Bidentate Ligand-Induced Oriented Transformation of CsPbBr₃ Perovskite Nanocrystals into Nanowires for X-ray Photodetectors

Shape and dimensionality control by ligands is an efficient way to fabricate high-quality perovskite nanocrystals (NCs) with optoelectronic properties. Herein, to realize oriented transformations between different morphologies of CsPbBr3 nanocrystals, we conceived of the use of defects and bidentate ligands to synergistically drive the reorientation of CsPbBr3 nanocrystals into CsPbBr3 nanowires (NWs). By employing aminocaproic acid as the bidentate ligand, CsPbBr3 NWs were reconstructed from the CsPbBr3 NCs (∼7 nm) with 20–60 nm in width and several micrometers in length, as well as a 527 nm photoluminescence (PL) peak, 59% PL quantum yield, and 98.5 ns PL lifetime. The bidentate ligand-directed anisotropic shape evolution and growth of perovskite NWs from NCs was elucidated by transmission electronmicroscopy and PL studies. The photodetectors fabricated with the reconstructed CsPbBr3 NWs displayed a photocurrent enhancement (2.75 × 10–11 A) compared with that of the devices based on solution-synthesized NWs (2.28 × 10–11 A). The device also showed a short response time, indicating its more sensitive photoelectric response. This process provides a viable approach to engineering diverse morphologies of perovskite nanocrystals for optoelectronic applications.