Sensitive and reversible sensing of oxygen based on transition metals doped quasi-2D layered perovskites with 4T1→6A1 luminescence

Abstract

Lead halide perovskites (LHPs) with rich optical properties have shown good prospects in sensing applications through rational design of their composition and structure. Although luminescent LHPs have been proposed as emerging probes for oxygen gas, their various oxygen-sensitive optical properties are still providing new ideas for oxygen sensing research, and oxygen sensing performance of these materials also needs to be improved. Here, a new class of metal-doped LHPs with quasi-two-dimensional (2D) layered structure and ⁴T₁→⁶A₁ luminescence has been fabricated, and their oxygen sensing capability has been demonstrated. As a representative, the layered perovskite A₂CsPb₂Cl₇ with a wealth of accessible Mn²⁺ dopants exhibits a sensitive response to the change of oxygen contents (I₀/I₁₀₀ = 9.75). By analyzing the effect of molecular oxygen on this material during sensing, we highlight that oxygen sensing responses of Mn²⁺-doped quasi-2D LHP are derived from the excited state of ⁴T₁→⁶A₁ luminescence. Dynamic deactivation of Mn²⁺-d excited state by O₂ molecules results in rapid quenching of Mn²⁺ emission and a reversible sensing phenomenon. In addition, Fe³⁺ dopants with the same ⁴T₁→⁶A₁ luminescence are introduced into the quasi-2D layered perovskite, so the possible mechanism has been further supported by similar oxygen sensing behaviors of Fe³⁺ emission. In our perception, above results make these perovskites candidates for oxygen sensing materials, for example, linear response was achieved at normal oxygen levels from 0 % to 21 %. Therefore, this work shows a new oxygen sensing platform based on the quasi-2D layered LHPs with ⁴T₁→⁶A₁ luminescence.