A Piezoelectric-Driven Electrochromic/Electrofluorochromic Dual-Modal Display Device

Electrochromic (EC) reflective displays offer great advantages in delivering information and providing visual data, but are limited in dark environments. Reflective/emissive dual-modal displays capable of electrochemically-induced color and fluorescence change simultaneously are highly desirable, especially possessing rapid response speed as well as long-term durability. Herein, an electroactive fluorescent ionic liquid based on triphenylamine and imidazole (EFIL-TPA) has been synthesized for reflective/emissive dual-modal display. The resultant device exhibits outstanding electrochromic/electrofluorochromic (EC/EFC) performance with low driving voltage (below 1.0 V), fast switching speed (0.57–1.8 s), and remarkable cycling durability (91% retention for 10 000 cycles). A piezoelectric nanogenerator (PENG) driven EC/EFC integrated system is fabricated to harvest energy from human motion and visually drive the color/fluorescence change for human motion indication in both bright and dark environments. This innovative EC/EFC dual-modal display device based on EFIL-TPA supports a huge space for the development of self-powered human motion visualized indication in all-light conditions.     

All-Printed Electrochromic Stickers

Displays are one of the most mature technologies in the field of printed electronics. Their ability to be manufactured in large quantities and at low cost has led to their recent uptake into the consumer market. Within this article this technology is extended to electrochromic display stickers. This is achieved using a recent reverse display architecture screen printed on textile and paper sticker substrates. The electrochromic stickers are comparable to plastic control substrates and show little performance difference even when adhered to curved surfaces. The electrochromic display technology is extended to sticker labels for authentication applications by patterning either the dielectric or the graphical layer. A proof-of-concept prototype emulating a wax seal on an envelope is presented to show that other colors can be implemented in this technology.     

From Amorphous Macroporous Film to 3D Crystalline Nanorod Architecture: A New Approach to Obtain High‐Performance V2O5 Electrochromism

A 3D crystalline V₂O₅ nanorod architecture on indium tin oxide substrates is prepared by simple annealing treatment of a colloidal crystal‐assisted electrodeposited amorphous three‐dimensionally ordered macroporous film at a low temperature of 350 °C. The crystalline nanorods exhibit a low length/diameter ratio with the typical width range of 80–180 nm, length range of 190–500 nm, and thickness of 30–50 nm. Colloidal sphere‐assisted heterogeneous nucleation during electrodeposition and the anisotropic bonding of the V₂O₅‐layered structure are two important factors for the morphological changes. Because of the large surface area, short lithium ion diffusion distance, and good electrolyte penetration, the 3D crystalline V₂O₅ nanorod architecture exhibits a highly reversible Li‐ion insertion/extraction process (columbic efficiency up to 96.9%) with a five‐color‐change electrochromic performance, good transmittance modulation, and acceptable response times (8.8 s for coloration and 9.3 s for bleaching), making it a promising film electrode for electrochromic devices.