Delayed radioluminescence of some heterostructured organic scintillators

Galunov, N.Z.; Gryn, Dmytro; Karavaeva, N.L.; Khromiuk, I.F.; Lazarev, Igor; Navozenko, O. M.; Naumenko, A. P.; Tarasenko, О.А.; Yashchuk, Valeriy M.

doi:10.1016/j.jlumin.2020.117477

Cited by 12 publications

(11 citation statements)

References 26 publications

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“…[15][16][17] However, the low X-ray absorption cross-section and subsequently poor detection sensitivity of organic scintillators due to their limited effective atomic number (as X-ray absorption increases exponentially with atomic number) and inefficient exciton utilization efficiency have significantly impeded their evolution and possible commercialization. [18][19][20] Therefore, the exploration of new photoactive organic materials with outstanding scintillation performance is a promising research direction, as such materials are urgently needed.…”

Section: Introductionmentioning

confidence: 99%

Heavy-atom engineering of thermally activated delayed fluorophores for high-performance X-ray imaging scintillators

et al. 2022

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The architectural design and fabrication of low-cost and reliable organic X-ray imaging scintillators with high light yield, ultralow detection limits, and excellent imaging resolution is becoming one of the most attractive research directions for chemists, materials scientists, physicists, and engineers due to the devices' promising scientific and applied technological implications. However, the optimal balance between the X-ray absorption capability, exciton utilization efficiency, and photoluminescence quantum yield (PLQY) of organic scintillation materials is extremely difficult to achieve because of several competitive nonradiative processes, including intersystem crossing and internal conversion. Here, we introduced heavy atoms (Cl, Br, I) into thermally activated delayed fluorescence (TADF) chromophores to significantly increase their X-ray absorption cross-section while maintaining their unique TADF properties and high PLQY. Most importantly, the X-ray imaging screens fabricated using TADF-Br chromophores exhibited a relative light yield of approximately 20,000 photons/MeV, which is comparable with some inorganic scintillators. In addition, the detection limit of 64.5 nGy s -1 is several times lower than the standard dosage for X-ray diagnostics, demonstrating its high potential in medical radiography. Moreover, a high X-ray imaging resolution of 18.3 line pairs (lp) mm -1 was successfully achieved, exceeding the resolution of all the reported organic scintillators and most conventional inorganic scintillators. This study could help revive research on organic X-ray imaging scintillators and pave the way toward exciting applications for radiology and security screening.

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Section: Introductionmentioning

confidence: 99%

Heavy-atom engineering of thermally activated delayed fluorophores for high-performance X-ray imaging scintillators

et al. 2022

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“…The presence of trapping sites has been evidenced in inorganic crystalline scintillators, both intrinsic , and extrinsic, − as well as perovskite scintillators . The development of a new class of organic and hybrid systems as promising materials for a wide range of applications − led to significant advancements in the study of charge-trapping phenomena in organic polymers, nanocrystal quantum dots, and metal–organic frameworks . Furthermore, the formation of defect complexes has been discovered and ascribed to a close spatial correlation between intrinsic traps and dopant ions. , However, the relationship between the presence of defects and their effects on the scintillation process is not fully understood, preventing a targeted approach to the optimization of the synthesis procedure.…”

Section: Introductionmentioning

confidence: 99%

Trapping Mechanisms and Delayed Recombination Processes in Scintillating Ce-Doped Sol–Gel Silica Fibers

et al. 2021

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The carrier trapping and recombination mechanisms occurring in Ce-doped silica fibers, produced by a sol−gel technique, are investigated by combining temperature-dependent steady-state X-ray-excited luminescence, wavelength-and timeresolved scintillation measurements, and wavelength-resolved thermally stimulated luminescence, focusing especially on the temperature range from 10 to 320 K. The scintillation decay features a decay time of the order of tens of nanoseconds, characteristic of the parity-and spin-allowed 5d−4f radiative transition of Ce 3+ ions. In addition, a slow and complex decay contribution in the microsecond timescale is detected. We interpret these features as due to the radiative recombination at Ce centers of carriers freed from a continuous distribution of trapping sites in the forbidden gap as well as to the occurrence of an athermal tunneling recombination process between traps and Ce 3+ ions. This interpretation is reinforced by good agreement between independent evaluations of trap depths and lifetimes obtained by both the numerical analysis of scintillation time decays and thermally stimulated luminescence experiments.

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“…The theoretical basis for such studies were presented by us in [6]. We note that in the case of this article, the probability of direct excitation to the T 1 state was increased due to the high optical radiation density.…”

Section: Introductionmentioning

confidence: 66%

Composite Scintillators Based on Organic Grains and Their Pulse Shape Discrimination Capability

Khromiuk¹,

Karavaeva²,

Krech³

et al. 2022

Problems of Atomic Science and Technology

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Delayed radioluminescence of some heterostructured organic scintillators

Cited by 12 publications

References 26 publications

Heavy-atom engineering of thermally activated delayed fluorophores for high-performance X-ray imaging scintillators

Heavy-atom engineering of thermally activated delayed fluorophores for high-performance X-ray imaging scintillators

Trapping Mechanisms and Delayed Recombination Processes in Scintillating Ce-Doped Sol–Gel Silica Fibers

Composite Scintillators Based on Organic Grains and Their Pulse Shape Discrimination Capability

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