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Ultraflexible organic photonic skin

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Science Advances  15 Apr 2016:
Vol. 2, no. 4, e1501856
DOI: 10.1126/sciadv.1501856
  • Fig. 1 Smart e-skin system comprising health-monitoring sensors, displays, and ultraflexible PLEDs.

    (A) Schematic illustration of the optoelectronic skins (oe-skins) system. (B) Photograph of a finger with the ultraflexible organic optical sensor attached. (C) Photographs of a human face with a blue logo of the University of Tokyo and a two-color logo. The brightness can be changed by the operation voltage. (D) Photograph of a red seven-segment PLEDs displayed on a hand.

  • Fig. 2 Characteristics of ultraflexible PLEDs and OPDs.

    Note that all the measurements were performed in air. (A) Structure of the ultraflexible PLED. The passivation layer was composed of alternating organic (500-nm-thick Parylene) and inorganic (200-nm-thick SiON) layers. (B) Picture of the ultraflexible green PLED that was crumpled. (C) The EQE of the OPD (black line) with the normalized electroluminescence (EL) spectra of blue (blue line), green (green line), and red (red line) PLEDs. a.u., arbitrary unit. (D) Current density–dependent EQE characteristics of the ultraflexible PLEDs. The inset figure shows L-V curves of ultraflexible PLEDs. (E) Picture of the freestanding ultraflexible OPD. (F) Light intensity–dependent J-V characteristics of the OPD under simulated solar illumination. Red, orange, green, light blue, blue, purple, gray, and black represent the light intensity of 1000, 706, 502, 400, 297, 199, and 99 W/m2 and the dark condition, respectively. (G) Characteristics of the ultraflexible OPD, measured using a solar simulator. Light intensity–dependent Voc of the OPD (red) and light intensity–dependent Jsc of the OPD (green).

  • Fig. 3 Demonstrations of extreme flexibility of ultrathin optical devices.

    (A) Images of an ultrathin red PLED adhered to a prestretched elastomer. The images from right to left represent the transition from the wrinkled state to the flat state. (B) Three-dimensional image of the wrinkled PLED state. The prestretch value was 60%. (C) Cyclic stretching test of the green PLED. After 1000 stretching cycle tests, the light intensity was decreased by only 10%. (D) Voc of the wrinkled OPD. The inset figure shows the flat and compressed OPD. (E) Cyclic stretching test of the OPD. After 300 stretching cycle tests, the characteristics did not show any degradation. The black circles and red triangles represent the Voc and normalized Jsc, respectively. The inset figure shows the J-V characteristics of the OPD (dot line, dark state; solid line, irradiated by green light). Black and red lines represent the initial state and the state after 300 stretching cycles, respectively.

  • Fig. 4 Ultraflexible organic pulse oximeter.

    (A) Device structure of the pulse oximeter. (B) Operation principle of the reflective pulse oximeter. (C) Light intensity–dependent J-V characteristics of the OPD when irradiated by a green PLED. (D) Light intensity–dependent J-V characteristics of the OPD when irradiated by a red PLED. (E) Long-term measurement of the pulse wave. The pulse wave was measured using a red PLED and OPD. (F) Air stability of the PPG signal. The PPG signal was measured using a red PLED and OPD. (G) Output signal from OPD with 99% oxygenation of blood. The green and red lines represent the signals when the green and red PLEDs, respectively, were operated. (H) Output signal from OPD with 90% of oxygenation of blood. The green and red lines represent the signals when the green and red PLEDs, respectively, were operated.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/2/4/e1501856/DC1

    fig. S1. Ultraflexible seven-segment display on hands (showing numbers from 0 to 9).

    fig. S2. Ultraflexible seven-segment display on hands (showing letters from A to Z).

    fig. S3. The fabrication process of ultraflexible PLEDs.

    fig. S4. Picture and characteristics of ultraflexible PLEDs.

    fig. S5. CIE 1931 chromaticity coordinates (x, y) of PLEDs on ultraflexible substrates.

    fig. S6. Lifetime test of the ultraflexible green PLEDs.

    fig. S7. Characteristics of green PLEDs on a glass substrate (red) and an ultraflexible substrate (blue).

    fig. S8. Surface roughness of the ultraflexible substrate.

    fig. S9. Surface roughness of ITO electrodes on an ultraflexible substrate.

    fig. S10. Characteristics of green PLEDs on 2-μm-thick transparent polyimide substrate (red) and 1.4-μm-thick polyethylene terephthalate substrates (blue).

    fig. S11. Fabrication process of ultraflexible OPDs.

    fig. S12. Green PLED characteristics before and after peeling from a supporting substrate.

    fig. S13. Measurement setup for the cyclic stretching test.

    fig. S14. J-V characteristics of the OPD (dot line, dark state; solid line, irradiated by a green laser (532 nm).

    fig. S15. Characteristics of the OPD with green and red PLED irradiation.

    fig. S16. Output signals from OPDs irradiated with PLEDs.

    fig. S17. Air stability of the PPG signal.

    fig. S18. Characteristics of the passivation layer.

    Supplementary Materials and Methods

    movie S1. Operation of seven-segment display on hands.

    movie S2. Operation of crumpled green PLED.

    movie S3. Demonstrations of extreme flexibility of ultraflexible PLEDs.

  • Supplementary Materials

    This PDF file includes:

    • fig. S1. Ultraflexible seven-segment display on hands (showing numbers from 0 to 9).
    • fig. S2. Ultraflexible seven-segment display on hands (showing letters from A to Z).
    • fig. S3. The fabrication process of ultraflexible PLEDs.
    • fig. S4. Picture and characteristics of ultraflexible PLEDs.
    • fig. S5. CIE 1931 chromaticity coordinates (x, y) of PLEDs on ultraflexible substrates.
    • fig. S6. Lifetime test of the ultraflexible green PLEDs.
    • fig. S7. Characteristics of green PLEDs on a glass substrate (red) and an ultraflexible substrate (blue).
    • fig. S8. Surface roughness of the ultraflexible substrate.
    • fig. S9. Surface roughness of ITO electrodes on an ultraflexible substrate.
    • fig. S10. Characteristics of green PLEDs on 2-μm-thick transparent polyimide substrate (red) and 1.4-μm-thick polyethylene terephthalate substrates (blue).
    • fig. S11. Fabrication process of ultraflexible OPDs.
    • fig. S12. Green PLED characteristics before and after peeling from a supporting substrate.
    • fig. S13. Measurement setup for the cyclic stretching test.
    • fig. S14. J-V characteristics of the OPD (dot line, dark state; solid line, irradiated by a green laser (532 nm).
    • fig. S15. Characteristics of the OPD with green and red PLED irradiation.
    • fig. S16. Output signals from OPDs irradiated with PLEDs.
    • fig. S17. Air stability of the PPG signal.
    • fig. S18. Characteristics of the passivation layer.
    • Supplementary Materials and Methods
    • Legends for movies S1 to S3

    Download PDF

    Other Supplementary Material for this manuscript includes the following:

    • movie S1 (.wmv format). Operation of seven-segment display on hands.
    • movie S2 (.wmv format). Operation of crumpled green PLED.
    • movie S3 (.wmv format). Demonstrations of extreme flexibility of ultraflexible PLEDs.

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