The invention discloses a method for synthesizing high-purity super-
crystal formamidine
bromide (FABr), which is characterized in that the FABr is synthesized by means of anti-
solvent addition and staged cooling, and the method comprises the following steps: (1) feeding for reaction; (2) extracting a crude product; (3) suction
filtration and washing; (4) crystallizing and purifying; and (5)
vacuum drying, through combination of a
neutralization reaction and a recrystallization process, impurities such as
metal ions and acetate ions can be effectively removed, the purity of a final product can reach 99.9% or above through
verification, the method is short in process
route and mild in reaction condition, the total yield can be stabilized to be 85% or above, the whole process is carried out at low temperature and in an
inert atmosphere,
thermal decomposition and oxidation of FABr are reduced, and the method is suitable for industrial production. The product has excellent
thermal stability and storage stability, the FABr
crystal obtained through temperature-controlled
crystallization is uniform in size, easy to store and used for subsequent preparation of a
perovskite precursor solution, used reagents are common, the cost is low, operation steps are simple, and industrial large-scale production is easy to achieve.