Photothermal-assisted for ultrafast response acetone sensing with ZIF-90/GO coated microfiber long period gratings

Volatile organic compound (VOC) sensors have recently been developed with sensitive coating layers to improve their performance. However, there are inevitable trade-offs in the performance of the VOC sensors with sensitive layers. It remains challenge to achieve higher sensitivity, faster response time, working at room temperature and better selectivity at the same time for real-world applications. In this work, we demonstrated a novel photothermal-assisted gas sensor using a microfiber long period grating (LPG) modified with zeolitic imidazolate framework-90 (ZIF-90)/graphene oxide (GO) for enhanced VOC acetone sensing. The GO-isolated ZIF-90 exhibited ultralow conductivity and high porosity, which significantly promoted light-to-heat energy conversion by trapping thermal and minimizing heat loss. Besides, the natural porosity and ultrahigh surface area of the ZIF-90 showed superior molecular adsorption making it a good choice for the acetone-sensitive layer. Based on the porous ZIF-90/GO nanohybrid and photothermal effects, the proposed sensor showed improved performance compared without adding laser towards acetone, with the sensitivity of 26.1 pm/ppm and low limit of detection of 760 ppb. Moreover, the proposed photothermal technology enhanced the response time down to 410 ms without sacrificing sensitivity. Thus, our proposed sensor constitutes a promising platform for effective acetone sensing systems that can be used for environmental monitoring and industry.