Ligand-Assisted Growth of 2D Perovskite Single Crystal for Highly Sensitive X-Ray Detectors

The emerging 2D layered perovskites have promising optoelectronic properties, good intrinsic stability and reduced ion migration, making them effective for detecting X-ray radiation. However, their application is constrained by poor out-of-plane carrier transport. In this study, inch-sized high-quality CsPb2Br5 layered single crystals (SCs) are developed using an organic ligand-assisted solution process. By modifying the surface energy, the anisotropy of crystal growth is conquered, resulting in CsPb2Br5 SCs with sufficient thickness for X-ray detection. Importantly, this modification significantly enhanced the crystal quality as the grown CsPb2Br5 SCs exhibited longer photoluminescence lifetime and smaller trap density. Notably, the CsPb2Br5 SCs demonstrate unprecedented out-of-plane carrier transport, achieving a high carrier mobility-lifetime product of 2.53 x 10(-2) cm(2)V(-1). This can be attributed to the small interlayer distance and the strong interlayer force of Cs & horbar;Br bonding. Furthermore, CsPb2Br5 SCs possess other intriguing attributes for X-ray detection, including high bulk resistivity and outstanding thermal stability. These advantageous properties enable high-performance vertical-structure X-ray detection with a superior sensitivity of up to 8865.6 mu C Gy(air)(-1)cm(-2) and a low detectable dose rate of 12.7 nGy(air)s(-1). Additionally, CsPb2Br5 SCs exhibit high spatial resolution in X-ray imaging and exceptional thermal stability, making them promising candidates for nondestructive determination.