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Abstract Stimulating and harnessing circularly polarized luminescence (CPL) is not only a sine qua non for fundamentally unveiling chirogenesis in physical chemistry, but also a pivotal prerequisite for implementation of such phenomenon in research fields including chiral optoelectronics and theranostics. Herein, red‐emissive carbonized polymer dots (CPDs)‐based helical structures were synthesized in this work via biomolecule‐tailored organic–inorganic co‐assembly strategy. The surface states‐related chirality exhibits enhanced circular dichroism (CD) and CPL activities with anisotropic factors as high as gCD,max = 5.4 × 10−3 and glum,max = 1.5 × 10−2, respectively. The obtained CPL signals can be further manipulated in an excitation‐dependent manner, indicating that a synergistic‐competition phenomenon exists between configurational chirality and intermolecular energy‐transfer dynamics, which is further supported by simulations based on density function theory (DFT). Such tunable CPL behavior triggers revolutionary designs and applications of these chiral CPDs into the realm of chirality‐related biological issues and next‐generation chiral optoelectronics.

Abstract Crystalline calcium aluminates are a critical setting agent in cement. To date, few have explored the microscopic and dynamic mechanism of the transitions from molten aluminate liquids, through the supercooled state to glassy and crystalline phases, during cement clinker production. Herein, the first in situ measurements of viscosity and density are reported across all the principal molten phases, relevant to their eventual crystalline structures. Bulk atomistic computer simulations confirm that thermophysical properties scale with the evolution of network substructures interpenetrating melts on the nanoscale. It is demonstrated that the glass transition temperature (Tg) follows the eutectic profile of the liquidus temperature (Tm), coinciding with the melting zone in cement production. The viscosity has been uniquely charted over 14 decades for each calcium‐aluminate phase, projecting and justifying the different temperature zones used in cement manufacture. The fragile–strong phase transitions are revealed across all supercooled phases coinciding with heterogeneous nucleation close to 1.2Tg, where sintering and quenching occur in industrial‐scale cement processing.

Iron nitride thin films have unique magnetic properties and wide applications, and copper nitride may have its potential applications in the electronics devices. In this work, iron-copper nitride thin films were fabricated by sputtering techniques. The film thickness varied from 70 nm to 160 nm depending on the deposition parameters such as power source, magnitude of applied power, deposition time and nitrogen/argon flowrates. Materials properties were characterized by scanning electron microscopy (SEM), x-ray diffraction (XRD), x-ray reflectivity (XRR), x-ray photoelectron spectroscopy (XPS) and vibration sample magnetometer (VSM). The effect of copper nitride on the magnetic properties of FeN thin films is observed. [ABSTRACT FROM AUTHOR]

100-nm-thick epitaxial BaTiO3 (BTO) films were prepared on the Nb-doped SrTiO3 (NSTO) single-crystal substrates by pulsed laser deposition. Bipolar resistive switching (RS) behavior was observed in the as-prepared BTO/NSTO samples, which was attributed to the formation and rupture of conductive filaments in the BTO films. The RS effect was suppressed after the samples were annealed in air due to the decrease in oxygen vacancies during annealing, which was confirmed by X-ray photoelectron spectroscopy (XPS) measurements. The current--voltage curves of the as-prepared samples show linear ohmic conduction at the low resistive state and space-charge-limited conduction (SCLC) at the high resistive state, respectively. SCLC dominated in the annealed samples. [ABSTRACT FROM AUTHOR]

BaSrTiO (BST) thin films were deposited on Pt and SrRuO(SRO)/Pt hybrid bottom electrodes by radio frequency magnetron sputtering. X-ray analysis indicated that both films were polycrystalline. Dielectric measurements showed that the films on SRO/Pt hybrid bottom electrode had lower dielectric constant and loss than the films on single Pt and the dielectric properties were frequency-independent. The leakage current density of BaSrTiO thin films on hybrid bottom electrode was also lower. Leakage mechanism investigations showed that the contact between the electrode-film interfaces of thin films on SRO/Pt hybrid bottom electrode was ohmic. Based on the results, the effects of SRO/Pt hybrid bottom electrode on the crystallization and electrical properties of BST thin films were discussed. [ABSTRACT FROM AUTHOR]

Barium strontium titanate (Ba1− xSr x)TiO3 (BST) thin films were deposited on Pt, Ru, RuO2, and Pt/RuO2 electrodes by radio frequency magnetron sputtering. The interfacial structure characteristic of the BST films deposited on various electrodes was investigated. X-ray photoelectron spectroscopy investigations showed that the interfacial diffusion layer in BST/Pt and BST/Ru are approximately 6 and 10 nm, respectively. The BST films are short of Ba and O elements comparing with the stoichiometry Ba0.65Sr0.35TiO3 in the interface region. Dielectric measurement of the BST films with thickness ranging from 70 to 400 nm revealed that the BST films deposited on Pt and Pt/RuO2 bottom electrodes have similar dielectric property, the BST films deposited on Ru have the highest bulk dielectric constant, and the thickness dependence of dielectric constant on the BST film deposited on RuO2 electrode can be neglected. The interfacial layer dielectric constant of BST films deposited on Pt and Ru electrodes are estimated to be about 34.5 and 157.1, respectively. The effect of interfacial dead-layer on the dielectric constant could be eliminated through selecting appropriate bottom electrodes. [ABSTRACT FROM AUTHOR]

The influence of lattice strain on the strength of dipoles in the Ho3+-doped barium-strontium titanate (BST) thin films has been analyzed. Thin films were produced by using the sol–gel technique on Si substrate. The resulting stress due to fabrication process was quantified by analyzing the {200} planes of the cubic perovskite structure and comparing them with the data for bulk materials. The influence of strain and changes due to Ho3+-ion doping were characterized by Raman and visible photoluminescence spectroscopy, which clearly show the evidence for the increased tetragonality due to weaker dipole interaction at B-sites of cubic perovskite in the presence of Ho3+-ions at concentrations larger than 3 mol%. The film strain can therefore be controlled to enhance the intensity of emitted light at 650 nm. [ABSTRACT FROM AUTHOR]

Perovskite nanocrystals (PeNCs) are attractive in high-color gamut display technology as light converters which can achieve saturated green and red lights, respectively. However, PeNCs are intrinsically fragile against ambient conditions, such as moisture and oxygen and it is hard to maintain their performance in long-term operation. In this work, a new hierarchical encapsulation method is proposed, integrated with surface modification by halide ions protection, nano-scaled encapsulation by in situ capping SiO2 and embedding into poly (methyl methacrylate) (PMMA) matrix composites, to achieve a stable perovskite light converting composite sheet for LED remote-type encapsulation. The storage stability, as well as the operational stability of perovskite composites, were confirmed by the spectra evolution from encapsulated LEDs with normalized blue emission intensity. The 2D maps of spectra and aging measurement indicate that the silica encapsulation can well protect the PeNCs in the PMMA matrix from the ambient circumstance during a long-term storage process. Additionally, the hierarchical encapsulation for PeNCs/silica/PMMA showed better operational stability than the direct encapsulation of PeNCs/PMMA, and the correspondent Commission Internationale de L’Eclairage color coordinates tracking also indicated more stable color properties, which demonstrates the great potential in photoluminescent display applications. [ABSTRACT FROM AUTHOR]