This paper reports that the radio frequency magnetron sputtering is used to fabricate ZnO and Mn-doped ZnO thin films on glass substrates at 500 ℃. The Mn-doped ZnO thin films present wurtzite structure of ZnO and ha...This paper reports that the radio frequency magnetron sputtering is used to fabricate ZnO and Mn-doped ZnO thin films on glass substrates at 500 ℃. The Mn-doped ZnO thin films present wurtzite structure of ZnO and have a smoother surface, better conductivity but no ferromagnetism. The x-ray photoelectron spectroscopy results show that the binding energy of Mn2p3/2 increases with increasing Mn content slightly, and the state of Mn in the Mn-doped ZnO thin films is divalent. The chemisorbed oxygen in the Mn-doped ZnO thin films increases with increasing Mn doping concentration. The photoluminescence spectra of ZnO and Mmdoped ZnO thin films have a similar ultraviolet emission. The yellow green emissions of 4 wt.% and 10 wt.% Mn-doped thin films are quenched, whereas the yellow green emission occurs because of abundant oxygen vacancies in the Mn-doped ZnO thin films after 20 wt.% Mn doping. Compared with pure ZnO thin film, the bandgap of the Mn-doped ZnO thin films increases with increasing Mn content.展开更多
This paper reports that a large amount of Mn-doped ZnO nanorods have been synthesized through thermal evaporation. The morphologies and properties are studied with x-ray diffraction, a scanning electron microscope, tr...This paper reports that a large amount of Mn-doped ZnO nanorods have been synthesized through thermal evaporation. The morphologies and properties are studied with x-ray diffraction, a scanning electron microscope, transmission electron microscope and Raman spectroscope. The results indicate that the manganese atoms occupy the zinc vacancies in the wurtzite lattice of ZnO without forming secondary phases. The exact manganese content has been studied by the x-ray fluorescence spectrum. Meanwhile, the magnetic moment versus temperature result proves that the as-prepared Mn-doped ZnO nanorods show ferromagnetic properties at temperatures as high as 400~K. These studies provide a good understanding of the origin of magnetic properties in diluted magnetic semiconductors.展开更多
A series of Mn-doped ZnO films have been prepared in different sputtering plasmas by using the inductively coupled plasma enhanced physical vapour deposition. The films show paramagnetic behaviour when they are deposi...A series of Mn-doped ZnO films have been prepared in different sputtering plasmas by using the inductively coupled plasma enhanced physical vapour deposition. The films show paramagnetic behaviour when they are deposited in an argon plasma. The Hall measurement indicates that ferromagnetism cannot be realized by increasing the electron concentration. However, the room-temperature ferromagnetism is obtained when the films are deposited in a mixed argon-nitrogen plasma. The first-principles calculations reveal that antiferromagnetic ordering is favoured in the case of the substitution of Mn^2＋ for Zn^2＋ without additional acceptor doping. The substitution of N for O （NO^-） is necessary to induce ferromagnetic couplings in the Zn-Mn-O system. The hybridization between N 2p and Mn 3d provides an empty orbit around the Fermi level. The hopping of Mn 3d electrons through the empty orbit can induce the ferromagnetic coupling. The ferromagnetism in the N-doped Zn-Mn-O system possibly originates from the charge transfer between Mn^2＋ and Mn^3＋ via NO^-, The key factor is the empty orbit provided by substituting N for O, rather than the conductivity type or the carrier concentration.展开更多
In this paper we investigated the optical properties of ZnO and Mn doped ZnO nanocrystals that were fabricated by a vapor phase transport growth process, using zinc acetate dihydrate with or without Mn in a constant O...In this paper we investigated the optical properties of ZnO and Mn doped ZnO nanocrystals that were fabricated by a vapor phase transport growth process, using zinc acetate dihydrate with or without Mn in a constant O2/Ar mixture gas flowing through the furnace at 400600℃, respectively. The as grown ZnO nanocrystals are homogeneous with a mean size of 19 nm observed by scanning electron microscope（SEM）. The optical characteristics were analyzed by absorption spectra and photoluminescence（PL） spectra at room-temperature. For ZnO nanocrystals, a strong and predominant UV emission peaked at 377 nm was found in the PL spectra. For Mn doped ZnO nanocrystals, in addition to the strong UV emission, a strong blue emission peaked at 435 nm was observed as well. By doping Mn ions, the major UV emission shifts from 377 nm to 408 nm, showing that Mn ions were not only incorporated into ZnO Ncs, but also introduced an impurity level in the bandgap. Moreover, with the concentration of Mn increasing, the relative intensities of the two emissions change largely, and the photoluminescence mechanism of them is discussed.展开更多
The absorption and emission spectra of the wurtzite Mn-doped GaN were calculated with cluster models.The predicted lattice parameters become slightly larger than those of undoped cluster.The average bond length of Mn...The absorption and emission spectra of the wurtzite Mn-doped GaN were calculated with cluster models.The predicted lattice parameters become slightly larger than those of undoped cluster.The average bond length of Mn–N is longer than that of Ga–N.Spin density shows that one Mn atom in these clusters has four single electrons with the same direction of the spin polarity.The new energy level with light Mn-doping appears at 1.37 eV above the valance band.The absorption spectra of Mn-doped GaN cover the visible light region.The calculated emission spectra show that the green luminescence of GaN material in experiment did not result from Mn dopant.With the increase of Mn doping,the emission intensity of yellow or blue band increases to different extent and the band-to-band emission band shows red shift from peak at 3.34 to 3.24 eV.展开更多
Electrolytic water splitting,as a promising route to hydrogen(H_(2))production,is still confronted with the sluggish anodic oxygen evolution reaction(OER)and its less value-added O2 production.Herein,we report a bifun...Electrolytic water splitting,as a promising route to hydrogen(H_(2))production,is still confronted with the sluggish anodic oxygen evolution reaction(OER)and its less value-added O2 production.Herein,we report a bifunctional electrode fabricated by in situ growth of Mn-doped CoSe_(2)nanonetworks on carbon fiber cloth(Mn-CoSe_(2)/CFC),which shows attractive electrocatalytic properties toward glycerol oxidation reaction(GOR)in alkali and hydrogen evolution reaction(HER)in acid.A flow alkali/acid hybrid electrolytic cell(fA/A-hEC)was then developed by coupling anodic GOR with cathodic HER with the Mn-CoSe_(2)/CFC bifunctional electrode.Such fA/A-hEC enables a rather low voltage of 0.54 V to achieve 10 mA cm^(-2),and maintain long-term electrolysis stability over 300-h operation at 100 mA cm^(-2)with Faraday efficiencies of over 99%for H_(2)and 90%for formate production.The designed bifunctional electrode in such innovative fA/A-hEC device provides insightful guidance for coupling energy-efficient hydrogen production with biomass upgradation.展开更多
