Skin‐Inspired Piezoelectric Tactile Sensor Array with Crosstalk‐Free Row+Column Electrodes for Spatiotemporally Distinguishing Diverse Stimuli

Abstract

Real‐time detection and differentiation of diverse external stimuli with one tactile senor remains a huge challenge and largely restricts the development of electronic skins. Although different sensors have been described based on piezoresistivity, capacitance, and triboelectricity, and these devices are promising for tactile systems, there are few, if any, piezoelectric sensors to be able to distinguish diverse stimuli in real time. Here, a human skin‐inspired piezoelectric tactile sensor array constructed with a multilayer structure and row+column electrodes is reported. Integrated with a signal processor and a logical algorithm, the tactile sensor array achieves to sense and distinguish the magnitude, positions, and modes of diverse external stimuli, including gentle slipping, touching, and bending, in real time. Besides, the unique design overcomes the crosstalk issues existing in other sensors. Pressure sensing and bending sensing tests show that the proposed tactile sensor array possesses the characteristics of high sensitivity (7.7 mV kPa−1), long‐term durability (80 000 cycles), and rapid response time (10 ms) (less than human skin). The tactile sensor array also shows a superior scalability and ease of massive fabrication. Its ability of real‐time detection and differentiation of diverse stimuli for health monitoring, detection of animal movements, and robots is demonstrated.

Piezotronics in two‐dimensional materials

“…The refraction, diffraction, boundary reflection, and photon scattering in 2D materials and arrayed devices might cause serial interference and influence the resolution of flexible devices during piezo‐phototronics experiments 217,218 . At the same time, the carrier generation and diffusion might lead to electrical serial interference in piezotronics, which is connected to the size, spacing, and distribution of single device, buffer layer thickness, and epitaxial layer thickness of arrayed devices 219,220 . In order to avoid the serial interference, independent electrodes for any single device in arrayed devices are needed, which are difficult for design and fabrication of arrayed devices.…”

Textile-Based Mechanical Sensors: A Review

“…During practical applications, mechanical sensors are subject to various mechanical stimuli such as stretching, squeezing, bending, etc., which require a good deformability of the electrodes and sensing elements in mechanical sensors, a stable sensing function in a large deformation state, and a structural and electrical performance reversibility after the release of deformation [67]. TMSs have unique advantages in terms of deformability, which is generally obtained by optimal structural and material design.…”

Crosstalk‐Free, Stretching‐Insensitive Sensor Based on Arch‐Bridge Architecture for Tactile Mapping with Parallel Addressing Strategy toward Million‐Scale‐Pixels Processing

“…[ 3 , 5 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ] However, efforts to improve the sensing abilities of these devices have tended to focus on increasing their pixel density (e.g., making them fingertip like) [ 3 , 11 , 12 , 16 ] or spatial coverage (e.g., making them skin like). [ 5 , 10 , 21 ] Both approaches lead to a steep growth in the number of pixels required at a quadratic rate and hence long addressing times. As a result, the performance of the sensors developed so far remains unsatisfactory for many applications owing to the poor real‐time spatiotemporal response, reliability, and durability of the large‐scale units.…”

“…This means that polling through 1 million pixels (or a square tactile platform with a resolution of 1 K) would take 125 s, which is unacceptably long for real‐time mapping. Although an alternative method called the “Row + Column” strategy, [ 3 , 9 , 21 ] in which all the x ‐ and y ‐coordinates are recorded at once to allow for 2D mapping was proposed, it resulted in “diagnose confusion” and failed to identify the locations between the reverse coordinates. This failure has limited its applicability in various areas, such as industrial control and aerospace technology.…”