Scintillators that exhibit X-ray-excited luminescence have great potential in radiation detection, X-ray imaging, radiotherapy, and non-destructive testing. However, most reported scintillators are limited to inorganic or organic crystal materials, which have some obstacles in repeatability and processability. Here we present a facile strategy to achieve the X-ray-excited organic phosphorescent scintillation from amorphous copolymers through the copolymerization of the bromine-substituted chromophores and acrylic acid. These polymeric scintillators exhibit efficient X-ray responsibility and decent phosphorescent quantum yield up to 51.4% under ambient conditions. The universality of the design principle was further confirmed by a series of copolymers with multi-color radioluminescence ranging from green to orange-red. Moreover, we demonstrated their potential application in X-ray radiography. This finding not only outlines a feasible principle to develop X-ray responsive phosphorescent polymers, but also expands the potential applications of polymer materials with phosphorescence features.
The adsorption of oleate on apatite was studied at pH values from 6 to 9.8 and oleate concentrations from 2 X 10"5 6to 3 X 10~4 mol Lr1. Diffuse reflectance infrared Fourier transform spectroscopy has been found to be superior to the transmission infrared technique for detecting adsorbed oleate species. Confusion in previous studies is clarified and a better understanding of the adsorption mechanism obtained. Chemisorbed oleate corresponds to a single peak at 1550 cm"1 and probably comprises one oleate ion bonding with one lattice calcium ion on the surface. Surface calcium oleate precipitate showing peaks at 1574 and 1538 cm-1 has a structure similar to that of bulk calcium oleate and probably adsorbs through ion-dipole interaction and hydrocarbon chain association. Oleic acid dimer and monomer adsorb via hydrocarbon chain association onto underlying chemisorbed oleate and correspond to a sharp peak at 1713 cm'1 and a shoulder at 1732 cm"1, respectively. Chemisorption of oleate on apatite occurred under all conditions studied and was accompanied by physical adsorption of calcium oleate precipitate and/or oleic acid monomer and/or oleic acid dimer, depending on the pH and concentration of the solution.
Thermally activated delayed fluorescence (TADF) has been explored actively in luminescent organic materials. Yet, realizing such TADF‐active, multifunctional emitters with high emission efficiency still remains hugely challenging. In this context, a series of twist‐conjugated organic molecules bearing diphenylsulfone and 9,9‐dimethylacridine moieties are designed and prepared, and are found to show, in one molecule, TADF, room‐temperature phosphorescence, triboluminescence, and aggregation‐induced emission enhancement. In addition, remarkably high photoluminescence quantum efficiency, up to ≈100%, is achieved for these novel molecules. Single‐crystal analysis and theoretical calculations reveal that the through‐space charge transfer (TSCT) effect in these molecules is responsible for both the multifunctional emission and high emission efficiency. A maximum external quantum efficiency of 20.1% is achieved, which is among the highest recorded in a solution‐processable device containing TSCT‐based TADF materials. These results illustrate a new approach to achieving highly efficient TADF‐active, multifunctional emitters.
There are few reports about purely organic phosphorescence scintillators, and the relationship between molecular structures and radioluminescence in organic scintillators is still unclear. Here, we presented isomerism strategy to study the effect of molecular structures on radioluminescence. The isomers can achieve phosphorescence efficiency of up to 22.8 % by ultraviolet irradiation. Under X-ray irradiation, both m-BA and p-BA show excellent radioluminescence, while o-BA has almost no radioluminescence. Through experimental and theoretical investigation, we found that radioluminescence was not only affected by non-radiation in emissive process, but also highly depended on the material conductivity caused by the different molecular packing. This study not only allows us to clearly understand the relationship between the molecular structures and radioluminescence, but also provides a guidance to rationally design new organic scintillators.Scintillators are a type of luminescence materials that can convert high energy photons or particles to visible photons, [1] which receive extensive attention in various fields, such as medical imaging [2] and irradiation detecting. [3] To date, scintillators are mainly divided into two categories, inorganic and organic scintillators. Compared with inorganic scintilla-
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