Fabrication of Low-cost and Flexible Potassium Ion Sensors based on Screen Printing and Their Electrochemical Characteristics

A low-cost and flexible potassium ion (K+) sensor was fabricated through a screen-printed process. Uniform and conformal coating of conductive inks was verified by scanning electron microscopy and optical microscopy measurements. The K+-sensors showed a high sensitivity, fast response time, and low detection limit. The sensitivity of K+-sensor was similar to that of both mechanically normal and bent states. The K+-sensor exhibited a good reproducibility with no hysteresis effect and excellent long term stability. In addition, the K+-sensor showed an excellent selectivity for K+ concentrations in the presence of other interfering cation ions. Successful measurements of K+ concentrations in sports drink samples were demonstrated by comparing K+ concentration values from K+-sensor to those of using a commercial K+-meter.