Recent Advances in Pen‐Based Writing Electronics and their Emerging Applications

Abstract

. Inspired by daily hand-writing, innovative and ubiquitously available pens can be employed to write conductive patterns on multiple substrates; such a low-cost, fast, and user-friendly direct writing paradigm has recently aroused remarkable research interest as a promising electronics prototyping strategy. In this review, state-of-art advances in techniques for direct writing of electronics are presented, and pros and cons of each fabrication route are discussed. Emerging applications of pen-based writing electronics are also summarized. Based on these, fi nal conclusions, limitations and challenges, as well as ongoing perspectives are illustrated. a polyester-based tattoo-like integrated epidermal electronic system has been developed that can perform real-time muscle movement, heart activities, and brain-wave detection without the engagement of expensive and bulky medical instrumentations, holding promises to empower doctors to timely monitor vital signs of patients in a simple and effi cient way. [ 3 ] For these applications, the ideal electronics should be low-cost, easily accessible, high-performance, rapid prototyping, and user friendly etc. Consequently, increasing attention has been devoted to discovering several factors closely related to fl exible electronics (e.g., substrates, conductive materials, and manufacturing techniques) for fabricating electronics with increased performance and decreased cost. [ 7 ] Among them, the development of fast and cost-effective fabrication strategies has drawn close attentions for realizing lowcost fl exible electronics. [8][9][10] Recently, various techniques have been developed to fabricate fl exible electronics, such as coating, [ 11,12 ] sputtering, [ 13 ] and printing techniques (e.g., gravure printing, [ 14 ] fl exo printing, [ 15 ] offset printing, [ 16 ] inkjet printing, [ 17 ] and screen printing [ 18 ] ). Specifi cally, printing techniques enable rapid prototyping of components and devices with accurate three-dimensional (3D) structures, thus facilitating achievement of functional 3D electronics. [19][20][21] Based on a newly developed embedded 3D printing system, the fabrication of strain and pressure sensors has been demonstrated to be viable within highly stretchable silicon polymer substrates, exhibiting huge potential for the production of fl exible electronics and wearable devices with arbitrary constructs and unique functions. [ 6 ] However, these sophisticated techniques may not live up to the emerging demand of low cost, easy accessibility and rapid prototyping for fl exible electronics fabrication, since the long processing period of coating, the high energy consumption of sputtering, and the inevitable enrollment of expensive professional equipment of printing are all intractable issues that can hardly be overlooked. [ 22,23 ] As an alternative technique and inspired from day-to-day hand writing, various writing instruments, such as brush pen, [ 22,24,25 ] pencil, [26][27][28][29] fountain pen, [ 30,31 ] and ball pen, [32][33][34][35] have been re...

Printable Semiconductors for Backplane TFTs of Flexible OLED Displays

“…The last printing technique is a handwriting process, which was recently proposed by Grey et al using a commercially available calligraphic parallel metal plate pen (Figure g) . This method is based on the increasing research interest toward easier, faster, and less expensive production for the transfer of functional inks onto various substrates . In this study, a hand‐drawn ZnO thin film exhibited a continuous and uniform surface.…”

Fine Art of Thermoelectricity

“…Nowadays, paper is often considered as a flexible substrate due to recent advances in printed and drawn electronics. 15,16 Despite the low electrical and thermal conductivity of paper, there are still only few reports on paper-based thin-film thermoelectric elements. 17,18 The lead in a pencil is usually made of graphite powder and inorganic clay in different ratios.…”

Low-Cost Printed Flexible Antenna by Using an Office Printer for Conformal Applications

“…Although the conventional office printer has also been used for printing the radiating part of the antenna on glossy paper by using AgNP ink to reduce the fabrication cost of the antenna, it requires long annealing time to exhibit reasonable conductivity for the antenna applications [11]. Some commercially available instantly chemically cured paints and markers are also available to avoid the thermal sintering process, but the large silver nanoparticle size (1 mm) with uneven and high sheet resistance of up to 55 Ω/sq limits their implementation as an instant prototyping technique [12][13][14]. Hence, the formation of an AgNP ink layer by an office inkjet printer is one of the viable additive fabrication techniques which offers the advantage of being compatible with low-cost roll-toroll processing [15].…”