TiO2 nano powders with Mn concentration of 0 at%-12 at% were synthesized by the sol-gel process, and were annealed at 500 ℃ and 800 ℃ in air for 2 hrs. X-ray diffraction （XRD） measurements indicate that the Mn-TiO...TiO2 nano powders with Mn concentration of 0 at%-12 at% were synthesized by the sol-gel process, and were annealed at 500 ℃ and 800 ℃ in air for 2 hrs. X-ray diffraction （XRD） measurements indicate that the Mn-TiO2 nano powders with Mn concentration of 1 at% and 2 at% annealed at 500 and 800 ℃ are of pure anatase and rutile, respectively. The scanning electron microscope （SEM） observations reveal that the crystal grain size increases with the annealing temperature, and the high resolution transmission electron microscopy （HRTEM） investigations further indicate that the samples are well crystallized, confirming that Mn has doped into the TiO2 crystal lattice effectively. The room temperature ferromagnetism, which could be explained within the scope of the bound magnetic polaron （BMP） theory, is detected in the Mn-TiO2 samples with Mn concentration of 2 at%, and the magnetization of the powders annealed at 500 ℃ is stronger than that of the sample treated at 800 ℃. The UV-VIS diffuse reflectance spectra results demonstrate that the absorption of the TiO2 powders could be enlarged by the enhanced trapped electron absorption caused by Mn doping.展开更多
Manganese(Mn)doped cadmium sulphide(Cd S)nanoparticles were synthesized using a chemical method.It was possible to decrease Cd S:Mn particle size by increasing Mn concentration.Investigation techniques such as ultravi...Manganese(Mn)doped cadmium sulphide(Cd S)nanoparticles were synthesized using a chemical method.It was possible to decrease Cd S:Mn particle size by increasing Mn concentration.Investigation techniques such as ultraviolet-visible(UV-Vis)absorption spectroscopy and photoluminescence(PL)spectroscopy were used to determine optical properties of Cd S:Mn nanoparticles.Size quantization effect was observed in UV-Vis absorption spectra.Quantum efficiency for luminescence or the internal magnetic field strength was increased by doping Cd S nanoparticles with Mn element.Orange emission was observed at wavelength~630 nm due to ^(4)T_1→^(6)A_1 transition.Isolated Mn~(2+)ions arranged in tetrahedral coordination are mainly responsible for luminescence.Luminescence quenching and the effect of Mn doping on hyperfine interactions in the case of Cd S nanoparticles were also discussed.The corresponding weight percentage of Mn element actually incorporated in doping process was determined by atomic absorption spectroscopy(AAS).Crystallinity was checked and the average size of nanoparticles was estimated using the X-ray diffraction(XRD)technique.Cd S:Mn nanoparticles show ferromagnetism at room temperature.Transmission electron microscopy(TEM)images show spherical clusters of various sizes and selected area electron diffraction(SAED)patterns show the polycrystalline nature of the clusters.The electronic states of diluted magnetic semiconductors(DMS)ofⅡ-Ⅵgroup Cd S nanoparticles give them great potential for applications due to quantum confinement.In this study,experimental results and discussions on these aspects have been given.展开更多
In this work,LiFe_(1-x)MnxPO_(4)@C(x=0,0.01,0.02,0.03)cathode materials were obtained by a simple co-precipitation method and heat treatment,and the influence of Mn-doped modification on the electrochemical performanc...In this work,LiFe_(1-x)MnxPO_(4)@C(x=0,0.01,0.02,0.03)cathode materials were obtained by a simple co-precipitation method and heat treatment,and the influence of Mn-doped modification on the electrochemical performance of LiFePO_(4)@C cathode materials was investigated.Results show that by doping an appropriate amount of Mn,the cell volume became larger,and the electronic conductivity increased,which improved the Li+diffusion rate and thus its rate capability and cycle performance of Li-ion batteries.Among them,LiFe_(0.98)Mn_(0.02)PO_(4)@C showed superior lithium storage capability;the discharge capacity can reach 150.7 mAh g^(−1)at 0.1 C.The cell could discharge up to 155.9 mAh g^(−1)at 1 C under high temperature at 45°C,which was higher than LiFePO_(4)@C(142 mAh g^(−1))under the same test conditions.The discharge capacity of 1 C at room temperature was 139.9 mAh g^(−1),and the cycle stability was 95.9%after 200 cycles.It showed that it had good rate capability and excellent cycle performance.These results indicate that Mn-doped LFP is a simple and effective strategy for developing high-performance cathode materials.展开更多
Although chemotherapy has been intensively applied in cancer treatments,its inadequate therapeutic efficacy and severe side effects are still under constant concerns.Nanoplatforms used as anti-tumor drug delivery syst...Although chemotherapy has been intensively applied in cancer treatments,its inadequate therapeutic efficacy and severe side effects are still under constant concerns.Nanoplatforms used as anti-tumor drug delivery system(DDS)have attracted tremendous attentions owing to their various intriguing properties.Herein,Mn-doped MoO_(2)nanoparticles coated with ZrO_(2)and capped with Bi_(2)O_(3)have been designed as a DDS,namely MMZB.MMZB possesses good magnetic properties,great photothermal conversion ability,sensitive tumor microenvironment(TME)responsiveness,and good biocompatibility in hemocompatibility in vitro.Thus,MMZB has been utilized to load the chemotherapeutic agent daunomycin(DNM)(MMZB@DNM)for chemo-photothermal combined therapy.MMZB@DNM demonstrates a more impressive anti-cancer effect than the individual photothermal or chemotherapy both in vitro and in vivo.Furthermore,the analysis of tumor specimen sections and serum levels after the treatment indicates negligible side effects for MMZB@DNM in vivo.This contribution provides a valuable concept in designing therapeutic agents for achieving significantly enhanced tumor treatments,which benefits from the synergistic combination of chemotherapy and photothermal therapy in one single nanoagent.展开更多
Olivine structured LiFePO 4 /C (lithium iron phosphate) and Mn 2+ -doped LiFe 0.98 Mn 0.02 PO 4 /C powders were synthesized by the solid-state reaction. The effects of manganese partial substitution and different carb...Olivine structured LiFePO 4 /C (lithium iron phosphate) and Mn 2+ -doped LiFe 0.98 Mn 0.02 PO 4 /C powders were synthesized by the solid-state reaction. The effects of manganese partial substitution and different carbon content coating on the surface of LiFePO 4 were considered. The structures and electrochemical properties of the samples were measured by X-ray diffraction (XRD), cyclic voltammetry (CV), charge/discharge tests at different current densities, and electrochemical impedance spectroscopy (EIS). The electrochemical properties of LiFePO 4 cathodes with x wt.% carbon coating (x= 3, 7, 11, 15) at =0.2C, 2C (1C= 170 mAh·g 1 ) between 2.5 and 4.3 V were investigated. The measured results mean that the LiFePO 4 with 7 wt.% carbon coating shows the best rate performance. The discharge capacity of LiFe 0.98 Mn 0.02 PO 4 /C composite is found to be 165 mAh·g 1 at a discharge rate, = 0.2C, and 105 mAh·g 1 at =2C, respectively. After 10 cycles, the discharge capacity has rarely fallen, while that of the pristine LiFePO 4 /C cathode is 150 mAh·g 1 and 98 mAh·g 1 at =0.2 and 2C, respectively. Compared to the discharge capacities of both electrodes above, the evident improvement of the electrochemical performance is observed, which is ascribed to the enhancement of the electronic conductivity and diffusion kinetics by carbon coating and Mn 2+-substitution.展开更多
