Centimeter-Sized Single Crystal of Two-Dimensional Halide Perovskites Incorporating Straight-Chain Symmetric Diammonium Ion for X-Ray Detection.

Two-dimensional (2D) AA'n-1 Mn X3n+1 type halide perovskites incorporating straight-chain symmetric diammonium cations define a new type of structure, but their optoelectronic properties are largely unexplored. Reported here is the synthesis of a centimeter-sized AA'n-1 Mn X3n+1 type perovskite, BDAPbI4 (BDA=NH3 C4 H8 NH3 ), single crystal and its charge-transport properties under X-ray excitation. The crystal shows a staggered configuration of the [PbI6 ]4- layers, a band gap of 2.37 eV, and a low trap density of 3.1×109  cm-3 . The single-crystal X-ray detector exhibits an excellent sensitivity of 242 μC Gyair -1  cm-2 under the 10 V bias (0.31 V μm-1 ), a detection limit as low as 430 nGyair  s-1 , ultrastable response current, a stable baseline with the lowest dark current drift of 6.06×10-9  nA cm-1  s-1  V-1 , and rapid response time of τrise =7.3 ms and τfall =22.5 ms. These crystals are promising candidates for the next generation of optoelectronic devices.