC2 and Al-doped was studied by density function and discrete variation ( DFT- DVM) method. When Al element is added into Ti3 SiC2 , there i...The relation among electronic structure, chemical bond and property of Ti3SiC2 and Al-doped was studied by density function and discrete variation ( DFT- DVM) method. When Al element is added into Ti3 SiC2 , there is a less difference of ionic bond, which does not play a leading role to influent the properties. After adding Al, the covalent bond of Al and the near Ti becomes somewhat weaker, but the covalent bond of Al and the Si in the same layer is obviously stronger than that of Si and Si before adding. Therefore, in preparation of Ti3 SiC2 , adding a proper quantity of Al can promote the formation of Ti3 SiC2 . The density of stnte shows that there is a mixed conductor character in both of Ti3 SiC2 and adding Al element. Ti3 SiC2 is with more tendencies to form a semiconductor. The total density of state near Fermi lever after adding Al is larger than that before adding, so the electric conductivity may increase after adding Al.展开更多
The optical components of the visible light band are widely used in daily life and industrial development. However due to the serious loss of light and the high cost, the application is limited. The broadband gap meta...The optical components of the visible light band are widely used in daily life and industrial development. However due to the serious loss of light and the high cost, the application is limited. The broadband gap metasurface will change this situation due to its low absorption and high efficiency. Herein, we simulate a size-adjustable metasurface of the Al doped ZnO (AZO) nanorod arrays based on finite difference time domain method (FDTD) which can realize the conversion of amplitude polarization and phase in the full visible band. The corresponding theoretical polarization conversion efficiency can reach as high as 91.48% (450 nm), 95.27% (530 nm), and 91.01% (65 nm). The modulation of focusing wavelength can be realized by directly adjusting the height of the AZO nanorod. The designed half-wave plate and metalens can be applied in the imaging power modulation halfwave conversion and enriching the spectroscopy.展开更多
(Fe_(73)Ga_(27−x)Al_(x))_(99.8)Tb_(0.2)(x=0,1,2,3,4,5)alloys were prepared by vacuum arc furnace to investigate the effect of Al addition on the microstructure,magnetic properties,and mechanical properties of alloys.R...(Fe_(73)Ga_(27−x)Al_(x))_(99.8)Tb_(0.2)(x=0,1,2,3,4,5)alloys were prepared by vacuum arc furnace to investigate the effect of Al addition on the microstructure,magnetic properties,and mechanical properties of alloys.Results show that the phase structure of the alloys is still A2 phase and Tb_(2)Fe_(17) phase,and the metallographic structure is composed of cellular crystal and columnar dendrite.The decrease in lattice constant,the intensification of(100)orientation,and the generation of Tb_(2)Fe_(17) phase at the grain boundary exert significant effect on the magnetostrictive properties.The fracture morphology of the alloys is intergranular brittle fracture and cleavage fracture,and the causes of fracture occurrence include the segregation of Tb and Al elements.The parallel magnetostrictive strain(λ_(∥))of(Fe_(73)Ga_(24)Al_(3))_(99.8)Tb_(0.2)alloy peaks at 1.04×10^(−4).It is worth noting that compared with those of(Fe_(73)Ga_(27))_(99.8)Tb_(0.2)alloy,theλ_(∥)and elongation of(Fe_(73)Ga_(26)Al_(1))_(99.8)Tb_(0.2)alloy increase by 18.3%and 53.4%,respectively.Besides,(Fe_(73)Ga_(26)Al_(1))_(99.8)Tb_(0.2)alloy possesses the characteristics of high saturation magnetization(Ms),low remanent magnetization(M_(r)),and coercivity(H_(c)),which is beneficial to reduce the cost in actual production,but its tensile strength and Vickers hardness decrease to a certain extent.Therefore,the investigation on the micro-mechanism of Al addition on Fe-Ga alloys is of great significance for the development of Fe-Ga alloy devices.展开更多
N2O is a powerful greenhouse gas and plays an important role in destructing the ozone layer. This present work investigated the effects of Pd doping on N2O formation over Pt/BaO/Al2O3 catalyst. Three types of catalyst...N2O is a powerful greenhouse gas and plays an important role in destructing the ozone layer. This present work investigated the effects of Pd doping on N2O formation over Pt/BaO/Al2O3 catalyst. Three types of catalysts, Pt/BaO/Al2O3, Pt/Pd mechanical mixing catalyst (Pt/BaO/Al203 + Pd/Al2O3) and Pt-Pd co-impregnation catalyst (Pt-Pd/BaO/Al2O3) were prepared by incipient wetness imoreenation method. These catalysts were first evaluated in NSR activity tests using H2/CO as reductants and then carefully characterized by