Disclosed herein is a thin film prepared using a mixture of nanocrystal particles and a molecular precursor. The nanocrystal is used in the thin film as a nucleus for crystal growth to minimize grain boundaries of the thin film and the molecular precursor is used to form the same crystal structure as the nanocrystal particles, thereby improving the crystallinity of the thin film. The thin film can be used effectively in a variety of electronic devices, including thin film transistors, electroluminescence devices, memory devices, and solar cells. Further disclosed is a method for preparing the thin film.