7647-17-8Relevant articles and documents
Time-dependent transformation routes of perovskites CsPbBr3and CsPbCl3under high pressure
Katrusiak, Andrzej,St?hl, Kenny,Szafrański, Marek
, p. 10769 - 10779 (2021/05/14)
All-inorganic halide perovskites are prospective materials for diverse applications in photovoltaic and optoelectronic devices. Their high performance is associated with good operational stability, which is the key problem of hybrid organic-inorganic perovskites. However, for these materials only fragmentary information is available on the mechanical robustness and response to external stress, fundamentally important for strain engineering in multilayers, pressure-assisted technologies, and flexible panels applications. Here we show that all-inorganic perovskites CsPbX3 (where X = Cl, Br) undergo various types of pressure-induced transformations, including reversible phase transitions, irreversible chemical reactions reducing the dimensionality of PbX6 frameworks, and amorphization. The transformation routes depend on the mode of the applied stress and are related to the kinetics of transitions to the most stable phases. The slow-kinetics transformations in a moderate pressure range of technological importance, between 0.5 and 1.5 GPa, can require days or even weeks, depending on the sample quality and external stimuli. The pressure-induced narrowing and widening of energy gaps has been explained by the mechanism combining Pb-X bond lengths and PbX6 octahedra tilts with the electronic structure of the crystals.
Soluble diamagnetic model for malaria pigment: Coordination chemistry of gallium(III)protoporphyrin-IX
Bohle, D. Scott,Dodd, Erin L.,Pinter, Tyler B. J.,Stillman, Martin J.
, p. 10747 - 10761 (2013/01/15)
The facile axial ligand exchange properties of gallium(III) protoporphyrin IX in methanol solution were utilized to explore self-association interactions by NMR techniques. Structural changes were observed, as well as competitive behavior with the ligands acetate and fluoride, which differed from that seen with the synthetic analogue gallium(III) octaethylporphyrin which lacks acid groups in its side-chains and has less solution heterogeneity as indicated by absorption and MCD spectroscopies. The propionic acid side chains of protoporphyrin IX are implicated in all such interactions of PPIX, and both dynamic metal-propionic interactions and the formation of propionate-bridged dimers are observed. Fluoride coordination provides an unusual example of slow ligand exchange, and this allows for the identification of a fluoride bridged dimer in solution. An improved synthesis of the chloride and hydroxide complexes of gallium(III) protoporphyrin IX is reported. An insoluble gallium analogue of hematin anhydride is described. In general, the interactions between solvent and the metal are found to confer very high solubility, making [Ga(PPIX)] + a useful model for ferric heme species.
Effect of residual stress on the optical properties of CsCl thin films
Kumar, Kuldeep,Arun,Ravi Kant, Chhaya,Mehra,Makinistian,Albanesi
, p. 163 - 169 (2010/06/18)
Large band gap alkali halides are known to have interesting optical properties. Though expected to be transparent in nature, defects in the crystal structure results in alkali halides having colors. The defects gives rise to new energy levels in the band structure, called color centers. Defects are easily generated on film fabrication and hence study of alkali halides promise to be interesting. In this manuscript we report the optical properties of cesium chloride (CsCl) thin films. We have correlated the optical properties of the films with the lattice size of the polycrystalline films, thus highlighting the strong relationship between the structure and optical properties of alkali halide films.