Supporting Information - How the Intrinsic and Anion Vacancy Defect-Induced Properties of Organic-Inorganic Hybrid Lead-Free Perovskite MA2AgIn(BrxI1-x)6 Vary with the Stoichiometry x Qi Liu and WanZhen Liangâ State Key Laboratory of Physical Chemistry of ⦠Frenkel Defect is one type of Point Defect; in fact, it is a combination of both Vacancy and Interstitial type of point defects. The anion vacancy is the dominate defect under Pb-rich condition and the cation vacancy prefers to form under I-rich condition. This latter defect situation is also often termed an anti-Frenkel defect structure. and the resulting vacancy are assumed to be doubly charged, the formation of a Frenkel defect pair may be written = + â¢â¢ MM vM Mi // (2.3) A corresponding equation may be written for the formation of an anion Frenkel defect pair. Schottky defects are a coupled pair of vacanciesâone cation and one anionâthat maintains electrical neutrality. These defects arise when some metal gets doped into the crystal, each atom of which gets ionised in to M+ and e- .This electron occupies a site that would otherwise be filled by a X- ion. Typically, when the defect is formed in non-ionic crystal it is referred to as lattice vacancy defect. This defect is caused due to anionic vacancies and by the presence of extra cations in the interstitial sites. When alkali metal halides are heated in an atmosphere of vapour of the alkali metal, anion vacancies are created. Metal deficiency defect is a type of crystal defect that occurs in crystal lattices in which either a cation vacancy or an extra anion causes the defect. The compound lattice has (equal) or small difference in sizes between the anion and cations. A Frenkel defect is an ion that occupies an incorrect site in the lattice. This anion is then diffuse to the surface of the crystal and combine with newly generated metal cations. However, most studies have concentrated on oxygen vacancy defects because of their low formation energy. The cation vacancies show the p-type semiconductor characteristic. A Frenkel defect is composed with which of the following? Anion vacancy defect-engineered catalysts have exhibited impressive activity in the electro/photocatalytic N 2 reduction reaction (NRR) because of their advantages in N 2 adsorption and activation. Schottky defect is found in highly ionic compounds or highly coordinated compounds. The generally used methods for creating anion defects (such as O, S, and P vacancies) and cation defects (such as Fe, Co, and Ni vacancies) are discussed in detail, including NaBH 4 and hydrogen reduction, plasma irradiation, thermal annealing, and chemical/electrochemical etching. This type of metal defects can be observed in metal complexes having a variable valency. The anion vacancies all are present the n-type semiconductor characteristic. Usually, this type of defect is observed in ionic solids, where size of anion is substantially larger than the size of cation. There are two types: Metal Deficiency Defect due to Cation Vacancy A Frenkel defect is an ion that occupies an incorrect site in the lattice. (a) A cation interstitial and a cation vacancy (b A cation interstitial and an anion interstitial (c) A catio (d) An anion interstitial and an anion vacancy Which of the following are the most common coordination numbers for ceramic materials? Every cation vacancy finds an anion vacancy as a fictive partner, forming a formal Schottky defect, and every cation interstitial finds a cation vacancy, too, for a formal Frenkel pair, and the concentration of the anion vacancies is just so that it meets both demands for partners. Schottky defects are a coupled pair of vacanciesâone cation and one anionâthat maintains electrical neutrality.
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