Organic Single Crystals Research Articles

Synthesis, crystal growth, structure, crystalline perfection, thermal, linear, and nonlinear optical investigations on 2-amino-5-nitropyridine 4-chlorobenzoic acid (1:1): a novel organic single crystal for NLO and optical limiting applications

Synthesis, crystal growth, structure, crystalline perfection, thermal, linear, and nonlinear optical investigations on 2-amino-5-nitropyridine 4-chlorobenzoic acid (1:1): a novel organic single crystal for NLO and optical limiting applications

Enhanced performance of white organic light-emitting devices based on ambipolar white organic single crystals

Organic single crystals are highly promising for applications in optoelectronic devices because of their higher mobility and thermal stability than amorphous thin films. Although white organic single crystals have been fabricated by the double-doped method and applied to realize white organic light-emitting devices (WOLEDs), the unbalanced carrier transport properties of the unipolar crystals severely limit the device performance. Here, ambipolar white organic single crystals are obtained by using mixed p- and n-type molecules as an ambipolar host for the red and green dopants. The white crystal with balanced carrier transport and balanced blue, green, and red emission intensity was applied to the single-crystal WOLEDs. The highest brightness of 1956 cd m−2 and the current efficiency of 1.31 cd A−1 are achieved, which are the best performance of the single-crystal WOLEDs reported to date. A high color rendering index is obtained, which varies between 82 and 87 with increasing driving current. It is expectable that this strategy would support the practical applications of organic single crystal-based OLEDs.

Investigation on the growth, structural, optical, thermal and third-order nonlinear optical (NLO) properties of 2,3-dimethyl-N-[(E)-2,4,5-trimethoxybenzylidene] aniline (DTA) organic single crystal

Good-quality organic nonlinear single crystal of 2,3-dimethyl-N-[(E)-2,4,5-trimethoxy benzylidene] aniline (DTA) was synthesized and successfully grown at room temperature by adapting slow evaporation technique using mixed solvent of acetone and methanol. The crystal structure was experimentally confirmed by single-crystal X-ray diffraction, where the DTA crystals crystallize in the centric space group (P $$\overline{1}$$ ) with triclinic crystal system. The surface morphology of DTA was examined by the Field Emission Scanning Electron Microscope (FE-SEM) technique. The presence of various modes of functional groups of the title crystal was analyzed by Fourier-Transform Infra-Red (FT-IR) spectra. Ultraviolet–Visible-Near Infrared (UV–Vis–NIR) spectrum showed high optical transparency of ~ 88% in the Vis and NIR region with a UV–Vis absorption edge of 390 nm. The result of photoluminescence studies suggests that the DTA crystal can be used as source material to exhibit green emission light. From thermogravimetric-differential scanning calorimetry (TG-DSC) analysis, the melting point of the grown crystal was found to be 111 °C. The standard Z-Scan technique was employed to evaluate the third-order nonlinear optical properties of the DTA crystal. The obtained third-order nonlinear parameters were compared with few of the already reported NLO crystals. All these findings indicate that the title crystal may be an attractive material for nonlinear optical device applications.

Lamellar Organic Light-Emitting Crystals Exhibiting Spectral Gain and 3.6% External Quantum Efficiency in Transistors

We report an organic lamellar single crystal as a versatile optoelectronic material in optical pumping and light-emitting transistors. The styrene derivative crystals with intrinsically ordered stacking structures, low impurities, and high photoluminescence efficiency offer a low threshold energy of 21 μJ cm–2 for amplified spontaneous emission and extraordinary device performance in terms of a striking external quantum efficiency of 3.63%, far exceeding the benchmark value in this field.

Investigation of structural, mechanical, optical, thermal and in vitro antimicrobial study of l-phenylalaninium formate single crystals

