Structure, Optical, and Thermal Properties of 9, 10-Diphenylanthracene Crystals

9,10-diphenylanthracene (DPA) single crystal is a promising scintillator material for fast-neutron detection. Two centimetre-sized polymorph crystals of DPA were grown by melting and solution methods (DPA-Melt and DPA-Solution, respectively), and characterised by single-crystal X-ray diffraction, Raman spectroscopy, Fourier-transform infrared spectroscopy, fluorescence spectroscopy, UV-Vis absorbance spectroscopy, and thermogravimetric/differential scanning calorimetry. The DPA-Melt crystal possessed a P21/n structure, with excitation bands at approximately 331, 348, 367, and 387 nm, and the strongest emission wavelength at approximately 454 nm. On the other hand, the DPA-Solution crystal possessed a C2/c structure, with excitation bands at approximately 335, 353, 372, and 396 nm, and the strongest emission wavelength at approximately 468 nm. The two kinds of DPA crystals have the same molecular formula but different crystal structures, crystal lattice constants, and cell parameters. The theoretical density of the DPA-Solution crystal was 1.239 g/cm3, while that of the DPA-Melt crystal was 1.211 g/cm3. The two types of crystals exhibited the same melting point, but the thermal stability of the DPA-Solution crystal is better than that of the DPA-Melt crystal.Keywords:diphenylanthracene;polymorph;crystal structure;scintillator;neutron detection