The success of metal halide perovskites in photovoltaic and light-emitting diodes (LEDs) motivates their application as a solid-state thin-film laser. Various perovskites have shown optically pumped stimulated emission of lasing and amplified spontaneous emission (ASE), yet the ultimate goal of electrically pumped stimulated emission has not been achieved. As an essential step toward this goal, here, a perovskite diode structure that simultaneously exhibits stable operation at high current density (≈1 kA cm −2 ) and optically excited ASE (with a threshold of 180 μJ cm −2 ) is reported. This diode structure achieves an electroluminescence quantum efficiency of 0.8% at 850 A cm −2 , which is estimated to be ≈3% of the charge carrier population required to reach ASE in the same device. It is shown that the formation of a large angle waveguide mode and the reduction of parasitic absorption losses are two major design principles for diodes to obtain a positive gain for stimulated emission. In addition to its prospect as a perovskite laser, a new application of electrically pumped ASE is proposed as an ideal perovskite LED architecture allowing 100% external radiation efficiency.

Thermal co-evaporation is a promising method for large-scale uniform perovskite deposition. However, the optimization of deposition parameters is an intricate process and often not reproducible between different laboratories. In this...

A comprehensive study of the optical properties of CsPbBr 3 perovskite multiple quantum wells (MQW) with organic barrier layers is presented. Quantum confinement is observed by a blue-shift in absorption and emission spectra with decreasing well width and agrees well with simulations of the confinement energies. A large increase of emission intensity with thinner layers is observed, with a photoluminescence quantum yield up to 32 times higher than that of bulk layers. Amplified spontaneous emission (ASE) measurements show very low thresholds down to 7.3 μJ cm −2 for a perovskite thickness of 8.7 nm, significantly lower than previously observed for CsPbBr 3 thin-films. With their increased photoluminescence efficiency and low ASE thresholds, MQW structures with CsPbBr 3 are excellent candidates for high-efficiency perovskite-based LEDs and lasers.

CsPbBr3 is an inorganic perovskite material that is promising for light‐emitting applications. Such applications are known to benefit from an island‐type active layer structure, which enhances the device's light emission efficiency. Here, the impact of the environment on the island formation in thermally deposited bilayers of CsPbBr3/LiBr is investigated. It is demonstrated that the island formation occurs only in humid environments, leading to an enhancement of the photoluminescence quantum yield by a factor of 350. Time‐resolved grazing‐incidence wide‐angle X‐ray scattering experiments document the island growth process and reveal that the LiBr has already changed the perovskite crystal orientation prior to the island formation.

No abstract