Bulk Organic Doped P-Terphenyl Crystals for X-ray Scintillators with Low Detection Limit, Nanoseconds Decay Time, and Tunable Fluorescence

There is a growing urgency to develop large-sized organic scintillator crystal materials with excellent responsivity and tunable photophysical properties to meet the demand of diverse industrial and medical applications. Here, the thermal field-elevating Bridgman method was used to grow a series of large-sized ((sic)15 mm x 60 mm) conjugated molecules (anthracene, tetracene, pentacene, chrysene, picene)-doped p-terphenyl crystals, achieving tunable luminescence from 360 to 680 nm under X-ray radiation. The results indicate that the pure p-terphenyl crystal possesses a fast decay lifetime of 2.36 ns, and the picene-doped p-terphenyl crystal exhibits an extremely low detection limit of 45.2 nGy s(-1). We also obtained insights into the analysis of the energy transfer interactions between host molecules and dopants through experimental investigations and theoretical calculations. This work provides efficient strategies for designing and growing organic X-ray scintillator crystal materials with tunable photophysical properties.