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2D Phosphorene: 2D Phosphorene: Epitaxial Growth and Interface Engineering for Electronic Devices (Adv. Mater. 47/2018)
摘要： In article number 1802207, Wei Chen and co-workers highlight their recent progress in the interface engineering of 2D phosphorene for applications in both epitaxial growth and electronic devices. Their detailed investigations reveal the critical role of substrates for epitaxial growth of 2D phosphorene, demonstrate a highly efficient surface transfer doping method, and provide a comprehensive understanding of the oxidation mechanism of black phosphorus in air.
关键词： 2D phosphorene,black phosphorus,interface engineering,surface transfer doping,oxidation mechanism,epitaxial growth,electronic devices
更新于2025-09-09 09:28:46
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Optical and Morphological properties of environmentally benign Cu-Tin Sulphide Thin films grown by Physical Vapor Deposition Technique
摘要： Present work has set about the synthesis of Tin-Diethyl dithiocarbamate Sn (S2CN (Et) 2) n]) and Copper diethyldithiocarbamate Cu (S2CN(Et)2) complex by utilizing single source method. Sn (S2CN (Et) 2) n]) complex are further used for deposition of Tin Sulphide thin films via Physical Vapor deposition with varying concentration of copper acting as dopant specie. The fabricated doped and un-doped films were confronted to functional group detection (FTIR), optical (Uv-Vis), structural (XRD) and morphological (SEM, EDX) analysis to retrieve the hidden information. FTIR peaks of Copper and Tin complex confirmed the formation of dithiocarbamate complexes by enumerating the stretching and bending vibrational modes of bonding and metal Sulphur linkage. X-ray diffraction elucidate the predominant phase of SnS with 1:1 ratio which depicted the fabrication at high temperature. Optical investigation represented the decrease in band gap by 6% extrinsic addition while increase at 10 % doping. The enhancement in band gap is also clear from the increased absorption edge upon 10% addition. Surface morphology of films was heterogeneous along flakes with compaction of spherical particles as demonstrated by SEM. The obtained results of material (SnS) being environmentally benign were therefore discussed to assess its aptness in optoelectronic devices.
关键词： Physical vapor deposition,band gap,doping,Tin Sulphide,FTIR
更新于2025-09-09 09:28:46
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Influence of Sm and Nb on the structural, electric, magnetic and magneto-electric properties of BaTiO3-Li0.5Fe2.5O4 composite ceramics grown by the conventional solid state technique
摘要： The Sm and Nb doped BaTiO3-Li0.5Fe2.5O4 composite ceramics having chemical formulae (90)BaTi(1?2x)NbxSmxO3 + (10) Li0.5Fe2.5O4 (x = 0, 0.05 and 0.1) were synthesized using conventional solid state technique. The structural, morphological, magnetic, dielectric, ferroelectric and magneto-electric properties of composites have been studied. The XRD measurement reveals the absence of peaks pertaining to impurities and strongly confirms the high crystalline nature of all the composites. From FESEM images, the average grain size of composites increases with increase in the concentration of Nb and Sm. The VSM studies confirm the soft magnetic nature of all the composites. The dielectric measurements confirm the increase in the transition temperature (Tc) of the BTL composite with an increase in the concentration of Nb and Sm. The P–E studies confirm that the ferroelectric nature of the BTL composite softens after doping Nb and Sm in it. The ME voltage coefficient value confirms the uniform growth of grains in all the composites and reveals a strong interaction between ferroelectric and magnetic orders.