In this investigation, an organic single crystal of l-phenylalaninium formate (LPAF) has been successfully synthesized and grown by slow evaporation technique at ambient temperature using double distilled water as a solvent and their physiochemical and antimicrobial activities were tested. Single crystal X-ray diffraction studies indicate that LPAF belongs to orthorhombic configuration. The interaction of characteristic functional groups was confirmed by FTIR spectra. Mechanical behavior has been assessed by employing Vickers microhardness test. The results explored that the synthesized crystal exhibited reverse indentation size effect and belonged to the category of soft materials. UV–visible spectral analysis of the title compound shows 85% of transmittance with lower cut-off wavelength at 220 nm and the linear refractive index of the material was found to be 1.59. The photoluminescence spectrum of LPAF reveals that the emission of light occurs at 490 nm and it can be used as a material for blue lightening. The thermal tolerance and decomposition mechanism of the synthesized compound was examined by simultaneous TG-DTG-DSC analysis, which showed that material is thermally stable up to 205 °C and the melting point was observed to be 226.17 °C. The morphology of the synthesized crystal was analyzed by HR-TEM with SAED analysis and the result shows that the grown LPAF crystal is of good crystallinity. The antimicrobial activity of the grown crystal was evaluated against Gram-negative and Gram-positive bacteria as well as fungal pathogens by Agar disk diffusion method. The results established that the newly synthesized compound has a dual antibacterial and antifungal activity. Besides that LPAF showed powerful antibacterial activity against Gram-negative bacterium Pseudomonas aeruginosa and antifungal activity against a Gram-positive fungal Aspergillus flavus with zone of inhibition of 21 mm and 14 mm, respectively. These results signify that LPAF is a potential candidate for biomedical, photonic, and optical applications.

Bulk growth of Iminodiacetic acid single crystal and its characterization for nonlinear optical applications

A bulk size transparent nonlinear organic single crystal of Iminodiacetic acid was harvested using slow evaporation solution growth technique in controlled atmosphere with a span of 4 weeks. The structural properties of titled crystal were examined by single-crystal X-ray diffraction. The quality of the ingot was determined by high-resolution X-ray diffraction and found that the sample is free from grain boundaries. From UV–Vis analysis, one can understand that there is less absorption in the entire wavelength range of visible region and observed cut-off wavelength is 242 nm. From photoluminescence analysis, the emission of wavelength is identified at 421 nm. Mechanical strength and various parameters like work-hardening coefficient and stiffness constant of ingot was measured using Vickers microhardness test and corresponding experimental data had been explained using distinct theoretical models. The variation measurement of dielectric constant and dielectric loss in respect of frequency was carried out to compute the electronic polarizability of titled compound using Penn model. The detailed analysis of third-harmonic generation was executed using Z-scan method. The values of nonlinear refractive index (n2) and two photon absorption coefficient (β) were obtained to be 2.19 × 10−17 cm2 W−1 and 4.25 × 10−12 cm W−1, respectively. The higher value of coupling factor suggests nonlinear absorption is more dominant and the crystal is suitable for optical limiting application.

Synthesis, growth, optical studies and antimicrobial activity of a new semiorganic nonlinear optical crystal L-valine bariumchloride

A semi organic nonlinear optical single crystal of L-valine barium chloride was grown from an aqueous solution by the method of slow evaporation technique at room temperature. The grown crystal was characterized by powder X- ray diffraction confirms the presence of chloride. Single crystal X-ray diffraction studies confirm that the grown crystal belongs to the monoclinic system. The functional groups presented in the crystal were confirmed by FT-IR technique. The UV–vis-NIR spectrum indicates that the crystal has very good absorption in the entire visible and NIR region spectrum indicating the stability of the materials for NLO applications. The grown crystal was subjected to EDX to confirm the presence of the elements. The crystal was stable up to 260⁰C and fully decomposed at 907⁰C. Hence the thermal behaviour and the stability of crystal were studied by TGA, DTA and DSC. The second harmonic generation SHG efficiency was studied by Kurtz-Perry powder technique. The minimum inhibitory concentration (MIC) of the crystal for antibacterial activity was studied using micro dilution bioassay as described by ELOFF.

Experimental and theoretical investigations of organic creatininium 2-chloroacetate nonlinear optical single crystal

The main aim of this work is to synthesize creatininium 2-chloroacetate (CR2ClA) single crystal by using slow evaporation technique and to analyze its structural, optical and mechanical properties with the aid of experimental and theoretical techniques. The Single Crystal X-ray Diffraction analysis (SXRD) is carried out to identify the structural parameters. Hirshfield surface analysis explains the interactions present in the synthesized material. The optical property has been examined by using UV–visible spectral analysis and the optical constants such as band gap energy, extinction coefficient and refractive index were evaluated. HOMO–LUMO and MESP maps were successfully generated and analysed. The emission behavior was analysed by fluorescence spectral analysis. Third order optical non linearity was confirmed by Z scan analysis and the theoretical nonlinear optical parameters are calculated and analysed. The optical limiting behaviour and laser damage threshold analysis explains the synthesized materials laser assisting property. Mechanical property of the material has been analysed by Vicker’s microhardness analysis and the mechanical parameters such as yield strength and elastic stiffness illustrates the materials excellent atomic package.

