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- additive-free inks (1)
- flexible electrochromics (1)
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- inkjet printing (2)
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- zin-ion storage (1)
Scientific Unit
Direct inkjet printing of functional inks is an emerging and promising technique for the fabrication of electrochemical energy storage devices. Electrochromic energy devices combine electrochromic and energy storage functions, providing a rising and burgeoning technology for next-generation intelligent power sources. However, printing such devices has, in the past, required additives or other second phase materials in order to create inks with suitable rheological properties, which can lower printed device performance. Here, tungsten oxide nanocrystal inks are formulated without any additives for the printing of high-quality tungsten oxide thin films. This allows the assembly of novel electrochromic pseudocapacitive zinc-ion devices, which exhibit a relatively high capacity (≈260 C g−1 at 1 A g−1) with good cycling stability, a high coloration efficiency, and fast switching response. These results validate the promising features of inkjet-printed electrochromic zinc-ion energy storage devices in a wide range of applications in flexible electronic devices, energy-saving buildings, and intelligent systems.
Abstract The direct printing of microscale quantum dot light-emitting diodes (QLEDs) is a cost-effective alternative to the placement of pre-formed LEDs. The quality of printed QLEDs currently is limited by nonuniformities in droplet formation, wetting, and drying during inkjet printing. Here, optimal ink formulation which can suppress nonuniformities at the pixel and array levels is demonstrated. A solvent mixture is used to tune the ejected droplet size, ensure wetting, and provoke Marangoni flows that prevent coffee stain rings. Arrays of green QLED devices are printed at a resolution of 500 pixels in.−1 with a maximum luminance of ≈3000 cd m−2 and a peak current efficiency of 2.8 cd A−1. The resulting array quality is sufficient to print displays at state-of-the-art resolutions.
