Fig. 7: Applications of flexible PeLEDs.

a NIR photographs of the large-area flexible PeLED (i), PeLED with a 0.5-inch circular window illuminating subcutaneous blood vessels on the human palm while in close contact (ii), and PeLED illuminating the back of a human fist (iii). Reproduced with permission from ref. ¹²³. Copyright 2020, Springer Nature. b Transparent flexible LETD wrapped to a 1 in. diameter vial and glowing in the form of letter “T” when stamped (i), and photograph of a LETD under 4 V bias when an “A”-shape stamp is pressed onto the surface of the AgNW–PU top electrode (ii). Reproduced with permission from ref. ¹²⁴. Copyright 2017, American Chemical Society. c Photograph of ultrathin multicolor PeLEDs attached to human skin (i), ultrathin PeLEDs attached to human skin under various deformations: 20% compression (ii) and twist (iii), ultrathin PeLEDs laminated on a leaf (iv), demonstration of the water resistance of ultrathin PeLEDs (v), and photograph of an ultrathin PeLED folded on a razor blade edge (vi). Under the terms of Creative Commons Attribution International License (CC-BY 4.0). d Schematic illustration of the working mechanism (LED mode) of the light-emitting/detecting bifunctional perovskite fiber (i), schematic of the structure of a perovskite EL fiber (ii), EL spectra of a green (iii) and a red (iv) electroluminescent perovskite fiber. Under the terms of Creative Commons Attribution International License (CC-BY 4.0).