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CN-122010901-A - D-A-D' asymmetric decoupling organic X-ray scintillator, and synthetic method and application thereof

CN122010901ACN 122010901 ACN122010901 ACN 122010901ACN-122010901-A

Abstract

The invention discloses a D-A-D' asymmetric decoupling organic X-ray scintillator, a synthesis method and application thereof. According to the invention, naphthalimide is used as an electron acceptor (A), a benzene bridge is used for connecting a donor (D) to realize self-selective orbit coupling, and a secondary donor (D') and the A are in linear face-to-face conjugation to construct the twisted luminophor. The configuration can independently regulate and control D and D' to balance a singlet-triplet state energy gap (delta E ST ) and Spin Orbit Coupling (SOC), accelerate intersystem crossing (ISC) and reverse intersystem crossing (RISC) processes, realize dual-mode temperature self-adaptive luminescence of phosphorescence dominant at low temperature, room temperature and TADF dominant above, inhibit aggregation-induced luminescence quenching, and ensure high luminous efficiency. N-CZ has photocatalysis performance, and can prepare flexible X-ray film through photopolymerization. The invention provides a new design idea and a preparation method for the next-generation high-performance organic X-ray scintillator.

Inventors

  • FAN JIANGLI
  • PAN QINGZE
  • ZONG SHENGLIN
  • DU JIANJUN
  • PENG XIAOJUN

Assignees

  • 大连理工大学

Dates

Publication Date
20260512
Application Date
20260108

Claims (10)

  1. 1. An organic X-ray scintillator with D-A-D' asymmetric decoupling, the structural formula of which is shown as the general formula I: I Wherein: R 1 is electron donor at any position of benzene ring selected from hydrogen, methyl, methoxy, N is selected from an integer of 1 to 12; Y is selected from O or S atoms; r 2 is selected from any one of the following substituents: 。
  2. 2. The organic X-ray scintillator of claim 1, having a temperature response of 70K to 550K and a triplet quantum yield of 10 to 80%.
  3. 3. The method for synthesizing an organic X-ray scintillator according to claim 1, comprising the steps of: (1) Uniformly mixing p-aniline modified by R 1 substituent groups with 4-bromo-1, 8-naphthalene dicarboxylic anhydride according to the molar ratio of (1-10): 1, then adding a first organic solvent, and fully reacting at 80-130 ℃ to obtain an intermediate 1; (2) And (3) under the nitrogen atmosphere, adding the intermediate 1, the R 2 substituted boric acid ester, the tetraphenylpalladium phosphate and the carbonate into toluene according to the molar ratio of 1 to 5 (0.01 to 0.5) to 1 to 10, fully mixing, fully reacting at 70 to 120 ℃, cooling, and carrying out column chromatography and recrystallization.
  4. 4. The method according to claim 3, wherein the molar ratio of the p-aniline modified by the R 1 substituent to the 4-bromo-1, 8-naphthalene dicarboxylic anhydride in the step (1) is (1-5): 1.
  5. 5. The method according to claim 3, wherein the first organic solvent in step (1) is at least one selected from the group consisting of ethanol, acetonitrile, toluene, DMF and acetic acid.
  6. 6. The method of claim 3, wherein in the step (2), the molar ratio of the intermediate 1 to the R 2 substituted borate, the tetraphenylpalladium phosphate and the carbonate is 1 to 3:0.01 to 0.2:1 to 4.
  7. 7. The method according to claim 3, wherein the carbonate in the step (3) is at least one selected from the group consisting of sodium carbonate, potassium carbonate, cesium carbonate, sodium hydroxide and potassium hydroxide.
  8. 8. The use of an organic X-ray scintillator as claimed in claim 1, including imaging at X-ray room temperature, temperature swing imaging, and the use of its excited state properties for the preparation of thin films by photocatalytic polymerization.
  9. 9. The method of claim 8, wherein the organic X-ray scintillator is dispersed in a photocurable resin and polymerized in situ by ultraviolet irradiation to form the flexible X-ray scintillation film.
  10. 10. The method of claim 9, wherein the lowest detection limit LOD of the film is lower than 6.6 mu Gy s-1, the line pair resolution is higher than 14 lp/mm, and the self-adaptive luminescence imaging can be realized in the temperature range of 77K to 400K.

