MA3Bi2I9 single-crystal enables X-ray detection down to nanograys per second

A zero-dimensional (0D) MA3Bi2I9 (MA=CH3NH3) single crystals with inch-sized were fabricated by solution methods. The 0D crystal structure leads to a high energy barrier for ion migration (0.46 eV) and a low dark carrier concentration (~ 10 6 cm-3). As a result, stable devices with a very limit of detection (LoD) of 0.62 nGyair s-1 were achieved, which approaches the background radiation on Earth (~0.1 nGyair s-1).