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Phase-change memory emerges as a top contender for non-volatile data storage applications. We report here a systematic change in local structure and crystallization kinetics of binary GeTe thin films using temperature-dependent resistivity measurements, which offers single-stage crystallization at around 187 °C, corroborated with x-ray diffraction. Furthermore, the change in chemical bonding upon crystallization is determined through x-ray photoelectron spectroscopy core level spectra, which reveals the existence of Ge and Te components that align with the GeTe crystal structure. Also, an investigation was carried out employing a UV–Vis–NIR spectrophotometer to explore the evolution of optical bandgaps (E g) , Tauc parameter (B) representing the local disorder, and Urbach energy (E u) of the GeTe material, as it undergoes the transition from a disordered amorphous state to a crystalline state. As crystallization progresses, a consistent shift of E g from 0.92 to 0.70 eV corresponds to as-deposited amorphous at room temperature and crystalline at 250 °C, respectively. In addition, the reduction in E u (from 199.87 to 141.27 meV) and a sudden increase of B around crystallization temperature is observed upon increasing temperature, indicating direct observation of enhanced medium-range order and distortion in short-range order, respectively, in GeTe thin films, revealing improved structural and optical properties. These enhancements make the GeTe material ideal for data storage applications of phase-change memory for next-generation computing technology. [ABSTRACT FROM AUTHOR]

The development of Ge-rich GeSbTe (GGST) alloys significantly enhanced the high-temperature stability required for Phase-Change Memory technology. Previous studies on Ge enrichment in GeSbTe (GST) materials with Sb-over-Te ratio lower than one (Sb / Te < 1) highlighted the segregation into cubic Ge and cubic GST phases. Such a segregated cubic GST phase is metastable and presents a polycrystalline structure with disordered grain boundaries that could lead to structural relaxation and then to drift phenomena. In this work, using resistivity measurements, Raman spectroscopy, and in situ x-ray diffraction analyses, we demonstrate for the first time to our knowledge that GGST with Sb/Te higher than one (Sb / Te > --> 1) upon annealing leads to the direct formation of a GST hexagonal phase featuring a high growth speed, bypassing the cubic metastable phase. Combined with Ge enrichment, the increased value of the activation energy of the nucleation of Sb / Te > --> 1 GGST alloys ensures a high stability of the amorphous phase. Finally, nitrogen introduction further stabilizes the system against the crystallization, without compromising the high crystalline growth speed and the formation of the stable GST hexagonal phase in alloys with Sb / Te > --> 1. These results demonstrate the possibility to tune the crystalline structure of the segregated phases in Ge-rich GeSbTe alloys, combining the stability at high temperature of the amorphous phase with the high crystallization speed and uniformity (with larger grains) of a targeted GST phase. [ABSTRACT FROM AUTHOR]

Upon osmotic compression, rotationally symmetric faceted colloidal particles can form translationally ordered, orientationally disordered rotator mesophases. This study explores the mechanism of rotator-to-crystal phase transitions where orientational order is gained in a translationally ordered phase, using rotator-phase forming truncated cubes as a testbed. Monte Carlo simulations were conducted for two selected truncations (s), one for s = 0.527 where the rotator and crystal lattices are dissimilar and one for s = 0.572 where the two phases have identical lattices. These differences set the stage for a qualitative difference in their rotator–crystal transitions, highlighting the effect of lattice distortion on phase transition kinetics. Our simulations reveal that significant lattice deviatoric effects could hinder the rotator-to-crystal transition and favor arrangements of lower packing fraction instead. Indeed, upon compression, it is found that for s = 0.527, the rotator phase does not spontaneously transition into the stable, densely packed crystal due to the high lattice strains involved but instead transitions into a metastable solid phase to be colloquially referred to as "orientational salt" for short, which has a similar lattice as the rotator phase and exhibits two distinct particle orientations having substitutional order, alternating regularly throughout the system. This study paves the way for further analysis of diffusionless transformations in nanoparticle systems and how lattice-distortion could influence crystallization kinetics. [ABSTRACT FROM AUTHOR]

In materials science, chiral perovskites stand out due to their exceptional optoelectronic properties and the versatility in their structure and composition, positioning them as crucial in the advances of technologies in spintronics and chiroptical systems. This review underlines the critical role of synthesizing and growing these materials, a process integral to leveraging their complex interplay between structural chirality and distinctive optoelectronic properties, including chiral-induced spin selectivity and chiroptical activity. The paper offers a comprehensive summary and discussion of the methods used in the synthesis and growth of chiral perovskites, delving into extensive growth techniques, fundamental mechanisms, and strategic approaches for the engineering of low-dimensional perovskites, alongside the creation of novel chiral ligands. The necessity of developing new synthetic approaches and maintaining precise control during the growth of chiral perovskites is emphasized, aiming to enhance their structural chirality and boost their efficiency in spin and chiroptical selectivity.

