Browse
Submit Data
Databases
API
Help

Dataset Information

15 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Synthesis and Characterization of Multiple-Cation Rb(MAFA)PbI₃ Perovskite Single Crystals.

ABSTRACT: We synthesized multiple-cation Rb(MAFA)PbI₃ perovskite single crystals for the first time. The effect of Rb⁺ substitution was systemically investigated, and the addition of 1.5?M 5% RbI was the optimum condition to obtain high-quality Rb(MAFA)PbI₃ single crystals. Lattice shrinkage occurred in the Rb(MAFA)PbI₃ single crystal because of the small ionic radius of Rb⁺, resulting in blue-shifted absorption and photoluminescence (PL) peaks. The 1.5?M 5% RbI-added (MAFA)PbI₃ single crystal showed the longest carrier lifetime of 18.35?ns, exhibiting the highest photoresponse than other crystals. We believe that this work will provide a basic insight into the mixed-cation perovskite single crystals for the future optoelectronic applications.

SUBMITTER: Kim H

PROVIDER: S-EPMC6376001 | biostudies-literature | 2019 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Synthesis and Characterization of Multiple-Cation Rb(MAFA)PbI3 Perovskite Single Crystals.

Kim Hyojung H Byun Hye Ryung HR Jeong Mun Seok MS

Scientific reports 20190214 1

We synthesized multiple-cation Rb(MAFA)PbI3 perovskite single crystals for the first time. The effect of Rb+ substitution was systemically investigated, and the addition of 1.5 M 5% RbI was the optimum condition to obtain high-quality Rb(MAFA)PbI3 single crystals. Lattice shrinkage occurred in the Rb(MAFA)PbI3 single crystal because of the small ionic radius of Rb+, resulting in blue-shifted absorption and photoluminescence (PL) peaks. The 1 ...[more]

PMID: 30765856

Similar Datasets

CH3NH3PbI3 perovskite single crystals: surface photophysics and their interaction with the environment.

Project description:Here we identify structural inhomogeneity on a micrometer scale across the surface of a CH3NH3PbI3 perovskite single crystal. At the crystal edge a local distortion of the crystal lattice is responsible for a widening of the optical bandgap and faster photo-carrier recombination. These effects are inherently present at the edge of the crystal, and further enhanced upon water intercalation, as a preliminary step in the hydration of the perovskite material.

| S-EPMC5512535 | biostudies-literature

Atomistic Surface Passivation of CH3NH3PbI3 Perovskite Single Crystals for Highly Sensitive Coplanar-Structure X-Ray Detectors.

Project description:Organic-inorganic halide perovskites (OIHPs) are recognized as the promising next-generation X-ray detection materials. However, the device performance is largely limited by the ion migration issue of OIHPs. Here, we reported a simple atomistic surface passivation strategy with methylammonium iodide (MAI) to remarkably increase the ion migration activation energy of CH3NH3PbI3 single crystals. The amount of MAI deposited on the crystal surface is finely regulated by a self-assemble process to effectively suppress the metallic lead defects, while not introducing extra mobile ions, which results in significantly improved dark current stability of the coplanar-structure devices under a large electric field of 100 V mm-1. The X-ray detectors hence exhibit a record-high sensitivity above 700,000 μC Gyair -1 cm-2 under continuum X-ray irradiation with energy up to 50 keV, which enables an ultralow X-ray detection limit down to 1.5 nGyair s-1. Our findings will allow for the dramatically reduced X-ray exposure of human bodies in medical imaging applications.

| S-EPMC7528034 | biostudies-literature

Phase Segregation in Cs-, Rb- and K-Doped Mixed-Cation (MA)x(FA)1-xPbI3 Hybrid Perovskites from Solid-State NMR.

Project description:Hybrid (organic-inorganic) multication lead halide perovskites hold promise for a new generation of easily processable solar cells. Best performing compositions to date are multiple-cation solid alloys of formamidinium (FA), methylammonium (MA), cesium, and rubidium lead halides which provide power conversion efficiencies up to around 22%. Here, we elucidate the atomic-level nature of Cs and Rb incorporation into the perovskite lattice of FA-based materials. We use 133Cs, 87Rb, 39K, 13C, and 14N solid-state MAS NMR to probe microscopic composition of Cs-, Rb-, K-, MA-, and FA-containing phases in double-, triple-, and quadruple-cation lead halides in bulk and in a thin film. Contrary to previous reports, we have found no proof of Rb or K incorporation into the 3D perovskite lattice in these systems. We also show that the structure of bulk mechanochemical perovskites bears close resemblance to that of thin films, making them a good benchmark for structural studies. These findings provide fundamental understanding of previously reported excellent photovoltaic parameters in these systems and their superior stability.

| S-EPMC5719467 | biostudies-literature

Characterizing temperature-dependent optical properties of (MA0.13FA0.87) PbI3 single crystals using spectroscopic ellipsometry.

