Effect of radiation-induced vacancy saturation on the first-order phase transformation in nanoparticles: insights from a model

• Aram Shirinyan and
• Yuriy Bilogorodskyy

Beilstein J. Nanotechnol. 2024, 15, 1453–1472, doi:10.3762/bjnano.15.117

• transitions and the zones of radiation stability for nanoparticles. We utilize nanoparticles exhibiting transitions from the body-centered cubic α phase to the face-centered cubic β phase, and the reverse transition from β phase to α phase, as a model system for first-order phase transformations. We

• incorporate nucleation through the appearance and growth of the nucleus of a new phase, resulting in the formation of a two-phase α+β system, and we highlight the importance of accounting for nucleation. Our model study reveals that very small α-phase particles are unstable (while very small β-phase particles

• cannot occur regardless of irradiation because of bulk driving forces; initially, α-phase particles are stable, whereas the β-phase particles are unstable. In some cases, nucleation requires a large additional energy change, resulting in a low probability of phase change fluctuations. This behavior is

Directed growth of quinacridone chains on the vicinal Ag(35 1 1) surface

• Niklas Humberg,
• Lukas Grönwoldt and
• Moritz Sokolowski

Beilstein J. Nanotechnol. 2024, 15, 556–568, doi:10.3762/bjnano.15.48

• on Ag(100), we know that the elevated temperature induces an irreversible phase transition into a heterochiral and commensurate structure, the so-called β-phase [23]. This phase is also obtained after deposition at 500 K and subsequent cooling to 300 K. This preparation was chosen here. The β-phase

• also consists of parallel molecular chains of QA dimers as the α-phase, but with periodic indents along the chains. The molecules in the domains of the β-phase exhibit the same azimuthal orientations as those in the α-phase. We find that the β-phase also forms on Ag(35 1 1), and the domains of the β

• . However, a striking difference is that, here, there is a very prominent inequivalence regarding the spot intensities. Half of the spots have significantly less intensity than the other half, which means that two domains of the β-phase are more prevalent than the other two domains. These are the domains A

Density functional theory study of Au-fcc/Ge and Au-hcp/Ge interfaces

• Olga Sikora,
• Małgorzata Sternik,
• Benedykt R. Jany,
• Franciszek Krok,
• Przemysław Piekarz and
• Andrzej M. Oleś

Beilstein J. Nanotechnol. 2023, 14, 1093–1105, doi:10.3762/bjnano.14.90

• , involving a hexagonal AuGe β phase present during the intermediate stages of growth. Interestingly, while the fcc crystallites were randomly oriented with respect to the Ge substrate, the hcp nanostructures were typically found with (001) planes at 60–65° to the (111) Ge planes [22]. In a recent experiment

A wearable nanoscale heart sound sensor based on P(VDF-TrFE)/ZnO/GR and its application in cardiac disease detection

• Yi Luo,
• Jian Liu,
• Jiachang Zhang,
• Yu Xiao,
• Ying Wu and
• Zhidong Zhao

Beilstein J. Nanotechnol. 2023, 14, 819–833, doi:10.3762/bjnano.14.67

• . Composition and β-phase content of the piezoelectric composite films were analyzed using X-ray diffraction. The morphology of the composite film fibers was observed through scanning electron microscopy. Finally, the P(VDF-TrFE)/ZnO/graphene composite film was encapsulated in a sandwich-structure heart sound

• utilized to analyze the composition and β-phase content of the composite piezoelectric nanofilms, while scanning electron microscopy (SEM) was employed to observe the morphology of the thin film filaments. Figure 6 displays the XRD patterns of the three composite piezoelectric nanofilms. In the P(VDF-TrFE

• XRD map of the composite nanofilm. This indicates that ZnO exists in the form of nanoparticles in the fiber film after being added to P(VDF-TrFE) [20][21]. P(VDF-TrFE)/ZnO/GR exhibits the highest β-phase content among the three films, with P(VDF-TrFE)/ZnO showing a slightly higher content than P(VDF

