Halide perovskites are soft, ionic semiconductors with exceptional optoelectronic properties. They typically have direct bandgaps in the visible spectrum that can be tuned by composition. For example, MAPbI₃ has a direct bandgap of about 1.5–1.6 eV, while replacing I⁻ by Br⁻ or Cl⁻ raises the gap to approximately 2.3 eV (green emission) or about 3.0 eV (blue) respectively. Depending on the halide used, the band gap can be tuned from around 1.6 eV (I) to approximately 3.2 eV (Cl). Mixed-halide perovskites allow continuous tuning across this range.

Comments

Post a Comment

Popular posts from this blog

Triazolopyrimidyl - The Structural and Physico-Chemical Properties of these Compounds - Non-Elaborate Posts - Post 9

    The inherent aromaticity of triazolopyrimidyl scaffolds provides a stable backbone for derivatization, however aromaticity is not monolithic.  Substituents can perturb resonance stabilization, influencing both chemical reactivity and biological affinity. Balancing substitution without disrupting the delicate aromatic equilibrium is a continual challenge for chemists optimizing scaffold activity. Tautomerism represents a further dimension of complexity.  Triazolopyrimidyl compounds can exist in multiple tautomeric forms depending on protonation state and solvent environment. These equilibria affect binding interactions, metabolic transformations, and physicochemical readouts. Analytical techniques such as variable-temperature NMR provide crucial windows into tautomeric dynamics.  
Read more
  For example, MAPbI₃ crystallizes in a tetragonal perovskite structure at room temperature, consisting of PbI₆ octahedra sharing corners, with MA⁺ cations occupying the interstitial spaces.  Variants of the perovskite structure also exist: for instance, layered (2D) perovskites have alternating organic and inorganic sheets (formula A₂BX₄), and “double” perovskites (e.g. A₂BB′X₆) replace Pb²⁺ by a combination of a monovalent and trivalent cation to eliminate lead. However, the defining feature of halide perovskites is the 3D corner-sharing BX₆ framework with monovalent A ions in the cavities
Read more

Solubility of Sucrose Ethanol - Nuclear Chemistry Topics - Non-Elaborate Posts - Post 2

Usage of a bit of a parallel post So, if we treat “room temperature” in nuclear terms as ground state (no external high energy input), many isotopes that are theoretically possible are not “soluble” in the sense that they do not exist stably — they decay too fast, or require too much energy to produce. Only certain “soluble” isotopes appear naturally or can be synthesized and persist. Similarly, increasing “temperature” or energy (in chemistry, heat; in nuclear, neutron flux, high energy collisions, or high excitation) can allow less stable isotopes to form or persist temporarily. As temperature helps solute dissolve more, energy inputs allow nuclear reactions to create isotopes that wouldn't exist at room, ambient nuclear conditions.
Read more