Project description:In this paper, we present spectroscopic ellipsometry measurements of (MA0.13FA0.87)PbI3 single crystals assessed at photon energies of 0.73-6.42?eV and at temperatures between 4.4 and 400?K. At room temperature, the refractive index was dispersed as a function of frequency, which is typical of a semiconductor. The absorption spectrum exhibited several electronic transitions. We estimated a room temperature direct band gap of 1.66?±?0.02?eV and exciton binding energy of 40?meV. With decreasing temperature, the refractive index increased. The room-temperature thermo-optic coefficients were -1.7?×?10-4 and -2.5?×?10-4?K-1 at wavelength of 600 and 1200?nm. The exciton peak position and bandgap energy exhibited a redshift, which was attributed to a reverse ordering of the band structures. Additionally, an anomaly in exciton peak position and bandgap occurred at approximately 100-200?K due to the structural phase transition. This phenomenon was associated with the coexistence of MA/FA-disordered and MA/FA-ordered domains. Our results provide a foundation for the technological development of lead halide perovskites-based photonic devices at various temperatures.

| S-EPMC6890668 | biostudies-literature

Two-Dimensional Perovskite (PEA)2PbI4 Two-Color Blue-Green Photodetector.

Project description:Perovskite materials have been widely used to fabricate solar cells, laser diodes and other photodevices, owing to the advantage of high absorption coefficient, long carrier life and shallow defect energy levels. However, due to easy hydrolysis, it is difficult to fabricate perovskite micro-nano devices. Herein, we developed a water-free device fabrication technology and fabricated a two-dimensional (C6H5C2H4NH3)2PbI4 ((PEA)2PbI4) two-color blue-green light detector, which exhibits high detection performance under the illumination of two-color lasers (λ = 460 nm, 532 nm). Compared with bulk devices, the dark current of the fabricated devices (10-11 A) was reduced by 2 orders of magnitude. The peak responsivity and detectivity are about 1 A/W and 1011 Jones, respectively. The photodetection performance of the device is basically the same under the two-color lasers. Our results provide a new process to fabricate perovskite microelectronic devices, and the fabricated photodetector shows great application prospects in underwater detection, owing to the blue-green window existing in water.

| S-EPMC9331230 | biostudies-literature

Pb clustering and PbI2 nanofragmentation during methylammonium lead iodide perovskite degradation.

Project description:Studying defect formation and evolution in MethylAmmonium lead Iodide (MAPbI3) perovskite layers has a bottleneck in the softness of the matter and in its consequent sensitivity to external solicitations. Here we report that, in a polycrystalline MAPbI3 layer, Pb-related defects aggregate into nanoclusters preferentially at the triple grain boundaries as unveiled by Transmission Electron Microscopy (TEM) analyses at low total electron dose. Pb-clusters are killer against MAPbI3 integrity since they progressively feed up the hosting matrix. This progression is limited by the concomitant but slower transformation of the MAPbI3 core to fragmented and interconnected nano-grains of 6H-PbI2 that are structurally linked to the mother grain as in strain-relaxed heteroepitaxial coupling. The phenomenon occurs more frequently under TEM degradation whilst air degradation is more prone to leave uncorrelated [001]-oriented 2H-PbI2 grains as statistically found by X-Ray Diffraction. This path is kinetically costlier but thermodynamically favoured and is easily activated by catalytic species.

| S-EPMC6522562 | biostudies-literature

Consolidation of the optoelectronic properties of CH3NH3PbBr3 perovskite single crystals.

