Ultrastable and high-performance amplified spontaneous emission in centimeter-scale inorganic CsPbBr3 single-crystal thin films.

In this work, high-quality and centimeter-scale CsPbBr₃ perovskite single-crystal thin films were grown using the metal-organic chemical vapor deposition method. Extremely flat surfaces without distinct grain boundaries were observed throughout the thin films. A high polarized degree of approximately 0.52 was measured from the single-crystal thin films by analyzing the polarization of the photoluminescence emission spectra. Low threshold amplified spontaneous emissions with an optical gain coefficient of 1215 cm⁻¹ under the excitation energy of 301 μJ/cm² and the highest value of 2857 cm⁻¹ under the excitation energy of 1.08 mJ/cm² were investigated under the excitation of a nanosecond laser at 266 nm. The CsPbBr₃ single-crystal thin films showed excellent stability where the optical gain coefficient could be maintained over 1800 cm⁻¹ after exposure to air for ten months. The results of this study not only provide high-quality single-crystal films for laser applications but also put forward a feasible scheme to improve the stability of the materials. [ABSTRACT FROM AUTHOR]