Water can be vitrified if it is cooled at high rates, which makes it possible to outrun crystallization in so-called no man's land, a range of deeply supercooled temperatures where water crystallizes rapidly. Here, we study the reverse process in pure water samples by flash melting amorphous ice with microsecond laser pulses. Time-resolved electron diffraction reveals that the sample transiently crystallizes despite a heating rate of more than 5 × 106 K/s, even though under the same conditions, vitrification can be achieved with a similar cooling rate of 107 K/s. Moreover, we observe different crystallization kinetics for amorphous solid water and hyperquenched glassy water. These experiments open up new avenues for elucidating the crystallization mechanism of water and studying its dynamics in no man's land. They also add important insights into the laser melting and revitrification processes that are integral to the emerging field of microsecond time-resolved cryo-electron microscopy. [ABSTRACT FROM AUTHOR]

In-depth research on the influencing mechanisms of particle size on the crystallization of silicate glass were conducted by calculating the crystallization kinetic parameters using exothermic peaks in differential thermal analysis curves and the Matusita-Sakka equation. A typical silicate glass, CaO-SiO2-B2O3, with a simple crystallization process that forms only one crystal (CaSiO3) was selected as the vehicle for this study. For the as-quenched glass sample, as the particle size distribution shifted from 2.5–1 mm to less than 0.061 mm, the crystal growth dimensionality shifted from a two- to a three-dimensional mechanism. The turning point of the particle size corresponding to the change in crystal growth dimensionality is defined as the boundary between fine and coarse particles and was found to be 0.104 mm. With decreasing particle size, the activation energy for crystal growth decreased slightly in the fine-particle starting material and increased in the coarse-particle starting material; the decrease being considerably higher than the increase. Although the as-quenched glass comprising fine particles is regarded to have saturated nucleation sites, as in the case of well-nucleated samples, it exhibited different crystal growth mechanisms because of its different nucleation mechanisms. [ABSTRACT FROM AUTHOR]

Organic semiconductor single crystals (OSSCs), which possess the inherent merits of long-range order, low defect density, high mobility, structural tunability and good flexibility, have garnered significant attention in the organic optoelectronic community. Past decades have witnessed the explosive growth of OSSCs. Despite numerous conceptual demonstrations, OSSCs remain in the early stages of implementation for applications that require high integration and multifunctionality. The commercialization trend of organic optoelectronic devices is driving the development of highly integrated OSSCs. Therefore, timely tracking of material requirements, crystallization demands, and key technologies for high integration, along with exploring their limitations and potential pathways, will provide critical guidance during this pivotal transition period. From the perspective of materials properties, multifunctional materials, such as ambipolar charge transport materials, high mobility emission materials and others, aiming at high integration, deserve our attention, and the material design rules are carefully discussed in the first section. Following this, we delve into the controllable growth of large-scale OSSCs based on crystallization thermodynamics and kinetics. Key technologies for achieving high integration are then discussed, with an emphasis on methods for growing wafer-scale organic single crystals and patterning single crystalline arrays. Subsequently, we outline the cutting-edge optoelectronic applications based on OSSCs, including organic logic circuits, electroluminescent displays, and image sensors. Moreover, explicitly recognizing as yet limitations and prospects on the road to 'lab-to-fab' transitions for OSSCs is crucial. Thus, we conclude by offering an objective assessment of key limitations and potential, encompassing aspects such as uniformity, integration density, stability, and driving capability, providing an instructive projection for future advancements. [ABSTRACT FROM AUTHOR]

The utilization of form-stable phase change materials (PCMs) represents a reliable technology for achieving energy conversion. In this study, starch was impregnated into the layers of expanded vermiculite (EVM) and subsequently carbonized at high temperatures to produce in situ carbon layers modified materials (EVMC), which enhance heat storage efficiency. The EVMC, characterized by its carbon network, acted as encapsulated material, leading to the development of paraffin (P)/EVCM-based shape-stable composite PCM (EVMCP). The latent heat of the EVMCP was measured at 179 J/g, surpassing that of EVMP at 144.8 J/g. This finding suggested that in situ porous carbon significantly improves the heat storage ability. Furthermore, non-isothermal crystallization curves indicated that EVMC markedly accelerated the nucleation and simultaneously restricted the non-isothermal crystal growth. [ABSTRACT FROM AUTHOR]

