Chameleon-inspired flexible photonic crystal lens-shaped dynamic pressure sensor based on structural color shift

Flexible sensors with high sensitivity and multifunctional integrated stimuli in the environment have been used in various applications. Here, we report the construction of a type of high-performance flex-ible photonic pressure sensor inspired by the principle of chameleon color change. The sensor is constructed based on a lens-shaped three-dimensional photonic crystal in combination with an algi-nate-based hydrogel. Low-pressure stimuli can lead to a slight change in the photonic band gaps that, consequently, cause the shifting of the maximal frequency and variation of the amplitude of reflective light. Ascribed to the substantially enlarged reflected spectra and the structural color shift, the sensor, with a diameter of 310 nm, exhibits an ultrahigh sensitivity of 32.2723 kPa-1, a peak shift of 30 nm, and a fast response time of 0.21 s. Furthermore, the density, sound velocity, and acoustic impedance of this confor-mally photonic sensor are matched with water. Therefore, this sensor provides a promising strategy for next-generation flexible photonic acoustic sensing devices.