A Plastic Scintillator Based on an Efficient Thermally Activated Delayed Fluorescence Emitter 9‐(4‐(4,6‐diphenyl‐1,3,5‐triazin‐2‐yl)‐2‐methylphenyl)‐3,6‐dioctyl‐9 <i>H</i> ‐carbazole for Pulse Shape Discrimination Measurement

Pulse shape discrimination (PSD)-capable plastic scintillator is in demand for the detection of high-energy neutrons presence gamma radiation background. Conventional PSD plastics are based on delayed fluorescent dye via triplet–triplet annihilation a additive, which inefficient to harvest energy triplet excitons. In recent years, thermally activated fluorescence (TADF) emitters have gained substantial success organic light-emitting diodes due their efficient utilization excitons and thereby achieving theoretical unity internal quantum efficiencies. Herein, highly TADF 9-(4-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-methylphenyl)-3,6-dioctyl-9H-carbazole reported application. This may be loaded up 30 wt% polyvinyltoluene matrix still retains high optical transparency. High scintillation light yield figures merit obtained from plastic. With introduction secondary further increase efficiency excitation energy, increased 6948 photons MeV−1. The measured alpha/gamma figure 1.12 at threshold 100 keVee neutron/gamma 1.32 1000 keVee.