(1) In recent years, an increase in the available functionality of non-ferrous alloys has been observed based on the modification and optimization of their chemical composition. This study investigated the effect of Sr addition on the structure and properties of hypereutectic Zn–Al–Cu alloys. The objective was to determine how a modification with Al–Sr master alloy affects the crystallization kinetics, microstructure, hardness, and abrasive wear resistance and whether the modification of the phase composition reduces the corrosion resistance. (2) The total influence of strontium was determined based on the microstructure, phase composition, and derivative curve changes of the tested Zn–Al–Cu alloys with added Sr. Optical microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were used to analyze the influence of chemical and phase composition, and thermo-derivative analysis (TDA) was used to investigate the crystallization kinetics of zinc alloys with different chemical compositions. (3) Sr modification caused the formation of primary Al2Sr phases in the Zn alloy and also secondary Zn13Sr and Al4Sr phases (depending on the melting temperature of the alloy). (4) The primary and secondary intermetallic phases with strontium increased the hardness by approx. 20% and the abrasion resistance by approx. 7.5%. [ABSTRACT FROM AUTHOR]

The influence of iodine doping on the thermal stability, degradation kinetics, and the melting and crystallization behaviors of polyethylene terephthalate (PET) films were investigated. Iodine doping was performed by immersing PET films in 0.4 M I2/l toluene. The thermal stability and degradation kinetics of PET and the semi-conducting PET/iodine complex films were studied using the thermogravimetric analysis-derivative thermogravimetric analysis (TGA-DTGA) studies and the differential scanning calorimetry (DSC). It was found that iodine incorporation accelerated the thermal degradation and weight loss through increased chain mobility owing to the imperfections formed by doping. Both pure and doped films exhibited appreciable thermal stability with the peak degradation temperature above 400 °C. DSC thermograms of the pristine PET and the PET/iodine films in the crystallization regions were recorded during the cooling scan and the significant parameters were studied. The peak crystallization temperature of PET increased from 192 to 209 °C after iodination. Doping initiated crystallization at an early stage of cooling with an increase in the rate of crystallization and smaller crystallization half time. Iodine catalyzed crystallization and acted as a nucleating agent. DSC scans were also used to study the melting characteristics of the polymer samples. The peak melting temperature was lower and the absolute crystallinity reduced for the iodine doped PET films. [ABSTRACT FROM AUTHOR]

Poly(ethylene furanoate) (PEF) has been identified as a bio-based alternative or supplement to poly(ethylene terephthalate) (PET) for various applications such as food packaging and bottles as well as technical- and high-performance fibers and yarns. In this study, the processing of PEF nonwovens in the meltblow process is successfully demonstrated and reported for the first time, according to our best knowledge The resulting fabrics achieved median fiber diameters of 2.04 µm, comparable to PET. The filtration efficiency of 25 g m−2 fabrics exceeded 50% comparable to PET and PBT of the same grammage and was raised to over 90% with post-process electrostatic charging, maintaining stability. As for other aromatic polymers, applying infrared heating modules into the process indicated the potential to minimize heat shrinkage. However, the suppressed ring rotation and slower crystallization kinetics of PEF showed the need for longer post-treatment times as the heat shrinkage remained between 20% and 40% at 10 °C. Overcoming this, PEF can be a viable, bio-based alternative to PET, particularly for such high-temperature nonwoven applications that require thin layers. [ABSTRACT FROM AUTHOR]

Aluminum alloys are still very useful materials for diverse application. The die-casting process of Al alloys is the most common technology to manufacture cast components. Therefore, the research on aluminum alloy solidification with high thermal conductivity has an important engineering significance and application value. Therefore, the purpose of this study was to determine the effect of a strontium addition on crystallization kinetics, the microstructure (including β—phase morphology) and properties of an Al-Si-Cu alloy after solidification and after precipitation hardening. In order to determine the effect of strontium on crystallization kinetics, thermal-derivative analysis (TDA) was performed. Microstructure observation, EDS chemical composition analysis and X-ray phase analysis were performed. Strontium changed the derivative curve of solidifying Al-Si-Cu alloys. After its addition, the morphology of the α + β eutectic was modified from lamellar to fibrous. [ABSTRACT FROM AUTHOR]

In this study, corn oil and essential oils from thirteen spices were used as the oil phase, with glyceryl monostearate (GMS) serving as the gelling agent to prepare the oleogels. The effects of varying the concentrations of the gel additives (2%, 4%, 6%, and 8%) on the texture, oil retention, and rheological properties of the oleogels were investigated using differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The results showed that GMS concentration markedly influenced the structure and properties of the gel. Positive correlations were observed between GMS concentration and the results of texture analysis, oil binding capacity, and microscopic morphology of the oleogels. Analyses via DSC and XRD demonstrated that gel formation was attributable to the crystalline network induced by GMS. Rheological assessments revealed that the oleogels exhibited pseudoplastic behavior and commendable thermal sensitivity. [ABSTRACT FROM AUTHOR]

