Mn-doped titania thin films prepared by spin coating

TiO₂ thin films doped with ≤7 mol% Mn (metal basis) were deposited on F-doped SnO₂-coated (FTO) glass substrates by spin coating. The structural, morphological, and optical properties of the films were investigated by glancing angle X-ray diffraction (GAXRD), laser Raman microspectroscopy, field emission scanning electron microscopy (FESEM), and ultraviolet–visible spectroscopy (UV–VIS). Mn doping of TiO₂ (anatase) extended the optical absorption edge to longer wavelengths (lower photon energies) significantly lowering the band gap from 3.32 eV (undoped) to 2.90 (7 mol% Mn). The absorption edges of all films were sharp and the transparencies in the visible region were in the range 60–75%. All of the films were homogeneous, fully dense, and essentially crack-free.     

不同退火温度下Mn掺杂ZnO纳米晶的结构和磁性

ZnO的激子束缚能高达60meV,具有优良的光学性质。因此,Mn掺杂的ZnO材料研究在磁性半导体领域广泛开展起来。文章采用溶胶-凝胶法制备了Mn掺杂的ZnO纳米晶,讨论了在不同退火温度下纳米晶的结构和磁性。XRD结果显示,所有样品均为六角纤锌矿结构。退火后,Mn掺杂ZnO纳米晶的晶格常数均略大于纯净ZnO的晶格常数,表明Mn2 已经替代Zn2 进入ZnO晶格。500℃退火的样品在4～300K温度范围内表现为顺磁性。将退火温度提高到900℃后,有少量尖晶石结构的ZnMn2O4存在。室温磁滞回线表明样品具有室温铁磁性,磁性来源于ZnMn2O4。     

Mn 掺杂 SiC 基稀磁半导体薄膜的结构和磁性研究

目的从原子水平探究Mn掺杂SiC薄膜的磁性起源。方法采用射频磁控溅射技术制备不同掺杂浓度的Mn掺杂SiC薄膜,并采用X射线衍射技术、X光电子能谱、同步辐射X射线近边吸收精细结构技术、物理性质测试系统对薄膜的结构、组分和磁性能进行研究。结果晶体结构和成分分析表明,1200℃退火后的薄膜形成了3C-SiC晶体结构,且随着Mn掺杂浓度的增加,3C-SiC晶体的特征峰向低角度移动。在Mn掺杂浓度(以原子数分数计)为3%,5%,7%的薄膜中,掺杂的Mn原子以Mn2+的形式存在;而在9%Mn掺杂的SiC薄膜中,则有第二相化合物Mn4Si7形成。局域结构分析表明,薄膜中均不存在Mn金属团簇和氧化物,在3%,5%和7%Mn掺杂的薄膜中,掺杂的Mn原子主要以代替C位的形式进入3C-SiC晶格中,而在9%Mn掺杂的薄膜中,掺杂的Mn原子以C替位形式和Mn4Si7共存。磁性测试表明,制备的Mn掺杂SiC薄膜具有室温铁磁性,且饱和磁化强度随着Mn掺杂浓度的提高而增加。结论薄膜的室温铁磁性是本征的,磁性来源与掺杂的Mn原子以Mn2+取代SiC晶格中C位后导致的缺陷有关,符合缺陷导致的束缚磁极子机制。     

Mn掺杂花状ZnO的合成及其光催化特性研究

采用液相沉积法,在室温条件下制备了不同Mn掺杂浓度(0,0.25%,0.5%和1.0%(摩尔分数))的花状ZnO微结构。利用X射线衍射(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)对制备的花状ZnO微结构的物相及形貌进行表征。以甲基橙溶液作为光催化反应模型污染物,对不同浓度的Mn掺杂花状ZnO微结构的光催化性能进行了研究。实验结果表明,Mn在ZnO材料中以两种形态存在,即进入晶格以Mn2+形式替代Zn2+和以Mn3O4形式附着在ZnO材料表面。且Mn掺杂提高了花状ZnO微球结构的光催化活性,当掺杂浓度为0.25%(摩尔分数)时光催化性能最优,紫外光照2.0h后,对甲基橙的光催化降解率可达88.7%。     

Mn掺杂ZnO基纳米纤维的制备与表征

有效地制备出均一单相的Mn掺杂ZnO基纳米纤维是构建微型自旋电子器件的前提和基础。采用静电纺丝法制备了5种不同浓度的Mn掺杂ZnO纳米纤维。通过调节控制纺丝过程中的工作电压,可以有效控制前驱体纤维的形貌和直径分布。在适当的热处理条件下,XRD图谱表征该5种掺杂浓度的纤维均呈现良好的六方纤锌矿结构。光致发光谱显示该纤维在400~1000nm的波长范围内出现了2个发光峰,且均随着Mn掺杂的进入而发生蓝移现象。     

核壳结构CdS：Mn/ZnS纳米晶的制备与光学性能研究

以3-巯基丙酸为稳定剂,采用共沉淀法在水相中合成了CdS∶Mn掺杂纳米晶,然后进一步将ZnS包覆于CdS∶Mn纳米晶表面,制备了CdS∶Mn/ZnS核壳结构纳米晶。利用X射线衍射（XRD）,透射电子显微镜（TEM）和紫外-可见吸收光谱（UV-Vis）对纳米晶的结构、形貌和光学性质进行了表征,发现制备的纳米晶具有优秀的单分散性,确认合成了CdS∶Mn/ZnS核壳结构纳米晶。通过荧光光谱（PL）研究了纳米晶的发光性质和光稳定性,结果表明包覆壳层后纳米晶的发光强度显著提高,最高可达8倍,且Mn2＋离子的发光峰峰位置随着ZnS壳层数的增加而红移。此外,核壳纳米晶的光稳定性大大提高。     

