Optical-electrical Dual-mode Electronic Skin For Detection And Differentiation Of Multiple Mechanical Stimuli

In the past few decades,electronic skin(e-skin)sensors,which mimic human skin functions,have been greatly developed due to their great potential for applications in artificial intelligence and human-machine interaction.E-skin can quantitatively evaluate external mechanical stimuli by measuring and analyzing changes in certain physical signals of the sensor(e.g.,resistance,capacitance,and voltage output)in response to external mechanical stimuli,which can assist intelligent robots to perform fine operations such as threading a needle.However,most current electronic skin sensors can only achieve the conversion of different mechanical stimuli into the same signal change trend,thus making it difficult to distinguish between different mechanical stimuli.In addition,the rapid development of the Internet of Things(Io T)in recent years relies on sensing networks with large-scale sensor units,so the energy consumption of sensors should not be underestimated.Notably,the emerging triboelectric nanogenerator technology has been shown to be applicable for building self-powered sensing networks.To solve these problems,this thesis combines two sensing mechanisms,TENG and mechanoluminescence(ML),to design e-skin sensors that can sense and distinguish multiple mechanical stimuli(including pressing,bending,and stretching stimuli)without external energy supply.The main content of the article is as follows.By combining two sensing mechanisms,TENG and ML,two electronic skin sensors with bimodal signal(electrical and optical signals)responses were designed.There are three main innovations in this paper.First,the signal responses of the TENG and ML sensing mechanisms are triggered only by the mechanical stimulus only,so that both sensors do not require external energy supply.The single-electrode mode TENG-based sensor exhibits excellent sensing performance and stability,with a sensitivity of up to 0.89 V/KPa in the pressure range of 0～60 KPa.In addition,we have designed a contact-separation mode TENG with a Zn S:Cu/PDMS composite film with ML performance as the spacer layer,which also exhibits excellent sensing performance and stability;second,the special structure design makes the device have different signal response patterns to different mechanical stimuli,so that different mechanical stimuli can be easily distinguished;finally,by fixing the device on the finger,we achieved real-time monitoring and differentiation of finger flexion motion and external mechanical stimuli.Meanwhile,we prepared a 4×4 sensor array for finger motion trajectory tracking and touch position sensing.Overall,this thesis presents an electronic skin sensor with a dual-mode signal response that combines both ML and TENG.The experimental results show that the sensor has promising applications in the fields of intelligent robotics,human-machine interaction,and personalized health monitoring.