BET, CO chemisorption, CO-DRIFTs and H2-TPR techniques. In addition, temperature programmed reactions of NO with H2/CO were conducted to obtain further information about NzO formation mechanism. Compared with Pt/BaO/Al2O3 (Pt/BaO/Al2O3 + Pd/Al2O3) produced less N2O and more NH3 during NOx storage and reduction process, while an opposite trend was found over (Pt-Pd/BaO/Al2O3 + Al2O3). Temperature programmed reactions of NO with H2/CO results showed that Pd/Al2O3 component in (Pt/BaO/Al2O3 + Pd/Al2O3) played an important role in NO reduction to NH3, and the formed NH3 could reduce NOx to N2 leading to a decrease in N2O formation. Most of N2O formed over (Pt-Pd/BaO/Al2O3 + Al2O3) was originated from Pd/BaO/Al2O3 component. H2-TPR results indicated Pd-Ba interaction resulted in more difficult- to-reduce PdOx species over Pd/BaO/Al2O3, which inhibits the NO dissociation and thus drives the selectivity to N2O in NO reduction.展开更多
In the work,supported catalysts of FeO_(x) and MnO_(x) co-supported on aluminum-modified CeO_(2)was synthesized for low-temperature NH_(3)-selective catalytic reduction(NH_(3)-SCR)of NO.Impressively,the SCR activity o...In the work,supported catalysts of FeO_(x) and MnO_(x) co-supported on aluminum-modified CeO_(2)was synthesized for low-temperature NH_(3)-selective catalytic reduction(NH_(3)-SCR)of NO.Impressively,the SCR activity of the obtained catalyst is markedly influenced by the adding amount of Al and the appropriate Ce/Al molar ratio is 1/2.The activity tests demonstrate that Fe-Mn/Ce1 Al2 catalyst shows over 90%NO conversion at 75-250℃and exhibits better SO_(2)resistance compared to Fe-Mn/CeO_(2).Fe-Mn/Ce1 Al2 shows the expected physicochemical characters of the ideal catalyst including the larger surface and increased active reaction active sites by controlling the amount of Al doping.Also,the better catalytic activity is well correlated with the present advantaged surface adsorption oxygen species,Mn^(4+)species,Ce^(3+)species and the enhanced reducibility of Fe-Mn/Ce1 Al2,which is superior to the Fe-Mn/CeO_(2)catalyst.More importantly,we further demonstrate that the amount and strength of surface acid sites are improved by Al-doping and more active intermediates(monodentate nitrate)is generated during NH_(3)-SCR reaction.This work provides certain insight into the rational creation of simple and practical denitration catalyst environmental purification.展开更多
The effect of Al doping on the J-V characteristics sol-gel derived of ZnO/p-Si photodiodes was investigated.The resistivity of Si was 0.1Ω·cm.ZnO films annealed at 500℃ were of the best quality.To investigate t...The effect of Al doping on the J-V characteristics sol-gel derived of ZnO/p-Si photodiodes was investigated.The resistivity of Si was 0.1Ω·cm.ZnO films annealed at 500℃ were of the best quality.To investigate the spectral response of the photodiodes,the J-V characteristics were measured under different monochromatic lights at wavelength 420,530,570 and 630 nm.The diodes exhibit strong responsivity in the blue region at 420 nm.The responsivity is 0.22 A/W for Al doped (0.8 wt pct) photodiode,whereas for the undoped photodiode,it was much lower.An estimate of the responsivity as a function of wavelength has been made in terms of the width of depletion region of photodiodes.展开更多
To evaluate the charge transport properties of as-grown high resistivity CdZnTe crystals doped with In/Al, the α particle spectroscopic response was measured using an un-collimated 241Am (5.48 MeV) radioactive sour...To evaluate the charge transport properties of as-grown high resistivity CdZnTe crystals doped with In/Al, the α particle spectroscopic response was measured using an un-collimated 241Am (5.48 MeV) radioactive source at room temperature. The electron mobility lifetime products (μτ)e of the CdZnTe crystals were predicted by fitting plots of photo-peak position versus electrical field strength using the single carrier Hecht equation. A TOF technique was employed to evaluate the electron mobility for CdZnTe crystals. The mobility was obtained by fitting the electron drift velocities as a function of the electrical field strengths, where the drift velocities were achieved by analyzing the rise-time distributions of the voltage pulses formed by a preamplifier. A fabricated CdZnTe planar detector based on a low In concentration doped CdZnTe crystal with (μτ)e = 2.3 × 10?3 cm2/V and μe =1000 cm2/(V·s), respectively, exhibits an excellent γ-ray spectral resolution of 6.4% (FWHM = 3.8 keV) for an un-collimated 241Am @ 59.54 keV isotope.展开更多
