Stabilizing Single‐Source Evaporated Perovskites with Organic Interlayers for Amplified Spontaneous Emission

Abstract Metal halide perovskites are promising semiconductors with promising applications in optoelectronic and photonic technologies. When coherent emission applications are targeted, materials with lower lasing thresholds and increased stabilities must be developed to increase the performance under continuous wave optical pumping condition and finally allow the realization of the long sought‐after electrically pumped lasers. Perovskite multiple‐quantum‐wells (MQWs) can potentially ease the population inversion by confining photoexcitation within the heterostructure's wells, but their fabrication process and structural design still require a delicate optimization to make them valuable photonic platforms. Here, perovskite MQWs are fabricated based on organic semiconductors and CsPbBr₃, using a facile and easily scalable sequential single‐source vacuum evaporation method. Perovskite with the organic interlayer shows radically enhanced phase stability, passivated defects, and improved radiative recombination properties. In this way, upon proper design of the heterostructure wells and barriers thicknesses, optically pumped amplified spontaneous emission can be achieved. This work reports an effective fabrication approach for perovskite MQWs, while providing a deeper understanding of their photophysical properties to foster their application as coherent light emitters.