Organic Single Crystals Research Articles

Purely organic 4HCB single crystals exhibiting high hole mobility for direct detection of ultralow-dose X-radiation

Purely organic 4HCB single crystals show a capability of directly detecting 241Am 5.49 MeV α particles and X-ray imaging under low-dose rate (below 50 μGyair s−1) exposure conditions.

Molecular doped organic semiconductor crystals for optoelectronic device applications

In this review, we give a timely summary of the current progress of molecular doped organic semiconductor single crystals in terms of material selection, crystal growth, resulting properties and device applications.

Investigation of third-order nonlinear optical semi organic potassium bromide malate single crystals for optoelectronic applications

L-Malic acid potassium bromide MAPB, a new semi organic material was synthesized successfully by solution growth method. Single crystal x-ray diffraction analysis reveals the cell parameters of the grown crystal and it crystallized in cubic system. The molecular structure of MAPB was identified by FTIR spectral analysis. The lower cut-off wavelength (λ = 272 nm), optical energy band gap (5049 eV) and Urbach energy (0.2381 eV) of MAPB crystal was determined by using UV–Vis-NIR spectral studies. The single electronic transitional band structure of the material was identified by photoluminescence spectrum. The various morphological formations on the grown crystal were analyzed by scanning electron microscope (SEM) study. The second order nonlinear optical properties of grown MAPB were measured by Kurtz and Perry powder technique. The thermal stability of MAPB crystal was studied by differential scanning calorimetric technique. The relative dielectric property was rigorously analyzed with various temperature ranges. Vickers micro hardness test suggest that the material belongs to soft material category. Z-scan study was employed to analyze the third order non-linear optical characteristics like refractive index (n2), the absorption coefficient (β) and third order susceptibility (χ3).

A study on the effects of mixed organic cations on the structure and properties in lead halide perovskites.

Recently, organic-lead halide perovskites have emerged as strong competitors in photovoltaic and general optoelectronic applications owing to their remarkable characteristics, including high balance hole and electron mobility, strong absorption coefficient and long carrier lifetime. However, the commercial applicability of these materials is hampered by their relative lack of stability compared to established inorganic and organic semiconductors. It has been found that it is possible to tune the properties and stability of the organic-lead halide perovskite materials by site-substitution at A sites of the ABX3 perovskite structure. Here, organic cations (NH4+, HC (NH2)2+, and CH3CH2NH3+) were successfully incorporated in the methylammonium-based perovskite crystal to investigate the role of organic cation size on structure, optical features, thermal stability, and electrical transport properties. Powder X-ray diffraction results indicate that the size of organic cations can not only cause lattice strain by lattice contraction or dilation but also may induce phase transitions by octahedral tilting. Meanwhile, band gaps of these crystals show that organic cations could tune the band gap energy of the perovskites by changing the Pb-I bond angle, which agrees with previous reports. The result of thermogravimetric analysis indicates that thermal stability is related to the probability of HI formation, which is directly related to the acidity of the organic species. These results represent an important step to highlight the role of organic cations in hybrid perovskite materials, which will further benefit the fundamental understanding of materials and device optimization.

Photoelectron spectroscopy on single crystals of organic semiconductors: experimental electronic band structure for optoelectronic properties

Methodologies and experimental achievements for exploration into electronic band structures of organic semiconductor and hybrid perovskite single crystals are reviewed.

Preparation of highly oriented single crystal arrays of C8-BTBT by epitaxial growth on oriented isotactic polypropylene

Device arrays are fabricated with organic single crystals epitaxially grown on highly oriented iPP films by solvent vapor annealing.

Unidirectional growth of organic single crystals of naphthalene, anthracene and pyrene by isothermal expansion of supercritical CO2.

Unidirectional single crystals without grain boundaries are highly important in optoelectronic applications. Conventional methods to obtain such crystals involve organic solvents or seed crystals, which have numerous drawbacks. We present here a supercritical CO2-mediated method of the single crystal formation of naphthalene, anthracene and pyrene on the (001) plane without using seed crystals. Single dominant peaks in powder XRD (PXRD) with low full width at half maxima (FWHM) are described. The dependency of crystal size on the rate of depressurization was measured by precise and isothermal expansion of scCO2 solutions. The experimental setup is illustrated for continuous preparation without emission of CO2 or discharge of material into the environment. The materials are shown to be fully converted into crystals indicating a rapid, scalable and environmentally benign process of single crystal formation with practically nil E factor.

