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Showing papers on "Single crystal published in 2021"



Journal ArticleDOI
TL;DR: In this article, single crystal growth of wafer-scale hexagonal boron nitride (hBN), an insulating atomic thin monolayer, on high-symmetry index surface plane Cu(111) was demonstrated.
Abstract: We demonstrate single crystal growth of wafer-scale hexagonal boron nitride (hBN), an insulating atomic thin monolayer, on high-symmetry index surface plane Cu(111). The unidirectional epitaxial growth is guaranteed by large binding energy difference, ~0.23 eV, between A- and B-steps edges on Cu(111) docking with B6N7 clusters, confirmed by density functional theory calculations.

133 citations


Journal ArticleDOI
TL;DR: In this article, a ligand core rebalances the in-plane and out-of-plane interactions that define anisotropic crystal growth, and a family of 2D π-conjugated metal-organic frameworks (MOFs) is derived from large single crystals of sizes up to 200 µm.
Abstract: Electrically conducting 2D metal–organic frameworks (MOFs) have attracted considerable interest, as their hexagonal 2D lattices mimic graphite and other 2D van der Waals stacked materials. However, understanding their intrinsic properties remains a challenge because their crystals are too small or of too poor quality for crystal structure determination. Here, we report atomically precise structures of a family of 2D π-conjugated MOFs derived from large single crystals of sizes up to 200 μm, allowing atomic-resolution analysis by a battery of high-resolution diffraction techniques. A designed ligand core rebalances the in-plane and out-of-plane interactions that define anisotropic crystal growth. We report two crystal structure types exhibiting analogous 2D honeycomb-like sheets but distinct packing modes and pore contents. Single-crystal electrical transport measurements distinctively demonstrate anisotropic transport normal and parallel to the π-conjugated sheets, revealing a clear correlation between absolute conductivity and the nature of the metal cation and 2D sheet packing motif. Two-dimensional MOFs can possess porosity and electrical conductivity but are difficult to grow as single crystals. Here, by balancing in-plane and out-of-plane interactions, single crystals of sizes up to 200 µm are grown, allowing in-plane transport measurements and atomic-resolution analysis.

130 citations


Journal ArticleDOI
TL;DR: In this article, a successful controlled incorporation of methylammonium (MA+ ) and cesium (Cs+ ) cations into the FAPbI3 lattice to grow inch-sized stable perovskite single crystal (FAMACs SC) is reported.
Abstract: Low ionic migration is required for a semiconductor material to realize stable high-performance X-ray detection. In this work, successful controlled incorporation of not only methylammonium (MA+ ) and cesium (Cs+ ) cations, but also bromine (Br- ) anions into the FAPbI3 lattice to grow inch-sized stable perovskite single crystal (FAMACs SC) is reported. The smaller cations and anions, comparing to the original FA+ and I- help release lattice stress so that the FAMACs SC shows lower ion migration, enhanced hardness, lower trap density, longer carrier lifetime and diffusion length, higher charge mobility and thermal stability, and better uniformity. Therefore, X-ray detectors made of the superior FAMACs SCs show the highest sensitivity of (3.5 ± 0.2) × 106 μC Gyair -1 cm-2 , about 29 times higher than the latest record of 1.22 × 105 μC Gyair -1 cm-2 for polycrystalline MAPbI3 wafer under the same 40 keV X-ray radiation. Furthermore, the FAMACs SC X-ray detector shows a low detection limit of 42 nGy s-1 , stable dark current, and photocurrent response. Finally, it is demonstrated that high contrast X-ray imaging is realized using the FAMACs SC detector. The effective triple-cation mixed halide strategy and the high crystalline quality make the present FAMACs SCs promising for next-generation X-ray imaging systems.

110 citations


Journal ArticleDOI
TL;DR: In this paper, three mononuclear metal complexes of the type ML, (M = Ni, Cu and Zn), with salen type tetradentate (ONNO) Schiff base, N,N′-bis(3,5-dibromosalicylidene)-1,3-diaminopropane (H2L), have been prepared and characterized using FT-IR, 1H NMR and elemental (CHN) analyses.