关键词： magneto-electric properties,BaTiO3-Li0.5Fe2.5O4,electric properties,magnetic properties,composite ceramics,Sm and Nb doping,structural properties
更新于2025-09-09 09:28:46
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Rational Design of Graphic Carbon Nitride Copolymers by Molecular Doping for Visible-Light-Driven Degradation of Aqueous Sulfamethazine and Hydrogen Evolution
摘要： Carbon nitride is a promising metal-free visible light driven photocatalyst and sustainable material for address contaminant pollution and water splitting. However, the insufficient visible light absorption and fast charge recombination of carbon nitride have limited its practical application. Herein, the self-assembly carbon nitride (denoted as TCN) by molecular doping copolymerization of urea and 2-thiobarbitucid acid (TA) was prepared. XPS and elemental analytical results indicated that TA was doped in the framework of carbon nitride successfully. The self-assembly copolymerization would result in the change of morphology, intrinsic electron and band structure of carbon nitride. Theoretical calculations and experiments confirm that the band gap of TCN could be adjusted by changing the amount of 2-thiobarbitucid acid. Moreover, the efficiency of charge carrier transfer and separation was greatly enhanced. As a result, the optimized photocatalyst TCN-0.03 exhibited superior activity with a high reaction rate of 0.058 min-1 for the degradation of sulfamethazine under visible light irradiation, which is 4.2 times higher than that of urea based carbon nitride (U-CN). As a multifunctional photocatalyst, TCN-0.03 showed enhanced activity for hydrogen production (55 μmol h-1), which was 11 times higher than U-CN. The apparent quantum efficiency reached to 4.8% at 420 nm. A possible mechanism was proposed to explain the photocatalytic reaction process. This work provides insight into the rational design of modified carbon nitride by other organic monomers copolymerization to enhance the photocatalytic activity.
关键词： Photocatalytic degradation,Photocatalytic hydrogen evolution,Carbon nitride,Charge carriers transfer,Molecular doping copolymerization
更新于2025-09-09 09:28:46
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An insight into the polarization mechanism of rutile based oxides with a wide doping levels in the TiO2-CuO-TaO2.5 ternary system
摘要： Excellent dielectric properties have been found in some acceptor-donor co-doped rutile TiO2 type materials, but the polarization mechanism has long been debated. In present work, the polarization behaviors of single solid solutions Ti1-x(Cu0.333Ta0.667)xO2 (0 < x ≤ 0.465) samples are systematically investigated by establishing the ternary phase diagram of Ti1-xCu2x-2.5yTayO2 (0.05 ≤ x ≤ 1, 0 ≤ y ≤ 0.667). Basing on the obtained phase diagram and the analysis about microstructure, element valence and dielectric behaviors of rutile Ti1-x(Cu0.333Ta0.667)xO2 compositions with various doping levels (x = 0%, 5%, 18%, 33% and 45%), it is demonstrated the existence of multiple polarization mechanisms in this ternary dielectric system, i.e. free carrier nearest-neighbor-hopping polarization as well as internal barrier and surface barrier layer capacitor effect, contribute together to the overall dielectric behaviors. This work would provide guidance to achieve new electronics material with desired structures and properties.
关键词： Impedance spectrum,Polarization mechanism,High doping level,Ternary phase diagram
更新于2025-09-09 09:28:46
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Ultrasensitive Heterojunctions of Graphene and 2D Perovskites Reveal Spontaneous Iodide Loss
摘要： Using an ultrasensitive, exfoliated 2D perovskite single-crystal sheet/graphene heterostructure device, spontaneous iodide loss is revealed as an important degradation pathway of perovskites, which n-dopes perovskites by generating positively charged iodide vacancies. Furthermore, covering perovskites with graphene can suppress iodide loss, significantly improving perovskite stability. Our work not only provides important insights for future stable perovskite optoelectronic device development, but also demonstrates the potential of graphene as an encapsulant as well as a sensitive diagnostic tool for device and material degradation studies.
关键词： perovskite stability,graphene diagnostic tool,n-type doping,graphene/perovskite heterojunction,Spontaneous iodide loss
更新于2025-09-09 09:28:46
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UV Luminescence and Lasing in Ensembles of Zinc-Oxide Microcrystals with Copper
摘要： Microrod arrays of zinc oxide with copper have been grown by chemical vapor deposition on single-crystal sapphire substrates preliminarily covered with a nanoscale copper layer. The presence of copper (about 0.3%) in zinc-oxide microrods has been experimentally shown to increase the photoluminescence intensity of the ZnO microcrystal arrays, reduce the lasing threshold, and lead to a small (by ~2.5 nm) blue shift of the radiation intensity peak of the ZnO microcrystals. It is shown that the laser-radiation character depends on the morphology of the ZnO microrod arrays.
