"Fire-beetles" inspired all-solid infrared sensor with bolometric and photomechanic dual sensing modes

By mimicking the structure of the infrared-sensing organs of the "fire-beetles" of genus Melanophilaacuminata, we herein designed and fabricated an all-soild "fire-beetles" inspired infrared sensor, the key components of which is composed of a stress-concentrated photothermal expansion dendrite structure made of polydopamine enabled polydimethylsiloxane nanocomposite elastomer and a highly-sensitive piezoresistive membrane processed by direct laser writing carbonization. Our sensor possesses bolometric and photomechanic dual sensing modes, with the optimal responsivity of 1.4 W1 and 2.2 W1, the detection limit of 0.03 mW/pHz and 0.23 mW/pHz, as well as the response time of 3.8 s and 2.5 s, respectively. The two-step photothermal and solid mechanics FEA modeling was performed to help understanding its sensing behavior in both bolometric and photomechanic operation modes, which indicates the possibility for orders-of-magnitude improvement on the responsiveness of our "fire-beetles" inspired IR sensor when increasing the bonding strength between the photothermal dendrite tip and the piezoresistive sensing membrane. The all-solid nature and the piezoresistive readout scheme as well as its good performance make our sensor valuable for low-cost IR sensing applications.& COPY; 2023 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).