73 citations


Journal ArticleDOI
TL;DR: In this paper, the defect density of perovskite single crystals is reduced by using 3-propane-sulfonate inner salt (DPSI) ligands anchoring with lead ions.
Abstract: A low defect density in metal halide perovskite single crystals is critical to achieve high performance optoelectronic devices. Here we show the reduction of defect density in perovskite single crystals grown by a ligand-assisted solution process with 3‐(decyldimethylammonio)‐propane‐sulfonate inner salt (DPSI) as an additive. DPSI ligands anchoring with lead ions on perovskite crystal surfaces not only suppress nucleation in solution, but also regulate the addition of proper ions to the growing surface, which greatly enhances the crystal quality. The grown CH3NH3PbI3 crystals show better crystallinity and a 23-fold smaller trap density of 7 × 1010 cm−3 than the optimized control crystals. The enhanced material properties result in significantly suppressed ion migration and superior X-ray detection sensitivity of CH3NH3PbI3 detectors of (2.6 ± 0.4) × 106 µC Gy−1air cm−2 for 60 kVp X-ray and the lowest detectable dose rate reaches (5.0 ± 0.7) nGy s−1, which enables reduced radiation dose to patients in medical X-ray diagnostics. The performance of a metal halide perovskite single crystal is governed by the defect density. Here, the authors report a high quality single crystal perovskite grown by a ligand-assisted solution process with DPSI achieving 23-fold smaller trap density than that without DPSI.

71 citations


Journal ArticleDOI
09 Oct 2021
TL;DR: In this paper, the in situ-grown perovskitoid TEAPbI3 layer on 3D MAPbI-3-based solar cells can inhibit the methylammonium (MA+) migration in a polar solvent, thus enhancing the thermal and moisture stability of perovskiy films.
Abstract: The efficiency and stability of typical three-dimensional (3D) MAPbI3 perovskite-based solar cells are highly restricted, due to the weak interaction between methylammonium (MA+) and [PbI6]4-octahedra in the 3D structure, which can cause the ion migration and the related defects. Here, we found that the in situ-grown perovskitoid TEAPbI3 layer on 3D MAPbI3 can inhibit the MA+ migration in a polar solvent, thus enhancing the thermal and moisture stability of perovskite films. The crystal structure and orientation of TEAPbI3 are reported for the first time by single crystal and synchrotron radiation analysis. The ultra-thin perovskitoid layer can reduce the trap states and accelerate photo-carrier diffusion in perovskite solar cells, as confirmed by ultra-fast spectroscopy. The power conversion efficiency of TEAPbI3-MAPbI3 based solar cells increases from 18.87% to 21.79% with enhanced stability. This work suggests that passivation and stabilization by in situ-grown perovskitoid can be a promising strategy for efficient and stable perovskite solar cells.

69 citations


Journal ArticleDOI
TL;DR: In this article, a new zero-dimensional Mn-based hybrid metal halide of C4H14N2MnBr4 single crystals by using bi-amine group organic ions incorporation, which shows bright orange emission at room temperature.

65 citations


Journal ArticleDOI
TL;DR: In this article, the second harmonic generation circular dichroism (SHG-CD) was developed in bulk single crystals of chiral one-dimensional (1D) [(R/S)-3-aminopiperidine]PbI4.
Abstract: The introduction of chirality into organic-inorganic hybrid perovskites (OIHPs) is expected to achieve excellent photoelectric and nonlinear materials related to circular dichroism. Owing to the existence of asymmetric center and intrinsic chirality in the chiral OIHPs, the different efficiencies of second harmonic generation (SHG) signal occurs when the circularly polarized light (CPL) with different phases passes through the chiral crystal, which is defined as second harmonic generation circular dichroism (SHG-CD). Here, the SHG-CD effect is developed in bulk single crystals of chiral one-dimensional (1D) [(R/S)-3-aminopiperidine]PbI4 . It is the first time that CPL is distinguished using chirality-dependent SHG-CD effect in OIHPs bulk single crystals. Such SHG-CD technology extends the detection range to near infrared region (NIR). In this way, the anisotropy factor (gSHG-CD ) through SHG-CD signal is as high as 0.21.

