The invention discloses an organic donor-
acceptor charge transfer eutectic self-supporting film, a
polymer self-supporting film, a flexible
transistor sensor thereof and a preparation method of the flexible
transistor sensor. The sensor comprises an interdigital
electrode, a
semiconductor layer, a
dielectric layer and the like, the
semiconductor layer is an organic donor-
acceptor charge transfer eutectic film, the
dielectric layer is a
polymer film, and the
semiconductor layer and the
dielectric layer are both prepared by a'water-solution-air 'interface film forming method; the preparation method of the sensor comprises the following steps: preparing the interdigital
electrode on the substrate, spreading and volatilizing a
mixed solution containing an organic donor and an organic
acceptor on the water surface, and forming a uniform organic eutectic semiconductor layer on the surface of the interdigital
electrode; and then, forming a
polymer dielectric layer on the semiconductor layer by using the
polymer solution through the same interface method, and finally preparing the gate electrode. According to the invention, various self-supporting single-
crystal, polycrystal and amorphous films can be obtained, the dependence of a traditional spin-
coating method on a substrate is overcome, and a novel semiconductor material for flexible sensing and a sensing mechanism are developed.