Synthesis,characterization, and applications with the manifestation of antifungal activity and seed germination properties of nickel doped zinc oxide nano platform by biochemical contrivance

In the recent era, nanotechnology, a rapidly emerging field, has been explored as the most studied field worldwide. The goal of this study is to use neem leaves extract as an effective ‘reducing agent’ and ‘stabilizing agent’ in the green synthesis of bio-medically important Zn_1-XNi_XO (X = 0.00, 0.04, 0.08, 0.12) nanoparticles. The molar concentrations of nickel nitrate and zinc nitrate are varied to produce nickel-doped ZnO nanoparticles. Color change is the first indicator of nanoparticle formation during this biosynthesis. The hexagonal wurtzite structure with good crystallinity is confirmed by X-ray diffraction. FTIR analysis reveals the fact that the Zn–O stretching vibration shifts with the introduction of impurities into the ZnO matrix. UV–Vis spectra show the typical surface plasma resonance around 370 nm and the hydrodynamic diameter is larger than the size calculated from the XRD value, according to DLS. The main finding of this study is that Ni_0.12Zn_0.88O has a strong antifungal activity against and a significant growth rate after treating wheat seeds with biologically synthesized Ni_0.12Zn_0.88O nanoparticles.     

Comparison of implantation and diffusion behavior of Ti, Sb and N in ion-implanted single crystal and polycrystalline ZnO: A SIMS study

Implantation and diffusion behavior of Sb, Ti and N in ZnO single crystal and sputter deposited thin films were studied through secondary ion mass spectrometric studies on ion-implanted and thermally annealed samples. Sb was implanted and Ti and N were co-implanted into ZnO single crystals and polycrystalline thin films on Si substrates at room temperature. The implanted samples were then annealed at 800 °C. Depth profiles of implant distributions before and after annealing were examined by Secondary Ion Mass Spectrometry (SIMS). As expected, implant range is sensitive to the mass of the dopants; and the dopant distribution is broadened as implanted elements migrate deeper into the film on thermal annealing. While diffusion of N in the ZnO thin film is not significant, Ti tends to diffuse deeper into the sample during annealing. For Ti and N co-implanted single crystal, annealing induced diffusion causes more redistribution of the lighter N than Ti. In general, implanted dopants diffuse more easily in thin films compared to the single crystal due to the presence of grain boundaries in the latter.     

Polyaniline–DNA microsphere formation by simple electropolymerization

Polyaniline (PANI) microspheres were prepared by electrochemical polymerization. To obtain PANI having novel micro- and nanostructures, by the potential scan technique, aniline was electropolymerized in the presence of DNA using four polymerizing solutions containing different acids: H₂SO₄, C₆H₅SO₃H, HClO₄, and CF₃COOH. The growth rate of the PANI film on the electrode surface decreased by the presence of DNA, suggesting that DNA interacted with the growing PANI molecules during the electropolymerization. The growth rate also depended on the type of acid, i.e., the anion, in the polymerizing solution and was in the order of SO₄ ²⁻ > C₆H₅SO₃ ⁻ > ClO₄ ⁻ > CF₃COO⁻, which significantly coincided with the reverse order of the Hofmeister series representing the lyophilicity of the anion. When aniline was electropolymerized in the CF₃COOH polymerizing solution containing DNA, PANI microspheres were obtained without any templates. This PANI showed a sufficient redox activity in the less acidic solution in which the ordinary PANI has a slight redox activity. On the other hand, the electronic state of the PANI differed from the ordinary ones; a new absorption band was evident at 620 nm. The difference in the redox activity and electronic state suggested that the DNA molecules were incorporated in the PANI and electronically interacted with the PANI molecules.     

Analysis of the Products from the Oxidation of Geting Bituminous Coal by Atmospheric Pressure Photoionization–Mass Spectrometry

Geting bituminous coal was directly oxidized in aqueous sodium hypochlorite. The reaction mixture was sequentially extracted with ethyl ether and ethyl acetate. Both extracts were esterified with diazomethane to obtain methyl esterified products, which were analyzed using high performance liquid chromatography–mass spectrometry with electrospray ionization or atmospheric pressure photoionization. A large number of low- and nonpolar products with relatively high molecular masses were determined using atmospheric pressure photoionization mass spectrometry. Toluene and a toluene/anisole mixture (vol/vol = 95:5) were added to the atmospheric pressure photoionization system as dopants. Toluene induced better ionization than the toluene/anisole mixture in both ion signal intensity and number of detected species. Most of the molecular associated compounds contained heteroatoms.     

