Fig. 1: Illustration of the spatial decoupled heavy atom-π strategy in hybridized local and charge transfer (HLCT) scintillators on the enhancement of radioluminescence (RL) performances.
From: High-resolution X-ray imaging via spatially decoupled heavy-atom antennas in organic scintillators
a The three types of organic scintillators with similar conjugated heavy atoms strategy and different charge transfer characters. b The conjugated coupled bromine-π interactions are present in the HLCT scintillators, where hole/electron extend to bromines, inducing high SOC(T1,S0) and severe non-radiative transitions that weaken RL efficiency. c The spatially decoupled bromine-π interactions are present in the HLCT scintillators, where hole/electron are isolated from bromines, inducing low SOC(T1,S0) and suppressed non-radiative decays that enhance RL efficiency. The HLCT scintillators with moderate CT characters and their advantages of short radiative lifetime, large Stokes shift, and narrow full width at half maximum (FWHM). RTP, room temperature phosphorescence; TADF, thermally activated delayed fluorescence; 1CT, charge transfer singlet state; 1LE, localized singlet sate; 1HLCT, hybridized local and charge transfer singlet state; hRISC, high-lying reversed intersystem crossing; T1, the first triplet state; Tn, the higher triplet state; IC, internal conversion; NR, non-radiative transition; D, donor; A, acceptor.