65 citations


Journal ArticleDOI
TL;DR: Most efficient perovskite solar cells are based on polycrystalline thin films as mentioned in this paper, however, substantial structural disorder and defective grain boundaries place a limit on their performance.
Abstract: Most efficient perovskite solar cells are based on polycrystalline thin films; however, substantial structural disorder and defective grain boundaries place a limit on their performance. Perovskite...

59 citations


Journal ArticleDOI
TL;DR: This work creates well-defined surface by directly growing porous CeO2 single crystals at 2 cm scale and confining Pt in lattice to construct isolated Pt1/CeO2 sites at continuously-twisted surface in a monolith and demonstrates significantly enhanced activation of lattice oxygen linked to Pt ions in contrast to Ce ions in local structures.
Abstract: Activating lattice oxygen linked to active sites at surface remains a fundamental challenge in many catalytic reactions. Here we create well-defined surface by directly growing porous CeO2 single crystals at 2 cm scale and confining Pt in lattice to construct isolated Pt1 /CeO2 sites at a continuously twisted surface in a monolith. We demonstrate significantly enhanced activation of lattice oxygen linked to Pt ions in contrast to Ce ions in local structures. We show complete CO oxidation with air at 67 °C without degradation being observed after operation of 300 hours. The isolated Pt1 /CeO2 sites at twisted surfaces not only contribute to the chemisorption of CO but also effectively activate the lattice oxygen linked to Pt ion for CO oxidation. The current work would open a new route to activate lattice oxygen by incorporating well-defined active structures confined at the surfaces.

Journal ArticleDOI
TL;DR: In this paper, a novel zero-dimensional (0D) organic-inorganic hybrid single crystal (TMA)2SbCl5·DMF was reported, which exhibits typical self-trapped exciton (STE) emission with an efficient yellow emission at 630 nm and high photoluminescence quantum yield (PLQY) of 67.2%.
Abstract: Lead-free lower-dimensional organic-inorganic metal halide materials have recently triggered intense research because of their excellent photophysical properties and chemical stability. Herein, we report a novel zero-dimensional (0D) organic-inorganic hybrid single crystal (TMA)2SbCl5·DMF (TMA = N(CH3)3, DMF= HCON(CH3)2), which exhibits typical self-trapped exciton (STE) emission with an efficient yellow emission at 630 nm and high photoluminescence quantum yield (PLQY) of 67.2%. The dual STE emission is attributed to the singlet and triplet STEs in inorganic [SbCl5]2-, respectively. Further, an ab initio molecular dynamics simulation was performed to estimate the stability of crystal structure at room temperature. The calculated excited-state structure indicates that the deformation parameter (Δd) of the excited-state structure is larger than that of the ground state, illustrating the origin of a large Stokes shift. These results indicate that these new 0D lead-free organic-inorganic hybrid metal halides are promising luminescent materials for optoelectronic applications.

Journal ArticleDOI
30 Aug 2021
TL;DR: In this paper, the surface deformation structures of turbine blade root of single crystal nickel-based superalloy produced under different creep feed grinding conditions were investigated and clarified and composed of a severely deformed layer with nano-sized grains (48-67 nm) at the topmost surface, a DFL with submicron sized grains (66-158 nm) and micron-sized laminated structures at the subsurface, and a dislocation accumulated layer extending to the bulk material.
Abstract: The service performance of the turbine blade root of an aero-engine depends on the microstructures in its superficial layer. This work investigated the surface deformation structures of turbine blade root of single crystal nickel-based superalloy produced under different creep feed grinding conditions. Gradient microstructures in the superficial layer were clarified and composed of a severely deformed layer (DFL) with nano-sized grains (48–67 nm) at the topmost surface, a DFL with submicron-sized grains (66–158 nm) and micron-sized laminated structures at the subsurface, and a dislocation accumulated layer extending to the bulk material. The formation of such gradient microstructures was found to be related to the graded variations in the plastic strain and strain rate induced in the creep feed grinding process, which were as high as 6.67 and 8.17×107 s-1, respectively. In the current study, the evolution of surface gradient microstructures was essentially a transition process from a coarse single crystal to nano-sized grains and, simultaneously, from one orientation of a single crystal to random orientations of polycrystals, during which the dislocation slips dominated the creep feed grinding induced microstructure deformation of single crystal nickel-based superalloy.