Introducing vacancy defects and unique morphology is an effective strategy to improve the catalytic performance of transition metal compounds.However,precisely controlling the amount of vacancy defects remains challen...Introducing vacancy defects and unique morphology is an effective strategy to improve the catalytic performance of transition metal compounds.However,precisely controlling the amount of vacancy defects remains challenging.Here,we propose a facile and efficient hydrothermal accompanying an annealing method to synthesize a series of Mn-doped CoO nanomaterials with controllable oxygen vacancies and unique morphology.The oxygen vacancies amount can be precisely controlled by adjusting the Mndoping content and is positively correlated with catalytic performance.It was found that the oxygen vacancies amount can reach up to 38.2%over the Mn-doped CoO nanomaterials,resulting in ultra-high hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)catalytic activity(HER:25.6 and 37 m V at 10 m A cm^(-2);OER:301 and 322 m V at 50 m A cm^(-2))under both basic and acidic conditions,while reaching 10 m A cm^(-2) for an ultra-low cell voltage of only 1.52 V,which exceeds that of Pt/C/RuO_(2) and all reported non-noble metal oxide catalysts.The DFT calculations reveal oxygen vacancies can optimize H*and HOO*intermediates adsorption free energy,thus improving the HER and OER performance.Interestingly,the Mn-doped CoO with rich oxygen vacancies exhibits excellent antibacterial properties in vitro of biomedicine.This work provides new ideas and methods for the rational design and precise control of vacancy defects in transition metal compounds and explores their potential application value in electrochemical water splitting and biomedical fields.展开更多
Heavily Mn-doped SiGe thin films were grown by radio frequency magnetron sputtering and then treated by postgrowth thermal annealing.Structural characterizations reveal the coexistence of Mn-diluted SiGe crystals and ...Heavily Mn-doped SiGe thin films were grown by radio frequency magnetron sputtering and then treated by postgrowth thermal annealing.Structural characterizations reveal the coexistence of Mn-diluted SiGe crystals and Mn-rich nanoclusters in the annealed films.Magnetic measurements indicate the ferromagnetic ordering of the annealed samples above room temperature.The data suggest that the ferromagnetism is probably mainly contributed by the Ge-rich nanoclusters and partially contributed by the tensile-strained Mn-diluted SiGe crystals.The results may be useful for room temperature spintronic applications based on group IV semiconductors.展开更多
This paper reported that the Mn-doped TiO2 films were prepared by radio frequency （RF） magnetron cosputtering. X-ray diffraction measurements indicate that the samples are easy to form the futile structure, and the ...This paper reported that the Mn-doped TiO2 films were prepared by radio frequency （RF） magnetron cosputtering. X-ray diffraction measurements indicate that the samples are easy to form the futile structure, and the sizes of the crystal grains grow big and big as the Mn concentration increases. X-ray photoemlssion spectroscopy measurements and high resolution transmission electron microscope photographs confirm that the manganese ions have been effectively doped into the TiO2 crystal when the Mn concentration is lower than 21%. The magnetic property measurements show that the Ti1-xMnxO2 （x = 0.21） films are ferromagnetic at room temperature, and the saturation magnetization, coercivity, and saturation field are 16.0 emu/cm^3, 167.5 × 80 A/m and 3740 × 80 A/m at room temperature, respectively. The room-temperature ferromagnetism of the films can be attributed to the new futile Ti1-xMnxO2 structure formed by the substitution of Mn^4＋ for Ti^4＋ into the TiO2 crystal .lattice, and could be explained by O vacancy （Vo）-enhanced ferromagnetism model.展开更多
Zn1-xMnxO （x = O.Olq3.1） thin films with a Curie temperature above 300K are deposited on Al2O3 （0001） substrates by pulsed laser deposition. X-ray diffraction （XRD）, ultraviolet （UV）-visible transmission and R...Zn1-xMnxO （x = O.Olq3.1） thin films with a Curie temperature above 300K are deposited on Al2O3 （0001） substrates by pulsed laser deposition. X-ray diffraction （XRD）, ultraviolet （UV）-visible transmission and Raman spectroscopy are employed to characterize the microstructural properties of these films. Room temperature ferromagnetism is observed by superconducting quantum interference device （SQUID）. The results indicate that Mn doping introduces the incorporation of Mn^2＋ ions into the ZnO host matrix and the insertion of Mn^2＋ ions increases the lattice defects, which is correlated with the ferromagnetism of the obtained films. The doping concentration is also proven to be a crucial factor for obtaining highly ferromagnetic Zn1-xMnxO films.展开更多
Three-dimensional Dirac semimetal Cd_(3)As_(2)has been considered as an excellent candidate for applications of electronic devices owing to its ultrahigh mobility and air-stability.However,current researches are focus...Three-dimensional Dirac semimetal Cd_(3)As_(2)has been considered as an excellent candidate for applications of electronic devices owing to its ultrahigh mobility and air-stability.However,current researches are focused mainly on the use of gate-voltage to control its carrier transport tunability,while the manipulation of transport properties by element-doping is quite limited.Here we report the tunable magneto-transport properties by adjusting Mn-doping in the Cd_(3)As_(2)compound.We find that Mnelement doping has a strong influence on the Fermi level positions,and the Fermi energy approaches to Dirac point with higher Mn-doping.More importantly,the introduction of Mn atoms transforms diamagnetic Cd_(3)As_(2)to anti ferromagnetic(Cd,Mn)_(3)As_(2),which provides an approach to control topological protected Dirac materials by ma nipulating antiferro magnetic order parameters.The Shubnikov-de Hass oscillation originates from the surface states,and the Landau fan diagram yields a nontrivial Berry phase,indicating the existence of massless Dirac fermions in the(Cd_(1-x)Mn_x)_(3)AS_(2)compounds.Our present results may pave a way for further investigating anti ferromagnetic topological Dirac semimetal and expand the potential applications in optoelectronics and spintronics.展开更多
