Organic-inorganic Layered Perovskite Research Articles

Optical properties of natural quantum-well compounds (C 6H 5-C nH 2 n-NH 3) 2PbBr 4 ( n=1–4)

This paper describes the synthesis and characterization of self-assembled organic–inorganic layered perovskite compounds, (C 6H 5-C n H 2 n -NH 3) 2PbBr 4 ( n=1–4). the effect of the number of carbon atoms of the alkyl chain length ( n) on optical properties has been studied. (C 6H 5-C n H 2 n -NH 3) 2PbBr 4 films fabricated by spin-coating are microcrystalline form, single phase and oriented with the c-axis. Crystallinity, the maximum PL intensity and the lifetime of exciton emissions varied with the number of carbon atoms. the lowest-energy exciton splits into a few fine-structure levels at low temperatures. Time-resolved photoluminescence spectra reveal that (C 6H 5-C n H 2 n -NH 3) 2PbBr 4 shows both singlet and triplet excitons. with decreasing temperature, triplet exciton emissions become dominant for (C 6H 5-C n H 2 n -NH 3) 2PbBr 4 ( n=1–3), while (C 6H 5-C 4H 8-NH 3) 2PbBr 4 shows mainly singlet exciton emissions. The intersystem crossing from excited singlet state to triplet state plays an important role in the relaxation process of excitons.

Electroluminescence Enhancement in Dry-Processed Organic-Inorganic Layered Perovskite Films

Organic-inorganic layered perovskite, (C6H5C2H4NH3)2PbI4, was grown on silica substrates or indium tin oxide (ITO) substrates by vacuum vapor deposition. High-quality layered perovskite films, which showed sharp and intense exciton peaks, were obtained when substrate surfaces were covered with either an octadecyltrichlorosilane (OTS) monolayer or a vacuum-deposited copper phthalocyanine (CuPc) layer. Light-emitting devices (LEDs) with structures of ITO/OTS/layered perovskite/2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP)/2,4-pentanedionato lithium (Li acac)/Al, ITO/CuPc/layered perovskite/BCP/Li acac/Al, and ITO/layered perovskite/BCP/Li acac/Al were fabricated. Sharp electroluminescence (EL) peaks from excitons stabilized in a quantum well structure were observed in each LED at 105 K. The LED with the CuPc layer exhibited the highest EL intensity and efficiency among the three LEDs. This EL enhancement is ascribed to the improvement in film properties and a decrease in the height of the hole injection barrier induced by growing the layered perovskite film on a CuPc layer.

Synthesis of Novel Organic-Inorganic Self-Organized Compounds Containing Quaternary Ammonium Ions and its Structural Characterization

Organic-inorganic layered perovskite compounds described by (RNH 3 ) 2 MX 4 [R: alkyl group, M: divalent metals, X: halogen] were reported to form self-organized quantum-well structures. In this study, we aimed to synthesize novel organic-inorganic self-organized compounds with quaternary ammonium ions instead of primary alkylammonium ions. New compounds, [(C 12 H 25 ) 2 (CH 3 ) 2 N]PbBr 2 (DLDMPbBr) and [(C 12 H 25 ) 2 (CH 3 ) 2 N]PbI 2 (DLDMPbI) were synthesized, and the structural characterizations were performed on X-ray diffraction and optical measurements. The absorption peaks of these compounds showed higher photon energy than those of conventional layered perovskite compounds with primary alkylammomium ions. This result indicated that novel quantum confinement structures were constructed with the DLDMPbBr and DLDMPbI.

Synthesis of Novel Organic-Inorganic Self-Organized Compounds Containing Quaternary Ammonium Ions and its Structural Characterization

Organic-inorganic layered perovskite compounds described by (RNH 3 ) 2 MX 4 [R: alkyl group, M: divalent metals, X: halogen] were reported to form self-organized quantum-well structures. In this study, we aimed to synthesize novel organic-inorganic self-organized compounds with quaternary ammonium ions instead of primary alkylammonium ions. New compounds, [(C 12 H 25 ) 2 (CH 3 ) 2 N]PbBr 2 (DLDMPbBr) and [(C 12 H 25 ) 2 (CH 3 ) 2 N]PbI 2 (DLDMPbI) were synthesized, and the structural characterizations were performed on X-ray diffraction and optical measurements. The absorption peaks of these compounds showed higher photon energy than those of conventional layered perovskite compounds with primary alkylammomium ions. This result indicated that novel quantum confinement structures were constructed with the DLDMPbBr and DLDMPbI.

PbBr-Based Layered Perovskite Organic-Inorganic Superlattice with Photochromic Chromophore-Linked Ammonium Molecules as an Organic Layer

Oriented films of novel organic-inorganic layered perovskites, which have a superlattice structure consisting of a PbBr-based semiconductor layer and a photochromic ammonium layer, were formed in a self-organizing manner by spin-coating from the solutions of PbBr2 and an ammonium bromide linked with a photochromic chromophore such as salicylidenaniline and stylbene.

Optical and magnetic properties for metal halide-based organic-inorganic layered perovskites

Layered perovskites (RNH 3) 2CuCl 4, where R was methyl-benzene C 6H 5–CH 2, 1-methyl-naphthalene 1-C 10H 9–CH 2, 1-propyl-naphthalene 1-C 10H 9–O(CH 2) 3 and 1-butyl-naphthalene 1-C 10H 9–O(CH 2) 4, were synthesized. These complexes showed ferromagnetism, with different Curie temperatures, T C, depending on the structure of the molecule. The change of T C by taking into account the overlap of the electronic states between the organic and the inorganic layers were discussed.

