Amplified Spontaneous Emission From Morphological Controlled All-Inorganic Peroveskite CsPbBr₃

Because of its advantages such as high absorption efficiency,low defect state density,high carrier mobility and adjustable band gap,perovskite shows great potential in the application of solar cells,light emitting diodes and so on.At the same time,its high photo luminescence,the simple preparation process and controllable morphology also make perovskite material to be an ideal laser gain medium.Since the phenomenon of amplified spontaneous emission of perovskite films researched in 2014,perovskite laser become an important research direction in field of luminescence.However,electrically pumped laser is still a huge challenges,so how to reduce the threshold of stimulated radiation is an urgent matter.For laser of perovskite waveguides,the morphology has a great influence on the the amplified spontaneous emission(ASE).In this thesis,the ASE from CsPbBr3 perovskite,as the laser gain medium was studied,and some interesting results were obtained.The details are as follows.(1)Polymer material PEO was used to optimize the morphology of the perovskite planar optical waveguide.As the research indicated,PEO can influence the crystallization process of perovskite and improve the surface coverage of the film,which makes high-quality planar optical waveguide structure formed and the scattering loss of light during propagation reduced.When the pump intensity reached 2.69kw/cm2,we observed ASE from the perovskite planar waveguide.(2)A variety of morphologies of perovskite nanocrystal were prepared using the anti-solvent steam method.Then we improved the preparation method,synthesizing perovskite microrods through hydrophobic treatment.Taking PTFE as the hydrophobic material,we approach the purpose which limit perovskite solution distribution and control crystallization of perovskite materials.Perovskite microrods was synthesized and applied to ASE.The amplified spontaneous emission form perovskite microrods was observed when the single-pulse energy reaches 0.196 ?J/pulse.(3)By applying a non-uniform electric field to the perovskite solution,we get a liquid film with uneven thickness,which can induce the growth of perovskite belt in some specific direction.Using this method,belt-like perovskite was synthesized.With the advantage of millimeter-sized surface area and flat surface,microbelt can be a high quality waveguide.Under the pump of a pulse laser,the ASE with a threshold of 0.225?J/pulse was observed.