Formaldehyde(HCHO) is one kind of common indoor toxic pollutant,the catalytic oxidation degradation of formaldehyde at room temperature is desired.In this work,a new single atomic catalyst(SAC),Al doped graphene,for t...Formaldehyde(HCHO) is one kind of common indoor toxic pollutant,the catalytic oxidation degradation of formaldehyde at room temperature is desired.In this work,a new single atomic catalyst(SAC),Al doped graphene,for the catalytic oxidation of HCHO molecules was proposed through density function theory(DFT) calculations.It is found that Al atoms can be adsorbed on graphene stably without aggre s sion.Then HCHO can be effectively oxidized into CO2 and H2 O in the presence of O2 molecules on Al doped graphene with a low energy barrier of 0.82 eV and releasing energy of 2.29 eV with the pathway of HCHO→HCOOH→CO→CO2.The oxidation reaction can happen promptly with reaction time τ=56.9 s at the speed control step at room temperature.Therefore,this work proposed a high-performance catalyst Al-doped graphene without any noble metal for HCHO oxidation at ambient temperature,and corresponding oxidation pathway and mechanism are also deeply understood.展开更多
Low-loss tungsten–bronze microwave dielectric ceramics are dielectric materials with potential application value for miniaturized dielectric filters and antennas in the fifth-generation(5G)communication technology.In...Low-loss tungsten–bronze microwave dielectric ceramics are dielectric materials with potential application value for miniaturized dielectric filters and antennas in the fifth-generation(5G)communication technology.In this work,a novel Al/Nd co-doping method of Ba_(4)Nd_(9.33)Ti_(18)O_(54)(BNT)ceramics with a chemical formula of Ba_(4)Nd_(9.33+z/3)Ti_(18−z)Al_(z)O_(54)(BNT–AN,0≤z≤2)was proposed to improve the dielectric properties through structural and defect modulation.Together with Al-doped ceramics(Ba_(4)Nd_(9.33)Ti_(18−z)Al_(4z/3)O_(54),BNT–A,0≤z≤2)for comparison,the ceramics were prepared by a solid state method.It is found that Al/Nd co-doping method has a significant effect on improving the dielectric properties compared with Al doping.As the doping amount z increased,the relative dielectric constant(εr)and the temperature coefficient of resonant frequency(τf)of the ceramics decreased,and the Q×f values of the ceramics obviously increased when z≤1.5.Excellent microwave dielectric properties ofεr=72.2,Q×f=16,480 GHz,andτf=+14.3 ppm/℃were achieved in BNT–AN ceramics with z=1.25.Raman spectroscopy and thermally stimulated depolarization current(TSDC)technique were firstly combined to analyze the structures and defects in microwave dielectric ceramics.It is shown that the improvement on Q×f values was originated from the decrease in the strength of the A-site cation vibration and the concentration of oxygen vacancies(VO××),demonstrating the effect and mechanism underlying for structural and defect modulation on the performance improvement of microwave dielectric ceramics.展开更多
A simple and efficient approach was presented to enhance up-conversion emissions significantly for the Er:Al2O3 nanocrystals by Mo support (Er-Mo:Al2O3) with a 976 nm laser diode excitation. Mo support had evident...A simple and efficient approach was presented to enhance up-conversion emissions significantly for the Er:Al2O3 nanocrystals by Mo support (Er-Mo:Al2O3) with a 976 nm laser diode excitation. Mo support had evident effects on the phase structure and up-conversion emissions for the Er:Al2O3 nanocrystals, which promoted the θ-(Al,Er)2O3 transformed to α-(Al,Er,Mo)203 phase, Compared with the Er:Al2O3, the maximal green and red up-conversion emissions intensities increased about 3×10^3 and 1.4×10^2 times for the Er-Mo:Al2O3 nanocrystals, respectively. It suggests that the enhancement of up-conversion emissions is caused by the high excited state energy transfer process from [4115/2, 3T2) state of the Er3+-MoO2- dimer to the 4F7/2 level of E3+.展开更多
MAKAROV and Trontelj first reported the WO<sub>3</sub>-based low voltage varistor material doped with MnO<sub>2</sub> and Na<sub>2</sub>CO<sub>3</sub> in 1994. This mate...MAKAROV and Trontelj first reported the WO<sub>3</sub>-based low voltage varistor material doped with MnO<sub>2</sub> and Na<sub>2</sub>CO<sub>3</sub> in 1994. This material is worth further study because of its low threshold voltage ( 【 10 V/mm). We have found that the doping of Co<sub>2</sub>O<sub>3</sub> can obviously improve the nonlinearity of WO<sub>3</sub>-MnO<sub>2</sub>-Na<sub>2</sub>CO<sub>3</sub> series with nonlinear coefficient α≈ 2,and a may be higher than 5 when the amount of Co<sub>2</sub>O<sub>3</sub> is 1% (mole percentage). However, the nonlinear characteristic almost vanished when 0.5% Al<sub>2</sub>O<sub>3</sub> was doped into this system at room temperature, and Al<sub>2</sub>O<sub>3</sub> showed very stable展开更多
