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

We report 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 CsPbBr₃nanocrystals, we conceived of the use of defects and bidentate ligands to synergistically drive the reorientation of CsPbBr3nanocrystals into CsPbBr₃nanowires (NWs). By employing aminocaproic acid as the bidentate ligand, CsPbBr₃NWs were reconstructed from the CsPbBr₃NCs (~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 CsPbBr₃NWs displayed a photocurrent enhancement (2.75 × 10^-11A) compared with that of the devices based on solution-synthesized NWs (2.28 × 10^-11A). 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.