The invention discloses a method for preparing an organic
ammonium metal halide film. A half-closed type carrier gas free hot wall type low-pressure
chemical vapor deposition method process is adopted to prepare the organic
ammonium metal halide film. The method comprises the following steps: firstly, preparing a
metal halide (MX2) film on a
quartz substrate by using a dry method or a wet method, and transferring the metal halide (MX2) film into a
glass tube for annealing, wherein one end of the
glass tube is sealed and the other end is grounded; secondly, transferring the energy to organic
ammonium (AX)
powder inside the
glass tube through a hot wall, forming steam blocks through self-
diffusion of AX steam in
low vacuum, performing
chemical reaction on MX2 with a hot substrate to generate the film which is uniform in thickness, good in appearance, high in light
absorption rate and smooth in surface, and performing in-situ annealing so as to generate the AMX3 film which is dense in structure and high in
crystallinity degree. The method has the advantages that in-situ annealing can be performed in the film formation process, continuous vacuuming is not needed, the preparation time is shortened, the
energy consumption is reduced, the filming efficiency is high, the charge capture trap in the film is reduced, and the carrier mobility is increased.