Research On Properties Of Organic Polymer And Perovskite Multilayer Laser Devices

With the development of science and technology,the research of monochromatic laser has become more and more mature.In recent years,the two-color or multi-color lasers have attracted wide attention of scientists and the public.They are considered to be the key approach to achieve breakthrough technology in the future,such as parallel quantum computing,laser display,laser lighting and so on.Both organic polymers and perovskite materials have demonstrated lower threshold and higher optical gain in laser field,and they are insoluble each other.In this work,it is innovatively proposed that organic polymer and perovskite can be fabricated into multilayer structure laser devices on the same substrate.In order to make device with multi wavelength laser output,it is very important to minimize the optical loss in the device.Firstly,the method of preparing perovskite films with low amplified spontaneous emission（ASE）threshold was discussed.Then,a low-cost,simple and controllable soft nano imprinting technology was developed in the aspect of substrate and perovskite film patterning.Finally,the multilayer structure was optimized gradually to realize the ASE phenomenon of organic materials and perovskite materials.The specific research contents of this thesis are as follows:（1）The fabrication process of perovskite film is optimized.The results show that when the concentration of lead acetate is 0.4 mmol/ml,the surface grain is even and smooth,the roughness is low,and the minimum ASE threshold is 0.24μJ/pulse（8.56μJ/cm²）.At the same time,when lead acetate is used as the precursor solution to prepare samples,there are relatively flexible annealing conditions.High quality perovskite films can be prepared at room temperature or high temperature（250℃）as long as the annealing time is well controlled.A variety of preparation processes that use traditional lead iodide as the lead source are summarized.Compared with this,the preparation method of lead acetate is simpler,easier to control and repeatable.（2）The nano-imprint technology is used to complete the transfer of the IPS template to the main template of the silicon wafer.The DFB grating was obtained by this transfer method.The perovskite（MAPb I₃）film was deposited on it to achieve the vertical single-mode laser emission at the near infrared wavelength.The FWHM is 0.6 nm and the laser threshold is 227.7μJ/cm².The pattern on IPS template was transferred to PFPE and PDMS respectively.PFPE transfer is an easier and effective way of soft grating printing.The perovskite grating structure with clear grooves can be obtained by directly imprinting the perovskite layer with PFPE template.A narrowed ASE peak（FWHM is 2 nm）can be achieved on this patterned perovskite layer.（3）The organic polymer F8BT and MAIPbI₃ perovskite were spin-coated to form a multilayer film laser device.After adding the PS and CA interface layers,the ASE double peak（567 nm and 788 nm）was realized under laser excitation at wavelength of 450 nm.By replacing the organic polymer F8BT with PFN-Br,the interface layer can be reduced by one layer.The PFN-Br+PS+MAPb I₃ sample achieved amplified spontaneous emission at 455 nm and 784 nm when pumping wavelength is at 415nm.