Structure-property relationships in cubic cuprous iodide: A novel view on stability, chemical bonding, and electronic properties

Abstract

Based on the combination of computational DFT and theory-group methods, we performed systematic modeling of γ-CuI structural design at the atomistic level. Being started from the metallic copper lattice, we treated a crystal assembly as a step-wise iodination process characterized in terms of a sequence of intermediate lattice geometries. These geometries were selected and validated via screening of possible structural transformations. The genesis of chemical bonding was studied for three structural transformations by analyzing the relevant changes in topology of valence electron densities. We determined structural trends driven by metal-ligand coupling. This allowed us to suggest the improved scenario of chemical bonding in γ-CuI. In particular, the unconventional effect of spatial separation of metallic and covalent interactions was found to be very important with respect to the preferred arrangements of valence electrons in the iodination process. We rigorously showed that useful electronic and optical properties of γ-CuI origin from the combination of two separated bonding patterns --strong covalency established in I-Cu tetrahedral connections and noncovalent interactions of copper cores caused by the 3d 10 closed-shell electron configurations.The other our finding is that the self-consistency of the GW calculations is crucial for correct determining the dynamic electronic correlations in γ-CuI. Detail reinvestigation of the quasi-particle energy structure by means of the self-consistent GW approach allowed us to explain how p-type electrical conductivity can be engineered in the material.

Defect‐Controlled Copper Iodide: A Promising and Ecofriendly Thermoelectric Material

“…The first principles studies have investigated the possible formation of native defects,i ncluding vacancy,interstitial, and antisite of bothC ua nd Ii ons. [40][41][42][43] It is proposed that Cu vacancy is the most easily occurring defectb ecause of its low formation energy compared to the formation energies of other possible defects.T his always makes CuI as ap -type semiconductor under ordinary conditions. Thec hemical stability of the compound upon release of I is quite importantt om ention.…”

Application of green synthesized nanocrystalline CuI in the removal of aqueous Mn(VII) and Cr(VI) ions

“…4 showed only the presence of elemental copper and iodine indicating high purity of the synthesized copper iodide nanoparticles. γ-CuI samples prepared by many experimental methods are reported to be of various dimensions, whereas the occurrence of an excess of Cu or I atoms in γ-CuI is highly unlikely [34]. The % atomic ratio as shown in Table 1 of Cu being slightly more than I may thus be attributed to the surface crystal defects in CuI making it a favorable adsorbent.…”

Low‐Temperature Fabrication and Performance of Polycrystalline CuI Films as Transparent p‐Type Semiconductors

“…Zinc‐blend‐type copper(I) iodide (CuI), which is a native p‐type semiconductor with E g = 3.1 eV, has been gradually attracting attention as a candidate for transparent p‐type semiconductors for transparent electronics . The electron holes in CuI originate from the copper vacancies, which introduce an acceptor level just above the VBM . Although transparent conducting CuI was first reported more than 100 years ago, the study of the material as a transparent p‐type semiconductor only began quite recently.…”