We propose a surface plasmon(SP) structure in electrically pumped multiple graphene-layer(MGL), and calculate the functions of dynamic conductivity and absorption coefficient. Meanwhile, the dependences of absorption ...We propose a surface plasmon(SP) structure in electrically pumped multiple graphene-layer(MGL), and calculate the functions of dynamic conductivity and absorption coefficient. Meanwhile, the dependences of absorption coefficient on different factors are simulated. SP can get gain when absorption coefficient is negative, and the SP gain can be enhanced by lowering temperature, applying high bias voltage and choosing the graphene with proper layer number and long momentum relaxation time. The study on SP gain is hopeful to be used in amplifiers and graphene-based plasmon devices.展开更多
Al doped zinc oxide (AZO) films were prepared by mid-frequency magnetron sputtering for silicon (Si) thin film solar cells. Then, the influence of deposition parameters on the electrical and optical properties of ...Al doped zinc oxide (AZO) films were prepared by mid-frequency magnetron sputtering for silicon (Si) thin film solar cells. Then, the influence of deposition parameters on the electrical and optical properties of the films was studied. Results showed that high conductive and high transparent AZO thin films were achieved with a minimum resistivity of 2.45 × 10^-4 Ω·cm and optical transmission greater than 85% in visible spectrum region as the films were deposited at a substrate temperature of 225℃ and a low sputtering power of 160 W. The optimized films were applied as back reflectors in a-SiGe:H solar cells. A relative increase of 19% in the solar cell efficiency was achieved in comparison to the cell without the ZnO films doped with Al (ZnO:Al).展开更多
文摘Solution-processed oxide semiconductors have been considered as a potential alternative to vacuum-based ones in printable electronics.However,despite spincoated InZnO(IZO)thin-film transistors(TFTs)have shown a relatively high mobil-ity,the lack of carrier suppressor and the high sensitivity to oxygen and water molecules in ambient air make them potentially suffer issues of poor stability.In this work,Al is used as the third cation doping element to study the effects on the electrical,optoelectronic,and physical properties of IZO TFTs.A hydrophobic self-assembled monolayer called octadecyltrimethoxysilane is introduced as the surface passivation layer,aiming to reduce the effects from air and understand the importance of top surface conditions in solution-processed,ultra-thin oxide TFTs.Owing to the reduced trap states within the film and at the top surface enabled by the doping and passivation,the optimized TFTs show an increased current on/off ratio,a reduced drain current hysteresis,and a significantly enhanced bias stress stability,compared with the untreated ones.By combining with high-capacitance AlO_(x),TFTs with a low operating voltage of 1.5 V,a current on/off ratio of>10^(4) and a mobility of 4.6 cm^(2)/(V·s)are demonstrated,suggesting the promising features for future low-cost,low-power electronics.
基金financial support from the Natural Science Foundation of Shandong Province (ZR2022QB140)the PhD Initiation Program of Liaocheng University (318052138)the Natural Science Foundation of Shandong Province (ZR2023MB002 and ZR2021MB114)。
文摘Cobalt-free cathode materials are attractive for their high capacity and low cost,yet they still encounter issues with structural and surface instability.AlPO_(4),in particular,has garnered attention as an effective stabilizer for bulk and surface.However,the impact of interfacial reactions and elemental interdiffusion between AlPO_(4) and LiNi_(0.95)Mn_(0.05)O_(2) upon sintering on the bulk and surface remains elusive.In this study,we demonstrate that during the heat treatment process,AlPO_(4) decomposes,resulting in Al doping into the bulk of the cathode through elemental interdiffusion.Simultaneously,PO_(4)^(3-)reacts with the surface Li of material to form a Li_3PO_(4) coating,inducing lithium deficiency,thereby increasing Li/Ni mixing.The suitable Li/Ni mixing,previously overlooked in AlPO_(4) modification,plays a pivotal role in stabilizing the bulk and surface,exceeding the synergy of Al doping and Li_3PO_(4) coating.The presence of Ni^(2+)ions in the lithium layers contributes to the stabilization of the delithiated structure via a structural pillar effect.Moreover,suitable Li/Ni mixing can stabilize the lattice oxygen and electrode-electrolyte interface by increasing oxygen removal energy and reducing the overlap between the Ni^(3+/4+)e_g and O^(2-)2p orbitals.These findings offer new perspectives for the design of stable cobalt-free cathode materials.
