▎ 摘　　要

NOVELTY - Preparation of thin film involves: providing a dispersion liquid comprising a p-type semiconductor material, a substrate and an inert gas atmosphere (A) doped with an aromatic compound, which is capable of dispersing or dissolving the p-type semiconductor material; and subjecting the dispersion liquid to film-forming treatment on the substrate under the atmosphere (A). USE - The method is useful for preparing thin film useful as hole functional layer in LED (claimed). ADVANTAGE - The method provides thin film, which has flat and compact surface, improves film appearance of hole functional layer and reduces the interface resistance of hole function layer and light emitting layer when applied to the hole functional layer of the LED, thus improving hole transmission efficiency, electron transport efficiency, photoelectric performance and service life of the device, and effectively balancing the empty space of the device. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for an LED, which comprises an anode and a cathode arranged opposite to each other, a light-emitting layer arranged between the anode and the cathode, and a hole functional layer, which is arranged between the anode and the light-emitting layer, and comprises the thin film.