The global demand for resource sustainability is growing. Thus, the development of single-source, environment-friendly colloidal semiconductor nanocrystal （NC） phosphors with broadband emission spectra is highly des...The global demand for resource sustainability is growing. Thus, the development of single-source, environment-friendly colloidal semiconductor nanocrystal （NC） phosphors with broadband emission spectra is highly desirable for use as color converters in white light-emitting diodes （WLEDs）. We report herein the gram-scale synthesis of single-source, cadmium-free, dual-emissive Mn-doped Zn-Cu-In-S NCs （d-dots） by a simple, non-injection, low-cost, one-pot approach. This synthesis method led to the formation of NCs with continuously varying compositions in a radial direction because each precursor had a different reactivity. Consequently, the d-dots exhibited two emission bands, one that could be attributed to Mn emission and a second that could be ascribed to the band edge of the Zn-Cu-In-S NCs. The emission peaks assigned to band edge were tunable by modifying the particle size and composition. The prepared d-dots also exhibited the characteristic zero self-absorption, a quantum yield of 46%, and good thermal stability. Combining a commercial blue light-emitting diode （LED） chip with optimized d-dots as color converters gave a high color rendering index of up to 90, Commission Internationale de l＇eclairage color coordinates of （0.332, 0.321）, and a correlated color temperature of 5,680 K. These results suggest that cadmium-free, thermally stable, single-phase d-dot phosphors have potential applications in WLEDs.展开更多
The photocatalytic oxidation of gaseous benzene,toluene and xylene(BTX)over un-doped,0.1 and 1 wt%Mn-TiO_(2)nanoparticles under ultraviolet and visible irradiation was studied in atmosphere of synthetic air or inert g...The photocatalytic oxidation of gaseous benzene,toluene and xylene(BTX)over un-doped,0.1 and 1 wt%Mn-TiO_(2)nanoparticles under ultraviolet and visible irradiation was studied in atmosphere of synthetic air or inert gas.The photocatalytic decomposition efficiency and the oxidation products were determined using a Static Photochemical Reactor coupled with FTIR spectroscopy.BTX underwent efficient decomposition over Mn-TiO_(2)photocatalysts under UV irradiation,more with oxygen presence and less without oxygen.More important toluene and xylene went substantial decomposition over 0.1 mol%Mn-TiO_(2)under visible irradiation with oxygen presence.The main final oxidation products in the UV photocatalysis of BTX were CO_(2),CO and H2O,with CO_(2) and CO yields 4 and 2 respectively.The conversion percentage of benzene,toluene,and xylene to CO_(2) were 63.6%,56.4%,51.8%,and to CO 29%,26.5%,23.2%,respectively.In the visible photocatalysis of toluene and xylene the yields of CO were insignificant.Formation of carbon containing deposits on TiO_(2)surfaces was observed after extensive UV photocatalysis of toluene and xylene,and such by-products surface coverage may reduce the photocatalytic activity of TiO_(2)samples.Some aspects of the photocatalytic mechanism were examined.展开更多
Superoxide dismutase(SOD) is an important antioxidant enzyme in the body. SOD has special physiological activity and is the primary substance for scavenging free radicals in living organisms.However, the expensive and...Superoxide dismutase(SOD) is an important antioxidant enzyme in the body. SOD has special physiological activity and is the primary substance for scavenging free radicals in living organisms.However, the expensive and complex extraction processes, low SOD yield, as well as difficult to store at room temperature have seriously hindered its application pace. Herein, the enzyme mimetic function of Mn-doped ZnS quantum dots(QDs) was discovered. The improved Marklund and McCord method both showed that Mn-doped ZnS QDs possess intrinsic SOD-like activity. The effects of temperature and pH on the mimetic enzyme activity of Mn-doped ZnS QDs have been investigated compared with SOD enzymes.The low cost and easy to synthesize white Mn-doped ZnS QDs with good biocompatibility are expected to be used as a new type of SOD nanozymes in the biology-relevant fields.展开更多
The synthesis of a novel water-soluble Mn-doped CdTe/ZnS core-shell quantum dots using a proposed ultra- sonic assistant method and 3-mercaptopropionic acid （MPA） as stabilizer is descried. To obtain a high luminesc...The synthesis of a novel water-soluble Mn-doped CdTe/ZnS core-shell quantum dots using a proposed ultra- sonic assistant method and 3-mercaptopropionic acid （MPA） as stabilizer is descried. To obtain a high luminescent intensity, post-preparative treatments, including the pH value, reaction temperature, reflux time and atmosphere, have been investigated. For an excellent fluorescence of Mn-doped CdTe/ZnS, the optimal conditions were pH 11, reflux temperature 100℃ and reflux time 3 h under N2 atmosphere. While for phosphorescent Mn-doped CdTe/ZnS QDs, the synthesis at pH 11, reflux temperature 100℃ and reflux time 3 h under air atmosphere gave the best strong phosphorescence. The characterizations of Mn-doped CdTe/ZnS QDs were also identified using AFM, IR, powder XRD and thermogravimetric analysis. The data indicated that the photochemical stability and the photolu- minescence of CdTe QDs are greatly enhanced by the outer inorganic ZnS shell, and the doping Mn2＋ ions in the as-prepared quantum dots contribute to strong luminescence. The strong luminescence of Mn-doped CdTe/ZnS QDs reflected that Mn ions act as recombination centers for the excited electron-hole pairs, attributing to the transition from the triplet state （4T1） to the ground state （6A1） of the Mn2＋ ions. All the experiments demonstrated that the surface states played important roles in the optical properties of Mn-doped CdTe/ZnS core-shell quantum dots.展开更多
基金Project supported by the State Key Development Program for Basic Research of China (Grant No 2004CB619302)
文摘This paper reports that the radio frequency magnetron sputtering is used to fabricate ZnO and Mn-doped ZnO thin films on glass substrates at 500 ℃. The Mn-doped ZnO thin films present wurtzite structure of ZnO and have a smoother surface, better conductivity but no ferromagnetism. The x-ray photoelectron spectroscopy results show that the binding energy of Mn2p3/2 increases with increasing Mn content slightly, and the state of Mn in the Mn-doped ZnO thin films is divalent. The chemisorbed oxygen in the Mn-doped ZnO thin films increases with increasing Mn doping concentration. The photoluminescence spectra of ZnO and Mmdoped ZnO thin films have a similar ultraviolet emission. The yellow green emissions of 4 wt.% and 10 wt.% Mn-doped thin films are quenched, whereas the yellow green emission occurs because of abundant oxygen vacancies in the Mn-doped ZnO thin films after 20 wt.% Mn doping. Compared with pure ZnO thin film, the bandgap of the Mn-doped ZnO thin films increases with increasing Mn content.
