Electrically assisted amplified spontaneous emission in perovskite light-emitting diodes

Abstract

Metal halide perovskites have emerged as promising gain materials for thin-film laser diodes. However, achieving electrically excited amplified spontaneous emission (ASE) in perovskite light-emitting diodes (PeLEDs), a pre-condition for perovskite laser diodes, is hindered by the conflicting requirements of high conductivity and high net modal gain of the device stack. Here we develop a transparent PeLED architecture that combines low optical losses with excellent current-injection properties. Using 2.3 ns optical pulses at 77 K, we achieve ASE with a threshold of 9.1 μJ cm−2. Upon submicrosecond electrical excitation at 77 K of the same device, we achieve current densities above 3 kA cm−2 with irradiance values above 40 W cm−2. Notably, co-pumping the PeLED with optical pulses that are synchronized with the leading edge of an intense electrical pulse results in a reduction of the ASE threshold by 1.2 ± 0.2 μJ cm−2, showing that electrically injected carriers contribute to optical gain. Furthermore, to assess the feasibility of a perovskite semiconductor optical amplifier, we probe the PeLED with 1-μs-long optical excitation and observe continuous-wave ASE at a threshold of 3.8 kW cm−2. Finally, we show that such intense electrical pulses generate electroluminescence brightness levels close to half the irradiance produced by continuous-wave optical pumping at the ASE threshold. This work shows that perovskite semiconductor optical amplifiers and injection lasers are within reach using this type of transparent PeLED.