An Organic–Inorganic Perovskitoid with Zwitterion Cysteamine Linker and its Crystal–Crystal Transformation to Ruddlesden‐Popper Phase

Abstract

We demonstrate synthesis of a new low‐D hybrid perovskitoid (a perovskite‐like hybrid halide structure, yellow crystals, P21/n space group) using zwitterion cysteamine (2‐aminoethanethiol) linker, and its remarkable molecular diffusion‐controlled crystal‐to‐crystal transformation to Ruddlesden‐Popper phase (Red crystals, Pnma space group). Our stable intermediate perovskitoid distinctly differs from all previous reports by way of a unique staggered arrangement of holes in the puckered 2D configuration with a face‐sharing connection between the corrugated‐1D double chains. The PL intensity for the yellow phase is 5 orders higher as compared to the red phase and the corresponding average lifetime is also fairly long (143 ns). First principles DFT calculations conform very well with the experimental band gap data. We demonstrate applicability of the new perovskitoid yellow phase as an excellent active layer in a self‐powered photodetector and for selective detection of Ni2+ via On‐Off‐On photoluminescence (PL) based on its composite with few‐layer black phosphorous.

Oxidation-induced phase transformations of hybrid tin bromide single crystals enable the occurrence of second-harmonic generation

“…Various types of single crystal structural transformations, including the generation of new bonds of organic ligands, 7 the coordination number changes of central metals and halogens, 2 the absorption and desorption of guests 2,3 are induced by external stimuli, such as selective solvent induction, 2 light, 7 pH regulation, 8 and chiral ligand induction 9 as well as internal factors including organic cation in-diffusion. 10 The phase transformation research can improve the fundamental properties of materials, such as lowering the structural dimension and improving the photoluminescence quantum efficiency (PLQE) by using the locally collective hydrogen bonding effect, 11 inducing the transformation from centrosymmetry to non-centrosymmetry through chiral ligands, 12 and even forming a new phase of the host through the insertion and removal of the guest. 13 The organicinorganic metal-halide hybrid family possess the advantages of organic cations' flexibility and inorganic framework lattice's rigidity, to form structural diversity, 14 which is an ideal platform for studying the phase-transformation.…”

Tolerance Factor for Stabilizing 3D Hybrid Halide Perovskitoids Using Linear Diammonium Cations

“…Other interesting structures of edge-shared dimers connected by one octahedron in corner-sharing have been reported using homopiperazine 24 and 2-aminoethanethiol. 25 Here, we report the new 3D bromide compounds with a combination of corner-and edge-sharing.…”

“…25 eV for (1,4BDA)Pb2Br6, (NMPA)Pb2Br6, (TMEA)Pb2Br6 and (DMEA)Pb2Br6, respectively. For (DMEA)Pb2Br6, even though the octahedra are connected by corner-sharing in the stacking direction, the Pb-Br-Pb bond angle is much smaller than 180° (~138°), which reduces the overlap of the Pb s-(p-) and Br p-(s-) orbitals, leading to the flatter valence (conduction) bands, thus leading to a larger bandgap.…”

Highly efficient and stable perovskite solar cells enabled by low-dimensional perovskitoids

“…However, the results from using this approach are not completely satisfactory due to the tendency of forming multicomponent structures in the quasi-2D phase and creating lattice strain during the formation of low-dimensional (LD) structures. Recently, perovskitoid has been proposed to describe the structures where the PbI 6 octahedra are linked by edge and face sharing or combinations of corner, edge, and face sharing (26)(27)(28)(29)(30)(31)(32). Perovskitoids have the potential to effectively modify 3D perovskite due to its diverse PbI 6 connection styles and high stability.…”