Journal ArticleDOI
01 Apr 2021-Small
TL;DR: In this article, a single-crystal LiNi0.8 Co0.15 Al 0.05 O2 (SC-NCA) cathode is efficiently prepared by spray pyrolysis (SP) technique followed by a simple solid-state lithiation reaction.
Abstract: For conventional polycrystalline Ni-rich cathode material consisting of numerous primary particles in disordered orientation, the crystal anisotropy in charge/discharge process results in the poor rate capability and rapid capacity degradation. In this work, highly-dispersed submicron single-crystal LiNi0.8 Co0.15 Al0.05 O2 (SC-NCA) cathode is efficiently prepared by spray pyrolysis (SP) technique followed by a simple solid-state lithiation reaction. Porous Ni0.8 Co0.15 Al0.05 Ox precursor prepared via SP exhibits high chemical activity for lithiation reaction, enabling the fabrication of single-crystal cathode at a relatively low temperature. In this way, the contradiction between high crystallinity and cation disordering is well balanced. The resulted optimized SC-NCA shows polyhedral single-crystal morphology with moderate grain size (≈1 μm), which are beneficial to shortening the Li+ diffusion path and improving the structural stability. As cathode for lithium ion batteries, SC-NCA delivers a high discharge capacity of 202 and 140 mAh g-1 at 0.1 and 10 C, respectively, and maintains superior capacity retention of 161 mAh g-1 after 200 cycles at 1C. No micro-crack is observed in the cycled SC-NCA particles, indicating such single-crystal morphology can greatly relieve the anisotropic micro-strain. This effective, continuous and adaptable strategy for preparing single-crystal Ni-rich cathode without any additive may accelerate their practical application.

Journal ArticleDOI
TL;DR: In this article, the fabrication and characterization of 2D Ruddlesden-Popper perovskites (2D PVK) single crystal FETs are reported, which exhibit reliable field effect electrical characteristics at low temperatures.
Abstract: 2D Ruddlesden–Popper perovskites (2D PVKs) have attracted huge interest because of their excellent optoelectronic properties, yet the understanding of their electrical properties is inadequate due to the difficulties in obtaining 2D PVK field‐effect transistors (FETs) with decent performance. Herein, the fabrication and characterization of 2D PVK ((BA)2(MA)n−1PbnI3n+1) single crystal FETs are reported, which exhibit reliable field effect electrical characteristics at low temperatures. Kelvin probe force microscopy (KPFM) results reveal that both ion migration and contact resistance seriously degrade device performance. While ion migration can be suppressed at low temperatures, contact resistance seems to fundamentally determine device performance. On one hand, Schottky contacts are observed to form at the metal/2D PVK interface because of Fermi level pinning, resulting in significant charge injection resistance, although this can be remarkably improved by replacing Au electrodes with Ca. On the other hand, the out‐of‐plane mobility is found to be three orders of magnitude lower than the in‐plane mobility in 2D PVKs, causing large interlayer transport resistance. Thus, a low work‐function metal and a thin crystal are important for achieving high device performance. This work provides important experimental insights into fabrication and electrical properties of 2D PVK FETs.


Journal ArticleDOI
TL;DR: In this article, a polymer-controlled nucleation process was proposed for the growth of simple ternary, mixed-cations and mixed-halide perovskite single crystals.
Abstract: Recently, there are significant progresses in the growth of organic-inorganic lead halide perovskite single crystals, however, due to their susceptible nucleation and growth mechanisms and solvent requirements, the efficient and generalized growth for these single crystals is still challenging Here we report the work towards this target with a polymer-controlled nucleation process for the highly efficient growth of large-size high-quality simple ternary, mixed-cations and mixed-halide perovskite single crystals Among them, the carrier lifetime of FAPbBr3 single crystals is largely improved to 10199 ns Mixed MA/FAPbBr3 single crystals are synthesized The crucial point in this process is suggested to be an appropriate coordinative interaction between polymer oxygen groups and Pb2+, greatly decreasing the nuclei concentrations by as much as 4 orders of magnitudes This polymer-controlled route would help optimizing the solution-based OIHPs crystal growth and promoting applications of perovskite single crystals Research into single crystal organic-inorganic halide perovskites have gained momentum due to the potential applications, yet the growth is still a challenge Here, the authors demonstrate a universal method based on polymer controlled nucleation process to achieve large-size and high-quality perovskite single crystals

