Flexible Metasurface QR Code for Simultaneous Identification and Sensing

This article presents a novel approach for using a flexible QR code as a metasurface for sensing and identification functionalities. This is achieved by developing conventional QR code, in part or completely, with functional materials such as thermochromic and photochromic papers. The physical stimuli (e.g., temperature) related colour changes on the QR metasurface were visually detected by the smartphone camera and analysed using a custom app. While the colour variation indicates the physical sensing parameter of the product with which QR code is used, the main QR code itself is used as the product identifier. The marriage of multiple functionalities in the conventional QR code, with no change in the code itself or addition of new sensors, is an attractive approach for attaining more functionality with lesser resources, cost-efficiency and sustainable ICT.