关键词： lasing,zinc-oxide microcrystals,UV luminescence,copper doping,chemical vapor deposition
更新于2025-09-09 09:28:46
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Microwave Induced Center-Doping of Transition Metals Ions in Aqueous CdS NCs with Special Optical Properties
摘要： Under microwave irradiation, we systematically studied the formation of transition metal ions (TM), Ag+, Mn2+, Cu2+, Fe2+, Co2+ and Ni2+, doped CdS semiconductor nanocrystals in a pure water solution. The center-doping strategy is essential for achieving efficient internal-doping to improve the optical properties and stability of doped nanocrystals. The resulting TM doped nanocrystals have a high photoluminescence quantum yield (~ 60%) and an amazingly large range of the visible spectrum (480 ~ 650 nm). For Mn2+ doped CdS nanocrystals, significant high photoluminescence quantum yield, between 20% and 50% even at more than 600 nm, was achieved and there is potential for them to be directly used as a consummate toner for multicolor sensing and encoding without ligand exchange. Highly emissive-doped nanocrystals synthesized under designed conditions have been found to have excellent stability; samples could be stored for months without precipitation. In practice, this approach has great potential to promote the metal doping of various semiconductor nanocrystals to realize the specific advantages of doped nanocrystals in water solution.
关键词： transition metal ions,microwave,nanocrystals,doping,CdS
更新于2025-09-09 09:28:46
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Green and Efficient Production of Boron Nitride Nanosheets via Oxygen Doping-Facilitated Liquid Exfoliation
摘要： As the structural analogue of graphene, boron nitride nanosheets (BNNSs) are anticipated to have a wide range of potential applications. BNNSs exhibit good mechanical properties, outstanding thermal conductivity, oxidation and chemical stability and are excellent electrical insulators. While BNNSs have gained recognition as one of the most versatile 2D materials in recent years, their application in research and industry is still hampered by the lack of methods to produce BNNSs in large quantity and a cost-effective way. In this study, we report highly efficient h-BN exfoliation via the oxygen doping-facilitated liquid exfoliation. Oxygen atoms are introduced into the hexagonal boron nitride (h-BN) structure via a facile thermal treatment. The relationship of thermal treatment, structural changes and h-BN exfoliation are studied to elucidate the key factor for advancing the BNNS production. The optimum concentration of hydroxyl groups and weakening of interlayer interactions have synergistically facilitated the delamination of h-BN in water under mild exfoliation conditions, resulting in up to 1255% yield increment and without noticeable new defects in the BNNS structure as compared with the untreated control. An efficient and environmentally friendly exfoliation process of h-BN is a crucial starting point towards the cost-effective and mass production of BNNSs which is needed for the currently identified and myriad future applications of BNNSs.
关键词： oxygen-doping,nanoplatelets,boron nitride nanosheets,2D nanomaterials
更新于2025-09-09 09:28:46
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Lead‐Free Semiconductors: Soft Chemistry, Dimensionality Control, and Manganese‐Doping of Germanium Halide Perovskites
摘要： Lead halide perovskites have drawn enormous interest due to their exceptional photovoltaic and optoelectronic properties. However, the toxic heavy metal lead is harmful to humans and the environment resulting in a need for strategies to replace this toxic element. Herein, we report a facile aqueous synthesis of CsGeX3 (X = I, Br) perovskite nanocrystals with size control achieved by varying the cysteammonium halide ligand concentration. We observe a variety of morphologies including pyramidal, hexagonal, and spheroidal. CsGeX3 nanocrystals undergo a lattice expansion due to partial replacement of Cs+ with larger cysteNH3+ cations into the lattice. We successfully dope Mn2+ into the CsGeX3 lattice for the first time with incorporation up to 29% in bulk and 16% in nano samples. XRD peak shifts and EPR hyperfine splitting strongly indicate that Mn2+ is doped into the lattice. Our results introduce a new member to the lead-free halide perovskite family and set the fundamental stage for their use in optoelectronic devices.
关键词： Germanium Halide Perovskites,Manganese(II) Doping,Perovskite Phases,Lead Substitution,Perovskite Nanocrystals
更新于2025-09-09 09:28:46