Optical properties of lead-free Cs 3 Bi 2 I 9 nanowire arrays prepared by template

Bismuth -based (Bi) perovskites have garnered significant interest as alternatives to lead -based (Pb) perovskites in photoelectric applications due to their non -toxicity and diverse structural properties. However, the inherent high limitation of electrons presents a significant challenge to their further utilization in various applications. Herein, all -inorganic Cs 3 Bi 2 I 9 nanowire arrays have been successfully prepared by AAO template combined with the twostep method of low -temperature solution. Compared to the Cs 3 Bi 2 I 9 film, the Cs 3 Bi 2 I 9 nanowire arrays obtained the higher photoluminescence intensity, indicating a strong interaction between Cs 3 Bi 2 I 9 and AAO, resulting from the significant weakening of the high electron confinement in the valence band of Cs 3 Bi 2 I 9 , which presenting as the valence band of the Cs 3 Bi 2 I 9 -AAO is mainly contributed by the O 2p orbital, while the conduction band does not change significantly. In addition, the Cs 3 Bi 2 I 9 nanowire arrays have been demonstrated with the enhanced environmental and thermal stability, which maintain 90 % of their initial photoluminescence intensity after 120 h (in a vacuum) heating at 80 degrees C or after 10 days in the air (relative humidity of 40 %).