Strong coupling of exciton and photon modes in photonic crystal infiltrated with organic–inorganic layered perovskite

Large vacuum Rabi-splitting, the evidence of strong coupling of photon and exciton modes, was observed at room temperature in an ordered array of silica microspheres infiltrated with organic–inorganic layered perovskite. By natural sedimentation of a colloidal suspension of monodispersed silica microspheres with a diameter of 256 nm, three-dimensional ordered array of silica microspheres (silica opal) were prepared. Into an air space of the silica opal, organic–inorganic perovskite, bis-(phenethylammonium) tetraiodoplumbate (PAPI), which exhibits intense exciton absorption at 2.40 eV, was infiltrated. The silica opal infiltrated with PAPI (23% of air space was filled) exhibited a stop band at 2.13 eV, when observed at a normal direction to the sample surface. By changing the observation angle, the coupling of the stop band at around 2.1–2.4 eV and the exciton band at 2.40 eV due to PAPI was attained. From angle-tuning measurements of reflection spectra, a vacuum Rabi-splitting of 240 meV was evaluated.

A Layered Solution Crystal Growth Technique and the Crystal Structure of (C6H5C2H4NH3)2PbCl4

Single crystals of the organic–inorganic perovskite (C6H5C2H4NH3)2PbCl4 have been grown at room temperature using a layered solution approach. The bottom solution layer, contained within a long straight tube, consists of PbCl2 dissolved in concentrated aqueous HCl. A less dense layer of methanol is carefully placed on top of the HCl/PbCl2 solution using a syringe. Finally, a stoichiometric quantity of C6H5C2H4NH2 (relative to the PbCl2) is added to the top of the column. As the layers slowly diffuse together, well-formed crystals of (C6H5C2H4NH3)2PbCl4 appear near the interface between the HCl/PbCl2 and C6H5C2H4NH2 solutions. The thick, plate-like crystals are well suited for X-ray crystallography studies. Room temperature intensity data were refined using a triclinic (P1) cell (a=11.1463(3) Å, b=11.2181(3) Å, c=17.6966(5) Å, α= 99.173(1)°, β=104.634(1)°, γ=89.999(1)°, V=2111.8(1) Å3, Z=4, Rf/Rw=0.031/0.044). The organic–inorganic layered perovskite structure features well-ordered sheets of corner-sharing distorted PbCl6 octahedra separated by bilayers of phenethylammonium cations. Tilting and rotation of the PbCl6 octahedra within the perovskite sheets, coupled with organic cation ordering, leads to the unusual in-sheet 2ap×2ap superstructure, where ap is the lattice constant for the ideal cubic perovskite.

Stability of Self-Assembled Organic-Inorganic Layered Perovskite

ABSTRACTPhoto-stability of (C6H5C2H4NH3)2PbX4 (X; Br and I) films was studied and the degradation processes were discussed. The prepared films were not stable against the UV-light irradiation. The PhE-PbX4 films were readily oxidized by the UV-light irradiation in air. In vacuum, the PhE-PbI4 films changed to β-phenethylamine intercalated PbI2 due to the elimination of halogen species. On the contrary, no degradation was observed for the PhE-PbBr4 films. These results suggested that the photo-irradiation induced photochemical reaction was one of the possible reasons for the degradation. To suppress the oxidation and halogen elimination induced by the photochemical reaction, PMMA-coated PhE-PbX4 films were also fabricated and their photo-stability was examined.

PbBr-Based Layered Perovskite Containing Chromophore-Linked Ammonium Molecule as an Organic Layer

Abstract Oriented thin films of new organic-inorganic layered perovskites having a quantum-well structure combined with PbBr-based semiconductor layer and a chromophore-linked ammonium molecule layer were formed in a self-organizing manner by a simple spin-coating from the solutions of stoichiometric amounts of lead bromide PbBr2 and an ammonium bromide linked with a chromophore such as naphthalene and azobenzene.

Synthesis, Crystal Structure, and Optical and Thermal Properties of (C4H9NH3)2MI4 (M = Ge, Sn, Pb)

Single crystals of the organic-inorganic layered perovskites (C4H9NH3)2MI4 (M = Ge, Sn, Pb) have been grown from aqueous hydriodic acid solutions. X-ray diffraction, thermal analysis, and photoluminescence spectroscopy were used to compare crystal structure, metal atom lone-pair stereoactivity, and physical properties as a function of group IVB element. The orthorhombic (C4H9NH3)2GeI4 structure, refined in the space group Pcmn, consists of single-layer-thick perovskite sheets of distorted corner-sharing GeI6 octahedra separated by n-butylammonium cation bilayers. (C4H9NH3)2SnI4 and (C4H9NH3)2PbI4 are structurally very similar but adopt the space group Pbca, with a more ideal octahedral iodine coordination around the divalent group IVB atoms. Within the more general tin(II)-based family, (C4H9NH3)2(CH3NH3)n-1SnnI3n+1, a structural comparison between the title semiconducting n = 1 compound and the previously reported semimetallic n = 3 and metallic n → ∞ members demonstrates a correlation between perovskite...