Ceramic Wafer Scintillation Screen by Utilizing Near‐Unity Blue‐Emitting Lead‐Free Metal Halide (C8H20N)2Cu2Br4

Abstract Scintillators with high light yield, low detection limit, large X‐ray attenuation efficiency as well as stable and nontoxic compositions are of great importance for radiation detection applications. Here, 0D (C 8 H 20 N) 2 Cu 2 Br 4 single crystals are obtained and show blue emission peaking at 468 nm with a near‐unity photoluminescence quantum yield of 99.7%, a large Stokes shift of 148 nm (i.e., negligible self‐absorption), and a good environmental stability along with strong X‐ray absorption capability. Moreover, a high light yield of up to ≈ 91 300 photons/MeV and a low detection limit of 52.1 nGy air s −1 are realized, which is more than one hundred times lower than the dose rate of 5.5 µGy air s −1 required for X‐ray medical diagnostics. (C 8 H 20 N) 2 Cu 2 Br 4 ceramic wafer scintillation screen is fabricated by a cold pressing sintering process, and the clear contrast images of opaque metal box and electronic component with a spatial resolution of 9.54 lp mm −1 are realized. This study not only designs a new lead‐free metal halide scintillator, but also develops a universal strategy for the preparation of large‐sized scintillator screen in nondestructive X‐ray imaging.