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Facile and Controllable Fabrication of High‐Performance Methylammonium Lead Triiodide Films Using Lead Acetate Precursor for Low‐Threshold Amplified Spontaneous Emission and Distributed‐Feedback Lasers

Organic–inorganic lead halide perovskites have emerged rapidly as the most attractive materials for photovoltaics in the last 10 years. Intense research has been done on crystal growth and morphology control to improve their power conversion efficiencies. Furthermore, perovskites also show great potential for optical amplification and lasing. Despite the numerous reports on how processing conditions affect the perovskite light‐harvesting properties, effects on amplified spontaneous emission (ASE) or lasing performance have attracted considerably less attention. Herein, a detailed study on the ASE performance of methylammonium lead triiodide (MAPbI3) films, processed with lead acetate (Pb(Ac)2) as lead source following a one‐step spin‐coating method and exposed to different post‐deposition conditions, is presented. It is found that the use of Pb(Ac)2 instead of lead iodide (PbI2) accelerates the crystal growth and simplifies the fabrication procedure. Even very thin MAPbI3 films (≈70 nm) can sufficiently support optical amplification and lasing in surface‐emitting distributed‐feedback (DFB) cavities. The facile and highly controllable MAPbI3 film formation observed with Pb(Ac)2 as precursor makes it a preferred choice with respect to PbI2 for future perovskite laser diodes.