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Abstract: Colloidal quantum dots (QDs) represent a versatile class of luminescent nanomaterials whose physicochemical and interfacial properties can be engineered for advanced bio-related applications. Herein, the wet-precipitation synthesis and surface engineering of ultra-small fluorine-doped ZnO quantum dots (F/ZnO QDs) were proposed and their formulation into stable amphiphilic nanosystems using synthetic glycoglycerolipids. To control aggregation and interfacial behavior, the QDs were first capped with oleylamine and subsequently functionalized through an emulsion-based approach with mono-acyl or di-acyl glycoglycerolipids, yielding double-coated amphiphilic nanoformulations. The resulting materials were extensively characterized by TEM, DLS, zeta-potential measurements, XRD, FTIR/ATR, UV–Vis, and fluorescence spectroscopy, allowing to explore correlations between surface chemistry, colloidal stability, and optical properties. Glycoglycerolipid functionalization led to a marked improvement in aqueous dispersibility and long-term colloidal stability while preserving the enhanced fluorescence induced by fluorine doping. Biological assays confirmed the cytocompatibility of the coated QDs and supported their suitability for further biointerface studies. This work highlights glycoglycerolipid-based amphiphilic coatings as an effective strategy to tailor the surface and colloidal properties of ZnO-based QDs, enabling the development of stable luminescent nanomaterials as biocompatible nanoprobes and for bio-interfacial applications.

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Abstract: The microstructure of organic small molecule (SM) layers in organic solar cells (OSCs) strongly influences device performance by impacting light absorption, charge transport, and recombination. We demonstrate that ellagic acid (EA), a naturally derived templating layer, induces substantial morphological and thus optoelectronic changes in the vacuum thermally evaporated (VTE) donor molecule DCV5T-Me(3,3). Using in situ grazing incidence wide-angle X-ray scattering (GIWAXS) during thin film deposition in the purpose-built MINERVA VTE chamber at Diamond Light Source, we show that a 5 nm EA layer reorients DCV5T-Me from an edge-on to a face-on molecular packing motif. This templating effect persists for up to around 90 nm of film thickness. Through UV-vis spectrophotometry and photoluminescence (PL) spectroscopy, we observe a shift towards H-aggregation and decreased light absorption in the donor molecule with the EA template. Atomic force microscopy (AFM) shows that the donor morphology changes as a function of thickness from the donor-templating interface. In DCV5T-Me(3,3):C60 bulk heterojunction devices, the EA layer helps retain donor crystallinity and enhances short circuit current (J ), despite the lower absorption. Maximum power conversion efficiency in our devices is achieved with a 5 nm templating layer, which provides sufficient structural templating while maintaining partial interfacial contact for efficient charge extraction. We hypothesise that the improvement in J is likely driven by enhanced charge carrier dynamics due to the orientation change, shift toward H-aggregation, and change in growth mode.

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Abstract: The superconducting gap is a characteristic feature of high-𝑇c superconductors and provides crucial information on the pairing mechanism underlying high-temperature superconductivity. Here, we employ high-resolution resonant inelastic x-ray scattering (RIXS) at the Cu 𝐿3 edge to investigate the superconducting gap in the overdoped cuprate Bi2⁢Sr2⁢Ca2⁢Cu3⁢O10+𝛿 (𝑇c⁢=107K). By analyzing antisymmetrized, temperature-dependent RIXS spectra over a range of in-plane momentum transfers, we observe a clear suppression of low-energy spectral weight below 𝑇c, indicative of superconducting-gap formation. This suppression is most pronounced at small momentum transfers [ | | | 𝒒∥ | | | ≤0.18 r.l.u. (reciprocal lattice units)] and corresponds to a gap size of approximately 2⁢Δ0∼130 meV. Comparison with theoretical calculations of the momentum-dependent charge susceptibility supports a 𝑑-wave symmetry of the superconducting gap, while an isotropic 𝑠-wave gap fails to reproduce key experimental features. These findings establish RIXS as a powerful, bulk-sensitive probe of superconducting-gap symmetry and highlight its utility for studying materials beyond the reach of surface-sensitive techniques such as ARPES and STM.

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Abstract: Formamidinium lead iodide (FAPbI3), which has a narrower band gap close to the Shockley-Queisser limit, offers higher power conversion efficiency (PCE) than other perovskite compositions, surpassing 27% [1]–[3]. However, under external stressors like moisture in ambient air processing conditions, its high tolerance factor value causes phase instability because of the larger ion size of FA+ [4]–[6]. Additionally, a higher annealing temperature (>390 K) is needed to reach the cubic α-phase of FAPbI3, whereas lower temperatures result in the formation of a non-photoactive δ-phase [7]. In recent years, FAPbI3 perovskite ink has been extensively incorporated with volatile methylammonium chloride (MACl) as a transitional stabilizer [8]. This substance effectively provides FAPbI3 black phase without annealing by decreasing the formation energy. However, the advantageous effects of MACl as an α-phase FAPbI3 inducer and stabilizer at room temperature are neutralized under ambient conditions and in the presence of non-volatile coordinating DMSO, which is frequently used as a co-solvent with toxic DMF to regulate the crystallization process [9]. DMSO accelerates the α-to-δ phase transition in air by displacing MACl from the intermediate film through the formation of stronger bonds with PbI2. In this work, we use recently emerged Triethyl Phosphate (TEP) as a green solvent to dissolve FAPbI3 precursors and in-situ study its crystallization kinetics in the presence of MACl and excess PbI2 under ambient condition using transmission wide angle x-ray scattering (T-WAXS) [10] and steady-state photoluminescence (PL) techniques. Our results show that, unlike DMSO containing solvent systems, TEP with appropriate coordination ability allows for direct solvent extraction during anti-solvent quenching process avoiding intermediate phase formation. Furthermore, it has been found that the addition of excess PbI2 to the perovskite solution, along with MACl, not only regulates the pre-nucleation stage, leading to larger and more ordered crystals, as opposed to MACl alone as an additive, but also accelerates the formation of α-phase FAPbI3 at room temperature and stabilizes it under ambient condition during spin casting. This study paves the way for achieving high efficiency FAPbI3 solar cells using a non-toxic solvent system and under ambient conditions.

Open Access

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Abstract: Fats are essential ingredients widely used in the food industry, as well as in cosmetic and pharmaceutical formulations. Solid fats are complex multicomponent systems primarily composed of triacylglycerols (TAGs), which determine the types and properties of the crystalline structures formed. TAGs crystallize in different polymorphs and stacking configurations, with distinct thermal and mechanical properties that influence the macroscopic structure and sensory profile of fat-based products. In this study, a comprehensive multi-technique analysis of animal-derived fats, specifically chicken and beef fats, was conducted. Chemical characterization was performed and solid fat content (SFC) was determined. Thermal behaviour was investigated using differential scanning calorimetry (DSC), whereas crystallization experiments were conducted using in situ turbidity measurements and synchrotron small-angle and wide-angle x-ray scattering (SAXS/WAXS) for structural characterization. Three different synchrotron experimental setups were used for crystallization experiments, including static and sheared conditions. The results demonstrate that the crystallization behaviour of beef and chicken fat samples closely correlate with their TAGs composition. Synchrotron x-ray scattering provided structural insights, highlighting how the polymorphic behaviour is influenced by fat origin and crystallization conditions. For both animal fat types, all three main polymorphs and possible transitions were detected. Moreover, the presence of shear promoted crystallization of stable polymorphs.