Field-Controllable Flexible Strain Sensors Using Pentacene Semiconductors

In this letter, we present the first flexible strain sensor based on pentacene semiconductors, employing a transistor-like Wheatstone bridge configuration, where the ON/OFF state of the sensor is controlled by the bottom gate bias. The sensor was characterized with bending at 0deg, 45deg, and 90deg with respect to the bridge bias direction for different strains of 1deg/_infin, 1.25deg/_infin, 1.67deg/_infin, and 2.5deg/_infin. The sensitivity values at the ON state for the 0deg, 45deg, and 90deg bending exhibit 1.6, 7.2, and 4.1 nA/deg/_infin, respectively, revealing the highest sensitivity for the diagonal (45deg) direction. It is expected that this field-controllable strain sensor leads to a reduced circuit complexity and a reduced cost when embedded into a large-area sensor array system by eliminating the need for additional switching devices.