2 results about "Grain growth" patented technology

The invention discloses a method for preparing small-size grain perovskite thin film by an in-situ method. In the preparation of polycrystalline perovskite thin films, alkylamine is introduced into the precursor solution to modify the surface of perovskite grains, grain growth is hindered and a film with small-size grains is obtained. The perovskite thin film is used as the light-emitting layer ofthe LED device, and the EQE is improved.

The invention discloses a process for improving yield of carbohydrazide. Dimethyl carbonate and hydrazine hydrate are used as raw materials, methanol is used as a solvent, a carbohydrazide solution is prepared, recrystallization is carried out, and the method concretely comprises the following steps: (1) reaction with insulation, (2) reduced pressure distillation, (3) crystallization, (4) centrifugation, and (5) drying. The method is advantageous in that the content of active component carbohydrazide reaches 98% or above, and the content of free hydrazine reduces to 400ppm or below; in the preparation process, a frequency conversion apparatus is used for separately controlling the temperature of the reaction with insulation, the temperature of reduced pressure distillation, and crystallization temperature; the reaction time is reduced, compared with traditional constant rotational speed process, the yield of the product is increased by 20% or above, at the same time, the content of free hydrazine is obviously reduced, and during crystallization, the rotating speed is low, the growth of crystal grains is uniform, later centrifugal operation is convenient, and appearance of the final product is more uniform.