Observation of Net Stimulated Emission in CsPbBr₃ Thin Films Prepared by Pulsed Laser Deposition

Abstract

Inorganic halid perovskites, such as CsPbX3 (X = Br, Cl, or I), have attracted a great deal of attention for next generation on‐chip optoelectronic devices for which high quality thin films are essential. So far, most utilized fabrication techniques for halide perovskite films have been based on solution synthesized methods, taking advantage of cost effectiveness and flexibility. Conventional solution processed thin films suffer from pinholes, poor morphology and/or low mole fraction when embedded in glass or polymer matrixes, unavoidably limiting their application‐level. Herein, we report the fabrication of high crystalline and coverage CsPbBr3 thin films by using a single‐step physical technique – pulsed laser deposition (PLD). As‐fabricated thin films demonstrate stimulated emission with low pump threshold at room temperature. Systematic investigations suggest that the mechanism of stimulated emission in our CsPbBr3 thin films originates from exciton−exciton inelastic scattering. These results not only shed light on high performance all‐inorganic CsPbBr3 perovskite films for various optoelectronic devices, but also enrich the comprehension of stimulated emission mechanism of all‐inorganic CsPbBr3 perovskite materials.

Laser‐Induced Secondary Crystallization of CsPbBr3 Perovskite Film for Robust and Low Threshold Amplified Spontaneous Emission

“…The exciton scattered into the polariton curve results in P-band emission with a smaller photon energy compare to 1st exciton (E ex ). The general form of the n th P-band emission can be expressed as, [49]…”

Amplified Spontaneous Emission with a Low Threshold from Quasi‐2D Perovskite Films via Phase Engineering and Surface Passivation

“…[40] Above the threshold, the ASE peak displays a slight redshift with a further increase in the pumping intensity (Figure S3, Supporting Information), which is related to the excitonic binding energies in the bi-excitonic emission mechanism. [40][41][42] It is well known that the phase distribution and morphology of quasi-2D RPPs strongly affect the charge carrier dynamics and the ASE performance, and the anti-solvent method is widely used for forming highly homogenous, pinhole-free perovskite films readily and providing morphology control. [43,44] Herein, chlorobenzene (CB) is dropped on the perovskite film as an anti-solvent to promote the crystallization of the quasi-2D RPPs by accelerating the formation of the perovskite nuclei.…”

Temperature-Dependent Amplified Spontaneous Emission in CsPbBr3 Thin Films Deposited by Single-Step RF-Magnetron Sputtering

“…CsPbBr 3 films obtained by vacuum-based co-deposition of CsBr and PbBr 2 precursors exhibited an ASE threshold down to 35 μJ/cm 2 at room temperature under nanosecond pumping [ 33 ]. Furthermore, CsPbBr 3 thin films fabricated by using a single-step physical technique, pulsed laser deposition (PLD), demonstrated stimulated emission with a low pump threshold at room temperature (18 μJ/cm 2 ) under femtosecond pumping [ 34 ]. These results thus show the improved ASE properties of films deposited by dry techniques with respect to solution processed films.…”