Bright 2D Polar Perovskite Scintillator with Ultrafast Decay by Suppressing Free Carrier Recombination

ABSTRACT High light yield and ultrafast decay time are highly demanded for scintillators in sensitive, rapid radiation detection and imaging, but both properties can hardly coexist in a scintillator so far. Herein, we report a design principle for spontaneous polarization‐enhanced scintillation in 2D organic–inorganic hybrid perovskites. As anticipated, the (4‐aminomethyl‐1‐cyclohexanecarboxylate) 2 PbBr 4 (APB) perovskite displays high light yield up to 19 660 photons/MeV and a lifetime of 0.90 ns. Combining the experimental and computational results, we demonstrate that enhancement of dielectric screening effect and suppression of free carrier recombination are responsible for the ultrafast decay time and high light yield, respectively. Moreover, the practical applications for fast neutron imaging and flash X‐ray radiography are successfully demonstrated with excellent spatial resolutions of 2.4 and 31 lp/mm, respectively. In addition, the potential for PET technique is verified by shorter CTR values than (Lu x Y 1‐x ) 2 SiO 5 : Ce (LYSO). This work will open up a new avenue for developing high‐performance ultrafast scintillators for practical applications in biomedical and nuclear detection techniques.