Stilbene Single Crystals Research Articles

Impact of doping on the Bridgman grown organic stilbene single crystal for third order NLO applications

Transparent 1, 3, 5-Triphenylbenzene doped Stilbene (TBS) single crystal was successfully grown by employing the Bridgman technique. SCXRD studies found crystallographic parameters, which reveal that the TBS single crystal has crystallized in a monoclinic crystal structure with the space group of P21/C. The identification of the functional groups in the TBS crystal was accomplished through the FTIR analysis. The UV–Vis spectral data shows that the TBS crystal exhibits minimal absorption across the visible spectrum, with a lower cutoff wavelength of 365 nm. The violet emission is observed at 380 and 405 nm in the fluorescence analysis. Additionally, the crystal's high quality was confirmed by a full width at half maximum value of 123 arcsec in the prominent rocking curve peak. Third-order nonlinear optical susceptibility χ(3) was determined to be 4.26 × 10−6 esu using the Z-scan technique. These are exciting findings that highlight the TBS crystal's suitability for various applications, including scintillation and optoelectronic device fabrication.

2 inch molecular organic glass scintillator for neutron–gamma discrimination

In this manuscript we report on the scintillation properties and pulse shape discrimination (PSD) performance of new organic glass scintillator. Two cylindrical samples with dimensions of 2 × 2 inches were tested. Additionally, this two samples were used in stack configuration in order to measure the PSD characteristics of a sample with a size of 2 × 4 inches. The study covers the measurements of neutron/gamma discrimination capability, emission spectra, photoelectron yield and analysis of the light pulse shapes originating from events related to gamma-rays and fast neutrons. The results were compared to data recorded previously using an EJ-276 plastic scintillator, an EJ-309 liquid scintillator and a stilbene single crystal.

Characterization of α-phenyl-4′-(diphenylamino)stilbene single crystal and its anisotropic conductivity

Presently, organic-semiconductor electronics suffer from low performance owing to their amorphous nature. Improving their crystallinity, and thus the charge transport properties is a crucial endeavor. Accordingly, this study aims to elucidate the conductivity mechanism of a novel triphenylamine-derivative single crystal. We successfully synthesized an α-phenyl-4′-(diphenylamino)stilbene (TPA) single crystal via a solution method employing the solubility and supersolubility curves of TPA in the tetrahydrofuran (THF) solvent. Its crystal structure was determined via single-crystal X-ray diffraction (SCXRD), which revealed that the obtained single crystal contains not only TPA but also THF. The molecular ratio of TPA to THF was found to be 2:0.74. We further analyzed the hole transport property in three directions of the single crystal, and the anisotropic conductivity was observed. Based on the results of the observed molecular packing and charge transport property, we confirm that the observed anisotropic conductivity is determined based on the orientation of the triphenylamine unit in each direction of the TPA single crystal. Overall, the findings can help in guiding the design of high-mobility organic semiconductors for realizing more effective organic electronic devices.

Hole Transport Property of α-phenyl-4'-(diphenylamino)stilbene Single Crystal Prepared Based on Solubility and Supersolubility Curves

Hole Transport Property of α-phenyl-4'-(diphenylamino)stilbene Single Crystal Prepared Based on Solubility and Supersolubility Curves

Analysis of the effect of experiment statistics on the evaluation of the measuring accuracy of the light output of scintillators

The work is devoted to the analysis of the experimental data statistics influence on the evaluation of indexes of the random components (precision and random error confidence limits) of the measurement accuracy of technical light output for different scintillators. Accuracy evaluations were carried out to establish the required number of measurements when performing metrological work at various levels.The technical light output, in photons/MeV (ph/MeV), of cylindrical scintillators based on NaI(Tl), CsI(Tl), CWO, BGO, p-terphenyl, anthracene, stilbene single crystals and PS, was determined.The accuracy of the scintillators technical light output measurements was estimated on the basis of a series of measurement results in certain conditions. Three series of measurements were performed under conditions of intra-laboratory reproducibility. Each of measurement series was carried out under repeatability conditions. The evaluation of the variability of the random component of a single measurement error was the value of the measurement precision — the standard deviation of a single measurement result performed under repeatability conditions. The absolute and relative values of the precision indexes and confidence limits of the random error for each series of measurements were calculated. The dependence of accuracy on the number of measurements in the series from 3 to 9 was studied.It has been shown that with an increase in the light output of scintillators from 2800 ph/MeV for BGO to 35500 ph/ MeV for CsI(Tl) for any number of measurements, the precision of the scintillators light output measurements decreases from about 2 % to 0.3 %, that is, the precision of the measurement is enhanced.It has been established that the ratio of the magnitude of the random error limit to the measurement precision index decreases from 2.5 to 0.8 as the number of measurements increases from 3 to 9.Based on the results obtained in the work, recommendations were given on the number of measurements required for metrological work at various levels.

