Thermally activated fluorescence in 9,10-DPA single crystals enabling high-performance fast neutron detection

Organic scintillators occupy a significant niche in the realm of fast neutron detection. Nevertheless, the cultivation of large-sized and high-quality organic single crystals has persistently posed a formidable challenge. 9,10-diphenylanthracene (DPA) was chosen as a prospective material for fast neutron detection. The two-dimensional nucleation growth mechanism of DPA was revealed by detailed analysis of the microstructure of the crystal surface. By systematically optimizing the growth parameters and processes, the nucleation and growth of DPA were effectively controlled, and centimetre-sized single crystal (27 × 20 × 7 mm³) was successfully grown. The thermally activated fluorescence emission mechanism of DPA crystal was revealed using power-dependent and temperature-dependent photoluminescence spectroscopy. The fluorescence intensity increased with increasing temperature, suggesting its potential for neutron/gamma pulse shape screening (PSD) at high temperatures. High-quality crystal was prepared, achieving a figure of merit (FOM) of 3.56, underscoring the potential of DPA as a superior material for fast neutron detection applications.