Doping manganese into CsPb(Cl/Br)3 quantum dots glasses: Dual-color emission and super thermal stability

CsPbX₃ (X = Cl, Br, I) perovskite quantum dots (QDs) represent bright and tunable photoluminescence, it is regrettable that the air instability and poor water resistant properties prevent their application in optoelectronic devices. At the same time, the toxicity of lead is also a major factor restricting its development. As a consequence, we demonstrate the partial replacement of Pb with Mn through conventional melt-quenching and heat-treatment method preparation of Mn-doped CsPb(Cl/Br)₃ QD glass. Mn-doped CsPb(Cl/Br)₃ QD glass exhibits high luminescent intensity like QDs. It is important that Mn-doped CsPb(Cl/Br)₃ QD glass with Dual-Color maintained the same lattice structure like Mn-doped CsPb(Cl/Br)₃ QDs, and highly homogeneous spectral characteristics of Mn luminescence. The intensity and position of this Mn-related emission are also tunable by altering the experimental parameters, such as the Pb-to-Mn feed ratio, annealing temperature. More importantly, the as-prepared orange Mn-doped CsPb(Cl/Br)₃ QD glass was employed to fabricate white LEDs combined with a commercial Ce³⁺:Y₃Al₅O₁₂ phosphor-in-glass (Ce-PiG) on top of a InGaN blue chip. And the constructed WLEDs generate a warm white with an optimal luminous efficacy (LE) of 67.00 lm/W, a high CRI of 81.4, and a low CCT of 4902 K.     

Synthesis and characterization of Mn-doped C@ZrSiO4 black pigment via non-hydrolytic sol-gel method

With the increasing popularity of the black decorative ceramics, the development of black pigment with good properties has become significant for the ceramic industry. A Mn-doped zirconium silicate encapsulated carbon (C@ZrSiO₄) black pigment was successfully prepared via non-hydrolytic sol-gel (NHSG) method at 800 °C, while MnCl₂ and carbon-containing precursors (tetraethoxysilane, TEOS) were used as Mn and in-situ carbon sources, respectively. The results demonstrated that the L* value of black pigment first decreased and increased with the increase of MnCl₂ content. The as-prepared pigment with the MnCl₂ content of 10 mol% showed a deep dark hue (L* = 27.64, a* = 0.67, b* = 0.68), while the pigment without Mn doping exhibited poor chromatic properties (L* = 51.18). Moreover, XPS and EPR results indicated that the Mn(II) and Mn(IV) replaced the Zr(IV) in ZrSiO₄, resulting in the formation of oxygen vacancies. In-situ carbon provided by TEOS incorporated into these oxygen vacancies, which can protect carbon from being oxidized. In addition, the prepared pigment exhibited higher chemical stability in acid/alkali solutions, favorable tinting strength and thermal stability in base transparent glaze, which displayed wide application prospect in the field of ceramic decoration.     

Synthesis and characterization of manganese doped CeO2 nanopowders from hydrolysis and oxidation of Ce37Mn18C45

The Mn-doped CeO 2 nanopowders with high catalysis activity were successfully fabricated through a simple hydrolyzed-oxidized approach.Firstly,the alloy Ce 37 Mn 18 C 45 was prepared in vacuum induction melting furnace.Subsequently,Mn-doped CeO 2 nanopowders with 142 m 2 /g of specific surface area were obtained through a simple hydrolyzed-oxidized procedure of the alloy.Those nanopowders were heat treated at different temperatures.The obtained materials were characterized by X-ray diffraction(XRD),transmission electron microscopy(TEM),high-resolution transmission electron microscopy(HRTEM) and energy dispersive spectroscopy(EDS).And the catalytic activity on vinyl chloride(VC) emission combustion was investigated.The results showed that those nanopowders after hydrolyzed-oxidized from Ce 37 Mn 18 C 45 mainly consisted of CeO 2 and Mn 3 O 4.Manganese element increased the thermal stability of CeO 2 nanopowders.The Mn-doped CeO 2 nanopowders had three morphologies.Small particles were Mn-doped CeO 2,square particles were Mn 3 O 4 and the rods were Mn 3 O 4 and Mn 2 O 3.The Mn-doped CeO 2 nanopowders had good vinyl chloride(VC) emission catalytic performance.     

Structural, magnetic and electrical properties of Bi1.4La0.6Sr2CaCu2−xMnxOy compounds

The Mn-doped compounds Bi_1.4La_0.6Sr₂CaCu₂O_y were prepared by sol-gel method. The structural variation was characterized systematically by X-ray diffraction (XRD), infrared (IR) spectra and Raman scattering spectra, respectively. The electrical and magnetic properties of the compounds were investigated by the temperature dependence of resistivity (R-T) and magnetic hysteresis loop (M (H)) measurements. Results indicate that the subtle change of lattice parameters has taken place in the compounds, which is attributed to CuO₂ planes canting and Mn valence alternation. In the condition of preserving Bi-2212 structure, Bi_1.4La_0.6Sr₂CaCu_2−xMn_xO_y compound has optimal resistivity and magnetism at x = 2%, which could provide a candidate as new barrier in Josephson junction in future.