The present study investigates the crystallization kinetics of the syndiotactic polypropylene/iron (sPP/Fe) composites using the rheological and Differential Scanning Calorimetry (DSC) techniques to evaluate the impact of varying iron content. Rheology, which is particularly sensitive under slow crystallization kinetics, was employed to complement the widely used DSC method. The current study aimed to integrate the aforementioned approaches to provide a comprehensive understanding of how the iron content influences the crystallization behavior of the sPP composites. Non-isothermal and isothermal crystallization experiments revealed that the increasing iron content significantly enhanced the crystallization and melting temperatures, indicating improved thermal stability and crystallinity. The rheological measurements, carried out using an Atomic Rheometric Expansion System (ARES), demonstrated higher sensitivity than the DSC at low iron concentrations, providing a more precise detection of crystallization kinetics. The results showed excellent agreement between the two techniques, confirming the robustness of rheology as a complementary method. This study underscores the importance of the iron content in tailoring the thermal and mechanical properties of sPP composites and highlights the value of integrating rheological methods with traditional thermal analysis for polymer characterization. [ABSTRACT FROM AUTHOR]

In this research, fully biobased composites consisting of poly(butylene 2,5-furandicarboxylate) (PBF) and cellulose nanocrystals (CNC) were successfully prepared through a common solution and casting method. The influence of CNC on the crystallization behavior, mechanical property, and hydrophilicity of PBF was systematically investigated. Under different crystallization processes, the crystallization of PBF was obviously promoted by CNC as a biobased nucleating agent. The Ozawa equation was not suitable to fit the nonisothermal melt crystallization kinetics of PBF and PBF/CNC composites. The nucleation activity of CNC was quantitatively calculated by the Dobreva method; moreover, the nucleation efficiency of CNC was further evaluated through the self-nucleation procedure. The isothermal melt crystallization kinetics of PBF and PBF/CNC composites was well described by the Avrami method; moreover, the crystallization mechanism and the crystal structure of PBF remained unchanged despite the presence of CNC. CNC also greatly enhanced both the mechanical property and hydrophilicity of PBF in the composites. In sum, low loadings of CNC simultaneously improved the crystallization, mechanical property, and hydrophilicity of PBF, which should be of significant importance and interest in fully biobased polymer composites from a sustainable viewpoint. [ABSTRACT FROM AUTHOR]

This study explores the impact of blending polyethylene terephthalate (PET) with polybutylene terephthalate (PBT) on the thermal, structural, and mechanical properties of 3D-printed materials. Comprehensive analyses, including Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and mechanical testing, were conducted to assess the influence of blend composition. FT-IR confirmed that PET and PBT blend physically without transesterification, while TGA showed enhanced thermal stability with increasing PET content. XRD revealed that PET and PBT crystallize separately, with the crystallinity decreasing sharply for blends with more than 50% PET. The DSC results indicated that PET effectively slows down the crystallization kinetics of PBT, promoting cold crystallization. Mechanical tests demonstrated that the elastic modulus remains relatively unchanged, but the strain at break decreases with a higher PET content, indicating increased stiffness and reduced ductility. Overall, incorporating PET into PBT improves 3D-printability and dimensional stability, reducing warpage and enhancing print precision, making these blends advantageous for 3D-printing applications. [ABSTRACT FROM AUTHOR]

In this paper, the reasons for the improved wear resistance of irradiation‐modified Polytetrafluoroethylene (RM‐PTFE) and its composites above the melting point were investigated from the microcrystalline point of view by using methods such as crystallization kinetics, and it was found that the linear wear rate of RM‐PTFE was only 0.3 um/km, with a 1000 times increase in wear resistance, which was due to the transformation of its crystals from flake crystals that were easily dislodged to spherical crystals that were more resistant to abrasion. It was also found that the linear wear rate of Polytetrafluoroethylene (PTFE) with coke and graphite was 0.2 and 0.1 μm/km, respectively, and the abrasion resistance was further improved, which was attributed to the lowering of spherical crystal grain size by coke and graphite, which had better mechanical properties. These studies lay the foundation for future research on the frictional wear mechanism of RM‐PTFE above the melting point. Highlights: Irradiation‐modified PTFE above the melting pointWear resistance of PTFE increases 1000 timesChanges in crystal morphology dramatically increase wear resistanceUse of crystallization kinetics to study the crystalline form of PTFESmall grain size improves wear resistance [ABSTRACT FROM AUTHOR]

