Silver\nNanowire-Based Printable Electrothermochromic\nInk for Flexible Touch-Display Applications

Abstract

Flexible,\nlightweight, low-power, and low-cost displays are an\nactive area of interest in the electronics community. In this work,\nwe have developed a composite electrothermochromic material consisting\nof silver nanowires (Ag NWs) and thermochromic powders, which exhibits\nreversible color (phase) change during biasing due to Joule heating.\nA wide variety of color combinations are possible with suitable thermochromic\nmaterial selection. We have formulated this composite material as\na printable ink so that patterned deposition can be achieved in a\nsingle step. A low processing temperature of 100 °C makes the\ncomposite compatible with a wide range of flexible substrates such\nas paper and polyethylene terephthalate (PET). The material (encapsulated\nwith polydimethylsiloxane (PDMS)) exhibits good flexibility and is\nobserved to be functional after 10 000 bending cycles with\n<7% resistance change. We have fabricated a low-power seven-segment\ncolor display to show the material’s suitability for practical\ndisplay applications. We have also demonstrated that the same layer\ncan function as a display and as a touch sensor because of its conducting\nand chromatic properties without additional active layers on top.\nThe material is suitable for the fabrication of low-cost, flexible\ntouch color displays for interactive electronic readers, digital posters,\nand flexible digital signboards.