Controllable molecular doping in organic single crystals toward high-efficiency light-emitting devices

Organic single-crystalline semiconductors have drawn significant attention in the area of organic electronic and optoelectronic devices due to their superiorities of highly ordered structure, high carrier mobility and low impurity content. Molecular doping technique has made great progress in improving device performance via optimizing the optical and electrical properties of organic semiconductors. In particular, this technique has been attempted by taking fluorescent dye-molecules as the emissive dopants to tune emission color and improve device performance of organic single crystals. Up to now, there are few reports about the use of molecular doping in organic single crystals to optimize their intrinsic electrical properties. Here, we have introduced the controllable molecular doping as a feasible approach toward manipulating charge carrier transport properties of organic single crystals. Upon optimization of doping concentration, balanced carrier transport can be realized in 5,5′-bis(4-trifluoromethyl phenyl) [2,2’] bithiophene (P2TCF3)-doped 1,4-bis(4-methylstyryl) benzene (BSB–Me) crystals. Organic light-emitting devices (OLEDs) based on these doped crystals achieve a maximum luminance of 423 cd/m2 and current efficiency of 0.48 cd/A. It demonstrates that high-efficiency crystal-based OLEDs are of great significance for the development of organic electronics, especially for display and lighting applications.

Chemical growth dynamics of 4-Methyl-4′-Hydroxy Benzylidene Aniline NLO single crystal structure and spectroscopic applications

An aromatic Schiff bases organic nonlinear optical single crystal of 4-methyl-4′-hydroxy benzylidene aniline (MHBA) was grown by slow evaporation solution growth technique and the solubility of MHBA in ethanol at increasing temperature was esteemed. The unit cell proportions were gained by both single crystal and powder X-ray diffraction analysis. The structural refinement of MHBA shows that it crystallizes in the orthorhombic system with space group Pbcn. The molecule chiefly consists of two non – planar benzene rings attached by carbon and nitrogen atoms. The various planes of reflection were identified from the powder X-ray diffraction study and the unit cell proportions were same for single crystal XRD. Functional assemblies were entrenched by using Fourier transform infrared and FT Raman analysis by the molecular vibrations in the MHBA crystal. The assignment of protons and carbons in the grown MHBA crystals were recognized from 1H and 13C Nuclear Magnetic Resonance Spectroscopy analyses. The UV- visible and fluorescence spectral evaluate were carried out and to find the optical transmission and emission range of MHBA. The second harmonic generation productivity of MHBA is about 1.04 times than that of a standard sample of potassium dihydrogen orthophosphate. The thermal constancy of the grown crystal was investigated by differential scanning calorimetric, thermo gravimetric and a differential thermal analysis which confirms the decomposition of the sample occurs at 120 °C. Mechanical stuff, the hardness number, yield strength and Young's modulus of the grown material were studied using Vickers micro hardness tester and the work hardening coefficient reveals that MHBA belongs to the family of soft materials. The dielectric measurements with frequency and temperatures were used to find the power dissipation of the grown MHBA crystals.

Growth, spectral, optical, thermal, mechanical, electrical and third-order nonlinear optical properties of a new organic bis (guanidinium) terephthalate trihydrate single crystal

Abstract A new organic single crystal of bis (guanidinium) terephthalate trihydrate (BGTTH) was successfully grown by slow evaporation solution method (SESM) at room temperature. The title compound possess to monoclinic system with the space group C2/c, it is identified through single crystal X-ray diffraction study. The characteristic functional groups of BGTTH crystal were confirmed by FTIR study. The optical absorption spectrum shows that the lower cut-off wavelength of bis (guanidinium) terephthalate trihydrate is 297 nm and has a wide transparency window. The luminescence study shows that the BGTTH crystal has high degree of luminescence. Thermal stability of BGTTH crystal was analyzed by thermogravimetric analysis. Microhardness measurement reveals that the BGTTH crystal belongs to soft material category. The third order nonlinear optical parameters (n2 = −5.5289 × 10−9 (cm2/W), β = 2.59 × 10−4 (cm/W) and χ (3) = 7.36 × 10−6 (esu)) were calculated by Z-scan technique.