基金supported by "973" Program of Ministry of Science and Technology of China (Grant No. 2006CB932402)National Natural Science Foundation of China (Grant Nos. 50702015, 10574034 and 10774032)
文摘This paper reports that a large amount of Mn-doped ZnO nanorods have been synthesized through thermal evaporation. The morphologies and properties are studied with x-ray diffraction, a scanning electron microscope, transmission electron microscope and Raman spectroscope. The results indicate that the manganese atoms occupy the zinc vacancies in the wurtzite lattice of ZnO without forming secondary phases. The exact manganese content has been studied by the x-ray fluorescence spectrum. Meanwhile, the magnetic moment versus temperature result proves that the as-prepared Mn-doped ZnO nanorods show ferromagnetic properties at temperatures as high as 400~K. These studies provide a good understanding of the origin of magnetic properties in diluted magnetic semiconductors.
基金Project supported by the Shanghai Nanotechnology Promotion Center (Grant No 0452nm071)the National Natural Science Foundation of China (Grant Nos 50702071 and 50772122)
文摘A series of Mn-doped ZnO films have been prepared in different sputtering plasmas by using the inductively coupled plasma enhanced physical vapour deposition. The films show paramagnetic behaviour when they are deposited in an argon plasma. The Hall measurement indicates that ferromagnetism cannot be realized by increasing the electron concentration. However, the room-temperature ferromagnetism is obtained when the films are deposited in a mixed argon-nitrogen plasma. The first-principles calculations reveal that antiferromagnetic ordering is favoured in the case of the substitution of Mn^2＋ for Zn^2＋ without additional acceptor doping. The substitution of N for O （NO^-） is necessary to induce ferromagnetic couplings in the Zn-Mn-O system. The hybridization between N 2p and Mn 3d provides an empty orbit around the Fermi level. The hopping of Mn 3d electrons through the empty orbit can induce the ferromagnetic coupling. The ferromagnetism in the N-doped Zn-Mn-O system possibly originates from the charge transfer between Mn^2＋ and Mn^3＋ via NO^-, The key factor is the empty orbit provided by substituting N for O, rather than the conductivity type or the carrier concentration.
基金supported in parts by the National Natural Science Foundation of China(No.60776004,60976071)the Laboratory for Thin Film Microfabrication of the Ministry of Education
文摘In this paper we investigated the optical properties of ZnO and Mn doped ZnO nanocrystals that were fabricated by a vapor phase transport growth process, using zinc acetate dihydrate with or without Mn in a constant O2/Ar mixture gas flowing through the furnace at 400600℃, respectively. The as grown ZnO nanocrystals are homogeneous with a mean size of 19 nm observed by scanning electron microscope（SEM）. The optical characteristics were analyzed by absorption spectra and photoluminescence（PL） spectra at room-temperature. For ZnO nanocrystals, a strong and predominant UV emission peaked at 377 nm was found in the PL spectra. For Mn doped ZnO nanocrystals, in addition to the strong UV emission, a strong blue emission peaked at 435 nm was observed as well. By doping Mn ions, the major UV emission shifts from 377 nm to 408 nm, showing that Mn ions were not only incorporated into ZnO Ncs, but also introduced an impurity level in the bandgap. Moreover, with the concentration of Mn increasing, the relative intensities of the two emissions change largely, and the photoluminescence mechanism of them is discussed.
基金supported by the National Natural Science Foundation of China (20673019, 20303002)the Key Project of Fujian Province (2005HZ01-2-6)the Foundation of State Key Laboratory of Structural Chemistry (20090060)
文摘The absorption and emission spectra of the wurtzite Mn-doped GaN were calculated with cluster models.The predicted lattice parameters become slightly larger than those of undoped cluster.The average bond length of Mn–N is longer than that of Ga–N.Spin density shows that one Mn atom in these clusters has four single electrons with the same direction of the spin polarity.The new energy level with light Mn-doping appears at 1.37 eV above the valance band.The absorption spectra of Mn-doped GaN cover the visible light region.The calculated emission spectra show that the green luminescence of GaN material in experiment did not result from Mn dopant.With the increase of Mn doping,the emission intensity of yellow or blue band increases to different extent and the band-to-band emission band shows red shift from peak at 3.34 to 3.24 eV.
基金supported by the National Natural Science Foundation of China(Project No.21875253)the CAS Commonwealth Scientific and Industrial Research Organization(CSIRO)Joint Research Projects(121835KYSB20200039)+3 种基金the Scientific Research and Equipment Development Project of CAS(YJKYYQ20190007)Fujian Natural Science Foundation(2021J01210293)the Fujian Science and Technology Pilot Project(Project No.2020H0039)the Joint Fund of the Yulin University and the Dalian National Laboratory for Clean Energy(Grant.YLUDNL Fund 2021011)。
文摘Electrolytic water splitting,as a promising route to hydrogen(H_(2))production,is still confronted with the sluggish anodic oxygen evolution reaction(OER)and its less value-added O2 production.Herein,we report a bifunctional electrode fabricated by in situ growth of Mn-doped CoSe_(2)nanonetworks on carbon fiber cloth(Mn-CoSe_(2)/CFC),which shows attractive electrocatalytic properties toward glycerol oxidation reaction(GOR)in alkali and hydrogen evolution reaction(HER)in acid.A flow alkali/acid hybrid electrolytic cell(fA/A-hEC)was then developed by coupling anodic GOR with cathodic HER with the Mn-CoSe_(2)/CFC bifunctional electrode.Such fA/A-hEC enables a rather low voltage of 0.54 V to achieve 10 mA cm^(-2),and maintain long-term electrolysis stability over 300-h operation at 100 mA cm^(-2)with Faraday efficiencies of over 99%for H_(2)and 90%for formate production.The designed bifunctional electrode in such innovative fA/A-hEC device provides insightful guidance for coupling energy-efficient hydrogen production with biomass upgradation.
