Low-temperature synthesis of carbon nanotubes on indium tin oxide electrodes for organic solar cells

• Andrea Capasso,
• Luigi Salamandra,
• Aldo Di Carlo,
• John M. Bell and
• Nunzio Motta

Beilstein J. Nanotechnol. 2012, 3, 524–532, doi:10.3762/bjnano.3.60

• segregation of Sn into clusters hundreds of nanometers in diameter [24], and also to increased inter-diffusion between the substrate and film [25]. Both effects can reduce the film conductivity by up to 50%, as reported elsewhere [26]. In our case, the interaction of the ITO film with the CVD process gases at

Size-dependent phase diagrams of metallic alloys: A Monte Carlo simulation study on order–disorder transitions in Pt–Rh nanoparticles

• Johan Pohl,
• Christian Stahl and
• Karsten Albe

Beilstein J. Nanotechnol. 2012, 3, 1–11, doi:10.3762/bjnano.3.1

• and low platinum concentration. A decrease of platinum surface segregation with increasing global platinum concentration was observed, when a second, ordered phase is formed inside the core of the particle. The order–disorder transitions were analyzed in terms of the Warren–Cowley short-range order

• parameters. Concentration-averaged short-range order parameters were used to remove the surface segregation bias of the conventional short-range order parameters. Using this procedure, it was shown that the short-range order in the particles at high temperatures is bulk-like. Keywords: Monte Carlo

• question of how to interpret a two-phase equilibrium in the particle, and the effects related to surface segregation are examined. Furthermore, we evaluate the Warren–Cowley short-range order (WC-SRO) parameters in order to investigate the order–disorder phase transitions in the particles. These parameters

Surface induced self-organization of comb-like macromolecules

• Konstantin I. Popov,
• Vladimir V. Palyulin,
• Martin Möller,
• Alexei R. Khokhlov and
• Igor I. Potemkin

Beilstein J. Nanotechnol. 2011, 2, 569–584, doi:10.3762/bjnano.2.61

• –shell cylindrical polymer brushes with a solvophobic inner (core) block and a solvophilic outer (shell) block in selective solvents [49]. Combs with two types of incompatible side chains (binary brushes) obviously represent quite intriguing objects due to the potential for intrachain segregation leading

• to Janus-like structure. Theoretical analysis, within the Flory–Huggins approach, of the intrachain segregation [50][51] demonstrated that, as the quality of the solvent worsens, segregation occurs at lower values of the parameter χAB. In the case of a poor solvent, the segregation condition χABM ~ 1

• qualitatively corresponds to the spinodal conditions for microphase segregation in melts of diblock copolymers [52]. Calculation of the free energy for a comblike copolymer with complete segregation of side chains showed that a molecule can spontaneously curve. A simulation study [53] confirmed the existence of

Recrystallization of tubules from natural lotus (Nelumbo nucifera) wax on a Au(111) surface

• Sujit Kumar Dora and
• Klaus Wandelt

Beilstein J. Nanotechnol. 2011, 2, 261–267, doi:10.3762/bjnano.2.30

• influencing the segregation behavior within the wax layer. As a consequence, the resultant surface composition of the wax film may favor vertical growth of the tubules. On the other hand, on Au(111) no such dangling bonds are available and hence the thin film might have a different surface composition upon

• which tubules grow horizontally. This substrate dependent segregation behavior, and hence, the different resultant concentration profile within the wax film, could be an explanation as to how the influence of the different substrates could be transferred to the surface of the wax film where the tubules

• special properties that lead to the unusual upright orientation of tubules on its surface. We have proposed as a hypothesis that ultimately the presence of free-standing dangling bonds on HOPG, and thereby a substrate specific segregation behavior within the wax materials, might be responsible for this

Extended X-ray absorption fine structure of bimetallic nanoparticles

• Carolin Antoniak

Beilstein J. Nanotechnol. 2011, 2, 237–251, doi:10.3762/bjnano.2.28

• indicating that the volume diffusion is still inadequate in this method. For gas phase synthesised nanoparticles, a possible surface segregation of Pt has recently been discussed [82] as it is also known for thin FePt films [83]. In addition, an indication of a stronger lattice expansion towards the surface

Structural and magnetic properties of ternary Fe_1–xMn_xPt nanoalloys from first principles

• Markus E. Gruner and
• Peter Entel

Beilstein J. Nanotechnol. 2011, 2, 162–172, doi:10.3762/bjnano.2.20

• significant percentage of surface atoms with diameters of a few nanometers. Several authors have therefore argued that at small particle sizes ordering is suppressed due to surface-induced disorder and segregation [21][24]. Both effects can be related to a change in the effective pair interactions between the

• properties than for the 3d elements Fe and Mn, which are neighbors in the periodic table. Again, the configurations were kept fixed for all calculations with the same morphology type and composition. This leaves aside possible effects due to segregation of one elemental species to the surface or internal

• framework of fully relativistic first principles calculations. It might also be necessary to investigate how far increased segregation of one species to surface and interfaces could affect the energetic order of the paradigmatic morphologies. Finding various phases with different structural and magnetic

Kinetic lattice Monte-Carlo simulations on the ordering kinetics of free and supported FePt L1₀-nanoparticles

• Michael Müller and
• Karsten Albe

Beilstein J. Nanotechnol. 2011, 2, 40–46, doi:10.3762/bjnano.2.5

• do not find significant differences in the ordering behavior. This holds true, even if we impose a massively increased thermodynamic driving force for interface segregation, because the nucleation of ordered domains on free facets is significantly faster than the bulk diffusion of the segregating

• metastable. If the particle composition is properly adjusted (taking into account the surface segregation effects), the ordering temperature is only a weak function of particle size [10]. The question to what extent the ordering kinetics is affected by the small particle size and how the ordering kinetics

• particle is studied and compared to a thin film geometry. Then, we investigate the role of a commensurate substrate by varying the thermodynamic driving force for interface segregation. Finally, we conclude with a summary of our results. Results and Discussion Simulation method and modified Ising-type

Preparation and characterization of supported magnetic nanoparticles prepared by reverse micelles

• Ulf Wiedwald,
• Luyang Han,
• Johannes Biskupek,
• Ute Kaiser and
• Paul Ziemann

Beilstein J. Nanotechnol. 2010, 1, 24–47, doi:10.3762/bjnano.1.5

• Pt segregation in the metallic state by annealing as well as their stability in ambient conditions are discussed. Section 3 focuses on the magnetic properties of Co, CoPt and FePt NPs. We show that magnetostatic interactions can be neglected for micelle-based NPs, which is used in a step where the

• and electronic structure of the sample. Moreover, due to its surface sensitivity, XPS can be used to obtain information on surface oxidation, phase separation and segregation both in films and in particles [66]. In this section some important findings are discussed which have impact on the

• as exhibited by larger or smaller FePt NPs can be consistently described by Pt segregation towards the particle surface. 2.3 Pt segregation in FePt nanoparticles For icosahedral FePt NPs, recent HRTEM observations have indicated a systematic increase of the lattice parameter towards the periphery of