Synthesis, Thermal and Antimicrobial Activity of Novel Organic Single Crystal of (E)-4-Bromo-2-[(phenylimino)methyl]phenol compound

This study focused on kinetic modelling of a specific type of multistep heterogeneous reaction comprising exothermic and endothermic reaction steps, as exemplified by the experimental kinetic curves for the thermal decomposition of (E)-4-Bromo-2-[(phenylimino)methyl]- phenol (4B2PMP) crystal. The crystal was grown by a slow evaporation method. The cell parameters and crystalline perfection of the grown crystal were studied by single and powder X-ray diffractions. Thermal stability and phase change of 4B2PMP crystal were analyzed by TG/DTA. The microhardness study has revealed the soft nature. UV-visible analysis reveals the wide range of optical window of the optical transmission from 199 nm to 1100 nm. The bandgap of the crystal is found to be 3.24 eV. The FESEM of the crystals was spherically shaped and consisted of a core-shell structure with internal aggregates. The antimicrobial activity of title crystal was tested against different microorganisms by disc diffusion method. The results reveal that the title compound have effective antimicrobial activities.

Organic single crystals of cyano-substituted p-phenylene vinylene derivatives as transistors with low surface trap density.

We obtained two high-quality lamellar crystals of cayno-substituted p-phenylene vinylene derivatives and fabricated their transistors. The transistors demonstrated hysteresis-free, low subthreshold swing values of 0.15 and 0.10 V dec-1, and high mobilities of 0.56 and 2.73 cm2 V-1 s-1, respectively. More importantly, the low defect density of 1 per 9.22 × 103 and 1.82 × 104 molecules, respectively, confirmed their high crystal quality.

Synthesis, Characterization, Thermal, NLO and Quantum-Chemical Studies on N-Acetyl-2,6-bis(4-methoxyphenyl)-3-ethylpiperidin-4-one

Growth of a new organic single crystal of N-acetyl-2,6-bis(4-methoxyphenyl)piperidin-4-one (APM3EPO) is reported by using a slow evaporation method. The characterization of the crystal was done by IR and NMR spectra. Further, electronic spectrum and TG/DTA studies have also been carried out. The SHG efficiency of the crystal was found to be closer to that of standard KDP (potassium dihydrogen orthophosphate) using the modified Kurtz-Perry powder test employing Nd: YAG laser as the source of IR radiation. The calculated hyperpolarizability values were also projected to confirm the aptness of the crystal for non-linear optical applications. Optimization of the molecular structure of APM3EPO is done at the basic level of B3LYP/6-311(d,p) and the corresponding molecular properties such as HOMO-LOMO and Mulliken charge analyses are carried out at the same level of theory.

Investigation on structural, optical, thermal and mechanical properties of 1, 3-dinitrobenzene (1,3-DNB) single crystal

An organic 1,3-Dinitrobenzene (1,3-DNB) single crystal have been grown by Bridgman-Stockbarger method and their structural, optical, thermal and mechanical properties were analyzsed by employing powder-XRD, FTIR, optical absorption, transmission, photoluminescence, TG-DTA, microhardness and SHG measurements. The obtained results explore the well suitable nature of the grown crystal for the NLO and optolectronic applications. The crystalline nature and structural properties of the material has been confirmed by using powder X-ray diffraction (PXRD) analysis. FTIR spectral study reveals the presence of fundamental stretching and bending mode vibrations of grown 1,3-DNB crystal. Linear optical properties of the grown organic single crystal have been studied by using UV–Vis–NIR spectrum analysis, which exhibit the cut-off wavelength at 431 nm. From the tauc’s plot, the calculated optical band gap energy value is 2.78 eV. The photoluminescence spectrum compresses three emission bands in the region centered at 388 nm, 452 nm and 569 nm and it is characterized through the CIE 1931 chromaticity diagram to observe the dominant emission color of the studied crystal. Thermal stability and melting point of the grown single crystal was carried out through the TG-DTA analysis. The microhardness test explores the mechanical strength of the titular crystal. Nonlinear optical efficiency of grown 1,3-DNB crystal was found to be 1.75 times greater than that of standard KDP crystal. In addition, theoretical studies of polarizability and hyperpolarizability, HOMO-LUMO energy gap and electrostatic potential (ESP) were also performed. Hirshfeld surface and two dimensional (2D) fingerprint plots were analyzsed from the crystal explorer 3.1 software and the results are discussed in detail.

