Flexible\nWearable Chemoresistive Ethylene Gas-Monitoring\nDevice Utilizing Pd/Ti<sub>3</sub>C<sub>2</sub>T<i><sub>x</sub></i> Nanocomposites for In Situ Nondestructive Monitoring of\nKiwifruit Ripeness

Kiwifruit,\nrenowned for its antioxidant properties and nutritional\nrichness, faces challenges in maintaining quality during transportation,\noften leading to suboptimal products reaching the market. To address\nthis issue, a wireless transmission flexible ethylene monitoring device\n(WFEMD) was developed. This device comprises a flexible ethylene gas\nsensor and a signal transmission processing unit integrated with electronic\ncomponents, enabling real-time monitoring capabilities. In this study,\nthe catalytic activity of Pd and Pd/Ti heterojunctions was leveraged\nto enhance the ethylene gas sensing. The impact of Ti<sub>3</sub>C<sub>2</sub>T<i><sub>x</sub></i> modified with varying masses\nof Pd nanoparticles on ethylene gas response levels was investigated.\nThe signal transmission processing unit, fabricated by using the laser\ndirect-writing method, was optimized to collect signals from the flexible\nethylene gas sensor, convert them into corresponding ethylene concentrations,\nand transmit data via an antenna. By introducing a random forest (RF)\nclassification algorithm, a remarkable 97.5% accuracy in predicting\nkiwifruit ripeness grades was achieved. The algorithm facilitated\nprecise classification by collecting key parameters such as ethylene\nand CO<sub>2</sub> during transportation. The WFEMD enables real-time\nacquisition of kiwifruit ethylene gas information, which is transmitted\nwirelessly for data visualization and traceability via mobile terminals.\nThis empowers managers with timely insights into ethylene emissions\nand ripeness predictions, facilitating informed decision-making processes.