基金Project supported by the Innovation Foundation of BUAA for PhD Graduates (Grant No. 292122)Equipment Research Foundation of China
文摘TiO2 nano powders with Mn concentration of 0 at%-12 at% were synthesized by the sol-gel process, and were annealed at 500 ℃ and 800 ℃ in air for 2 hrs. X-ray diffraction （XRD） measurements indicate that the Mn-TiO2 nano powders with Mn concentration of 1 at% and 2 at% annealed at 500 and 800 ℃ are of pure anatase and rutile, respectively. The scanning electron microscope （SEM） observations reveal that the crystal grain size increases with the annealing temperature, and the high resolution transmission electron microscopy （HRTEM） investigations further indicate that the samples are well crystallized, confirming that Mn has doped into the TiO2 crystal lattice effectively. The room temperature ferromagnetism, which could be explained within the scope of the bound magnetic polaron （BMP） theory, is detected in the Mn-TiO2 samples with Mn concentration of 2 at%, and the magnetization of the powders annealed at 500 ℃ is stronger than that of the sample treated at 800 ℃. The UV-VIS diffuse reflectance spectra results demonstrate that the absorption of the TiO2 powders could be enlarged by the enhanced trapped electron absorption caused by Mn doping.
文摘Manganese(Mn)doped cadmium sulphide(Cd S)nanoparticles were synthesized using a chemical method.It was possible to decrease Cd S:Mn particle size by increasing Mn concentration.Investigation techniques such as ultraviolet-visible(UV-Vis)absorption spectroscopy and photoluminescence(PL)spectroscopy were used to determine optical properties of Cd S:Mn nanoparticles.Size quantization effect was observed in UV-Vis absorption spectra.Quantum efficiency for luminescence or the internal magnetic field strength was increased by doping Cd S nanoparticles with Mn element.Orange emission was observed at wavelength~630 nm due to ^(4)T_1→^(6)A_1 transition.Isolated Mn~(2+)ions arranged in tetrahedral coordination are mainly responsible for luminescence.Luminescence quenching and the effect of Mn doping on hyperfine interactions in the case of Cd S nanoparticles were also discussed.The corresponding weight percentage of Mn element actually incorporated in doping process was determined by atomic absorption spectroscopy(AAS).Crystallinity was checked and the average size of nanoparticles was estimated using the X-ray diffraction(XRD)technique.Cd S:Mn nanoparticles show ferromagnetism at room temperature.Transmission electron microscopy(TEM)images show spherical clusters of various sizes and selected area electron diffraction(SAED)patterns show the polycrystalline nature of the clusters.The electronic states of diluted magnetic semiconductors(DMS)ofⅡ-Ⅵgroup Cd S nanoparticles give them great potential for applications due to quantum confinement.In this study,experimental results and discussions on these aspects have been given.
基金the Natural Science Research Project of the Education Department of Guizhou Province(grant No.QJ[2022]001).
文摘In this work,LiFe_(1-x)MnxPO_(4)@C(x=0,0.01,0.02,0.03)cathode materials were obtained by a simple co-precipitation method and heat treatment,and the influence of Mn-doped modification on the electrochemical performance of LiFePO_(4)@C cathode materials was investigated.Results show that by doping an appropriate amount of Mn,the cell volume became larger,and the electronic conductivity increased,which improved the Li+diffusion rate and thus its rate capability and cycle performance of Li-ion batteries.Among them,LiFe_(0.98)Mn_(0.02)PO_(4)@C showed superior lithium storage capability;the discharge capacity can reach 150.7 mAh g^(−1)at 0.1 C.The cell could discharge up to 155.9 mAh g^(−1)at 1 C under high temperature at 45°C,which was higher than LiFePO_(4)@C(142 mAh g^(−1))under the same test conditions.The discharge capacity of 1 C at room temperature was 139.9 mAh g^(−1),and the cycle stability was 95.9%after 200 cycles.It showed that it had good rate capability and excellent cycle performance.These results indicate that Mn-doped LFP is a simple and effective strategy for developing high-performance cathode materials.
基金supported by the National Natural Science Foundation of China(Nos.22271178 and 22001156)Project of Special Key Fields in Guangdong Province(No.2021ZDZX4019)+1 种基金the Science and technology innovation strategy of Guangdong province(No.51361212)Guangdong Provincial Science and Technology Innovation Strategy Special Fund Approval Project(No.pdjh2021b0266)。
文摘Although chemotherapy has been intensively applied in cancer treatments,its inadequate therapeutic efficacy and severe side effects are still under constant concerns.Nanoplatforms used as anti-tumor drug delivery system(DDS)have attracted tremendous attentions owing to their various intriguing properties.Herein,Mn-doped MoO_(2)nanoparticles coated with ZrO_(2)and capped with Bi_(2)O_(3)have been designed as a DDS,namely MMZB.MMZB possesses good magnetic properties,great photothermal conversion ability,sensitive tumor microenvironment(TME)responsiveness,and good biocompatibility in hemocompatibility in vitro.Thus,MMZB has been utilized to load the chemotherapeutic agent daunomycin(DNM)(MMZB@DNM)for chemo-photothermal combined therapy.MMZB@DNM demonstrates a more impressive anti-cancer effect than the individual photothermal or chemotherapy both in vitro and in vivo.Furthermore,the analysis of tumor specimen sections and serum levels after the treatment indicates negligible side effects for MMZB@DNM in vivo.This contribution provides a valuable concept in designing therapeutic agents for achieving significantly enhanced tumor treatments,which benefits from the synergistic combination of chemotherapy and photothermal therapy in one single nanoagent.
