Interlaced crystals having a perfect Bravais lattice and complex chemical order revealed by real-space crystallography

Abstract

The search for optimal thermoelectric materials aims for structures in which the crystalline order is disrupted to lower the thermal conductivity without degradation of the electron conductivity. Here we report the synthesis and characterisation of ternary nanoparticles (two cations and one anion) that exhibit a new form of crystalline order: an uninterrupted, perfect, global Bravais lattice, in which the two cations exhibit a wide array of distinct ordering patterns within the cation sublattice, forming interlaced domains and phases. Partitioning into domains and phases is not unique; the corresponding boundaries have no structural defects or strain and entail no energy cost. We call this form of crystalline order 'interlaced crystals' and present the example of hexagonal CuInS 2 . Interlacing is possible in multi-cation tetrahedrally bonded compound with an average of two electrons per bond. Interlacing has minimal effect on electronic properties, but should strongly reduce phonon transport, making interlaced crystals attractive for thermoelectric applications.

Catalytic and antibacterial properties of 3‐dentate carboxamide Pd/Pt complexes obtained via a benign route

“…The positive point is that we thus obtain a rough structure of 2R . This might be another example of interlaced crystals, but this assertion would need experimental confirmation.…”

Polymorphic Metastability in Colloidal Semiconductor Nanocrystals

“…In 2010, we discovered that CuInSe 2 nanocrystals could be synthesized in a metastable wurtzite‐like crystal structure, analogous to that of wurtzite CuInS 2 , by using a Ph 2 Se 2 diselenide precursor [20] . Here, we use the term “wurtzite‐like” because these metastable hexagonal phases on the nanoscale often display long‐range cation ordering within the crystal structures, whereas cations in the true wurtzite structure are not ordered [79,80] . Expanding upon the discovery of this new metastable phase of CuInSe 2 , we hypothesized that trends in dichalcogenide precursor reactivity could be employed to control the reaction kinetics in the syntheses of CuInSe 2 nanocrystals, providing synthetic pathways for thermodynamically or kinetically driven mechanisms, thus enabling predictable phase control of this material system simply by changing the dichalcogenide precursor.…”

Synthesis of CuInS2nanocrystals from a molecular complex – characterization of the orthorhombic domain structure

“…S8. ‡ Recently Shen et al 29 interpreted the electron diffraction pattern of CuInS 2 nanoplates as a range of cation-ordered wurtzite-like structures. 5 ) comparatively more stable than the exclusively use of DOP.…”