Journal ArticleDOI
TL;DR: A novel one-dimensional (1D) lead-free CsMnCl 3 (H 2 O) 2 single crystal is reported with solvatochromic photoluminescence properties that can expand potential applications for low-dimensional lead- free perovskites.
Abstract: The development of lead-free perovskite photoelectric materials has been an extensive focus in the recent years. Herein, a novel one-dimensional (1D) lead-free CsMnCl3 (H2 O)2 single crystal is reported with solvatochromic photoluminescence properties. Interestingly, after contact with N,N-dimethylacetamide (DMAC) or N,N-dimethylformamide (DMF), the crystal structure can transform from 1D CsMnCl3 (H2 O)2 to 0D Cs3 MnCl5 and finally transform into 0D Cs2 MnCl4 (H2 O)2 . The solvent-induced crystal-to-crystal phase transformations are accompanied by loss and regaining of water of crystallization, leading to the change of the coordination number of Mn2+ . Correspondingly, the luminescence changes from red to bright green and finally back to red emission. By fabricating a test-paper containing CsMnCl3 (H2 O)2 , DMAC and DMF can be detected quickly with a response time of less than one minute. These results can expand potential applications for low-dimensional lead-free perovskites.

Journal ArticleDOI
TL;DR: In this article, the authors describe a confinement of trace amount of Fe atoms (0.66 at. ‰) in Mo lattice, via a chemical vapor transport growth of MoS2 single crystal.
Abstract: In this study, we describe a confinement of trace amount of Fe atoms (0.66 at. ‰) in Mo lattice, via a chemical vapor transport growth of MoS2 single crystal. In the Fenton-like reaction for the degradation of atrazine, the Fe@MoS2 as catalyst to activate PMS could produce more reactive oxygen species and exhibit a rate constant (1.30 min−1) three times higher than that of pristine MoS2 (0.43 min−1). Theoretical simulation suggests that the diluted confinement of Fe atoms in Mo sites activates the inert basal plane of MoS2, creating new active sites of Mo both nearby the Fe site and afar, for the adsorption and decomposition of PMS. Our work provides a clear atomic mechanism of the improvement of the chemical reactivity of MoS2 single crystal in Fenton-like reaction via heteroatom confinement.

Journal ArticleDOI
TL;DR: In this article, a single-crystal LiNi0.83Co0.12Mn0.05O2 cathode material, which can deliver a high specific capacity (∼209 mAh g-1 at 0.1 C, 2.8-4.3 V) and meanwhile display excellent cycling stability.
Abstract: The capacity degredation in layered Ni-rich LiNixCoyMnzO2 (x ≥ 0.8) cathode largely originated from drastic surface reactions and intergranular cracks in polycrystalline particles. Herein, we report a highly stable single-crystal LiNi0.83Co0.12Mn0.05O2 cathode material, which can deliver a high specific capacity (∼209 mAh g-1 at 0.1 C, 2.8-4.3 V) and meanwhile display excellent cycling stability (>96% retention for 100 cycles and >93% for 200 cycles). By a combination of in situ X-ray diffraction and in situ pair distribution function analysis, an intermediate monoclinic distortion and irregular H3 stack are revealed in the single crystals upon charging-discharging processes. These structural changes might be driven by unique Li-intercalation kinetics in single crystals, which enables an additional strain buffer to reduce the cracks and thereby ensure the high cycling stability.

