Fig. 5. Description of UOP films for afterglow display, anti-counterfeiting and visual frequency detection under ambient conditions.
a, b Transparent art crafts with UOP feature by Chinese paper-cutting technology based on the flexible films containing one or two emitters. Inset: photographs of the art crafts taken under sunlight and a 302 nm UV lamp as well as removal of the excitation, respectively. c Demonstration of self-healing property of the CzA/PVA film. Inset: photographs of the film after self-healing taken under a 302 nm UV lamp on/off. d Photographs of an emissive 3D cube (2 × 2 × 2 cm3) under a 302 nm lamp on/off. e Ribbons fabricated by self-heal under 302 nm (left) and 365 nm (right) lamps on and off. f A demo of afterglow display made of different UOP emitters under DC on/off. g Path tracing from A to B with colorful afterglow by controlling DC on and off. The tracks from blue to white then to yellow can be captured. h Demonstration of afterglow indicators by reversible cycle of afterglow colors. With frequency of electrical power change from 0.2 to 5.0 Hz, the afterglow cycles are I–II–III–IV, I–II–III and I–II, respectively.