The invention relates to the field of organic electrochemical transistors (OECT), in particular to a modified
organic semiconductor material, a
composite film, a preparation method, application and an
organic electrochemical transistor, and the preparation method of the modified
organic semiconductor material comprises the following steps: carrying out gradient thermal
polymerization modification treatment on a
semiconductor polymer material and a modifier in a formula 1 (1), the modified
organic semiconductor material is prepared; the gradient thermal
polymerization modification treatment comprises a low-temperature heat preservation
polymerization process and a high-temperature heat preservation polymerization process; wherein the temperature in the low-temperature heat preservation polymerization process is 100-150 DEG C; the temperature in the high-temperature insulation polymerization process is 200-280 DEG C. According to the material prepared by the method and the constructed film, the optimal balance is achieved between the mechanical flexibility and the volume stability, the Young modulus is remarkably reduced, and swelling and
stress concentration caused by
ion embedding are effectively relieved; therefore, the operation stability and the service life of the
organic electrochemical transistor in long-time electrochemical circulation and air environment are remarkably improved, and meanwhile, the basic
electrical performance of a device is not influenced.