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 0 degrees, 45 degrees, and 90 degrees with respect to the bridge bias direction for different strains of 1 parts per thousand, 1.25 parts per thousand, 1.67 parts per thousand., and 2.5 parts per thousand. The sensitivity values at the ON state for the 0 degrees, 45 degrees, and 90 degrees bending exhibit 1.6, 7.2, and 4.1 nA/parts per thousand, respectively, revealing the highest sensitivity for the diagonal (45 degrees) 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