Electroactive Soft Photonic Devices for the Synesthetic Perception of Color and Sound

Color, as perceived through the eye, transcends mere information in the visible range of electromagnetism and serves as an agent for communication and entertainment. Mechanochromic systems have thus far only aimed at satisfying the sense of vision and have overlooked the possibility of generating acoustic vibrations in concert with their visual color responses that would enable the simultaneous satisfaction of the auditory system. Transcending the boundaries of the two senses (i.e., sound and color), herein a strategy for their concurrent and synesthetic fulfillment is elucidated by electrically actuating an organogel photonic device, controlled by a single input signal. This new class of devices that integrate a color module with a speaker is fabricated from a mechanochromic layer that comprises close-packed photonic lattice with an organogel matrix pervading the void fraction. Exploiting a dielectric elastomer actuator, the system's mechanical response permits the simultaneous, yet independent, exploration of visible-light reflection alongside audible sound-wave generation. Large areal strains at low frequencies of actuation tune the photonic stop-band, whereas the layer remains incompressible and exhibits negligible strain when actuated at higher frequencies (e.g., tens of Hz), thereby making it amenable to modulate sound and color simultaneously yet independently.