Photoluminescence of a new polycrystalline scintillator based on stilbene

Photoluminescence and excitation spectra of stilbene single crystals, polycrystals, and solutions are investigated in the temperature range of 5-280 K. With the increase in the temperature, the photoluminescence bands shift to the short-wavelength region by 600 cm−1, which indicates the existence of Gaussian-distributed localized states. Such states are associated both with different arrangements of the benzene rings with respect to the C = C bond and with different molecule environments in the crystal lattice. The photoluminescence intensity of the polycrystals depends on the grain size and reaches 87% of the single crystal photoluminescence intensity, when the grain size is 2.5 mm.

Neutron/gamma discrimination properties of composite scintillation detectors

A composite scintillator is a solid solution, which contains the grains of organic molecular single crystal introduced into a polymer matrix and placed inside the housing. Hereunder, we present n/γ discrimination properties of four composite scintillators; two of the them are based on p-terphenyl and two others-on stilbene. The results obtained with a stilbene single crystal and a liquid scintillator BC501A are shown as a comparison. Initial conclusion, which is drawn from the paper, is that composite scintillators could be an alternative substitution for commonly used liquid scintillators.

Stilbene crystalline powder in polymer base as a new fast neutron detector

A new organic scintillation material consisting of stilbene grains in a polymer glue base is presented. The crystalline grains of stilbene are obtained by mechanical grinding of stilbene single crystals. The resulting composite scintillators have been studied as detectors for fast neutrons.

Study of two-photon excitation spectra of organic compounds absorbing in the UV region

A method is proposed for recording two-photon excitation (TPE) spectra of organic compounds with the help of picosecond pulses from a dye laser tunable in the range from 550 to 640 nm. The TPE spectra are obtained for organic scintillators and drugs: paraterphenyl in liquid and solid phases, stilbene single crystal and Streptocid powder, having a one-photon absorption band in the region from 270 to 350 nm. It is shown that the vibronic structure in the TPE spectra of these compounds is independent of their aggregate state and is an individual characteristic of each of the compounds.

Investigations on the growth of anthracene and trans-stilbene single crystals using vertical Bridgman technique

Various parameters associated with the growth of anthracene and stilbene single crystals have been optimized. The quality improvement of the grown crystals is identified using various characterization tools. The grown crystals were characterized using NMR, UV-visible transmission spectral studies, and fluorescence. Decay time of scintillation emission to gamma sources 60Co and 137Cs have been also studied.

The Growth of Stilbene Single Crystals with High Structural Perfection

Abstract The peculiarities of the growth of stilbene single crystals from melt doped with electron-seeking addition agents (ESAA) are discussed.

The influence of controlled electron‐seeking addition agents of the melt on stilbene single crystal structure and radioluminescence properties

AbstractThe study of certain radioluminescence characteristics of stilbene single crystals is performed. Doping the stilbene melt with electron‐seeking (ES) addition agents of benzol and benzophenone halogen derivatives allowed to control the structure perfection of the crystal grown. The root‐mean‐square random orientation of single crystal mosaic structure, and concentration of the deep traps of charge carriers and excitons were minimum for the single crystals grown from the melt containing 0.1 mol% ES addition agent. Doping the melt with ES addition agents did not cause the appearance of additional luminescence impurity centres or quench luminescence centres in the single crystals grown.

Free Charges and Excitons in Stilbene Single Crystals Excited by Electron Pulses

AbstractThe kinetics of relaxation currents, light absorption, and luminescence after excitation of stilbene single crystals by a pulse of accelerated electrons with τ = 40 × 10−9 s is measured. The excitation results in bulk generation of free charges and excitons. The microscopic mobilities are found to μp = 2.2 cm2 V−1 and μ, = 0.2 cm2 V−1 s−1. The radiation yield of the charges is G(p, e) = 0.25 ± 0.02, and of triplet excitons G(T) = 3.6. The optical absorption spectrum of triplet excitons is recorded, and it is found that vmax = 2.22 × 104 cm−1, the absorption coefficient Kvmax = 0.17 cm−1, and the oscillator strength of the T2 ← T1 optical transition band f = 0.20. The probability of creation of charges .