基金supported by the National Natural Science Foundation of China(52022109 and 51834008)Beijing Municipal Natural Science Foundation(2202047)+1 种基金National Key Research and Development Program of China(2021YFC2901100)Science Foundation of China University of Petroleum,Beijing(2462021QNX2010,2462020YXZZ019,2462020YXZZ016,and 2462022QZDX008)。
文摘The poor structural stability and capacity retention of the high-voltage spinel-type LiNi_(0.5)Mn_(1.5)O_(4)(LNMO)limits their further application.Herein,Al and Co were doped in LNMO materials for a more stable structure and capacity.The LNMO,LiNi_(0.45)Al_(0.05)Mn_(1.5)O_(4)(LNAMO)and LiNi_(0.45)Co_(0.05)Mn_(1.5)O_(4)(LNCMO)were synthesized by calcination at 900℃ for 8 h,which was called as solid-phase method and applied universally in industry.XRD,FT-IR and CV test results showed the synthesized samples have cation disordering Fd-3m space group structures.Moreover,the incorporation of Al and Co increased the cation disordering of LNMO,thereby increasing the transfer rate of Li+.The SEM results showed that the doped samples performed more regular and ortho-octahedral.The EDS elemental analysis confirmed the uniform distribution of each metal element in the samples.Moreover,the doped samples showed better electrochemical properties than undoped LNMO.The LNAMO and LNCMO samples were discharged with specific capacities of 116.3 mA·h·g^(-1)and 122.8 mA·h·g^(-1)at 1 C charge/discharge rate with good capacity retention of 95.8% and 94.8% after 200 cycles at room temperature,respectively.The capacity fading phenomenon of the doped samples at 50℃ and 1 C rate was significantly improved.Further,cations doping also enhanced the rate performance,especially for the LNCMO,the discharge specific capacity of 117.9 mA·h·g^(-1)can be obtained at a rate of 5 C.
基金the National Natural Science Foundation of China(51972233 and 52172225)the Natural Science Foundation of Shanghai(19ZR1459200)+1 种基金the Science and Technology Commission of Shanghai Municipality(19DZ2271500)the Fundamental Research Funds for the Central Universities.
文摘LaTaON_(2)is an attractive visible-light-active photocatalyst for water splitting due to its broad visible light absorption as far as 650 nm and proper band edge positions.Notwithstanding these promising properties,LaTaON_(2)generally exhibits poor photocatalytic activity because of its high defect concentration that severely hinders charge separation.Here,LaTaON_(2)has been modified by doping Al into the Ta sublattice,i.e.,LaTa_(1−x)Al_(x)O_(1+y)N_(2−y)(0≤x≤0.20).Al doping not only inhibits the defect concentration and increases surface hydrophilicity but also maintains the desired visible light absorption of LaTaON_(2).These important modifications substantially ameliorate the charge separation conditions within LaTaON_(2)and are responsible for a much enhanced photocatalytic performance for water redox reactions under visible light illumination.Under optimal conditions,the Al-doped LaTaON_(2)delivers an apparent quantum efficiency of 1.17%at 420±20 nm for water oxidation into O_(2),outperforming most LaTaON_(2)-based photocatalysts.These findings highlight Al as a useful dopant to open up the photocatalytic potential of metal oxynitrides whose activity is often undermined by a high defect concentration.
基金supported by Anhui Province Research and Development Innovation Project for Automotive Power Battery Efficient Recycling System, China
文摘A uniform Al-doped LiNi_(0.5)Co_(0.2)Mn_(0.3)O_(2) cathode material was prepared using a coprecipitation method to take advantage of the positive effect of Al on regenerated NCM(Ni,Co,Mn)cathode materials and ameliorate cumbersome and high-cost impurity removal processes during lithium-ion battery recycling.When the Al^(3+) content in the leachate was 1 at.%with respect to the total amount of transition metals(Ni,Co,and Mn),the produced Al-doped NCM cathode material increased concentrations of lattice oxygen and Ni^(2+).The initial specific capacity at 0.1C was 167.4 mA·h/g,with a capacity retention of 79.1%after 400 cycles at 1C.Further,this Al-doped sample showed improved rate performance and a smaller electrochemical impedance.These findings provide a reference for developing industrial processes to resynthesize cathode materials with improved electrochemical performance by incorporating Al^(3+) impurities produced during lithium-ion battery recycling.
基金the Natural Science Foundation of Heilongjiang, China(Grant No.E2004-24).
文摘LiNi0.78 Co0.2 Al0.02O2 cathode materials were prepared with a novel co-precipitation method followed by heat-treating. The properties of the materials were characterized. XRD patterns showed that no secondary phase appeared and the hexagonal lattice parameter c of LiNi0.rsCoo.2AI^0202 was larger than that of LiNi0.8Co0.2O2. The SEM images indicated that the powders of the material were submicron size. The results of the ICP-AES analysis proved that elemental compositions of the material were similar to those of the targeted one. Cyclic voltammetry (3.0- 4. 2 V) illustrated that the new material had good lithium-ion intercalation/de-intercalation performance. The results of galvanostatic cycling showed that the initial specific discharge capacity of the prepared material was 181.4 mAh/g, and the specific discharge capacity was 177.3 mAh/g after 100 cycles (0. 2C, 3.0 - 4. 2 V, vs. Li^+/Li) with the capacity retention ratio of 97.7%.
文摘The relation among electronic structure, chemical bond and property of Ti3SiC2 and Al-doped was studied by density function and discrete variation ( DFT- DVM) method. When Al element is added into Ti3 SiC2 , there is a less difference of ionic bond, which does not play a leading role to influent the properties. After adding Al, the covalent bond of Al and the near Ti becomes somewhat weaker, but the covalent bond of Al and the Si in the same layer is obviously stronger than that of Si and Si before adding. Therefore, in preparation of Ti3 SiC2 , adding a proper quantity of Al can promote the formation of Ti3 SiC2 . The density of stnte shows that there is a mixed conductor character in both of Ti3 SiC2 and adding Al element. Ti3 SiC2 is with more tendencies to form a semiconductor. The total density of state near Fermi lever after adding Al is larger than that before adding, so the electric conductivity may increase after adding Al.
