Self-Powered Smart Textile Based on Dynamic Schottky Diode for Human-Machine Interactions

Abstract

The growing demand for sustained self-powered devices with multifunctional sensing networks is one of the main challenges for smart textiles, which are the critical elements for the future Internet of Things (IoT) and Point of Care (POC). Here, cellulose-based smart textile is integrated with dynamic Schottky diode (DSD) to generate sustained power source (current density of 8.9 mA m⁻² ) for self-powered built-in sensing network. In response to normal and shear motions, a pressure sensor with a sensitivity of 0.12 KPa⁻¹ and an impact sensor are demonstrated, respectively. The woven structure of the textile contributes to signal amplification, which can also form a matrix of sensing elements for distributed sensing. The proposed strategy of fabricating self-powered and multifunctional sensing networks with smart textiles shows tremendous potential for future intelligent society.

Keywords: biaxial detection; dynamic Schottky diodes; self-powered; sensing network; smart textile.

Figure 1

Self‐powered Dynamic Schottky Diodes‐based Smart Textile. Schematic of A) the hierarchical structure of cellulose textile. B) Biaxial motions detection and sensing networks with the smart textile. C) A representative thread junction acting as a Schottky diode. D) Energy band diagram of the DC generation in Dynamic Schottky Diode under short‐circuit condition.

Figure 2

Material characterization: fiber & textile. A) SEM image of a single cellulose fiber. B) SEM image of the cross‐section of cellulose fiber. C) SEM image of twisting threads. D) SEM image of the nonwoven textile. E) Optical image of the woven textile (nylon). F–H) Optical images of thread F), nonwoven textile G), and woven textile H) before (upper) and after (lower) being coated with PEDOT: PSS. I–J) Tensile tests of thread, nonwoven textile, and woven textile without (I) & with (J) coating PEDOT: PSS. K) Ultimate strains for PEDOT: PSS treated and untreated fibers, nonwoven textiles, and woven textiles.

Figure 3

Interfacial mechanism and characterizations of the DC output. A) Comparison of outputs decaying over time in dry and oil‐sealed smart textiles. B) Interval cycling performance comparison of oil‐sealed sample and sample under wet conditions. C) Comparison of interval cycling performance showing decaying of DSD outputs (J _SC). D) Schematic mechanism of electrochemical decay and oil‐sealing strategy. E,F) Different kinds of E) short‐circuit current density (J _SC) and F) open‐circuit voltage (V _OC) output of Al‐Al pair under different moisture conditions (wet and dry) and motion conditions (static and dynamic). G) Comparison of DSD signals in different pairs of electrodes. H) Comparison of EC signals in different pairs of electrodes. I) Al atomic percentage at interface 1&2 of electrode pairs under different conditions.

Figure 4

Demonstration and characterizations of biaxial sensing networks. A) Schematic of the scenario of smart textile for detecting normal pressure (I) and shear motion (II). B) Voltage outputs of sliding motion under different normal pressure. C) Characterizations of pressure‐dependent sensors in terms of voltage and current outputs. D) Measurement and photos of voltage outputs in response to mechanical impact. E–F) Measurement of voltage outputs in pressure sensor matrix under 1‐junction (E) and 2‐junction (F) conditions. G) Photo of woven structure in smart textile. H) Demonstration of the motion sensing array of different distributions. I) Effective in‐parallel circuit of woven structure and its output as a function of the number of rows.