基金supported by the National Science Foundation for Young Scholars (No. 11004032)National Natural Science Foundation of China (No. 11074039)Fujian Province Science Foundation for Young Scholars (No.2008F3039)
文摘Olivine structured LiFePO 4 /C (lithium iron phosphate) and Mn 2+ -doped LiFe 0.98 Mn 0.02 PO 4 /C powders were synthesized by the solid-state reaction. The effects of manganese partial substitution and different carbon content coating on the surface of LiFePO 4 were considered. The structures and electrochemical properties of the samples were measured by X-ray diffraction (XRD), cyclic voltammetry (CV), charge/discharge tests at different current densities, and electrochemical impedance spectroscopy (EIS). The electrochemical properties of LiFePO 4 cathodes with x wt.% carbon coating (x= 3, 7, 11, 15) at =0.2C, 2C (1C= 170 mAh·g 1 ) between 2.5 and 4.3 V were investigated. The measured results mean that the LiFePO 4 with 7 wt.% carbon coating shows the best rate performance. The discharge capacity of LiFe 0.98 Mn 0.02 PO 4 /C composite is found to be 165 mAh·g 1 at a discharge rate, = 0.2C, and 105 mAh·g 1 at =2C, respectively. After 10 cycles, the discharge capacity has rarely fallen, while that of the pristine LiFePO 4 /C cathode is 150 mAh·g 1 and 98 mAh·g 1 at =0.2 and 2C, respectively. Compared to the discharge capacities of both electrodes above, the evident improvement of the electrochemical performance is observed, which is ascribed to the enhancement of the electronic conductivity and diffusion kinetics by carbon coating and Mn 2+-substitution.
基金supported by the National Natural Science Foundation of China(52072196,52002199,52002200,52102106)the Major Basic Research Program of the Natural Science Foundation of Shandong Province(ZR2020ZD09)+1 种基金the Innovation and Technology Program of Shandong Province(2020KJA004)the Taishan Scholars Program of Shandong Province(ts201511034)。
文摘Introducing vacancy defects and unique morphology is an effective strategy to improve the catalytic performance of transition metal compounds.However,precisely controlling the amount of vacancy defects remains challenging.Here,we propose a facile and efficient hydrothermal accompanying an annealing method to synthesize a series of Mn-doped CoO nanomaterials with controllable oxygen vacancies and unique morphology.The oxygen vacancies amount can be precisely controlled by adjusting the Mndoping content and is positively correlated with catalytic performance.It was found that the oxygen vacancies amount can reach up to 38.2%over the Mn-doped CoO nanomaterials,resulting in ultra-high hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)catalytic activity(HER:25.6 and 37 m V at 10 m A cm^(-2);OER:301 and 322 m V at 50 m A cm^(-2))under both basic and acidic conditions,while reaching 10 m A cm^(-2) for an ultra-low cell voltage of only 1.52 V,which exceeds that of Pt/C/RuO_(2) and all reported non-noble metal oxide catalysts.The DFT calculations reveal oxygen vacancies can optimize H*and HOO*intermediates adsorption free energy,thus improving the HER and OER performance.Interestingly,the Mn-doped CoO with rich oxygen vacancies exhibits excellent antibacterial properties in vitro of biomedicine.This work provides new ideas and methods for the rational design and precise control of vacancy defects in transition metal compounds and explores their potential application value in electrochemical water splitting and biomedical fields.
基金Project supported by the National Key R&D Program of China(Grant No.2017YFB0405702)the National Natural Science Foundation of China(Grant No.51671137).
文摘Heavily Mn-doped SiGe thin films were grown by radio frequency magnetron sputtering and then treated by postgrowth thermal annealing.Structural characterizations reveal the coexistence of Mn-diluted SiGe crystals and Mn-rich nanoclusters in the annealed films.Magnetic measurements indicate the ferromagnetic ordering of the annealed samples above room temperature.The data suggest that the ferromagnetism is probably mainly contributed by the Ge-rich nanoclusters and partially contributed by the tensile-strained Mn-diluted SiGe crystals.The results may be useful for room temperature spintronic applications based on group IV semiconductors.
基金Project supported by the Aeronautical Science foundation of China (Grant No 2003ZG51069)the National Defence BaseResearch of China
文摘This paper reported that the Mn-doped TiO2 films were prepared by radio frequency （RF） magnetron cosputtering. X-ray diffraction measurements indicate that the samples are easy to form the futile structure, and the sizes of the crystal grains grow big and big as the Mn concentration increases. X-ray photoemlssion spectroscopy measurements and high resolution transmission electron microscope photographs confirm that the manganese ions have been effectively doped into the TiO2 crystal when the Mn concentration is lower than 21%. The magnetic property measurements show that the Ti1-xMnxO2 （x = 0.21） films are ferromagnetic at room temperature, and the saturation magnetization, coercivity, and saturation field are 16.0 emu/cm^3, 167.5 × 80 A/m and 3740 × 80 A/m at room temperature, respectively. The room-temperature ferromagnetism of the films can be attributed to the new futile Ti1-xMnxO2 structure formed by the substitution of Mn^4＋ for Ti^4＋ into the TiO2 crystal .lattice, and could be explained by O vacancy （Vo）-enhanced ferromagnetism model.
基金Supported by the Natural Science Foundation of Hebei Province under Grant No E2006001006, and the Programme for New Century Excellent Talents at the University of the Ministry of Education of China.
文摘Zn1-xMnxO （x = O.Olq3.1） thin films with a Curie temperature above 300K are deposited on Al2O3 （0001） substrates by pulsed laser deposition. X-ray diffraction （XRD）, ultraviolet （UV）-visible transmission and Raman spectroscopy are employed to characterize the microstructural properties of these films. Room temperature ferromagnetism is observed by superconducting quantum interference device （SQUID）. The results indicate that Mn doping introduces the incorporation of Mn^2＋ ions into the ZnO host matrix and the insertion of Mn^2＋ ions increases the lattice defects, which is correlated with the ferromagnetism of the obtained films. The doping concentration is also proven to be a crucial factor for obtaining highly ferromagnetic Zn1-xMnxO films.
