Room-temperature synthesis of Ag- and Mn-doped Cs2NaBiCl6 octahedrons for dye photodegradation

Abstract

All-inorganic lead halide perovskite (LHP) nanomaterials have been recognized as a competitive candidate for optoelectronic applications. However, the lead toxicity and intrinsic instability have limited their commercialization. Herein, a facile room-temperature approach is developed for the synthesis of an environmentally friendly all-inorganic orange-red-emitting Ag-doped and Mn-doped lead-free halide double perovskite Cs₂NaBiCl₆ (CNBC) in the shape of an octahedron. Only very weak orange-red photoluminescence (PL) is observed in the undoped CNBC octahedrons. However, both Ag and Mn doping heavily enhance the PL intensity of the CNBC samples. The stability of the representative Ag-doped and Mn-doped CNBC is studied under various conditions such as an ambient environment, high temperatures up to 400 °C, and UV irradiation. The alcohol-based photocatalytic performances of the samples are investigated by degradation of Rhodamine B (RhB), methyl orange (MO) and methylene blue (MB) in ethanol, demonstrating a strong and stable photodegradation activity. This work will offer a facile and cost-effective protocol in doped lead-free double perovskites as a stable and environmentally friendly alternative for environmental photocatalysts.