Fig. 5

Applications of triboelectric plasma in surface treatment and luminescence. a, b Contact angle of fluorinated ethylene propylene (FEP) surface before and after microplasma treatment. a Schematic of surface treatment in use of triboelectric plasma. b Untreated surface, 1 min, 3 min, and 6 min treated by argon plasma, respectively. c, d Example of microplasma luminescence photograph showing patterns of triboelectric nanogenerator (TENG), Tsinghua, and Georgia Tech (scale bar, 20 mm). d No Photoshop (NIKON D700 @ 70 mm, ISO 6400, 30 s, f/2.8). e, f A plasma disk driven by freestanding rotary (FR) TENGs (scale bar, 20 mm). f Photos with different exposure time (NIKON D700 @ 70 mm, ISO 6400, f/7.1)