基金Project supported by the National Key Research and Development Program of China (Grant No. 2017YFB0403101).
文摘The optical components of the visible light band are widely used in daily life and industrial development. However due to the serious loss of light and the high cost, the application is limited. The broadband gap metasurface will change this situation due to its low absorption and high efficiency. Herein, we simulate a size-adjustable metasurface of the Al doped ZnO (AZO) nanorod arrays based on finite difference time domain method (FDTD) which can realize the conversion of amplitude polarization and phase in the full visible band. The corresponding theoretical polarization conversion efficiency can reach as high as 91.48% (450 nm), 95.27% (530 nm), and 91.01% (65 nm). The modulation of focusing wavelength can be realized by directly adjusting the height of the AZO nanorod. The designed half-wave plate and metalens can be applied in the imaging power modulation halfwave conversion and enriching the spectroscopy.
基金Inner Mongolia Autonomous Region Science and Technology Plan Project(2020GG0284)。
文摘(Fe_(73)Ga_(27−x)Al_(x))_(99.8)Tb_(0.2)(x=0,1,2,3,4,5)alloys were prepared by vacuum arc furnace to investigate the effect of Al addition on the microstructure,magnetic properties,and mechanical properties of alloys.Results show that the phase structure of the alloys is still A2 phase and Tb_(2)Fe_(17) phase,and the metallographic structure is composed of cellular crystal and columnar dendrite.The decrease in lattice constant,the intensification of(100)orientation,and the generation of Tb_(2)Fe_(17) phase at the grain boundary exert significant effect on the magnetostrictive properties.The fracture morphology of the alloys is intergranular brittle fracture and cleavage fracture,and the causes of fracture occurrence include the segregation of Tb and Al elements.The parallel magnetostrictive strain(λ_(∥))of(Fe_(73)Ga_(24)Al_(3))_(99.8)Tb_(0.2)alloy peaks at 1.04×10^(−4).It is worth noting that compared with those of(Fe_(73)Ga_(27))_(99.8)Tb_(0.2)alloy,theλ_(∥)and elongation of(Fe_(73)Ga_(26)Al_(1))_(99.8)Tb_(0.2)alloy increase by 18.3%and 53.4%,respectively.Besides,(Fe_(73)Ga_(26)Al_(1))_(99.8)Tb_(0.2)alloy possesses the characteristics of high saturation magnetization(Ms),low remanent magnetization(M_(r)),and coercivity(H_(c)),which is beneficial to reduce the cost in actual production,but its tensile strength and Vickers hardness decrease to a certain extent.Therefore,the investigation on the micro-mechanism of Al addition on Fe-Ga alloys is of great significance for the development of Fe-Ga alloy devices.
基金Acknowledgements This work was financially supported by the National Key Research and Development Program (No. 2017YFC0211002) and the National Natural Science Foundation of China (Grant No. 21476170).
文摘N2O is a powerful greenhouse gas and plays an important role in destructing the ozone layer. This present work investigated the effects of Pd doping on N2O formation over Pt/BaO/Al2O3 catalyst. Three types of catalysts, Pt/BaO/Al2O3, Pt/Pd mechanical mixing catalyst (Pt/BaO/Al203 + Pd/Al2O3) and Pt-Pd co-impregnation catalyst (Pt-Pd/BaO/Al2O3) were prepared by incipient wetness imoreenation method. These catalysts were first evaluated in NSR activity tests using H2/CO as reductants and then carefully characterized by BET, CO chemisorption, CO-DRIFTs and H2-TPR techniques. In addition, temperature programmed reactions of NO with H2/CO were conducted to obtain further information about NzO formation mechanism. Compared with Pt/BaO/Al2O3 (Pt/BaO/Al2O3 + Pd/Al2O3) produced less N2O and more NH3 during NOx storage and reduction process, while an opposite trend was found over (Pt-Pd/BaO/Al2O3 + Al2O3). Temperature programmed reactions of NO with H2/CO results showed that Pd/Al2O3 component in (Pt/BaO/Al2O3 + Pd/Al2O3) played an important role in NO reduction to NH3, and the formed NH3 could reduce NOx to N2 leading to a decrease in N2O formation. Most of N2O formed over (Pt-Pd/BaO/Al2O3 + Al2O3) was originated from Pd/BaO/Al2O3 component. H2-TPR results indicated Pd-Ba interaction resulted in more difficult- to-reduce PdOx species over Pd/BaO/Al2O3, which inhibits the NO dissociation and thus drives the selectivity to N2O in NO reduction.
