Highly conductive and flexible fiber for textile electronics obtained by extremely low-temperature atomic layer deposition of Pt

Abstract

Thermal atomic layer deposition (ALD) of metal has generally been achieved at high temperatures of around 300°C or at relatively low temperatures with highly reactive counter reactants, including plasma radicals and O 3 , which can induce severe damage to substrates. Here, the growth of metallic Pt layers by ALD at a low temperature of 80°C is achieved by using [(1,2,5,6-η)-1,5-hexadiene]-dimethyl-platinum(II) (HDMP) and O 2 as the Pt precursor and counter reactant, respectively. ALD results in the successful growth of continuous Pt layers at the low temperature without any reactive reactants owing to the low activation energy of the HDMP precursor for surface reactions. Because of the high reactivity of the precursor, the growth of a pure Pt layer is achieved on various thermally weak substrates, leading to the fabrication of high-performance conductive cotton fibers by ALD. A capacitive-type textile pressure sensor is successfully demonstrated by stacking elastomeric rubber-coated conductive cotton fibers perpendicularly and integrating them onto a fabric with a 7 × 8 array configuration to identify the features of the applied pressure, which can be effectively utilized as a new platform for future wearable and textile electronics. INTRODUCTIONAtomic layer deposition (ALD) has widely attracted considerable interest for various high technologies, such as semiconductor devices and display devices, 1-3 because of its superb ability to deposit ultrathin films with excellent controllability and conformality even on complex three-dimensional (3D) structures. 1-8 Based on these superior properties, ALD has been intensively studied for several applications. In particular, textile electronics using the ALD is one of the promising fields since several materials can be readily deposited at temperatures lower than 150°C by ALD, leading to the effective functionalization of thermally fragile substrates such as plastics, cellulose papers and polymeric textiles. [9][10][11][12] Chen et al. 13 demonstrated hydrophobic silk fabrics with a high laundering durability and robustness due to a TiO 2 coating deposited by ALD. However, in the case of metal ALD, since temperatures as high as 300°C are generally required to achieve successful deposition with the thermal energy of the precursor reactions, it is difficult to deposit conformal metal films onto thermally weak substrates using ALD, causing difficulties in a wide range of applications, including textile electronics. 14,15 To ensure successful metal ALD at low temperatures, ALD in which the

Electrically Conductive Coatings for Fiber-Based E-Textiles

“…into electrical signals that can then be monitored. Pressure and strain sensing can be achieved by various principles, including optical [120][121][122][123], piezoelectric [124], hybrid piezoelectric and triboelectric [125], resistive [116,126], and capacitive sensing [24,26,127]. Resistive and capacitive type sensors are most often employed due to their facile fabrication, ease of use, and relatively simple electronics [128,129].…”

“…Electrical conductivity at the fiber level can be achieved by using either intrinsically conducting polymers (ICPs) in forming the fiber or by coating conventional insulating fibers with conducting materials [21]. Various materials such as ICPs [22,23], conducting polymer composites [24,25], metals [21,26], and carbon based materials, such as carbon nanotubes [27,28], carbon nanopowders [1] and graphene [29,30], have been used to achieve this. These materials have been applied using coating methods such as electro-and electroless deposition [31][32][33], dip-coating [34,35], and chemical vapor deposition (CVD) [23,30] to achieve such electrically conductive e-textile coatings.…”

“…The electrically conductive coated fibers can be used in a variety of applications in e-textiles. However, we limit the scope of this review to cover one of the most explored areas in e-textiles-the fiber-based sensors [25][26][27]. A sensor is a device that can respond to an external stimulus by generating a measurable signal.…”

Toward Fully Manufacturable, Fiber Assembly–Based Concurrent Multimodal and Multifunctional Sensors for e‐Textiles

“…Piezoresistive sensors in the form of fibers/yarns and printed layers on fabrics have been proposed for monitoring motion, posture, and various physiological signals for patient monitoring and rehabilitation . For pressure measurements, multicore fibers consisting of layers of soft dielectric and conductive polymers or thin metal films, sets of orthogonal fibers, or fabric‐like structures with soft dielectric and conductive fibers have been employed to form capacitive structures. While remarkable progress has been made in e‐textiles, practical real‐life products in e‐textiles remain elusive.…”

Room-temperature processing of silver submicron fiber mesh for flexible electronics

“…[1][2][3][4][5][6][7] Ultrafine metal fibers are one of the key components used to prepare flexible electronics devices fulfilling the above characteristics, [8][9][10][11] and they have been extensively studied in a variety of fields, such as smart windows, 12 touch screen, [13][14][15] nanocircuits, [16][17][18] artificial electronic skin, 19-24 solar cells, 25 and interactive electronics. 26 In the context of these applications, how to use the ultrafine metal fibers on flexible substrate is a pivotal problem.…”