Browse
Submit Data
Databases
API
Help

Dataset Information

20 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Significant THz absorption in CH₃NH₂ molecular defect-incorporated organic-inorganic hybrid perovskite thin film.

ABSTRACT: The valid strong THz absorption at 1.58?THz was probed in the organic-inorganic hybrid perovskite thin film, CH₃NH₃PbI₃, fabricated by sequential vacuum evaporation method. In usual solution-based methods such as 2-step solution and antisolvent, we observed the relatively weak two main absorption peaks at 0.95 and 1.87?THz. The measured absorption spectrum is analyzed by density-functional theory calculations. The modes at 0.95 and 1.87?THz are assigned to the Pb-I vibrations of the inorganic components in the tetragonal phase. By contrast, the origin of the 1.58?THz absorption is due to the structural deformation of Pb-I bonding at the grain boundary incorporated with a CH₃NH₂ molecular defect.

SUBMITTER: Maeng I

PROVIDER: S-EPMC6456617 | biostudies-literature | 2019 Apr

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Significant THz absorption in CH3NH2 molecular defect-incorporated organic-inorganic hybrid perovskite thin film.

Maeng Inhee I Lee Young Mi YM Park Jinwoo J Raga Sonia R SR Kang Chul C Kee Chul-Sik CS Yu Byung Deok BD Hong Suklyun S Ono Luis K LK Qi Yabing Y Jung Min-Cherl MC Nakamura Masakazu M

Scientific reports 20190409 1

The valid strong THz absorption at 1.58 THz was probed in the organic-inorganic hybrid perovskite thin film, CH3NH3PbI3, fabricated by sequential vacuum evaporation method. In usual solution-based methods such as 2-step solution and antisolvent, we observed the relatively weak two main absorption peaks at 0.95 and 1.87 THz. The measured absorption spectrum is analyzed by density-functional theory calculations. The modes at 0.95 and 1.87 THz are assigned to the Pb ...[more]

PMID: 30967593

Similar Datasets

Strong Linear Correlation between CH3NH2 Molecular Defect and THz-Wave Absorption in CH3NH3PbI3 Hybrid Perovskite Thin Film.

Project description:To control the density of a CH3NH2 molecular defect, which strongly contributed to a significant THz-wave absorption property in the CH3NH3PbI3 hybrid perovskite thin film formed by the sequential vacuum evaporation method, we performed post-annealing processes with various temperatures and times. In the thin film after post-annealing at 110 °C for 45 min, the density of the CH3NH2 molecular defect was minimized, and CH3NH3I and PbI2 disappeared in the thin film after the post-annealing process at 150 °C for 30 min. However, the density of the CH3NH2 molecular defect increased. Moreover, the THz-wave absorption property for each thin film was obtained using a THz time-domain spectroscopy to understand the correlation between the density of a molecular defect and the THz-wave oscillation strength at 1.6 THz, which originated in the molecular defect-incorporated hybrid perovskite structure. There is a strong linear correlation between the oscillator strength of a significant THz-wave absorption at 1.6 THz and the CH3NH2 molecular defect density.

| S-EPMC7221770 | biostudies-literature

Colloids of Naked CH3NH3PbBr3 Perovskite Nanoparticles: Synthesis, Stability, and Thin Solid Film Deposition.

Project description:A novel preparation of lead halide, CH3NH3PbBr3, perovskite nanoparticle solid films from colloidal "naked" nanoparticles, that is, dispersible nanoparticles without any surfactant, is reported. The colloids are obtained by simply adding potassium ions, whose counterions are both more lipophilic and less coordinating than bromide ions, to the perovskite precursor solutions (CH3NH3Br/PbBr2 in dimethylformamide) following the reprecipitation strategy. The naked nanoparticles exhibit a low tendency to aggregate in solution, and they effectively self-assembled on a substrate by centrifugation of the colloid, leading to homogeneous nanoparticle solid films with arbitrary thickness. These results are expected to spur further the interest in lead halide perovskites due to the new opportunities offered by these films.

| S-EPMC6641344 | biostudies-literature

Nonstoichiometric acid-base reaction as reliable synthetic route to highly stable CH3NH3PbI3 perovskite film.

Project description:Perovskite solar cells have received worldwide interests due to swiftly improved efficiency but the poor stability of the perovskite component hampers the device fabrication under normal condition. Herein, we develop a reliable nonstoichiometric acid-base reaction route to stable perovskite films by intermediate chemistry and technology. Perovskite thin-film prepared by nonstoichiometric acid-base reaction route is stable for two months with negligible PbI2-impurity under ?65% humidity, whereas other perovskites prepared by traditional methods degrade distinctly after 2 weeks. Route optimization involves the reaction of PbI2 with excess HI to generate HPbI3, which subsequently undergoes reaction with excess CH3NH2 to deliver CH3NH3PbI3 thin films. High quality of intermediate HPbI3 and CH3NH2 abundance are two important factors to stable CH3NH3PbI3 perovskite. Excess volatile acid/base not only affords full conversion in nonstoichiometric acid-base reaction route but also permits its facile removal for stoichiometric purification, resulting in average efficiency of 16.1% in forward/reverse scans.

| S-EPMC5476796 | biostudies-literature

Modulated CH3NH3PbI3-xBrx film for efficient perovskite solar cells exceeding 18.