Synthesis and crystal growth of 2, 3-dimethyl-N-[2-(hydroxy) benzylidene] aniline: An organic second-order non-linear optical crystal for non-linear optical (NLO) applications

Abstract Optically transparent organic single crystal of 2,3-Dimethyl-N-[2-(hydroxy) benzylidene] aniline (DHBA) has been successfully prepared, and the single crystals were grown with dimensions up to 10 × 5 × 2 mm3 by using slow evaporation solution growth method in methanol. Single crystal X-ray diffraction (SCXRD) study revealed that the DHBA was crystallized in an orthorhombic crystal structure with P212121 space group, which is a crucial parameter for the second harmonic generation. The existence of various functional groups in the DHBA molecular structure was characterized by FT-IR, FT-Raman, and 1H NMR techniques. UV–Vis–NIR absorption study reveals that the lower cut-off wavelength at 464 nm with transparency over the Vis-NIR spectral regions. The photoluminescence (PL) spectra of DHBA crystal exhibit a green emission centered at 538 nm. The thermal stability and melting temperature of DHBA was assessed by TG/DTA analysis. Vickers microhardness studies have also been investigated to check the mechanical stability of the grown crystal. The dielectric properties of DHBA have been tested in various frequency ranges from 50Hz to 5 MHz at three different temperatures (308K, 323K, and 348K), and the results are discussed. The second order NLO efficiency of the powdered DHBA crystal is three times greater than that of KDP. All of these results imply that DHBA crystal could be a desirable candidate for non-linear optical applications.

Doped Highly Crystalline Organic Films: Toward High-Performance Organic Electronics.

Today's organic electronic devices, such as the highly successful OLED displays, are based on disordered films, with carrier mobilities orders of magnitude below those of inorganic semiconductors like silicon or GaAs. For organic devices such as diodes and transistors, higher charge carrier mobilities are paramount to achieve high performance. Organic single crystals have been shown to offer these required high mobilities. However, manufacturing and processing of these crystals are complex, rendering their use outside of laboratory‐scale applications negligible. Furthermore, doping cannot be easily integrated into these systems, which is particularly problematic for devices mandating high mobility materials. Here, it is demonstrated for the model system rubrene that highly ordered, doped thin films can be prepared, allowing high‐performance organic devices on almost any substrate. Specifically, triclinic rubrene crystals are created by abrupt heating of amorphous layers and can be electrically doped during the epitaxial growth process to achieve hole or electron conduction. Analysis of the space charge limited current in these films reveals record vertical mobilities of 10.3(49) cm2 V−1 s−1. To demonstrate the performance of this materials system, monolithic pin‐diodes aimed for rectification are built. The f3db of these diodes is over 1 GHz and thus higher than any other organic semiconductor‐based device shown so far. It is believed that this work will pave the way for future high‐performance organic devices based on highly crystalline thin films.

Squaraine Organic Crystals with Strong Dipole Effect Toward Stable Lithium-Organic Batteries

Although organic redox molecules as electrode materials can achieve a high specific capacity through molecular design engineering, effective strategies to overcome their low cycling stability have not yet been developed. Herein, we establish a novel strategy that utilizes a strong dipole effect to suppress the high solubility of organic molecules and, thus, improve cycling stability. Two organic single crystals of squaraine derivative molecules with different substituents, 2,4-di(piperidin-1-yl)cyclobutane-1,3-dione (SAPD) and 2,4-di(pyrrolidin-1-yl)cyclobutane-1,3-dione (SAPL), were synthesized by facile routes. In particular, the SAPL cathode exhibited a discharge capacity of 371 mAh g-1 at 40 mA g-1 (0.2 C) and a nearly 78% capacity retention after 1000 cycles at 0.2 A g-1 (1 C). It also exhibited a capacity of 135 mAh g-1 even at 4 A g-1v (20 C) without hybridizing with graphene or carbon nanotubes. We studied the molecular interactions of SAPD and SAPL via detailed density functional theory calculations and revealed their lithium-ion storage mechanisms by using ex-situ technologies. Through comparing their intermolecular interactions, we found the stronger dipole effect can elevate cycling performance better. Hence, our design strategy can serve as a promising path for constructing high-performance lithium-organic batteries with long-term cycling stability.

