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)M(n)X(3n+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)M(n)X(3n+1)type perovskite, BDAPbI(4)(BDA=NH3C4H8NH3), 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 3.1x10(9) cm(-3). The single-crystal X-ray detector exhibits an excellent sensitivity of 242 mu C Gy(air)(-1) cm(-2)under the 10 V bias (0.31 V mu m(-1)), a detection limit as low as 430 nGy(air) s(-1), ultrastable response current, a stable baseline with the lowest dark current drift of 6.06x10(-9) nA cm(-1) s(-1) V-1, and rapid response time of tau(rise)=7.3 ms and tau(fall)=22.5 ms. These crystals are promising candidates for the next generation of optoelectronic devices.