Manipulating Nanowire Assemblies toward Multicolor Transparent Electrochromic Device

Assembling various nanowires together, enabling the assemblies with tailored optical, electrical, and multifunctional properties, represents a promising technology for next generation multifunctional electronics. Here we demonstrate a novel multicolor electrochromic device by coassembling W₁₈O₄₉ and V₂O₅ nanowires using solution-based Langmuir-Blodgett technique. The transparent W₁₈O₄₉ nanowire film became orange with the increasing addition of V₂O₅ nanowires and the film underwent a dynamic color change (orange, green, and gray) on application of different electrochemical biases of 2, 0, and -0.5 V (vs Ag/AgCl). Both the transmittance and color of the device can be easily controlled by manipulating the layers of coassembled nanowires and the ratios between the two nanowires. On the basis of this approach, different patterns can be easily fabricated with the addition of corresponding masks, and the solid electrochromic device is assembled, suggesting its significant potentials in smart windows and multicolor electrochromic displays.