Overlarge Gauge Factor Yields a Large Measuring Error for Resistive-Type Stretchable Strain Sensors

Stretchable strain sensors have recently attracted great attention due to their extensive applications in advanced devices. Plenty of work has been devoted to enlarging the gauge factor (GF) (reaching as high as 10(7)), since the conventional wisdom holds that a high GF indicates a low limit of detection and a high resolution of a sensor. Here, the effects of the GF on the measurement accuracy is investigated for resistive-type strain sensors, via the basic approach based on Ohm's law and the commonly used method of Wheatstone bridge, respectively. It is found that a bigger GF is not always better for improvement of the measurement accuracy, which is contrary to conventional wisdom. Overlarge gauge factor yields a large measuring error for resistive-type stretchable strain sensors (reaching the measuring error of 50% for GF = 5 x 10(4)under a typical measurement condition). This finding is of much significance for providing theoretical guidance for the sensor design and avoid more efforts on overlarge GF.