Project description:Ultralow trap densities, exceptional optical and electronic properties have been reported for lead halide perovskites single crystals; however, ambiguities in basic properties, such as the band gap, and the electronic defect densities in the bulk and at the surface prevail. Here, we synthesize single crystals of methylammonium lead bromide (CH3NH3PbBr3), characterise the optical absorption and photoluminescence and show that the optical properties of single crystals are almost identical to those of polycrystalline thin films. We observe significantly longer lifetimes and show that carrier diffusion plays a substantial role in the photoluminescence decay. Contrary to many reports, we determine that the trap density in CH3NH3PbBr3 perovskite single crystals is 1015?cm-3, only one order of magnitude lower than in the thin films. Our enhanced understanding of optical properties and recombination processes elucidates ambiguities in earlier reports, and highlights the discrepancies in the estimation of trap densities from electronic and optical methods.Metal halide perovskites for optoelectronic devices have been extensively studied in two forms: single-crystals or polycrystalline thin films. Using spectroscopic approaches, Wenger et al. show that polycrystalline thin films possess similar optoelectronic properties to single crystals.

| S-EPMC5605602 | biostudies-literature

Improving Two-Step Prepared CH3NH3PbI3 Perovskite Solar Cells by Co-Doping Potassium Halide and Water in PbI2 Layer.

Project description:Incorporating additives into organic halide perovskite solar cells is the typical approach to improve power conversion efficiency. In this paper, a methyl-ammonium lead iodide (CH3NH3PbI3, MAPbI3) organic perovskite film was fabricated using a two-step sequential process on top of the poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) hole-transporting layer. Experimentally, water and potassium halides (KCl, KBr, and KI) were incorporated into the PbI2 precursor solution. With only 2 vol% water, the cell efficiency was effectively improved. Without water, the addition of all of the three potassium halides unanimously degraded the performance of the solar cells, although the crystallinity was improved. Co-doping with KI and water showed a pronounced improvement in crystallinity and the elimination of carrier traps, yielding a power conversion efficiency (PCE) of 13.9%, which was approximately 60% higher than the pristine reference cell. The effect of metal halide and water co-doping in the PbI2 layer on the performance of organic perovskite solar cells was studied. Raman and Fourier transform infrared spectroscopies indicated that a PbI2-dimethylformamide-water related adduct was formed upon co-doping. Photoluminescence enhancement was observed due to the co-doping of KI and water, indicating the defect density was reduced. Finally, the co-doping process was recommended for developing high-performance organic halide perovskite solar cells.

| S-EPMC6566305 | biostudies-literature

Alkali Metal Doping for Improved CH3NH3PbI3 Perovskite Solar Cells.

Project description:Organic-inorganic hybrid halide perovskites are proven to be a promising semiconductor material as the absorber layer of solar cells. However, the perovskite films always suffer from nonuniform coverage or high trap state density due to the polycrystalline characteristics, which degrade the photoelectric properties of thin films. Herein, the alkali metal ions which are stable against oxidation and reduction are used in the perovskite precursor solution to induce the process of crystallization and nucleation, then affect the properties of the perovskite film. It is found that the addition of the alkali metal ions clearly improves the quality of perovskite film: enlarges the grain sizes, reduces the defect state density, passivates the grain boundaries, increases the built-in potential (Vbi), resulting to the enhancement in the power conversion efficiency of perovskite thin film solar cell.

| S-EPMC5827644 | biostudies-literature

Structure of Pb(Fe2/3W1/3)O3 single crystals with partial cation order.

Project description:Despite intensive studies on the complex perovskite Pb(Fe2/3W1/3)O3 (PFWO) relaxor, understanding the exact nature of its multifunctional properties has remained a challenge for decades. In this work we report a comprehensive structural study of the PFWO single crystals using a combination of synchrotron X-ray diffraction and high-resolution electron microscopy. The set of {h + ½, k + ½, l + ½} superlattice reflections was observed for the first time based on single-crystal synchrotron X-ray experiments (100-450 K) and transmission electron microscopy investigations, which indicates some kind of B-cation ordering in PFWO which had been thought to be totally disordered. It was found that (1) the crystal structure of PFWO should be described by a partly ordered cubic perovskite (i.e. Fm - 3m), (2) the weak ferromagnetic properties and excess magnetic moment of PFWO can be understood based on non-random distribution of Fe cations between the 4a and 4b sites, and (3) the Pb displacement disorder is present in this material and the cations are probably displaced along the <100> directions. The X-ray diffraction results of this investigation show that partial cation ordering indeed exists in PFWO, which makes it necessary to revisit the generally accepted interpretations of the results obtained up to date. In agreement with X-ray diffraction study the main results of TEM study include: (1) a long range order that can be described with the Fm - 3m symmetry is reliably detected, (2) the coherence length of that long range order is in the order of 1-2 nm and (3) no remarkable chemical inhomogeneity is found in the tested PFWO crystal, excluding the possibility of a compositional ordering arising from substitutional defects in the perovskite structure.

| S-EPMC7471969 | biostudies-literature