Fig. 2. Photophysical properties of the PBBr copolymers by X-ray irradiation under ambient conditions.
a Normalized steady-state photoluminescence (PL, blue line) and phosphorescence (gray line) spectra of the PBBr-50 film under UV light excitation, as well as radioluminescence (RL) spectrum (green line) at a dose rate of 278 μGy s−1. Insets are the corresponding ultraviolet (UV) light- and X-ray-excited photographs. b A lifetime decay curve of emission band at 496 nm for PBBr-50 film. c PL efficiency and RL intensity variation of copolymer films from PBBr-3 to PBBr-800. d RL spectra of different PBBrs at a dose rate of 278 μGy s−1. Note: the examination was quantitative for each group. e RL measurements of the PBBr-5 film as a function of dose rate in the range of 0.688 to 278 μGy s−1. f Emission photostability of the PBBr-5 film at 500 nm under repeated on-off cycles of X-ray at a dose rate of 278 μGy s−1.