Chemoselective synthesis, X-ray characterization and DFT studies of new organic single crystal: S-(2-aminophenyl) cyclohexylcarbamothioate

Chemoselective manner of 2-aminothiophenol reaction with cyclohexyl isocyanate under the different conditions was investigated. The product, S-(2-aminophenyl) cyclohexylcarbamothioate, was characterized by 1H, 13C NMR, FT-IR, HRMS and single crystal X-ray diffraction analysis. Single crystal of the molecular structure, C13H18N2OS, crystallizes in monoclinic form, space group P 21/n with a = 6.1808(4) Å, b = 24.8308(12) Å, c = 9.7080(8) Å, β = 103.674(6)°, V = 1303.73(13) Å3, F (000) = 36. The structure exhibits disorder over the phenyl ring, with site occupancies of 0.913(4) and 0.087(4) for the major and minor components, respectively. The conformation is stabilized by intra- and intermolecular N–H. O, N–H. N, and C– H. S hydrogen bonds into running along the a-axis. The title compound has been optimized by DFT/B3LYP/6-31 + G (d, p) basis set, and compared with experimental findings. Natural bond orbital charges of probable intramolecular hydrogen bonds have been calculated to compare with experimental data, and frontier orbital analysis and molecular electrostatic potential (MEP) analysis were also carried out.

Synthesis, physicochemical properties and third-order optical nonlinearities of cadmium (II) dibromide l - Proline monohydrate for optical limiting application

Metal-semi organic NLO single crystal of Cadmium (II) dibromide l - Proline monohydrate (CBLPM) has been synthesized and the crystal was grown from solution by room temperature slow evaporation method. The crystal structure and cell parameters were refined by Rietveld refinement technique and confirmed that the metal-semi organic samples are in the orthorhombic system with space group P212121. The crystal structure of CBLPM is stabilized by intermolecular N–H…O, N–H….Br, O–H….O and O–H….Br hydrogen bonds. The water molecules serve as donors for the weak O–H⋯O and O–H⋯Br hydrogen bonds which link adjacent chains forming a three-dimensional structure. A Hirshfeld surface analysis suggests that the most significant contribution to the crystal packing is by H⋯Br contacts (26.2%). The complete vibrational features and electronic absorption spectra of the title compound were analyzed by FT-IR, FT-Raman and UV–visible spectra combined with density functional theory and time-dependent density functional computations. The second-order hyperpolarizability value of the molecule was also calculated at density functional theory method. The third-order nonlinear optical properties of the crystal were studied by Z-scan techniques using CW laser with wavelength 532 nm. The open aperture result exhibits the saturation absorption, which indicates that this material has potential candidate for optical limiting applications.

Crystal structure, DFT and third order non-linear optical studies of an organic bisguanidinium isophthalate monohydrate single crystal

A conventionally grown organic nonlinear optical crystal bisguanidinium isophthalate monohydrate was structurally investigated using single crystal X-ray diffraction study. The lattice constants, supramolecular arrangements and the hydrogen bond formation of the title compound confirm the formation of novel organic crystalline material. The various functional groups present in the crystalline material were resoluted by employing FT-IR spectral analysis. The wide-range optical transparency of the compound in the entire visible region ensures the optical quality with a lower cut-off wavelength at 298 nm was analysed experimentally using UV–vis–NIR spectrometer. The support of DFT was scrutinized to report the optimized structure, electronic state properties, hyper-conjugative interactions and frontier molecular energy gap of the bisguanidinium isophthalate compound. The charge transfer mechanism of bisguanidinium isophthalate compound from isophthalic acid to guanidine compound was also interpreted using theoretical DFT. The computational evaluation of charge stabilities as a result of charge delocalization was construed with the ratification of natural bonding orbital (NBO). The assessed thermal stability of bisguanidinium isophthalate crystal is 120 °C which was analysed by thermogravimetric and differential thermal analyses. To determine the third-order nonlinear optical property with quantitative results of nonlinear refractive index, nonlinear absorption coefficient and optical susceptibility was ascertained using Z-scan technique.

The Emergence of Organic Single-Crystal Electronics.

Organic semiconducting single crystals are perfect for both fundamental and application-oriented research due to the advantages of free grain boundaries, few defects, and minimal traps and impurities, as well as their low-temperature processability, high flexibility, and low cost. Carrier mobilities of greater than 10 cm2 V-1 s-1 in some organic single crystals indicate a promising application in electronic devices. The progress made, including the molecular structures and fabrication technologies of organic single crystals, is introduced and organic single-crystal electronic devices, including field-effect transistors, phototransistors, p-n heterojunctions, and circuits, are summarized. Organic two-dimensional single crystals, cocrystals, and large single crystals, together with some potential applications, are introduced. A state-of-the-art overview of organic single-crystal electronics, with their challenges and prospects, is also provided.

An Organic Crystal with High Elasticity at an Ultra-Low Temperature (77 K) and Shapeability at High Temperatures.

