Rational Design of Photofunctional Ionic Manganese(II) Bromide Materials Through Isomer Engineering for High-Performance X-Ray Imaging
摘要
The development of low-cost scintillators with excellent photophysical properties plays an important role for high-performance X-ray imaging. Serving as the good candidates for X-ray scintillators with excellent radioluminescence (RL) properties, phosphorescent manganese(II) complexes have attracted an increasing interest. In this work, we proposed an isomer engineering strategy for designing three new photofunctional ionic manganese(II) bromides (oMn, mMn, and pMn) by introducing methyl groups into the ortho (o)-, meta (m)-, or para (p)-position of the phenyl groups in ethyl triphenylphosphonium cation. The position of the methyl groups shows influences on the photophysical properties and molecular packing in crystals. Under the UV light, these ionic manganese(II) bromide materials exhibit strong green emission from 515 nm to 522 nm and narrow full width at half maxima (FWHM) from 46 nm to 50 nm, and high photoluminescence quantum yields (PLQYs) of complexes oMn, mMn, and pMn are determined to be 82%, 91%, and 72%, respectively. Moreover, under the irradiation of X-ray, they also show intense radioluminescence with a high relative light yield of up to 77,204 photons MeV−1 and a low limit of detection of 13.13 nGy s−1. We further use them as scintillators for high-performance X-ray imaging and realize a high spatial resolution up to 15 lp/mm, indicating their great potential for future X-ray imaging. The results here will make a contribution to the field of photofunctional materials.
Graphical Abstract