By incorporating nanomaterials into polymer matrices, nanocomposites can be produced with enhanced properties, combining the ease of processing thermoplastics with the superior physical characteristics of nanoparticles. In this study, fully bio‐based polyamide 1010 was used as the polymer matrix, with graphene oxide (GO), hexagonal‐boron nitride (h‐BN), and molybdenum disulfide (MoS2), both individually and in hybrids, serving as fillers. The tensile behavior of these nanocomposites was evaluated at room temperature and −40 °C, along with their morphology and microstructure. Results showed that the nanomaterials slightly shifted the polymer's crystallization temperature upward, indicating a small nucleating effect, but also hindered the development of crystalline domains, reducing the crystallization kinetics. Despite no change in the final crystalline form, nanocomposites with h‐BN and MoS2 showed lower microstructural order as evidenced by XRD. Regarding tensile behavior, GO provided the greatest toughening at room temperature due to its larger lateral dimensions and good chemical affinity with the matrix. However, at low temperatures, h‐BN‐based nanocomposites maintained the toughening effect better than GO‐based ones. This can be attributed to the lower order of the polymer's semi‐crystalline structure promoted by h‐BN, allowing greater energy dissipation. Surprisingly, hybrid fillers did not exhibit synergistic effects, with one nanomaterial hampering the effect of the other. However, SEM analysis indicated that the fracture mechanisms of the nanocomposites remained unchanged from the neat polymer, which makes them interesting options for applications that require desirable mechanical properties at a wide temperature range. Highlights: GO showed the best toughening of polyamide 1010 at room temperature.Toughening at room temperature is mainly due to nanomaterials physical traits.Most nanofillers lowered polyamide's overall microstructural order.Toughening at −40 °C is mainly due to lower microstructural order. [ABSTRACT FROM AUTHOR]

Multifunctional polymer materials are extensively applied to regulate the crystallization process of perovskite films. However, a comprehensive understanding of the correlations among spatial structure of polymers, crystallization modulation, and device performance is still lacking. Here, a restricted assembly strategy is proposed to prepare high‐quality perovskite films by systematically studying the effect of space configurations of polymers on modulating the crystallization of cesium lead triiodide (CsPbI3) perovskite. The results confirm the importance of high backbone coplanar space configurations in promoting nucleation, accelerating phase transitions, and enhancing crystalline orientation. The polymer with the high backbone coplanar structure not only facilitates the formation of uniform and dense nucleation sites by precisely controlling the spatial distribution of colloidal particles but also enhances the crystal orientation through the orientational growth induced by the coplanar structure. As a result, the efficiency of the CsPbI3 solar cells increases from 17.84% to 20.39%. Additionally, the unencapsulated devices show excellent storage and operational stability. [ABSTRACT FROM AUTHOR]

Bulk metallic glasses (BMGs) are promising materials. However, to form an amorphous structure, they require liquid quenching, which does not allow the production of large bulk products with an amorphous structure. Selective laser melting (SLM) is an additive technology in which powders are treated layer after layer to form a component according to a three-dimensional model. In SLM, the cooling rate exceeds the critical cooling rate for BMG, which indicates a possibility for using SLM for BMG. The purpose of this work is to determine the parameters of crystallization kinetics in SLM by theoretical analysis of a particular example of the process with subsequent assessment of the applicability of selected parameters to other samples. A comparison of calculations with an experiment has shown a broad range of applicability of the obtained parameters. [ABSTRACT FROM AUTHOR]

Recent research has shown the potential of polyhydroxyalkanoates (PHAs), particularly poly(3–hydroxybutyrate) (P3HB), to form nonwoven structures with fine fiber diameter distributions ranging from 2.5 µm to 20 µm during the meltblow process. The shortcomings of existing fabrics of this type include high brittleness, low elongation at break (max. 3%), and a lack of flexibility. Furthermore, the high melt adhesion and the special crystallization kinetics of PHAs have commonly been regarded as constraints in filament and nonwoven processing so far. However, these two properties have now been used to elaborate a three-dimensional fiber arrangement on a matrix, resulting in the creation of dimensionally and temperature-stable "nonwoven-parts". Moreover, this study investigated the PHA copolymer poly(3–hydroxybutyrate–co–3–hydroxyhexanoate) (PHBH), revealing a similar processability to P3HB and PHBV in the meltblow process. A significant increase in the (peak load) elongation in the machine direction was observed, reaching values between 5% and 10%, while the tensile strength retained unaltered. The addition of the bio-based plasticizer acetyltributylcitrate (ATBC) to PHBH resulted on an increase in elongation up to 15%. The three-dimensional fabric structure of PHBH exhibited complete resilience to compression, a property that differentiates it from both P3HB and PHBV. However, the addition of the plasticizer to P3HB did not lead to any improvements. This interesting array of properties results in moderate air permeability and hydrophobicity, leading to impermeability to water. [ABSTRACT FROM AUTHOR]

