a Temporal changes in open-circuit voltage of an EATS on a glass substrate during heat cycles (from 22 to 26 °C, 30, 34, and 38 °C, respectively) at high humidity (green) and low humidity (blue). b Variation in open-circuit potential upon changes in humidity (alternating between RH = 30% and RH = 4%) at 22 °C, for an open EATS (dashed line) and for an encapsulated EATS (solid line). c Changes in open-circuit voltage versus temperature at high (green) and low (blue) humidity for open (unfilled markers and dashed lines) and encapsulated EATS (filled markers and solid lines). Each data point (error bar) represents the average value (standard deviation) from three series of measurements. The inset shows a photograph of an encapsulated EATS device. d Change in open-circuit voltage generated by an encapsulated EATS (green) and a commercial TC (red) upon touch by a human hand (yellow shaded areas).