Supplementary Materials for

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1 advances.sciencemag.org/cgi/content/full/2/4/e /dc1 Ultraflexible organic photonic skin Supplementary Materials for Tomoyuki Yokota, Peter Zalar, Martin Kaltenbrunner, Hiroaki Jinno, Naoji Matsuhisa, Hiroki Kitanosako, Yutaro Tachibana, Wakako Yukita, Mari Koizumi, Takao Someya Published 15 April 2016, Sci. Adv. 2, e (2016) DOI: /sciadv 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- m-thick transparent polyimide substrate (red) and 1.4- m-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.

2 Supplementary Materials and Methods Legends for movies S1 to S3 Other Supplementary Material for this manuscript includes the following: (available at advances.sciencemag.org/cgi/content/full/2/4/e /dc1) 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.

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

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

5 fig. S3. The fabrication process of ultraflexible PLEDs.

6 fig. S4. Picture and characteristics of ultraflexible PLEDs: (a) The green PLED was bent on a razor. The razor thickness is only 100 µm. (b) J-V curves of PLEDs: red, green, and blue lines represent the red, green, and blue PLEDs, respectively.

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

8 fig. S6. Lifetime test of the ultraflexible green PLEDs. The life time was measured at 20 ºC and 60% of humidity. Each line represents: a glass substrate PLED with glass passivation (red), an ultraflexible PLED with 5-layer passivation (blue), parylene passivation (green), and without passivation (black), respectively.

9 fig. S7. Characteristics of green PLEDs on a glass substrate (red) and an ultraflexible substrate (blue): (a) electroluminescence spectra of ultraflexible PLEDs, (b) L-V curves of PLEDs, (c) J-V curves of PLEDs, and (d) EQE characteristics of PLEDs.

10 fig. S8. Surface roughness of the ultraflexible substrate: (a), (b) AFM and SEM images of a parylene substrate without a planarization layer; (c), (d) AFM and SEM images of a parylene substrate with a planarization layer.

11 fig. S9. Surface roughness of ITO electrodes on an ultraflexible substrate: (a), (b) AFM and SEM images of ITO on a parylene substrate without a planarization layer; (c), (d) AFM and SEM images of ITO on a parylene substrate with a planarization layer.

12 fig. S10. Characteristics of green PLEDs on 2-µm-thick transparent polyimide (PI) substrate (red) and 1.4-µm-thick PET substrates (blue): (a) electroluminescence spectra of ultraflexible PLEDs, (b) L-V curves of PLEDs, (c) J-V curves of PLEDs, and (d) external quantum efficiency current density curves of PLEDs.

13 fig. S11. Fabrication process of ultraflexible OPDs.

14 fig. S12. Green PLED characteristics before and after peeling from a supporting substrate: (a) picture of PLED at 10 V before peeling and (b) after peeling. (c) L-V and (d) J-V curves of the PLED before and after peeling. The blue and red lines represent characteristics of the PLED before and after peeling, respectively.

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

16 fig. S14. J-V characteristics of the OPD (dot line: dark state, solid line: irradiated by a green laser (532 nm). Black and red lines represent the initial state and 37% compressed state, respectively.

17 fig. S15. Characteristics of the OPD with green and red PLED irradiation. (a) Lightintensity-dependent Voc and Jsc of the OPD when irradiated by a red and green PLED.

18 fig. S16. Output signals from OPDs irradiated with PLEDs. Green and red PLEDs were alternately turned on and off per every 5 seconds.

19 fig. S17. Air stability of the PPG signal. The PPG signal was measured using an ultraflexible red PLED and OPD.

20 fig. S18. Characteristics of the passivation layer. (a) AFM image of the SiON layer on parylene substrate. (b) The transmittance spectrum of the 200-nm-thick SiON film. (c) The water vapor transmission rate of the passivation layers.

21 Supplementary Materials and Methods 1. 7-segment display (figs. S1 and S2, and Movie S1) A red seven-segment display was fabricated on our ultraflexible substrate. The 7- segment display was operated by a Semiconductor Switch Matrix (707A, Keithley Instruments, USA). Figs. S1 and S2 show the numbers and letters projected. 2. Ultraflexible PLED (figs. S3 S6) Summary of the ultraflexible PLED device characteristics. The light-emitting area was 2 mm 2 mm. The fabricated devices were evaluated by a light distribution measurement system (C , Hamamatsu Photonics K.K., Japan) and an external quantum efficiency measurement system (C , Hamamatsu Photonics K.K., Japan). To evaluate the lifetime of PLEDs, we used a lifetime evaluation system (EAS-31C, System Engineer s Co., LTD., Japan). Each PLED was driven at constant current of 12.5 A/m Comparing PLED characteristics on glass substrates and ultraflexible substrates (fig. S7) We compared the characteristics of a green PLED on a glass substrate with those of a green PLED on a planarized 1-µm-thick parylene substrate. The light-emitting area was 2 mm 2 mm. The fabricated devices were evaluated by a light distribution measurement system (C , Hamamatsu Photonics K.K., Japan) and an external quantum efficiency measurement system (C , Hamamatsu Photonics K.K., Japan). The ultraflexible device showed almost the same characteristics as the device

