Improved Photoluminescence, Electroluminescence, and Laser Characteristics of 1-Naphthylmethylamine-Based Quasi-Two-Dimensional Perovskite Films at Lower Temperatures

In recent years, halide perovskite materials have made significant progress in optically pumped lasing. Among many reported perovskites, 1-naphthylmethylamine (NMA)-based quasi-two-dimensional (quasi-2D) perovskite films are promising as a gain medium for low-threshold optical lasing. However, their optical laser thresholds are still high for the realization of electrically pumped lasing. To explore the possibility of reducing the thresholds, we investigate temperature-dependent laser characteristics of NMA-based quasi-2D perovskite films fabricated on top of a circularly shaped distributed feedback resonator. Although the laser threshold of these films is already low (∼2 μJ cm^-2) at room temperature (298 K), their threshold is further reduced by ∼1/200 to ∼0.01 μJ cm^-2 as the film temperatures go down to 73 K. From the optical threshold at 73 K, the threshold current density required for the electrical lasing is estimated at a very low value of ∼3.4 A cm^-2. However, the optical laser threshold and estimated current threshold are, respectively, increased to ∼6 μJ cm^-2 and ∼2.04 kA cm^-2 because of the presence of an optical loss in actual devices with a metal electrode. Therefore, future optimization of device architectures to reduce the optical loss is crucial to realizing the electrical lasing.