Investigation of electron-induced cross-linking of self-assembled monolayers by scanning tunneling microscopy

• Patrick Stohmann,
• Sascha Koch,
• Yang Yang,
• Christopher David Kaiser,
• Julian Ehrens,
• Jürgen Schnack,
• Niklas Biere,
• Dario Anselmetti,
• Armin Gölzhäuser and
• Xianghui Zhang

Beilstein J. Nanotechnol. 2022, 13, 462–471, doi:10.3762/bjnano.13.39

• were first imaged by STM, then exposed to 1 keV or 50 eV electrons at a series of doses, and imaged again by STM (see Figure 1). Characterization of TPT SAMs on Au(111) The TPT SAMs prepared from dimethylformamide (DMF)-based solution display two molecular arrangements: the α-phase and the β-phase

• to the surface normal [65]. Figure 2b (bottom panel) shows a high-resolution image of the β-phase, which is characterized by rows of oval spots aligned at an angle of ≈60° with respect to the stripe direction. Each oval spot contains two TPT molecules. Such superstructure is caused by point-on-line

• notation as relative to the substrate crystallographic directions and , with n being close to 8 [65]. The area per molecule of the β-phase is 0.288 nm2 (n = 8). The corresponding tilt angle of the molecular backbone is in the range of 33–49° with respect to the surface normal. The α-phase is thus

Enhancement of the piezoelectric coefficient in PVDF-TrFe/CoFe₂O₄ nanocomposites through DC magnetic poling

• Marco Fortunato,
• Alessio Tamburrano,
• Maria Paola Bracciale,
• Maria Laura Santarelli and
• Maria Sabrina Sarto

Beilstein J. Nanotechnol. 2021, 12, 1262–1270, doi:10.3762/bjnano.12.93

• investigated piezoelectric polymers, due to the high β phase content resulting from specific curing or processing conditions. However, to obtain a high piezoelectric coefficient (d33) alignment of the β phase domains is needed, which is usually reached through applying a high electric field at moderate

• consisting of CoFe2O4 nanoparticles dispersed in PVDF-TrFe with enhancement of the β phase alignment through an applied DC magnetic field. The magnetic poling was demonstrated to be particularly effective, leading to a piezoelectric coefficient d33 with values up to 39 pm/V. This type of poling does not need

• phases, the so-called TGTG′ (trans-gauche-trans-gauche) chain conformation, show a weak piezoelectric response after electric poling. The β phase, the so-called TTT (all trans) planar zigzag chain conformation, is the one responsible for the electroactive response of the polymer. It is a polar phase that

Extended iron phthalocyanine islands self-assembled on a Ge(001):H surface

• Rafal Zuzak,
• Marek Szymonski and
• Szymon Godlewski

Beilstein J. Nanotechnol. 2021, 12, 232–241, doi:10.3762/bjnano.12.19

• nearest FePc molecules reaches approximately 3.79 Å [68]. While the neighboring columns contain molecules rotated in opposite directions, the separation between every second column is reported to be 23.9 Å. The β phase is characterized by a slightly larger rotation angle of the molecules within columns

• , therefore, shall correspond to the half of the unit cells of the α and the β phase. While the majority of phthalocyanines exhibits alternate rotation of the molecules within neighboring columns, there are examples of structures, in which the molecules are rotated uniformly, that is, CuPc on a wetting layer

The influence of an interfacial hBN layer on the fluorescence of an organic molecule

• Christine Brülke,
• Oliver Bauer and
• Moritz M. Sokolowski

Beilstein J. Nanotechnol. 2020, 11, 1663–1684, doi:10.3762/bjnano.11.149

Piezoelectric sensor based on graphene-doped PVDF nanofibers for sign language translation

• Shuai Yang,
• Xiaojing Cui,
• Rui Guo,
• Zhiyi Zhang,
• Shengbo Sang and
• Hulin Zhang