Perovskite light‐emitting diodes (PeLEDs) present potential applications for next‐generation displays due to their excellent luminescent properties and solution processing. The formamidinium‐caesium lead bromide (FAxCs1−xPbBr3) mixed cation strategy is one of the primary methods to achieve high‐performance of Cs‐dominate PeLEDs system. However, the inhomogeneous distribution of cations is detrimental to the photoelectronic performance of Cs‐dominated PeLEDs. Here, in mixed FA/Cs perovskite films, it is observed that Cs, Br and trace Pb elements precipitated on the surface of the perovskite films. It is found that the segregation of cations is induced by the uncontrollable crystallization process of Cs/FA cations. By introducing biuret additive, the hydrogen bonding interaction of biuret and FA cation balances crystallization rate, which therefore significantly improves the crystal quality and cations distribution of perovskite films. As a result, green PeLEDs with a high external quantum efficiency of 28.8% are obtained, and represent five times enhancement in half‐life time (T50) of 2.48 h at an initial luminance of 100 cd m−2 relative to the control device. The results help to understand the relationship between cationic distribution and PeLEDs properties, offering significant insights for modulating the performance of PeLEDs. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) can utilize the residual photons from indoor light and continuously supplement the energy supply for low-power electron devices, thereby showing the great potential for sustainable energy ecosystems. However, the solution-processed perovskites suffer from serious defect stacking within crystal lattices, compromising the low-light efficiency and operational stability. In this study, we designed a multifunctional organometallic salt named sodium sulfanilate (4-ABS), containing both electron-donating amine and sulfonic acid groups to effectively passivate the positively-charged defects, like under-coordinated Pb ions and iodine vacancies. The strong chemical coordination of 4-ABS with the octahedra framework can further regulate the crystallization kinetics of perovskite, facilitating the enlarged crystal sizes with mitigated grain boundaries within films. The synergistic optimization effects on trap suppression and crystallization modulation upon 4-ABS addition can reduce energy loss and mitigate ionic migration under low-light conditions. As a result, the optimized device demonstrated an improved power conversion efficiency from 22.48% to 24.34% and achieved an impressive efficiency of 41.11% under 1000 lux weak light conditions. This research provides an effective defect modulation strategy for synergistically boosting the device efficiency under standard and weak light irradiations. [ABSTRACT FROM AUTHOR]

Development of Amorphous Solid Dispersion (ASD) requires an in-depth characterization at different stages due to its structural and functional complexity. Various tools are conventionally used to investigate the processing, stability, and functionality of ASDs. However, many subtle features remain poorly understood due to lack of nano-scale characterization tools in routine practice. Atomic force microscopy (AFM) is a type of scanning probe microscopy, used for high resolution imaging and measuring features at the nano-scale. In recent years AFM has been used increasingly as a characterization tool in different areas of the development of ASD, including drug-polymer miscibility, localized characterization of the phase separated domains, lateral molecular diffusivity on ASD surface, crystallinity and crystallization kinetics in ASD, phase behavior of ASD during dissolution, and conformation of polymer during dissolution. In this review, we have highlighted the current applications of AFM in capturing critical aspects of stability and dissolution behavior of ASD. Potential areas of future development in this domain have been discussed. [Display omitted] [ABSTRACT FROM AUTHOR]

• Comparison of different HPMCAS grades as ASD polymers. • Interplay between pH, HPMCAS grade and release extent from posaconazole-HPMCAS ASDs. • Interactions of HPMCAS with posaconazole molecularly dissolved drug and drug-rich amorphous nanodroplets. Hydroxypropyl methyl cellulose acetate succinate (HPMCAS) is one of the polymers of choice in formulating amorphous solid dispersions (ASDs) and helps to sustain high levels of drug supersaturation by delaying drug crystallization. Herein, the impact of HPMCAS chemistry on the solution crystallization kinetics of a fast-crystallizing lipophilic drug, posaconazole (PCZ), from the aqueous bulk phase and the drug-rich phase generated by liquid-liquid phase separation (LLPS), was studied. Three grades of HPMCAS: L, M, and H, which differ in the degree of acetyl and succinoyl substitution (A/S ratio), were compared. The influence of the polymers on the nucleation induction time, and LLPS concentration of PCZ, as well as the size, ζ-potential and composition of the nano-sized drug-rich phase was determined. An increase in the nucleation induction time was observed with an increase in the polymer A/S ratio. A blue shift in the fluorescence emission spectrum of PCZ suggested a greater extent of interaction between PCZ and HPMCAS with an increase in the A/S ratio. More polymer partitioning into the drug-rich phase was also observed with an increase in the A/S ratio, resulting in smaller droplets. A greater extent of ionization of HPMCAS upon increasing the pH from 5.5 to 7.5 decreased the hydrophobicity of the polymer resulting in shorter nucleation induction times. The phase behavior of PCZ in ASD release studies was consistent with these observations, where the shortest duration of supersaturation was observed with the L grade. Although the H grade provided the best inhibition of crystallization, complete release was only observed at higher pH. HPMCAS grade thus influences the kinetics of PCZ crystallization following release from an ASD, as well as the extent of release at physiologically relevant pH conditions. This study provides insights into the role of HPMCAS chemistry and ionization as factors influencing its ability to act as a crystallization inhibitor. [Display omitted] [ABSTRACT FROM AUTHOR]