Project description:The organic-inorganic lead halide perovskite layer is a crucial factor for the high performance perovskite solar cell (PSC). We introduce CH3NH3Br in the precursor solution to prepare CH3NH3PbI3-xBrx hybrid perovskite, and an uniform perovskite layer with improved crystallinity and apparent grain contour is obtained, resulting in the significant improvement of photovoltaic performance of PSCs. The effects of CH3NH3Br on the perovskite morphology, crystallinity, absorption property, charge carrier dynamics and device characteristics are discussed, and the improvement of open circuit voltage of the device depended on Br doping is confirmed. Based on above, the device based on CH3NH3PbI2.86Br0.14 exhibits a champion power conversion efficiency (PCE) of 18.02%. This study represents an efficient method for high-performance perovskite solar cell by modulating CH3NH3PbI3-xBrx film.

| S-EPMC5355988 | biostudies-literature

A Compact and Smooth CH?NH?PbI? Film: Investigation of Solvent Sorts and Concentrations of CH?NH?I towards Highly Efficient Perovskite Solar Cells.

Project description:Four solvents (isopropanol (IPA), n-butyl alcohol (NBA), n-amyl alcohol (NAA), and n-hexyl alcohol (NHA)) were investigated to prepare CH?NH?I (methylammonium iodide, MAI) solutions to transform PbI? film into CH?NH?PbI? (MAPbI?) film. It was found that the morphology of the perovskite MAPbI? film was not only affected by the chain of the solvent molecule, but also by the concentration of MAI. The use of solvents with a long alkyl chain (NAA and NHA) allowed the MAPbI? to grow via an in situ transformation step, which easily made the perovskite films compact, but with a high surface roughness due to the growth of unexpected nanorods/nanoplates. The solvent with a short alkyl chain (IPA) led to the dissolution-crystallization growth mechanism, resulting in rapid generation of perovskite films with a number of pinholes. A high-quality (compact, smooth, pinhole-free) perovskite film was obtained with NBA and an optimized MAI concentration of 8 mg/mL. The corresponding perovskite solar cells achieved a maximum power conversion efficiency (PCE) of 16.66% and average PCE of 14.76% (for 40 cells).

| S-EPMC6265889 | biostudies-other

Clean interface without any intermixed state between ultra-thin P3 polymer and CH3NH3PbI3 hybrid perovskite thin film.

Project description:Hole transport layers (HTL) are crucial materials to improve the power conversion efficiency in organohalide hybrid perovskite-based solar-cell applications. Two important physical properties are required in HTL materials: good hole mobility and air-protection. After HTL solution-based deposition, an intermixed chemical state at the interface between HTL and hybrid perovskite is key to confirming the physical property of HTL. We performed high-resolution x-ray photoelectron spectroscopy to investigate the chemical states at the interface between an ultra-thin P3 polymer and CH3NH3PbI3 hybrid perovskite thin film. At the interface, we found no apparent intermixed chemical state. Furthermore, we confirmed that the P3 HTL with the ultra-thin layer (7 nm) protected the hybrid perovskite material against air-exposure for 2 weeks.

| S-EPMC6659629 | biostudies-literature

Room temperature three-photon pumped CH3NH3PbBr3 perovskite microlasers.

Project description:Hybrid lead halide perovskites have made great strides in next-generation light-harvesting and light emitting devices. Recently, they have also shown great potentials in nonlinear optical materials. Two-photon absorption and two-photon light emission have been thoroughly studied in past two years. However, the three-photon processes are rarely explored, especially for the laser emissions. Here we synthesized high quality CH3NH3PbBr3 perovskite microstructures with solution processed precipitation method and studied their optical properties. When the microstructures are pumped with intense 1240 nm lasers, we have observed clear optical limit effect and the band-to-band photoluminescence at 540 nm. By increasing the pumping density, whispering-gallery-mode based microlasers have been achieved from CH3NH3PbBr3 perovskite microplate and microrod for the first time. This work demonstrates the potentials of hybrid lead halide perovskites in nonlinear photonic devices.

| S-EPMC5368977 | biostudies-literature

Crystal Structure Formation of CH₃NH₃PbI3-xClx Perovskite.

Project description:Inorganic-organic hydride perovskites bring the hope for fabricating low-cost and large-scale solar cells. At the beginning of the research, two open questions were raised: the hysteresis effect and the role of chloride. The presence of chloride significantly improves the crystallization and charge transfer property of the perovskite. However, though the long held debate over of the existence of chloride in the perovskite seems to have now come to a conclusion, no prior work has been carried out focusing on the role of chloride on the electronic performance and the crystallization of the perovskite. Furthermore, current reports on the crystal structure of the perovskite are rather confusing. This article analyzes the role of chloride in CH₃NH₃PbI3-xClx on the crystal orientation and provides a new explanation about the (110)-oriented growth of CH₃NH₃PbI₃ and CH₃NH₃PbI3-xClx.

| S-EPMC5456724 | biostudies-other

Optically switched magnetism in photovoltaic perovskite CH3NH3(Mn:Pb)I3.

Project description:The demand for ever-increasing density of information storage and speed of manipulation boosts an intense search for new magnetic materials and novel ways of controlling the magnetic bit. Here, we report the synthesis of a ferromagnetic photovoltaic CH3NH3(Mn:Pb)I3 material in which the photo-excited electrons rapidly melt the local magnetic order through the Ruderman-Kittel-Kasuya-Yosida interactions without heating up the spin system. Our finding offers an alternative, very simple and efficient way of optical spin control, and opens an avenue for applications in low-power, light controlling magnetic devices.

| S-EPMC5123013 | 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