Exploring the influence of CdCl2 on the nonlinear properties of 4–N, N–dimethylamino – 4–N–methyl – stilbazolium tosylate (DAST) crystal for optoelectronic applications

ABSTRACT This article describes the enhancement of optical and NLO properties of a novel cadmium chloride doped DAST organic single crystals, which have been effectively grown by slow evaporation technique. The as-prepared crystals were inspected by various experimental characterisation such as SXRD and PXRD, FT-IR, UV–Vis–NIR, EDAX, and SHG analysis. The structural analysis and elemental analysis confirmed the incorporation of dopant materials and their effect on the structural aspects. The optical studies of the pure and doped crystals showing the desirable changes in the cut-off wavelengths, mostly affected by n – π* electronic transition in this case. Interestingly, the SHG efficiencies of the Cd doped DAST crystals were enhanced to be 1.29, 1.41 and 1.79 times greater than pure DAST crystal. The estimated optical parameters and the efficient SHG efficiency of Cd doped DAST single crystal reveals that they could be prominent materials for optoelectronic and nonlinear optical (NLO) applications.

Anticrossing Behavior in Nanolayered Heterostructures Caused by Coupling between a Planar Waveguide Mode in an Anthracene Single Crystal and a Silver Surface Plasmon Polariton Mode: Implications for Attenuated Total Reflection Spectroscopy

Coupling between a planar waveguide (PWG) mode in an organic single crystal and a surface plasmon polariton (SPP) mode is investigated in this paper. Anticrossing behavior appearing under the stron...

Growth and characterization of pure and metals-doped organic nonlinear optical single crystal: l-alanine alaninium nitrate (LAAN)

The pure and metal ion (Cu2+, Zn2+ and Mg2+)-doped LAAN single crystal was developed by slow evaporation technique under ambient temperature. Cell parameters of the grown crystal were identified using single crystal X-ray diffraction analysis and found that the material crystallizes in orthorhombic crystal system with space group of P21.The presence of functional groups and the spectral properties were assessed by FTIR analysis. Transmittance spectrum reveals that the crystal has a low UV cut-off of 360 nm and has a good transmittance in the entire visible region. The band gap energy of LAAN and doped (Zn, Cu and Mg) LAAN crystals were estimated to be 3.38, 3.22, 2.75, and 3.13 eV by Tauc plot. Prevention of the recombination process of electron–hole pair was also confirmed by photoluminescence spectra analysis. The dielectric constant of pure crystal was found to be less than that of doped crystals. The AC conductivity was found to increase after doping and with the increase in temperature. Second harmonic generation efficiency of the grown crystal has been measured by Kurtz and Perry technique and it was found that Cu-doped LAAN is 3.2 times higher than that of KDP and 2.1, 1.5, and 1.8 times more prominent than pure, Zn, and Mg-doped LAAN crystals, respectively.

A temperature-reduced method for the rapid growth of hybrid perovskite single crystals with primary alcohols

In this work, we present the simple and temperature-reduced reactive inverse temperature crystallisation (RITC) method to rapidly grow high-quality organic lead trihalide perovskite single crystals.

Growth and characterization of organic material 2-bromobenzyl alcohol single crystal by vertical Bridgman technique

The organic material 2-bromobenzyl alcohol (C7H7BrO) single crystal was grown by using vertical Bridgman technique. The lattice parameters of the 2-bromobenzyl alcohol crystal were determined by single-crystal X-ray diffraction technique. The Fourier Transform Infrared spectroscopy is used to identify the functional groups of the grown 2-bromobenzyl alcohol. Thermal analyses were carried out to analyze the melting and decomposition points of the grown crystal. The UV–Vis–NIR and Fluorescence studies assessed the optical properties of the grown crystals. The second-harmonic generation study analyzed non-linear properties. The laser damage threshold value for the grown 2-bromobenzyl alcohol single crystal was measured by using Q-switched Nd:YAG laser. The photoconductivity measurements of the grown crystal were estimated by KEITHLEY 6487 instrument. The dielectric permittivity was analyzed at various temperatures with different frequencies from 1 to 5 MHz. The mechanical strength of the grown crystal was analyzed by using Vickers microhardness analysis.

Dual self-trapped exciton emission of (TBA)2Cu2I4: optical properties and high anti-water stability

We report zero-dimensional organic copper iodide single crystals of (TBA)2Cu2I4 with high anti-water stability, which can be stable in water for 24 hours. Upon photoexcitation, this compound exhibits a cool-white emission.