Biomimetic Metal-Organic Framework-Based Photonic Crystal Sensor for Highly Sensitive Visual Detection and Effective Discrimination of Benzene Vapor

Due to the large specific surface area and continuouspores instructures, metal-organic frameworks (MOFs) show great advantagesin the adsorption of volatile organic compounds (VOCs). Photonic crystal(PC) sensors derived from MOFs are promising for the visual detectionof VOC gases. However, they still have problems of low sensitivityand poor color saturation and tunability. Here, inspired by vapor-sensitivescales of Tmesisternus isabellae beetleand scattering light absorption of polydopamine, a porous one-dimensionalPC sensor is constructed by combining ZIF-8 with TiO2@PDAnanoparticles. The PC sensor shows significant color changes underdifferent concentrations of benzene vapor and reaches a detectionlimit of 0.8 g/m(3). It has a response time of less than1 s and maintains stable optical performance after 100 times of reuse.Moreover, ZIF-67 and ZIF-7 are both incorporated into the PCs forcomparison; it reveals that ZIF-8 shows superior benzene detectingproperty. Additionally, the synergistic adsorption of VOCs in innerand outer holes of the ZIF-8 layer is demonstrated by real-time massmonitoring with quartz crystal microbalance with dissipation. Thisstudy provides a valuable reference for the fabrication of high-qualityMOF-based PC sensors and sensing mechanism study between microscopicmolecular adsorption and macroscopic performance.

Automated summary

A porous one-dimensional photonic crystal (PC) sensor is constructed by combining ZIF-8 with TiO2@PDAnanoparticles, which shows significant color changes under different concentrations of benzene vapor and reaches a detection limit of 0.8 g/m(3). The sensor has a response time of less than 1 s and maintains stable optical performance after 100 times of reuse. This study provides valuable insights for the fabrication of high-quality MOF-based PC sensors and the study of the sensing mechanism between microscopic molecular adsorption and macroscopic performance.