Organic doped diode rectifier based on parylene-electronic beam lithogrpahy process for radio frequency applications

We have adapted a “peel-off” process to structure stacked organic semiconductors (conducting polymers or small molecules) and metal layers for diode microfabrication. The fabricated devices are organic diode rectifier in a coplanar waveguide structure. Unlike conventional lithographic process, this technique does not lead to destroy organic active layers since it does not involve harsh developer or any non-orthogonal solvent that alter the functionality of subsequentially deposited materials.This process also involves recently reported materials, as a p-dopant of an organometallic electron-acceptor Copper (II) trifluoromethanesulfonate, that play the role of hole injection layer in order to enhance the performances of the diode.Comparatively to self-assembled monolayers based optimized structures, the fabricated diodes show higher reproducibility and stability. High rectification ratio for realized pentacene and poly (3-hexylthiophene) diodes up to 10⁶ has been achieved. Their high frequency response has been evaluated by performing theoretical simulations. The results predict operating frequencies of 200 MHz and 50 MHz for pentacene and P3HT diode rectifiers respectively, with an input oscillating voltage of 2 V peak-to-peak, promising for RFID device applications or for GSM band energy harvesting in low-cost IoT objects.     

Ⅱ-Ⅵ族碲化物体单晶低温光致发光谱研究

采用熔体法生长Ⅱ-Ⅵ族碲化物体单晶时,不同的生长条件及热经历过程会导致生长态晶体材料中,占主导的点缺陷类型存在较大的差异,进而影响了晶体的物理性能及器件的使用。低温光致发光(PL)谱作为一种无损检测方法,可以用于研究不同条件下生长的Ⅱ-Ⅵ族碲化物体单晶中的点缺陷和杂质的能级状态。对比富Te条件下生长的未掺杂ZnTe和CdTe晶体在8.6 K下的PL谱可以发现,电阻率较低的p型ZnTe晶体,其PL谱中,电子到中性受主复合发光峰(e, A0)强度高于施主-受主对复合发光峰(DAP),而高电阻率阻n型CdTe晶体则刚好相反,这可能是由于生长速率及降温过程的热经历不同导致占主导的本征点缺陷类型不同造成的。按化学计量比生长的未掺杂CdZnTe晶体,其PL谱中自由激子发光峰(D0, X)占主导,而(e, A0)峰强度高于DAP峰,变温PL谱测试表明当温度高于15 K时,(e, A0)峰与DAP峰逐渐叠加在一起。In掺杂导致在富Te条件下生长的CdZnTe晶体的PL谱中产生明显的A中心复合发光峰,与导带的能量差约为0.15 eV,主要与In补偿Cd空位形成的复合体[In+_CdV2-_Cd]-有关,且其强度与In掺杂元素的含量成正比。     

给体-受体-给体窄带隙染料掺杂聚芴发光二极管

合成了一系列给体-受体-给体型窄带隙荧光分子, 并将其作为掺杂剂与主体(Host)宽带隙聚芴共混制备发光二极管. 荧光分子为4,7-二呋喃-苯并噻二唑(O-S)、4,7-二噻吩-苯并噻二唑(S-S)、4,7-二(N-甲基吡咯)-苯并噻二唑(N-S)、4,7-二硒吩-苯并噻二唑(Se-S)和4,7-二(N-甲基吡咯)-苯并硒二唑(N-Se). 溶液中荧光分子的紫外-可见吸收峰位于447~472 nm, 荧光发射峰位于563~637 nm. 该系列荧光分子掺杂聚芴(PFO)发光器件的电致发光峰位于580~633 nm. 当器件结构为ITO/PEDOT/PVK/PFO+N-Se/Ba/Al时, 最大外量子效率为1.28%, 电流效率1.31 cd/A.     

一种反求杂质浓度的数值方法——基于CV数据的逐点反求多次循环法

根据CV数据用数值模拟反求杂质浓度时,遇到了不确定性问题。本文认为这实际上是用CV数据反求杂质浓度时的非单值性问题。针对数值方法的非单值性问题,本文提出了逐点反求多次循环的算法。本算法已成功地应用于分布陡峻的高斯离子注入分布及矩形阶跃分布,反求的杂质浓度分布与理论杂质浓度分布符合得很好。     

Properties of Si δ-layers embedded in GaAs

An ultrathin, a few monolayers (MLs) thick Si δ-layer, has been embedded in GaAs. The Si δ-layer properties have been electrically and structurally characterized. A conductivity transition has been observed, when going from free carrier transport in thin (1 ML) ordered δ-layers to the disordered conditions for Si δ-layers thicker than 4 MLs. Two novel emission bands are observed in photoluminescence (PL) for Si δ-layers in the width range 1–4 MLs, but solely at below bandgap excitation. The pronounced 2D properties of these δ-layers have been clearly demonstrated by an observed blue shift of the PL characterization as the thickness of the Si δ-layer is reduced. The so-derived results on the transition energies and the electronic structure are in good agreement with theoretical predictions obtained by a self-consistent approach.