Core-shell structure perovskite film, its preparation method and controllable fluorescence display method
A core-shell structure and display method technology, applied in the field of fluorescent display, can solve the problems of inability to prepare large-area perovskite films, poor thermal and humidity stability of perovskite films, etc., and achieves temperature response sensitivity, simple preparation method, fluorescence Restoration effect
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[0041] As mentioned in the background technology, the fluorescence efficiency of the all-inorganic perovskite film itself is very low. Due to the low activation energy, the perovskite film will be destroyed in the face of high temperature and humidity, which limits its use in light-emitting diodes. in the application. In order to solve this problem, the invention provides a method for preparing a core-shell structure perovskite film, comprising:
[0042] In an air environment with a humidity of 10% to 70%, reacting the perovskite film with water vapor for 1 to 60 hours, so that a protective layer is formed on the surface of the perovskite film, thereby obtaining the perovskite film with a core-shell structure ;
[0043] Wherein, the perovskite molecule in the perovskite film is selected from one of the following molecules:
[0044] CsPbCl 3 , CsPbBr 3 , CsPbI 3 , CsPbCl x Br 3-x , CsPbBr x I 3-x (1<x<3); and their dopant molecules;
[0045] The doping materials in th...
Embodiment 1
[0076] This embodiment provides a method for preparing an all-inorganic lead system perovskite film, specifically as follows:
[0077] Take about 50mg of cesium bromide, 80mg of lead bromide, and 10mg of sodium bromide, and add them to the three evaporation sources of the vacuum thermal deposition instrument, and then place the glass substrate above the evaporation chamber so that the medicine can deposited directly on the substrate. Close the vacuum chamber and pump the air pressure in the chamber to 10 -5 Pa. Then heat the three evaporation sources in sequence, first evaporate cesium bromide with a thickness of 6.5nm, then evaporate sodium bromide with a thickness of 0.5nm, and then evaporate lead bromide with a thickness of 7.9nm, and cycle three to four times. The thickness and molar ratio of each material need to be calibrated by a step meter. The above data is the corresponding film thickness obtained from the experiment. For different evaporators, the film thickness n...
Embodiment 2
[0082] This embodiment provides a method for improving the fluorescence of an all-inorganic lead-based perovskite film, specifically as follows:
[0083] The perovskite film prepared in Example 1 was left standing in the air for more than 24 hours, and the humidity was maintained at about 30%. The naked eye could see that the film became rougher and rougher, and at the same time, its fluorescence gradually increased under the irradiation of an ultraviolet lamp. This is Because water will strip off the cesium bromide on the surface, so that the film is in a lead-rich state, at this time, the addition of doping material sodium bromide accelerates the pure CsPbBr 3 into CsPb 2 Br 5 The process of forming a core-shell structure enhances the dielectric trapping effect, thereby enhancing the fluorescence.
[0084] The TEM and SEM images of the above-mentioned highly fluorescent perovskite film after standing in the air are as follows: image 3 As shown, the schematic diagram of t...
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