Publications by authors named "F G Alabarse"
Hybrid perovskites exhibit complex structures and phase behavior under different thermodynamic conditions and chemical environments, the understanding of which continues to be pivotally important for tailoring their properties toward improved operational stability. To this end, we present for the first time a comprehensive neutron and synchrotron diffraction investigation over the pressure-temperature phase diagram of the paradigmatic hybrid organic-inorganic perovskite methylammonium lead iodide (MAPbI). This ambitious experimental campaign down to cryogenic temperatures and tens of kilobars was supported by extensive molecular dynamics simulations validated by the experimental data, to track the structural evolution of MAPbI under external physical stimuli at the atomic and molecular levels.
View Article and Find Full Text PDFWe investigated the site-disorder and thermal expansion of O(BO) ( = Pr, Nd, Gd, Er, Tm) through a single crystal structural study conducted between 100 and 300 K. Additionally, a high-pressure synchrotron X-ray diffraction study at low temperatures was conducted to determine the compressibility of both ordered and disordered prototype oxyborate lanthanides, specifically NdCaO(BO) and ErCaO(BO). The study revealed distinct behaviors consistent with their respective ionic radii.
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- * The structure of CsPb(Br,I) changes from a two-dimensional tetragonal framework at lower temperatures to a three-dimensional cubic structure at higher temperatures, especially above 630 K, where significant deficiencies in Cs and (Br,I) occur.
- * Studies reveal a very low thermal conductivity linked to the material’s properties, alongside optical gap measurements that align with theoretical calculations, indicating promise for use in energy applications.
Article Synopsis
- Pressure can transform the single crystal form of the porous aluminophosphate AlPO-17 into an amorphous state starting at 0.6 GPa, without breaking into smaller crystals.
- The amorphous material maintains the shape and orientation of the original crystal while compressing around the empty pores, indicating a direct structural relation between the two forms.
- This process could lead to the creation of high-quality amorphous materials, known as "perfect glasses," with enhanced mechanical properties due to a notable memory effect upon decompression.
Carbon dioxide (CO) is widespread in astrochemically relevant environments, often coexisting with water (HO) ices and thus triggering a great interest regarding the possible formation of their adducts under various thermodynamic conditions. Amongst them, solid carbonic acid (HCO) remains elusive, yet being widely studied. Synthetic routes followed for its production have always been characterised by drastic irradiation on solid ice mixtures or complex procedures on fluid samples (such as laser heating at moderate to high pressures).
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