Method of forming perovskite thin film and light-emitting device including layer manufactured thereby

A method of forming a perovskite thin film, the method comprising:

• preparing a substrate;
• spraying a first solution of a first perovskite compound precursor through an inner nozzle of a dual nozzle including the inner nozzle and an outer nozzle;
• spraying a second solution of a second perovskite compound precursor through the outer nozzle;
• forming a perovskite compound solution by reacting the first solution of the first perovskite compound precursor and the second solution of the second perovskite compound precursor;
• forming a membrane on the substrate from the perovskite compound solution;
• and
• evaporating a solvent of the perovskite compound solution from the membrane on the substrate.