Self-powered triboelectric-mechanoluminescent electronic skin for detecting and differentiating multiple mechanical stimuli

Electronic skin (e-skin) with the ability to sense and differentiate multiple stimuli is crucial for the development of intelligent robots and personalized medical monitoring. Here, a self-powered triboelectric-mechanoluminescent electronic skin (STMES) with the ability to discriminate multiple stimuli is proposed by introducing a strain-sensitive mechanoluminescent spacer layer in a contact-separation mode triboelectric nanogenerator (TENG). The STMES is sensitive to normal force and with a maximum sensitivity of 2 V/N when served as a contact-separation mode TENG, while the mechanoluminescent spacer exhibits optical strain response up to 35%. Both electrical and optical signals are driven by mechanical stimuli only (without the need for external power). In addition, with different signal response patterns to multiple mechanical stimuli, the device can differentiate among mechanical stimuli including pressing, bending, and stretching. Furthermore, continuous tracking of finger movements and external mechanic stimuli is achieved by attaching the STMES to the finger. And a 4 x 4 sensor array demonstrates the capability of the STMES in spatial position detection. Featuring with these characteristics, the STMES may have great potential for human-machine interaction, wearable electronics, and robotic manipulation applications.