Fig. 1. Concept of self-powered E-paper (SPEP). (a) Schematical illustration of an SPEP with handwriting input and its structure in a pixel. (b) Prototype of the chromatic type SPEP before and after one-time color changing. (c) Possible applications of the SPEP in various fields.

Fig. 2. Operational characteristics of a monochromic E-paper under the voltage pulse mode. (a) Profiles of driving current, equivalent impedance, and intensity of reflective light during each driving process by a constant voltage. (b) Schematic diagrams of the identified five stages and in situ optical microscopy photos of an individual microcapsule. Profiles of (c) current and (d) equivalent impedance of the E-paper driven by different voltages.

Fig. 3. Comparison of the E-paper driven by constant current and voltage sources. V-t and I-t plots of various sizes of E-papers under (a) current source mode and (b) voltage source mode, respectively. The inset photos show their correspondent grayscales. Equivalent electrical circuits and schematic diagrams of the E-paper driven by (c) a constant current source and (d) a constant voltage source are illustrated, respectively.

Fig. 4. Characteristics of the sliding-mode TENG and typical responses of the E-paper driven by the TENG. (a) Working mechanism of the sliding-mode TENG and its photo. (b) The output short-circuit current of a TENG. (c) The summarized maximum amplitude of a short-circuit current of TENG with different structural parameters and sliding speeds. (d) The peak current of the TENG at different external loading resistance. (e) The rectified short-circuit current of the TENG. (f) Peak output power of a TENG (w=2  mm and v=0.5  m/s) at different external loading resistance. (g)‒(i) Current (inset is the peak current), voltage (inset is the valley value of voltage), and grayscale change (insets are photos of E-papers) of an E-paper driven by the TENG, respectively. Other than (c), all are measured with TENG parameters of w=2  mm and v=0.5  m/s.

Fig. 5. Influential parameters for driving E-papers with the TENG. (a) Grayscale changes of the E-paper driven by TENGs with different electrode widths (v=0.25  m/s, A=12  cm2). (b) Grayscale changes of the E-paper driven by TENGs at different sliding speeds (w=1  mm, A=16  cm2). (c) Grayscale changes of the E-paper with different sizes (w=1  mm, v=0.25  m/s). (d) Photos of grayscale changing of monochromic and chromatic E-papers (A=12  cm2) along with sliding motion times of the TENG.

Fig. 6. Self-powered E-paper (SPEP) integrated with a transparent TENG. (a) Schematic illustration of an all-in-one SPEP with a transparent TENG on the top. (b) The rectified short-circuit current of the TENG with hand sliding (w=1  mm). (c) Transmittance and photos (inset) of the transparent TENG. (d) The grayscale changes and inset photos of the SPEP driven by hand sliding. (e) The grayscale of the E-paper before and after bending.