基金the National Natural Science Foundation of China(No.51771197)the Chinese Academy of Sciences(No.KJZD-EW-M05)the Liaoning Revitalization Talents Program(No.XLYC1807122)。
文摘Three-dimensional Dirac semimetal Cd_(3)As_(2)has been considered as an excellent candidate for applications of electronic devices owing to its ultrahigh mobility and air-stability.However,current researches are focused mainly on the use of gate-voltage to control its carrier transport tunability,while the manipulation of transport properties by element-doping is quite limited.Here we report the tunable magneto-transport properties by adjusting Mn-doping in the Cd_(3)As_(2)compound.We find that Mnelement doping has a strong influence on the Fermi level positions,and the Fermi energy approaches to Dirac point with higher Mn-doping.More importantly,the introduction of Mn atoms transforms diamagnetic Cd_(3)As_(2)to anti ferromagnetic(Cd,Mn)_(3)As_(2),which provides an approach to control topological protected Dirac materials by ma nipulating antiferro magnetic order parameters.The Shubnikov-de Hass oscillation originates from the surface states,and the Landau fan diagram yields a nontrivial Berry phase,indicating the existence of massless Dirac fermions in the(Cd_(1-x)Mn_x)_(3)AS_(2)compounds.Our present results may pave a way for further investigating anti ferromagnetic topological Dirac semimetal and expand the potential applications in optoelectronics and spintronics.
基金This work was supported by the National Natural Science Foundation of China （Nos. 21373097 and 51072067） and the National Basic Research Program of China （No. 2011CB935800）.
文摘The global demand for resource sustainability is growing. Thus, the development of single-source, environment-friendly colloidal semiconductor nanocrystal （NC） phosphors with broadband emission spectra is highly desirable for use as color converters in white light-emitting diodes （WLEDs）. We report herein the gram-scale synthesis of single-source, cadmium-free, dual-emissive Mn-doped Zn-Cu-In-S NCs （d-dots） by a simple, non-injection, low-cost, one-pot approach. This synthesis method led to the formation of NCs with continuously varying compositions in a radial direction because each precursor had a different reactivity. Consequently, the d-dots exhibited two emission bands, one that could be attributed to Mn emission and a second that could be ascribed to the band edge of the Zn-Cu-In-S NCs. The emission peaks assigned to band edge were tunable by modifying the particle size and composition. The prepared d-dots also exhibited the characteristic zero self-absorption, a quantum yield of 46%, and good thermal stability. Combining a commercial blue light-emitting diode （LED） chip with optimized d-dots as color converters gave a high color rendering index of up to 90, Commission Internationale de l＇eclairage color coordinates of （0.332, 0.321）, and a correlated color temperature of 5,680 K. These results suggest that cadmium-free, thermally stable, single-phase d-dot phosphors have potential applications in WLEDs.
基金a research grant from the Hellenic Ministry of Education with the acronym FORECO(11SYN-8-944)under the program SYNERGASIA 11 within ESPA 2007e2013The support of project“Electronics Beyond Silicon Era”(ELBESIER)ErasmustΚА2 programme acknowledged.Also,this work was carried out as part of European funding programs under the FP7 Clear-up IP project no 211948 and FP7 REGPOT 20122013 under grant agreement No 316165.
文摘The photocatalytic oxidation of gaseous benzene,toluene and xylene(BTX)over un-doped,0.1 and 1 wt%Mn-TiO_(2)nanoparticles under ultraviolet and visible irradiation was studied in atmosphere of synthetic air or inert gas.The photocatalytic decomposition efficiency and the oxidation products were determined using a Static Photochemical Reactor coupled with FTIR spectroscopy.BTX underwent efficient decomposition over Mn-TiO_(2)photocatalysts under UV irradiation,more with oxygen presence and less without oxygen.More important toluene and xylene went substantial decomposition over 0.1 mol%Mn-TiO_(2)under visible irradiation with oxygen presence.The main final oxidation products in the UV photocatalysis of BTX were CO_(2),CO and H2O,with CO_(2) and CO yields 4 and 2 respectively.The conversion percentage of benzene,toluene,and xylene to CO_(2) were 63.6%,56.4%,51.8%,and to CO 29%,26.5%,23.2%,respectively.In the visible photocatalysis of toluene and xylene the yields of CO were insignificant.Formation of carbon containing deposits on TiO_(2)surfaces was observed after extensive UV photocatalysis of toluene and xylene,and such by-products surface coverage may reduce the photocatalytic activity of TiO_(2)samples.Some aspects of the photocatalytic mechanism were examined.
基金the National Natural Science Foundation of China(Nos.61571426,61671435,81630053)Beijing Natural Science Foundation(No.4161003)for financial support
文摘Superoxide dismutase(SOD) is an important antioxidant enzyme in the body. SOD has special physiological activity and is the primary substance for scavenging free radicals in living organisms.However, the expensive and complex extraction processes, low SOD yield, as well as difficult to store at room temperature have seriously hindered its application pace. Herein, the enzyme mimetic function of Mn-doped ZnS quantum dots(QDs) was discovered. The improved Marklund and McCord method both showed that Mn-doped ZnS QDs possess intrinsic SOD-like activity. The effects of temperature and pH on the mimetic enzyme activity of Mn-doped ZnS QDs have been investigated compared with SOD enzymes.The low cost and easy to synthesize white Mn-doped ZnS QDs with good biocompatibility are expected to be used as a new type of SOD nanozymes in the biology-relevant fields.
基金Project supported by the Hubei Science Foundation （No. 2010CDA061）, the Science Foundation of the Education Department of Hubei Province （No. D200922005） and Team Foundation of the Education Department of Hubei Province, and the Scientific Foundation of Huangshi City.
文摘The synthesis of a novel water-soluble Mn-doped CdTe/ZnS core-shell quantum dots using a proposed ultra- sonic assistant method and 3-mercaptopropionic acid （MPA） as stabilizer is descried. To obtain a high luminescent intensity, post-preparative treatments, including the pH value, reaction temperature, reflux time and atmosphere, have been investigated. For an excellent fluorescence of Mn-doped CdTe/ZnS, the optimal conditions were pH 11, reflux temperature 100℃ and reflux time 3 h under N2 atmosphere. While for phosphorescent Mn-doped CdTe/ZnS QDs, the synthesis at pH 11, reflux temperature 100℃ and reflux time 3 h under air atmosphere gave the best strong phosphorescence. The characterizations of Mn-doped CdTe/ZnS QDs were also identified using AFM, IR, powder XRD and thermogravimetric analysis. The data indicated that the photochemical stability and the photolu- minescence of CdTe QDs are greatly enhanced by the outer inorganic ZnS shell, and the doping Mn2＋ ions in the as-prepared quantum dots contribute to strong luminescence. The strong luminescence of Mn-doped CdTe/ZnS QDs reflected that Mn ions act as recombination centers for the excited electron-hole pairs, attributing to the transition from the triplet state （4T1） to the ground state （6A1） of the Mn2＋ ions. All the experiments demonstrated that the surface states played important roles in the optical properties of Mn-doped CdTe/ZnS core-shell quantum dots.
