Gas sensor, sensor array and display panel

The invention discloses a gas sensor, a sensor array and a display panel. The gas sensor comprises a sensing piece and a thin film field effect transistor; the sensing piece is used for contacting external gas and reacting; the sensing element is arranged between the drain electrode and the source electrode of the thin film field effect transistor; before the sensing piece reacts, the current between the drain electrode and the source electrode is a first current; after the sensing piece reacts, the current between the drain electrode and the source electrode is second current; the first current and the second current are used for reflecting parameters of external gas. The sensing piece is arranged between the drain electrode and the source electrode of the thin film field effect transistor, so that the sensing piece prevents the current between the drain electrode and the source electrode from being converted into the second current from the first current before and after the external gas reacts, and the cur