基金Project supported by the National Natural Science Foundation of China(21806077,21773106,2197681)。
文摘In the work,supported catalysts of FeO_(x) and MnO_(x) co-supported on aluminum-modified CeO_(2)was synthesized for low-temperature NH_(3)-selective catalytic reduction(NH_(3)-SCR)of NO.Impressively,the SCR activity of the obtained catalyst is markedly influenced by the adding amount of Al and the appropriate Ce/Al molar ratio is 1/2.The activity tests demonstrate that Fe-Mn/Ce1 Al2 catalyst shows over 90%NO conversion at 75-250℃and exhibits better SO_(2)resistance compared to Fe-Mn/CeO_(2).Fe-Mn/Ce1 Al2 shows the expected physicochemical characters of the ideal catalyst including the larger surface and increased active reaction active sites by controlling the amount of Al doping.Also,the better catalytic activity is well correlated with the present advantaged surface adsorption oxygen species,Mn^(4+)species,Ce^(3+)species and the enhanced reducibility of Fe-Mn/Ce1 Al2,which is superior to the Fe-Mn/CeO_(2)catalyst.More importantly,we further demonstrate that the amount and strength of surface acid sites are improved by Al-doping and more active intermediates(monodentate nitrate)is generated during NH_(3)-SCR reaction.This work provides certain insight into the rational creation of simple and practical denitration catalyst environmental purification.
基金supported by Department of Science and Technology (DST) under the project SR/WOS-A/PS-06/2006by Defence Research and Development Organization (DRDO),Govt. of India under the project ERIP/ER/0503515/M01/847
文摘The effect of Al doping on the J-V characteristics sol-gel derived of ZnO/p-Si photodiodes was investigated.The resistivity of Si was 0.1Ω·cm.ZnO films annealed at 500℃ were of the best quality.To investigate the spectral response of the photodiodes,the J-V characteristics were measured under different monochromatic lights at wavelength 420,530,570 and 630 nm.The diodes exhibit strong responsivity in the blue region at 420 nm.The responsivity is 0.22 A/W for Al doped (0.8 wt pct) photodiode,whereas for the undoped photodiode,it was much lower.An estimate of the responsivity as a function of wavelength has been made in terms of the width of depletion region of photodiodes.
文摘To evaluate the charge transport properties of as-grown high resistivity CdZnTe crystals doped with In/Al, the α particle spectroscopic response was measured using an un-collimated 241Am (5.48 MeV) radioactive source at room temperature. The electron mobility lifetime products (μτ)e of the CdZnTe crystals were predicted by fitting plots of photo-peak position versus electrical field strength using the single carrier Hecht equation. A TOF technique was employed to evaluate the electron mobility for CdZnTe crystals. The mobility was obtained by fitting the electron drift velocities as a function of the electrical field strengths, where the drift velocities were achieved by analyzing the rise-time distributions of the voltage pulses formed by a preamplifier. A fabricated CdZnTe planar detector based on a low In concentration doped CdZnTe crystal with (μτ)e = 2.3 × 10?3 cm2/V and μe =1000 cm2/(V·s), respectively, exhibits an excellent γ-ray spectral resolution of 6.4% (FWHM = 3.8 keV) for an un-collimated 241Am @ 59.54 keV isotope.
基金National Natural Science Foundation of China (Nos.21777033,21607029 and 41425015)Science and Technology Planning Project of Guangdong Province (No. 2017B020216003)the Innovation Team Project of Guangdong Provincial Department of Education (No.2017KCXTD012)。
文摘Formaldehyde(HCHO) is one kind of common indoor toxic pollutant,the catalytic oxidation degradation of formaldehyde at room temperature is desired.In this work,a new single atomic catalyst(SAC),Al doped graphene,for the catalytic oxidation of HCHO molecules was proposed through density function theory(DFT) calculations.It is found that Al atoms can be adsorbed on graphene stably without aggre s sion.Then HCHO can be effectively oxidized into CO2 and H2 O in the presence of O2 molecules on Al doped graphene with a low energy barrier of 0.82 eV and releasing energy of 2.29 eV with the pathway of HCHO→HCOOH→CO→CO2.The oxidation reaction can happen promptly with reaction time τ=56.9 s at the speed control step at room temperature.Therefore,this work proposed a high-performance catalyst Al-doped graphene without any noble metal for HCHO oxidation at ambient temperature,and corresponding oxidation pathway and mechanism are also deeply understood.
基金This work was supported by the National Key R&D Program of China(No.2017YFB0406301)the Key-Area Research and Development Program of Guangdong Province(No.2020B010176001)the National Natural Science Foundation of China(No.51872160).