Journal ArticleDOI
TL;DR: In this article, the Gaussian process regression model was used to predict lattice misfits for Ni-based single crystal superalloys based on chemical composition, temperature, and two morphological indicators.
Abstract: Ni-based single crystal superalloys exhibit superb mechanical strength, particularly, creep resistance at elevated temperature. The unique microstructure, which is consisted of $$\gamma$$ and $$\gamma ^{\prime }$$ phases, is a major factor that determines the mechanical behavior of these alloys. The lattice misfit between the two phases is of particular interest in understanding and predicting the deformation mechanism. The measurement of the lattice misfit by advanced analytical instruments is costly and difficult. In current study, we develop the Gaussian process regression model to predict lattice misfits for Ni-based single crystal superalloys based on chemical composition, temperature, and two morphological indicators. The model is highly stable and accurate and promising as a fast, robust, and low-cost tool for lattice misfit estimations.

Journal ArticleDOI
TL;DR: In this paper, the synthesis and physical analysis of vanillin isonicotinic hydrazide (VINH), an organic single crystal, produced by the method of slow evaporation at room temperature, is presented.

Journal ArticleDOI
TL;DR: In this paper, a review of the literature on oriented attachment in colloidal suspensions is presented, where the authors discuss the reasons for their thermodynamic (meta)stability and how this stability can be lowered such that oriented attachment can occur as a spontaneous thermodynamic process.
Abstract: ConspectusIntuitively, chemists see crystals grow atom-by-atom or molecule-by-molecule, very much like a mason builds a wall, brick by brick. It is much more difficult to grasp that small crystals can meet each other in a liquid or at an interface, start to align their crystal lattices and then grow together to form one single crystal. In analogy, that looks more like prefab building. Yet, this is what happens in many occasions and can, with reason, be considered as an alternative mechanism of crystal growth. Oriented attachment is the process in which crystalline colloidal particles align their atomic lattices and grow together into a single crystal. Hence, two aligned crystals become one larger crystal by epitaxy of two specific facets, one of each crystal. If we simply consider the system of two crystals, the unifying attachment reduces the surface energy and results in an overall lower (free) energy of the system. Oriented attachment often occurs with massive numbers of crystals dispersed in a liquid phase, a sol or crystal suspension. In that case, oriented attachment lowers the total free energy of the crystal suspension, predominantly by removal of the nanocrystal/liquid interface area. Accordingly, we should start by considering colloidal suspensions with crystals as the dispersed phase, i.e., "sols", and discuss the reasons for their thermodynamic (meta)stability and how this stability can be lowered such that oriented attachment can occur as a spontaneous thermodynamic process. Oriented attachment is a process observed both for charge-stabilized crystals in polar solvents and for ligand capped nanocrystal suspensions in nonpolar solvents. In this last system different facets can develop a very different reactivity for oriented attachment. Due to this facet selectivity, crystalline structures with very specific geometries can be grown in one, two, or three dimensions; controlled oriented attachment suddenly becomes a tool for material scientists to grow architectures that cannot be reached by any other means. We will review the work performed with PbSe and CdSe nanocrystals. The entire process, i.e., the assembly of nanocrystals, atomic alignment, and unification by attachment, is a very complex and intriguing process. Researchers have succeeded in monitoring these different steps with in situ wave scattering methods and real-space (S)TEM studies. At the same time coarse-grained molecular dynamics simulations have been used to further study the forces involved in self-assembly and attachment at an interface. We will briefly come back to some of these results in the last sections of this review.

Journal ArticleDOI
TL;DR: In this article, (C4H9)4NCuCl2 single crystals with a luminous intensity that remains largely the same after soaking in water for 24 hours were reported, which provides a new idea for the design of lead-free anti-water stability metal halide materials.
Abstract: Here, we report (C4H9)4NCuCl2 single crystals with a luminous intensity that remains largely the same after soaking in water for 24 h. (CH9)4NCuCl2 has a new type zero-dimensional framework, in which the isolated [CuCl2]- anions are wrapped by organic (C4H9)4N+ cations. As expected, (C4H9)4NCuCl2 shows a broad emission band at 508 nm with a photoluminescence quantum yield of approximately 82% at room temperature, stemming from self-trapped exciton (STE) emission. Temperature-dependent photoluminescence measurement reveals that there is an energy barrier ΔE (24.0 meV) between the intrinsic state and STE state, which leads to the increase in emission intensity with an increase in temperature (98-278 K), while the emission intensity begins to decrease when the temperature is higher than 278 K due to the effects of both thermal quenching and carrier scattering. Our findings provide a new idea for the design of lead-free anti-water stability metal halide materials.