The paper is dedicated to the process of obtaining hollow castings on a horizontal centrifugal casting machine. The influence of mold rotation speed and the melt pouring process mechanical properties of as-cast parts made of AlMg5, alloyed by small amount of transition and rare earth metals, is represented. Mold pouring processes and crystallization kinetics depend on mold rotational speeds 1100, 1500 and 2000 rpm were studied by using numerical modeling. The influence of the specified mold rotation speeds on the structure and mechanical properties of castings is shown. It is also determined that the installation of a foam ceramic filter in the pouring cup of a centrifugal casting machine ensures melt laminar flow when pouring it into a mold. It was determined that 1500 rpm is the most favorable rotating speed from the points of optimal hydrodynamic mold filling processes and casting crystallization kinetics. It was also shown that with the increase of a mold rotation speed from 1100 to 2000 rpm, the thickness of the defective inner layer decreases, the alloy structure refines, and the mechanical properties of as-cast detail increase the next way: at 1500 rpm (σ0.2–by 10%, σB − by 25%, δ − 3 times), at 2000 rpm (σ0.2–by 18%, σB − by 31%, δ − 4 times), compared to products obtained by steel mold gravity casting. Centrifugal casting technology ensures the mechanical properties of cast blanks even higher than those of deformed AlMg5 alloys, the values of which approach those of AlMg6 alloy products. [ABSTRACT FROM AUTHOR]

To significantly improve the crystallinity and crystallization rate of polylactide (PLA), plasticizer (polyethylene glycol, PEG) and nucleating agent (cellulose nanofibers, CNFs) were melt-blended with PLA to prepare PLA/PEG/CNF nanocomposites. The effects of PEG and/or CNFs and cooling rate on the crystallization kinetics of PLA were investigated by HS-POM, DSC, and WAXD. The non-isothermal crystallization kinetics of modified PLA samples were evaluated by the Jeziorny's, Ozawa's, and Mo's models, while their non-isothermal crystallization activation energies were determined by Friedman's method. The polarized optical micrographs showed that CNFs served as effective nucleating agents, increasing the nucleation density of PLA spherulites, but reducing their spherulite sizes; PEG improved the mobility of PLA chains and accelerated the growth rate of PLA spherulites, thus leading to larger spherulite sizes. The non-isothermal crystallization kinetics revealed that the crystallization temperature (Tc), crystallinity (XC), and crystallization half-time (t1/2) of all PLA-based samples decreased with increasing cooling rate. At the same cooling rate, the incorporation of 15 wt% PEG or 3 wt% CNFs increased Tc and XC but decreased t1/2 of PLA by enhancing spherulite growth rate and providing more crystal nuclei, respectively. Moreover, SEM micrographs showed that the addition of PEG improved the dispersion of CNFs within the PLA matrix, and the synergistic effect of PEG and CNFs more significantly increased Tc and XC, but reduced t1/2. The above results demonstrated that the combination of PEG and CNFs significantly enhanced the crystallization performance of PLA, providing insights for the design of high-performance PLA-based materials. [ABSTRACT FROM AUTHOR]

