Rechargeable Cyborg Insects with Ultrathin Organic Solar Cell Module

Cyborg insects have been proposed for applications such as urban search and rescue. Body-mounted energy-harvesting devices are critical for expanding the range of activity and functionality of cyborg insects. However, achieving a power output of 10 mW or higher using energy harvesters mounted on living movable insects for wireless locomotion control remains challenging. To integrate devices into small animals with limited surface areas and carry loads29, device design and integration strategy of large-area solar cells is required to obtain sufficient power output and simultaneously maintain the basic behavioral abilities of insects. Because the output power of the solar cell is proportional to the area, both the load of the device and the contact between the device and the moving joints considerably impair motion abilities.<br/>Here, we report a power-rechargeable cyborg insect that uses a mounted ultrasoft organic solar cell module that does not impair the insect’s basic motion abilities and demonstrates recharging wireless locomotion control with all components integrated on insects. We developed a combined strategy of ultrathin film electronics and an adhesive–nonadhesive interleaving structure on the insect abdomen to secure their basic motion abilities, confirming their effectiveness quantitatively with traversing obstacles and self-righting ability from an upside-down orientation on the ground. These tests revealed that a 5 µm thick or less polymer (having Young’s modulus of several GPa) adhered with an interleaving structure could secure unchanged motion abilities. The ultrathin organic solar cell module (3 series connection) adhered onto a 3D-printed curved insect surface model achieves a power output of 17.2 mW, which corresponds to power per weight of 8.69 W g–1. Finally, recharging and wireless locomotion control was realized using living cyborg insects that contained electronic components. After the simulated sunlight illumination was applied to the organic solar cell module on G. portentosa for 30 min, turn-right locomotion control was wirelessly conducted. The stimulation signals were wirelessly transmitted for 2.1 min with the charged battery. During this period, locomotion control was attempted multiple times, which confirmed that the wireless control was successfully performed repeatedly. The approach presented in this study contributes to expanding the range of activity and realizes diverse functions for the cyborg insects.