Description

D-A-D' asymmetric decoupling organic X-ray scintillator, and synthetic method and application thereof Technical Field The invention belongs to the technical field of organic photoelectric functional materials, and particularly relates to a pure organic X-ray scintillator with a D-A-D' asymmetric structure, a synthesis method thereof and application thereof in radiation detection and imaging. Background The X-ray imaging technology is used as a core technology for supporting the key fields of aerospace high-energy physical experiments, public safety security inspection, industrial nondestructive detection, modern medical diagnosis and the like, and the performance improvement of the X-ray imaging technology is closely related to the development of scintillator materials. The scintillator is used as a core medium for converting X-rays and visible light, and the sensitivity, resolution and application scene suitability of the imaging system are directly determined. In the existing scintillator material, although the inorganic material and the organic metal complex have strong X-ray absorption capability, the existing scintillator material has the defects of high-temperature condition required for synthesis, complex preparation process, high production cost, environmental pollution caused by heavy metal elements and the like, and severely limits the application range of the scintillator material. The organic scintillator has the advantages of easily available raw materials, low preparation cost, good mechanical flexibility, easy processing, large-area preparation and the like, and becomes an important development direction of scintillator materials. However, the traditional organic scintillator is based on fluorescent chromophore, and is limited by spin forbidden mechanism, transition from singlet excitons (S 1) to triplet excitons (T 1) is blocked, only about 25% of singlet excitons participate in luminescence, and the rest 75% of triplet excitons dissipate energy through non-radiative relaxation, so that the utilization rate of excitons is extremely low, and the performance improvement of the organic scintillator is restricted. The Thermal Activation Delayed Fluorescence (TADF) material provides a new way for solving the problem of exciton utilization rate by means of small singlet-triplet state energy gap (delta E ST), potential 100% exciton utilization rate and characteristics, and the Room Temperature Phosphorescence (RTP) material directly radiates transition luminescence through triplet state excitons, thereby exhibiting application potential in flexible X-ray imaging. However, both materials are highly sensitive to temperature changes, which not only limits the working temperature range, but also easily causes exciton quenching, and how to improve the thermal stability and realize the efficient luminescence in a wide temperature range becomes a scientific difficulty to be solved urgently. Research shows that the scintillator is required to have both small delta E ST and large spin-orbit coupling parameters (SOC) to realize dual-mode temperature self-adaptive switching of low-temperature phosphorescence/high-temperature TADF. The design of a high-twist donor-acceptor (D-A) structure through a bond charge transfer (TBCT) or space charge transfer (TSCT) mechanism is an effective strategy for regulating delta EST and SOC, but no molecular configuration can cooperatively realize independent regulation of TBCT and TSCT at present, and the combination of donor and acceptor is limited, so that the small delta EST and the strong SOC are difficult to be compatible. In summary, the difficulty of existing organic scintillators in maintaining stable, efficient luminescence over a wide temperature range (e.g., from liquid nitrogen temperatures to above room temperature) severely limits their application in complex environments (e.g., space exploration, polar scientific research, certain industrial settings). Therefore, it is important to develop an organic scintillator capable of adaptively adjusting the light emission mode in a wide temperature range while maintaining a high exciton utilization. Disclosure of Invention A first object of the present invention is to provide a class of D-a-D' asymmetrically decoupled organic X-ray scintillators. The scintillator realizes the compatibility of a small singlet-triplet state energy gap (delta EST) and strong Spin Orbit Coupling (SOC) through a coordinated regulation and control bond charge transfer (TBCT) and space charge transfer (TSCT) mechanism, so that the low-temperature phosphorescence and room-temperature Thermally Activated Delayed Fluorescence (TADF) modes are adaptively switched within a wide temperature range of 77K to 400K, and the exciton utilization efficiency is remarkably improved. The technical scheme is specifically as follows: Firstly, the invention discloses a D-A-D' asymmetric decoupling organic X-ray scintillator, the structural formula of which is sh