Beilstein J. Nanotechnol. 2020, 11, 1655–1662, doi:10.3762/bjnano.11.148

• used to characterize the material (Figure 2d). It was found that as the GR concentration increases, the fraction of the β-phase of PVDF also increases, which is considered to have a positive effect on the piezoelectricity of PVDF. The influence of the GR concentration on the tensile strength of the

Preparation, characterization and photocatalytic performance of heterostructured CuO–ZnO-loaded composite nanofiber membranes

• Wei Fang,
• Liang Yu and
• Lan Xu

Beilstein J. Nanotechnol. 2020, 11, 631–650, doi:10.3762/bjnano.11.50

• studies. FTIR and XRD analysis: FTIR was used to characterize the CNFMs with different [Cu(Ac)2/Zn(Ac)2]/[PVDF/PAN] weight ratios (Figure 7). The peaks at 879 cm−1 correspond to the asymmetric stretching vibration of –CF2– in PVDF. The peaks at 1070 and 1276 cm−1 represent the β-phase of PVDF. There was

• (Figure 11a, b) as well as of pure PVDF/PAN CNFMs (Figure 11c) show three peaks at 1070, 2250 and 2942 cm−1.These three peaks represent the stretching vibration of –C–C– in the β-phase of PVDF, the stretching vibration of –CN– in PAN and the telescopic vibration of –CH2– in PAN, respectively. By

Tailoring the magnetic properties of cobalt ferrite nanoparticles using the polyol process

• Malek Bibani,
• Romain Breitwieser,
• Alex Aubert,
• Vincent Loyau,
• Silvana Mercone,
• Souad Ammar and
• Fayna Mammeri

Beilstein J. Nanotechnol. 2019, 10, 1166–1176, doi:10.3762/bjnano.10.116

• crystallinity, with NPs acting as nucleating points. Also, as established by Costa et al., the presence of these NPs promotes the crystallization of PVDF in its β-phase, the most electroactive one, instead of its other allotropic forms [10]. Finally, another improvement consists in making the size of the

Hydrogen-induced plasticity in nanoporous palladium

• Markus Gößler,
• Eva-Maria Steyskal,
• Markus Stütz,
• Norbert Enzinger and
• Roland Würschum

Beilstein J. Nanotechnol. 2018, 9, 3013–3024, doi:10.3762/bjnano.9.280

• V, while PdHα disappears at potentials below −0.99 V. Nanostructured materials can exhibit a significant narrowing of the miscibility gap in the phase diagram compared to the bulk metal [33], which can drive the onset of β-phase formation to higher hydrogen concentrations and/or lower potentials

• . For nanoporous palladium produced in this work, a cf value of about 0.07 for the β-phase onset can be estimated from the data presented in Figure 4, which is in good agreement with a value of 0.06 determined for palladium nanoparticles [30]. The saturation of PdHβ formation and the corresponding

• depletion of PdHα at a value below −0.99 V is consistent with values reported for palladium thin films [31][32]. The threshold values for the palladium hydride β-phase formation (−0.96 V) and the potential of α-phase depletion (−0.99 V) can be used for a phase distinction in current-controlled experiments

Formation of ferromagnetic molecular thin films from blends by annealing

• Peter Robaschik,
• Ye Ma,
• Salahud Din and
• Sandrine Heutz

Beilstein J. Nanotechnol. 2017, 8, 1469–1475, doi:10.3762/bjnano.8.146

• instance, at room temperature, films commonly adopt the α-phase (φ = 65°) and can be transformed to the thermodynamically stable β-phase (φ = 45°) by annealing in vacuum at 330 °C [7][8][9]. However, such temperatures are too high for most flexible substrates, and therefore limit one of the main

• fabrication advantages of molecular materials. The β-phase is particularly attractive for MnPc, where it leads to ferromagnetism in polycrystalline powders and single crystals [10][11]. Due to the arrangement in molecular columns with a stacking angle of 45° the Mn ion lies directly underneath a nitrogen atom

• vacancies in the mixed films generate sufficient free volume around the MnPc molecules for a rearrangement to the thermodynamically stable β-phase (Figure 1c), which normally forms above 300 °C [7][8]. Film morphology, structure and composition Optical micrographs in Figure 2 reveal the surface morphology

