All‐Inorganic Hetero‐Structured Cesium Tin Halide Perovskite Light‐Emitting Diodes With Current Density Over 900 A cm−2 and Its Amplified Spontaneous Emission Behaviors

Pursuing novel new materials for fabricating efficient electrically pumped lasers is the emphasis of researchers for decades. Although organic semiconductors with high gain have been reported previously, a significant challenge remains in using them for electrically pumped lasers due to their low carrier mobility. Recently, hybrid halide perovskites have been reported to possess high carrier mobility and optical gain which allows them to be used for various optoelectronic applications. To explore the feasibility of using them as possible candidates for electrically pumped lasers, tin (Sn)‐based perovskite light‐emitting diodes (PeLEDs) with all‐inorganic heterostructure are fabricated by the vapor‐deposition process. The all‐inorganic hetero‐structured PeLEDs exhibited a maximum EQE of ≈0.34%, and withstood current density up to 915 A cm −2 with small emission zone of 0.01 mm 2 . In addition, by vacuum vapor deposition, extremely smooth and uniform cesium tin halide perovskite films with small grain size (≈60 nm) are obtained, in which low threshold (≈7 µJ cm −2 ) of their amplified spontaneous emission was presented. These characteristics demonstrate the great potential of using them as gain media for electrically pumped lasers.