22 fabricated on a glass substrate (fig. S7). 4. Polyimide planarization layer of the parylene substrate (figs. S8 and S9) A 500-nm-thick polyimide planarization layer (KEMITITE CT4112, Kyocera Chemical, Japan) was deposited on a parylene substrate by spin-coating (4000 rpm, 60 s) and cured at 90 ºC for 1 h, 120 ºC for 1 h, and 150 ºC for 1 h in nitrogen. The surface roughness is reduced from 2.4 nm rms to 0.35 nm rms (see fig. S8). After forming the planarization layer, 70-nm-thick ITO electrodes were deposited by sputtering (SH-250- T04, ULVAC, Inc., Japan). Without a planarization layer, the surface roughness of the ITO electrode is 2.9 nm rms. After adding the planarization layer, the surface roughness of the ITO electrode is dramatically reduced to 0.25 nm rms (fig. S9). 5. Device characteristics of PLED on several kinds of ultraflexible substrate (fig. S10) We fabricated green PLEDs on several kinds of ultraflexible substrates. We used 2-µmthick transparent polyimide (Mitsui Chemicals, Inc., Japan), which was formed by spincoating (5000 rpm, 60 s) on a glass substrate, and 1.4-µm-thick polyethylene terephthalate (PET) film (Mylar 1.4 CW02, Teijin DuPont Films Japan Limited, Japan). The transparent polyimide film was annealed at 270 ºC for 2 h after spin-coating. We used a glass substrate, whose surface was covered with PDMS (Sylgard 184, Dow Corning Toray Co., Ltd., Japan) as the supporting substrate for the PET film (fig. S10).

23 6. Ultraflexible OPD (fig. S11) The characteristics of the OPDs were measured using a solar simulator with an AM 1.5G filter based and a 150 W Xe lamp (PEC-L11, Peccell Technologies). 7. Peeling test of the ultraflexible PLED (fig. S12) First, the fabricated device was passivated by 1-µm-thick parylene. After forming a passivation layer, we made a via hole using a green laser (Telecentric Green Laser Marker MD-T1000, KEYENCE Corp., Japan) and deposited a 100-nm-thick gold layer as a via fill and contact pad. We then laminated a 12.5-µm-thick polyimide, whose surface was covered with a 1-µm-thick parylene-based flexible contact pad by thermocompression bonding (3.2 MPa, 160 ºC, 10 s) (fig. S12a). After evaluating the device characteristics, we peeled the device from the glass supporting substrate (fig. S12b). The PLED showed almost the same characteristics before and after peeling (fig. S12c and d). 8. Stretchable test (figs. S13, S14 and movie S2) We evaluated the flexibility of our PLEDs and OPDs. The device was laminated on 60% pre-stretched silicone rubber. The device was stretched by a tensile testing machine (AG-Xplus, Shimadzu Corporation, Japan). The emission area of PLED was 2 2 cm 2. We also measured the luminance of PLED after stretching the cycle test using the cycle test system (fig. S13). 9. The sensitivity of the OPD with green and red PLED (fig. S15) We checked the sensitivity of the OPD using red and green PLEDs (fig. S15 and Figs.

24 4c and 4d). 10. Pulse Oximeter (figs. S16 and S17) We laminated the pulse oximeter on the finger and measured the SpO2. The long-term stability of the Voc is shown in fig. S16. The amplitude of pulse wave was stable. When we measured the SpO2, the red and green PLED were alternately turned on and off every 5 seconds (fig. S16). The air stability of PPG signal is shown (fig. S17). 11. Passivation layer (fig. S18) We formed the inorganic/organic multilayer passivation films by plasma-enhanced CVD and CVD. The passivation layer was composed of 5 alternating SiON and parylene layers. The thickness of the SiON and parylene layer was 200 nm and 500 nm, respectively. The water vapor transmission rate was measured using the PEN film substrate (125 µm). Surface images by AFM and the transparency of the SiON layer formed on a glass substrate (fig. S18).

25 movie S1. Operation of a 7-segment display on hands. movie S2. Operation of a crumpled green PLED. movie S3. Demonstrations of the extreme flexibility of ultraflexible PLEDs.