Surface ligand engineering of CsPbBr3 perovskite nanowires for high-performance photodetectors.

Surface ligand engineering is of great importance for the preparation of one-dimensional (1D) CsPbBr3 nanowires for high-performance photodetectors. The traditional long-chain terminated ligands such as oleylamine/oleic acid (C18) used in the preparation of CsPbBr3 nanowires will form an electrically insulating layer on the surface of the nanowires, which hinders the effective transport of charge carriers in optoelectronic devices. In this paper, short-chain ligands, including dodecylamine/dodecanoic acid (C12), octylamine/octanoic acid (C8) and hexylamine/hexanoic acid (C6), are introduced to partially replace long-chain ligands (C18) to successfully prepare various CsPbBr3 nanowires via a solvothermal method. Microstructure characterization indicates that the four kinds of nanowires before/after surface ligand engineering, which are named as C18-CsPbBr3, C12/18-CsPbBr3, C8/18-CsPbBr3 and C6/18-CsPbBr3, all have high aspect ratio and purity. As compared with CsPbBr3 with long-chain terminated ligands, the C8/18-CsPbBr3 and C6/18-CsPbBr3 nanowires with shorter chain ligands exhibit superior photoluminescence (PL) performance and stability under adverse conditions such as ultraviolet irradiation and high temperature. The constructed photodetectors based on C8/18-CsPbBr3 and C6/18-CsPbBr3 nanowires have shown improved performances. This work provides a new idea for the preparation of CsPbBr3 nanowires with high optical properties, stability and charge transport, and the prepared CsPbBr3 nanowires have potential application prospects in optoelectronic devices.