Organic single crystals with elastic bending capability and potential applications in flexible devices and sensors have been elucidated. Exploring the temperature compatibility of elasticity is essential for defining application boundaries of elastic materials. However, related studies have rarely been reported for elastic organic crystals. Now, an organic crystal displays elasticity even in liquid nitrogen (77 K). The elasticity can be maintained below ca. 150 °C. At higher temperatures, the heat setting property enables us to make various shapes of crystalline fibers based on this single kind of crystal. Through detailed crystallographic analyses and contrast experiments, the mechanisms behind the unusual low-temperature elasticity and high-temperature heat setting are disclosed.

Synthesis, structural, growth, optical, electrical, thermal and third order nonlinear optical properties of a novel organic single crystal: p -Toluidinium malonate

Abstract Novel organic nonlinear optical material; p-Toluidinium malonate (PTM) was grown from aqueous solution by slow evaporation technique. The lattice parameters were evaluated from single crystal X-ray diffraction analysis and found that crystal system belongs to monoclinic with centrosymmetric space group P21/c. The solid state parameters; valence electrons, Plasma energy, Penn gap and Fermi energy were evaluated theoretically. These estimated values are used to calculate the electronic polarizability of PTM crystal. The functional groups exist in the compound were identified using FT-IR and FT-RAMAN spectroscopy. PTM crystal showed transmittance in the entire visible region with lower cut off wavelength of 311 nm and band gap energy of 3.8 eV. The photoluminescence spectrum was recorded to explore the emission and thermal behaviour of PTM crystal by employing TG/DTA analysis. Dielectric measurement was carried out on the grown crystal at different temperatures to evaluate electrical properties. The third-order nonlinear optical parameters were estimated by Z-scan technique using 532 nm diode pumped CW Nd:YAG Laser.

High-Performance Ambipolar Organic Phototransistors Based on Core–Shell p–n Junction Organic Single Crystals

Electronic devices based on organic single-crystal semiconductors have been used in a range of applications, suggesting their possible use as core components of high-performance electronic devices. Various electronic devices based on unipolar organic semiconducting crystals have high electrical and optoelectronic properties compared to thin-film-based devices due to the intrinsic nature of the single crystal, such as a long-range order and a high degree of structural perfection. However, only a few studies have examined electronic devices using organic single crystals with ambipolar characteristics. This study investigated the electrical and optoelectronic characteristics of a core–shell organic semiconducting crystal composed of an n-type single-crystal nanowire as the core and p-type single crystal as the shell. The device showed ambipolar behavior with balanced electron and hole mobilities (maximum electron and hole mobility of the core–shell ambipolar crystal; 1.41 × 10–1 and 8.31 × 10–2 cm2 V–1 s–1, ...

Defect states of organic lead halide single crystals grown by inverse-temperature crystallization

We investigated the defect states of organic lead halide (CH3NH3PbX3: CH3NH3+) methylammonium (MA; X = Br− and I−) by using optical pulse-induced conductance transient spectroscopy. Organic lead halide single crystals having a bandgap ranging from 2.16 to 1.45 eV were grown by inverse temperature crystallization. The shallow trap energy level of MAPbBr2.5I0.5 was Ev + 0.06 eV. The deep level traps of MAPbBr3 and MAPbI3 were Ev + 1.24 and Ev + 0.84 eV, respectively. The deep level traps of organic lead halide may have decreased the reactivity between iodide and bromide ions in the crystal lattice. Varying the ratio of halides in the perovskite can change the defect species in the crystals and can increase the photoconversion efficiency by decreasing the density of deep level traps.

Growth of 4-N,N-Dimethylamino-4'-N'-methyl-stilbazolium Tosylate (DAST) Organic Single Crystals Controlled by Oleic Acid

4-N,N-Dimethylamino-4'-N'-methyl-stilbazolium Tosylate (DAST) organic single crystals controlled by (Z)-Octadec-9-enoic acid (oleic acid, OA) was grown by a slow-cooling method. The as-grown DAST single crystals were systematically characterized by FTIR, X-ray diffraction, second harmonic generation, and UV-vis spectroscopy. Results indicate that addition of OA into the DAST solutions leads to the controlled growth of DAST single crystals and consequently, the crystal quality and optical properties can be modified. Particularly, the DAST crystals grown under the control of OA exhibit larger sizes, higher crystallinities, and better optical qualities with higher optical band gaps and lower defect density, compared with those grown in the absence of OA. These results are helpful for better understanding the controlled growth of DAST organic single crystals and modifying their properties for practical applications.