Journal ArticleDOI
TL;DR: In this paper, the 3-chloro-2,6-bis (4-chlorophenyl)-3-methylpiperidin-4-one (CCMP) compound has been characterized by FT-IR, 1H-NMR, 13C-NMRI and single-crystal X-ray diffraction and the optimized geometric parameters and frequency values were theoretically calculated using DFT/B3LYP method with B3lyP/6-31+G(d,p) basis set.
Abstract: The 3-chloro-2,6-bis(4-chlorophenyl)-3-methylpiperidin-4-one (CCMP) compound have been characterized by FT-IR, 1H-NMR, 13C-NMR, 1H-1H NOESY spectroscopy and single-crystal X-ray diffraction. The title compound crystallizes in the orthorhombic space group Pna21. The single crystal measurements reveal a distorted chair conformation [puckering parameter Q = 0.557 (3) A°; θ = 167.8 (3)° and Ψ = 206.8 (13)°]. The optimized geometric parameters and frequency values were theoretically calculated using DFT/B3LYP method with B3LYP/6–31+G(d,p) basis set. The XRD single crystal measurement parameters are good agreed with the optimized parameters. The spectral and optimized parameters showed that the piperidine-4-one ring adopts normal chair conformation with equatorial orientations of all the substituents except chlorine. The frontier molecular orbitals HOMO and LUMO were computed to know the chemical reactivity and kinetic stability of the molecular compound. Hirshfeld surface analysis was also performed. Hirshfeld surface analysis (dnorm surface, two-dimensional fingerprint plots and molecular electrostatic potantials) revealed the nature of intermolecular interactions. The most important contributions for the crystal packing are from H···H (35%), Cl···H/H···Cl (32.3%), C···H/H···C (15%) and O···H/H···O (7.5%) interactions. In this study, spectroscopic properties of a new piperidine-4-one crystal compound and it’s DFT structural investigation compared with experimental were gained to literature.



Journal ArticleDOI
TL;DR: In this article, the properties of 3-amino-7,7′-azo-[1,2,4] triazolo[4,3-b][1, 2,4]-triazole and 3-6-diamino-6,7-′-ado]-1.2-n=n-N-N triazole were determined by single crystal X-ray diffraction.

Journal ArticleDOI
19 Mar 2021-Small
TL;DR: This study provides a strategy for the controllable synthesis of structurally defined Cu NCs with NIR luminescence, which enables essential insights into the origins of their optical properties.
Abstract: Due to their atomically precise structure, photoluminescent copper nanoclusters (Cu NCs) have emerged as promising materials in both fundamental studies and technological applications, such as bio-imaging, cell labeling, phototherapy, and photo-activated catalysis. In this work, a facile strategy is reported for the synthesis of a novel Cu NCs coprotected by thiolate and phosphine ligands, formulated as [Cu15 (PPh3 )6 (PET)13 ]2+ , which exhibits bright emission in the near-infrared (NIR) region (≈720 nm) and crystallization-induced emission enhancement (CIEE) phenomenon. Single crystal X-ray crystallography shows that the NC possesses an extraordinary distorted trigonal antiprismatic Cu6 core and a, unique among metal clusters, "tri-blade fan"-like structure. An in-depth structural investigation of the ligand shell combined with density functional theory calculations reveal that the extended CH···π and π-π intermolecular ligand interactions significantly restrict the intramolecular rotations and vibrations and, thus, are a major reason for the CIEE phenomena. This study provides a strategy for the controllable synthesis of structurally defined Cu NCs with NIR luminescence, which enables essential insights into the origins of their optical properties.

Journal ArticleDOI
TL;DR: In this article, high-power pulsed laser experiments were conducted on single, poly-, and nanocrystalline iron, generating tensile pulses with strain rates approaching the Debye frequency.