文摘Low-loss tungsten–bronze microwave dielectric ceramics are dielectric materials with potential application value for miniaturized dielectric filters and antennas in the fifth-generation(5G)communication technology.In this work,a novel Al/Nd co-doping method of Ba_(4)Nd_(9.33)Ti_(18)O_(54)(BNT)ceramics with a chemical formula of Ba_(4)Nd_(9.33+z/3)Ti_(18−z)Al_(z)O_(54)(BNT–AN,0≤z≤2)was proposed to improve the dielectric properties through structural and defect modulation.Together with Al-doped ceramics(Ba_(4)Nd_(9.33)Ti_(18−z)Al_(4z/3)O_(54),BNT–A,0≤z≤2)for comparison,the ceramics were prepared by a solid state method.It is found that Al/Nd co-doping method has a significant effect on improving the dielectric properties compared with Al doping.As the doping amount z increased,the relative dielectric constant(εr)and the temperature coefficient of resonant frequency(τf)of the ceramics decreased,and the Q×f values of the ceramics obviously increased when z≤1.5.Excellent microwave dielectric properties ofεr=72.2,Q×f=16,480 GHz,andτf=+14.3 ppm/℃were achieved in BNT–AN ceramics with z=1.25.Raman spectroscopy and thermally stimulated depolarization current(TSDC)technique were firstly combined to analyze the structures and defects in microwave dielectric ceramics.It is shown that the improvement on Q×f values was originated from the decrease in the strength of the A-site cation vibration and the concentration of oxygen vacancies(VO××),demonstrating the effect and mechanism underlying for structural and defect modulation on the performance improvement of microwave dielectric ceramics.
基金supported by the National Natural Science Foundation of China (Grant No. 11004021)the Fundamental Research Funds for the Central Universities (Grant Nos. DC12010117 and DC120101174)
文摘A simple and efficient approach was presented to enhance up-conversion emissions significantly for the Er:Al2O3 nanocrystals by Mo support (Er-Mo:Al2O3) with a 976 nm laser diode excitation. Mo support had evident effects on the phase structure and up-conversion emissions for the Er:Al2O3 nanocrystals, which promoted the θ-(Al,Er)2O3 transformed to α-(Al,Er,Mo)203 phase, Compared with the Er:Al2O3, the maximal green and red up-conversion emissions intensities increased about 3×10^3 and 1.4×10^2 times for the Er-Mo:Al2O3 nanocrystals, respectively. It suggests that the enhancement of up-conversion emissions is caused by the high excited state energy transfer process from [4115/2, 3T2) state of the Er3+-MoO2- dimer to the 4F7/2 level of E3+.
文摘MAKAROV and Trontelj first reported the WO<sub>3</sub>-based low voltage varistor material doped with MnO<sub>2</sub> and Na<sub>2</sub>CO<sub>3</sub> in 1994. This material is worth further study because of its low threshold voltage ( 【 10 V/mm). We have found that the doping of Co<sub>2</sub>O<sub>3</sub> can obviously improve the nonlinearity of WO<sub>3</sub>-MnO<sub>2</sub>-Na<sub>2</sub>CO<sub>3</sub> series with nonlinear coefficient α≈ 2,and a may be higher than 5 when the amount of Co<sub>2</sub>O<sub>3</sub> is 1% (mole percentage). However, the nonlinear characteristic almost vanished when 0.5% Al<sub>2</sub>O<sub>3</sub> was doped into this system at room temperature, and Al<sub>2</sub>O<sub>3</sub> showed very stable
基金supported by the National Natural Science Foundation of China(No.61001018)the Natural Science Foundation of Shandong Province of China(No.ZR2012FM011)+3 种基金the Project of Shandong Province Higher Educational Science and Technology Program(No.J11LG20)the Qingdao Science&Technology Project(No.11-2-4-4-(8)-jch)the Qingdao Economic & Technical Development Zone Science & Technology Project(No.2013-1-64)the Shandong University of Science and Technology Foundation in China(No.YC140108)
文摘We propose a surface plasmon(SP) structure in electrically pumped multiple graphene-layer(MGL), and calculate the functions of dynamic conductivity and absorption coefficient. Meanwhile, the dependences of absorption coefficient on different factors are simulated. SP can get gain when absorption coefficient is negative, and the SP gain can be enhanced by lowering temperature, applying high bias voltage and choosing the graphene with proper layer number and long momentum relaxation time. The study on SP gain is hopeful to be used in amplifiers and graphene-based plasmon devices.
基金Acknowledgements This work was supported by Key Project of Natural Science Foundation of Hubei Province (No. 2009CBA025). The authors would like to thank Analytical and Testing Center of Huazhong University of Science and Technology.
文摘Al doped zinc oxide (AZO) films were prepared by mid-frequency magnetron sputtering for silicon (Si) thin film solar cells. Then, the influence of deposition parameters on the electrical and optical properties of the films was studied. Results showed that high conductive and high transparent AZO thin films were achieved with a minimum resistivity of 2.45 × 10^-4 Ω·cm and optical transmission greater than 85% in visible spectrum region as the films were deposited at a substrate temperature of 225℃ and a low sputtering power of 160 W. The optimized films were applied as back reflectors in a-SiGe:H solar cells. A relative increase of 19% in the solar cell efficiency was achieved in comparison to the cell without the ZnO films doped with Al (ZnO:Al).