In material processing and handling processes, premixed interlayer often replace the ideal Ni/Al interface, which would become a new origin of alloying reaction. This work investigates shock-induced reaction mechanism and kinetics of premixed Ni/Al nanolaminates with molecular dynamics simulations and theoretical analysis. The reaction is found to be driven by the crystallization evolution in premixed interlayer and the diffusion of premixed atoms. Among them, multi-stage reaction patterns are strongly manifested by the crystallization evolution characteristics. Specifically, "crystallization-dissolution-secondary growth" and "crystallization-dissolution" of B2 phase respectively correspond to the solid-state and solid-liquid reaction cases, where crystallizations are fitted well by Johnson–Mehl–Avrami kinetics model. Interestingly, the different growth mechanisms of B2 grain are revealed, namely nuclei coalescence and atomic diffusion. Moreover, the analysis of microscopic diffusion theory indicates a certain non-random diffusion nature for solid-state reaction initiation, but near-purely random diffusion for solid-liquid reaction initiation. The diffused Al atoms possess a limited diffusion coefficient and enhanced diffusion correlation, resulting in extremely slow mixing rate in Ni layer. In addition, the influence law of Ni concentration in premixed interlayer on reactivity parameters can be quantitatively described by a quadratic function. [ABSTRACT FROM AUTHOR]

A comprehensive non-isothermal kinetics study on polymer crystallization processes taking place in a set of industrial polyamides comprising nylon 6, nylon 6,6, nylon 11 and nylon 12, individually, is reported. The kinetics studies elucidated that the phenomena of nucleation/diffusion underlying the nylons crystallization go to completion in a single-step. Notwithstanding, the nylons diffusion activation energies do not correspond to the universal value of segmental jump activation energy signifying polymer chains diffusion processes. The polymer chain transport phenomenon was probably the slowest one in the case of nylon 6 and nylon 6,6, and the fastest in the case of nylon 12, while intermediate for nylon 11. Furthermore, the nucleation barrier during the course of polymer crystallization was the highest for nylon 6,6, followed by nylon 6, nylon 11 and nylon 12. Our kinetics studies further predict that the crystallization of nylon 12 and nylon 11 follows, respectively, diffusion-controlled 2D growth of spherulites and a somewhat complicated nucleation/growth phenomenon. The thermodynamics of the nylons crystallization suggests that the highest structural orientation of the activated complex was attained in the case of the nylon 12 crystallization process. Interestingly, while the thermodynamics and majority of the kinetic parameters of nylon 6 and nylon 6,6 were similar/comparable, the two follow widely differing crystallization mechanisms. The most probable physical meanings of the obtained kinetics and thermodynamics parameters and their practical significance are given and discussed. [ABSTRACT FROM AUTHOR]

The phase transition temperature and crystallization kinetics of phase-change materials (PCMs) are crucial characteristics for their performance, data retention, and reliability in memory devices. Herein, the crystallization behavior and kinetics of a compositionally optimized, N-doped Ge-rich Ge–Sb–Te alloy (GGST) in the slow crystallization regime are systematically investigated using synchrotron x-ray diffraction (XRD) in situ during heat treatment. Uniform thin films (50, 25, 10, and 5 nm) of initially amorphous N-doped GGST are investigated. The specimens were heated up to 450 °C at a rate of 2 °C/min to estimate crystallization onsets by quantifiying the crystallized quantity during material transformation from the XRD patterns. Subsequent isothermal anneals have been performed to assess crystallization behavior and activation energies. Nucleation-controlled crystallization that progresses in two steps is observed, together with the emergence of Ge preceding cubic Ge2Sb2Te5, with a mild dependence of crystallization temperature on film thickness that is inverse to what has been observed in other systems. Ge and GST crystallization may be described occurring in three-time stages: (i) an incubation period; (ii) a fast growth period; and (iii) a very slow-growth period. Very high activation energies (between 3.5 and 4.3 eV) for each phase are found for the incubation time t0. The activation energy for Ge in the fast growth regime is close to the one reported for the crystallization of pure Ge films. In the case of Ge, the incubation time is strongly thickness-dependent, which may have important consequences for the scaling of memories fabricated with this class of materials. [ABSTRACT FROM AUTHOR]

The performance of sustainable polymers can be modified and enhanced by incorporating functional groups in the backbone of the polymer chain that increases intermolecular interactions, thus impacting the thermal properties of the material. However, in-depth studies on the role of intermolecular interactions on the crystallization of these polymers are still needed. This work aims to ascertain whether incorporating functional groups able to induce intermolecular interactions can be used as a suitable systematic strategy to modify the polymer thermal properties and crystallization kinetics. Thus, amide and additional ester groups have been incorporated into aliphatic polyesters (PEs). The impact of intermolecular interactions on the melting and crystallization behavior, crystallization kinetics, and crystalline structure has been determined. Functional groups that form strong intermolecular interactions increase both melting and crystallization temperatures but retard the crystallization kinetics. Selecting appropriate functional groups allows tuning the crystallinity degree, which can potentially improve the mechanical properties and degradability in semicrystalline materials. The results demonstrate that it is possible to tune the thermal transitions and the crystallization kinetics of PEs independently by varying their chemical structure. [ABSTRACT FROM AUTHOR]