Inorganic Ions Assisted the Anisotropic Growth of CsPbCl₃ Nanowires with Surface Passivation Effect

All-inorganichalide perovskite nanowires (NWs) exhibit improvedthermal and hydrolysis stability and could thus play a vital rolein nanoscale optoelectronics. Among them, blue-light-based devicesare extremely limited because of the lack of a facile method to obtainhigh-purity CsPbCl3 NWs. Herein, we report a direct andfacile method for the synthesis of CsPbCl3 NWs assistedby inorganic ions that served both as a morphology controlling agentfor the anisotropic growth of nanomaterials and a surface passivationspecies modulating the surface of nanomaterials.

This new approachallows us to obtain high-purity and size-uniform NWs as long as 500nm in length and 20 nm in diameter with high reproducibility. X-rayphotoelectron spectroscopy and ultrafast spectroscopic measurementsconfirmed that a reduced band gap caused by the surface species ofNWs relative to nanocubes (NCs) was achieved at the photon energyof 160 eV because of the hybrid surface passivation contributed byadsorbed inorganic ions.

The resulting NWs demonstrate significantlyenhanced photoelectrochemical performances, 3.5-fold increase in thephotocurrent generation, and notably improved stability compared totheir NC counterparts. Our results suggest that the newly designedNWs could be a promising material for the development of nanoscaleoptoelectronic devices.