All-in-One Iontronic Sensing Paper

Paper has been utilized as an ideal platform for chemical, biological, and mechanical sensing for its fibrous structures and properties in addition to its low cost. However, current studies on pressure-sensitive papers have not fully utilized the unique advantages of papers, such as printability, cuttability, and foldability. Moreover, the existing resistive, capacitive, and triboelectric sensing modalities have long-standing challenges in sensitivity, noise-proofing, response time, linearity, etc. Here, a novel flexible iontronic sensing mechanism, referred to as iontronic sensing paper (ISP), is introduced to the classic paper substrates by incorporating both ionic and conductive patterns into an all-in-one flexible sensing platform. The ISP can then be structured into 2D or 3D tactile-sensitive origamis only by the paper-specific manipulations of printing, cutting, folding, and gluing. Notably, the ISP device possesses a device sensitivity of 10 nF kPa ⁻¹ cm ⁻² , which is thousands of times higher than that of the commercial counterpart, a resolution of 6.25 Pa, a single-millisecond response time, and a high linearity (R ² > 0.996). Benefiting from the unique properties of the fibrous paper structures and its remarkable performances, the ISP devices hold enormous potential for the emerging human–machine interfaces, including smart packaging, health wearables, and pressure-sensitive paper matrix.