Low power stretchable active-matrix red, green, blue (RGB) electrochromic device array of poly(3-methylthiophene)/Prussian blue

We report the fabrication of a stretchable array of active-matrix (AM) electrochromic devices (ECDs). The ECD is made of poly(3-methylthiophene) and Prussian blue electrodes with a mixed gel electrolyte of acetonitrile, poly(methyl methacrylate), propylene carbonate, and lithium perchlorate. The ECD displays can express red, green, or blue (RGB) depending on the applied voltage and has a high stability in air. It exhibits low power consumption levels of 331 and 378 μW cm ⁻² (10 s duration) at −1.0 and 1.0 V, respectively, and a high coloration efficiency of 201.6 cm ² C ⁻¹ at 1.0 V. A 4 × 4 AM ECD array is integrated on a deformable Ecoflex substrate via a dry transfer method using patterned liquid metal interconnections. The display shows a mechanical stability under bending and biaxial stretching by 30%. Finite element method analysis of the strain distribution also confirms that strain is not applied to the ECDs, guaranteeing stable operation of the array under deformation. Furthermore, a stretchable 6 × 6 AM ECD array for higher resolution display also exhibits mechanical stability under 30% biaxial stretching. This work demonstrates the high potential of our stretchable ECD array in low power-consuming displays for stretchable electronics, wearable devices, and electronic skin.