The longstanding challenge of the nanocrystallization of 1,3,5-trinitroperhydro-1,3,5-triazine (RDX)

• Florent Pessina and
• Denis Spitzer

Beilstein J. Nanotechnol. 2017, 8, 452–466, doi:10.3762/bjnano.8.49

• (needle-like, irregular and aggregated) were produced by ASES at all operating conditions, whereas GAS led to regular shapes with the desired β-phase. Dou et al. [54] sprayed RDX dissolved in DMF to obtain micrometer-sized particles of high polydispersity. However, sub-micrometer-sized polymers and

Silica-coated upconversion lanthanide nanoparticles: The effect of crystal design on morphology, structure and optical properties

• Uliana Kostiv,
• Miroslav Šlouf,
• Hana Macková,
• Alexander Zhigunov,
• Hana Engstová,
• Katarína Smolková,
• Petr Ježek and
• Daniel Horák

Beilstein J. Nanotechnol. 2015, 6, 2290–2299, doi:10.3762/bjnano.6.235

• XRD. The crystal structure of NaYF4 typically exhibits two polymorphic forms: the metastable cubic α-phase and the thermodynamically stable hexagonal β-phase. The latter is a much better host lattice for the luminescence of various optically active lanthanide ions. Altering reaction temperature is a

• diffractograms of the OM–NaYF4:Yb3+/Er3+ nanoparticles prepared at lower temperatures exhibited both α- and β-phases, but the average α-phase crystallite size decreased from about 9 to 6 nm with increasing temperature (Table 1). In contrast, the average size of the β-phase crystals increased from 12 to 21 nm

• approximately 10 nm and the particle size distribution was rather narrow (Table 1 and Table 2). The degree of crystallinity according to XRD (Figure 3b) was approximately 75 wt % (Table 2). A small amorphous halo originated primarily from OM on the nanoparticle surface. In α- and β-phase particles, the presence

Mapping of elasticity and damping in an α + β titanium alloy through atomic force acoustic microscopy

• M. Kalyan Phani,
• Anish Kumar,
• T. Jayakumar,
• Walter Arnold and
• Konrad Samwer

Beilstein J. Nanotechnol. 2015, 6, 767–776, doi:10.3762/bjnano.6.79

• cantilever with damped flexural modes. The cantilever dynamics model considering damping, which was proposed recently, has been used for mapping of indentation modulus and damping of different phases in a metallic structural material. The study indicated that in a Ti-6Al-4V alloy the metastable β phase has

• of 178 mm. An indexing algorithm based on eight detected bands was utilized. Results and Discussion The amount of the α- and β-phases present at different heat-treatment temperatures for Ti-6Al-4V alloy, as obtained by the JMatPro® simulation, is shown in Figure 2. The volume fraction of the β-phase

• is very low (ca. 6.57%) at 923 K and it increases to 26% and 70.9% at 1123 K and 1223 K, respectively. The JMatPro® simulation indicates a β-transus temperature of 1275 K, above which only the β-phase is observed. This is in good agreement with the earlier reported experimental value of the β-transus

Functionalized nanostructures for enhanced photocatalytic performance under solar light

• Liejin Guo,
• Dengwei Jing,
• Maochang Liu,
• Yubin Chen,
• Shaohua Shen,
• Jinwen Shi and
• Kai Zhang

Beilstein J. Nanotechnol. 2014, 5, 994–1004, doi:10.3762/bjnano.5.113

• compared to single hexagonal or cubic CdS. However, the relation of electronic interaction between different phases with the photocatalytic activities was not discussed in their study [70]. Li and co-workers have demonstrated the greatly enhanced photocatalytic overall water splitting over an α–β phase

• junction of Ga2O3 [71]. The improved photocatalytic activity results from the efficient charge separation and transfer across the α–β phase junctions of the Ga2O3 particles. We have found that spherical twin-containing noble-metal-free Cd0.5Zn0.5S is a superb photocatalyst for hydrogen production, showing