Photo-patternable and Transparent Films Using Cellulose Nanofibers for Stretchable, Origami Electronics

Transcription

1 Supplementary information for Photo-patternable and Transparent Films Using Cellulose Nanofibers for Stretchable, Origami Electronics Sangyoon Ji 1, 4, Byung Gwan Hyun 1, 4, Kukjoo Kim 1, 4, Sang Yun Lee 2, Si-Hoon Kim 3, Ju-Young Kim 3, Myoung Hoon Song 2, Jang-Ung Park 1 1 School of Materials Science and Engineering, Wearable Electronics Research Group, Smart Sensor Research Center, Ulsan National Institute of Science and Technology (UNIST), Ulsan Metropolitan City, , Republic of Korea 2 School of Materials Science and Engineering and KIST-UNIST Ulsan Center for Convergent Materials, Ulsan National Institute of Science and Technology (UNIST), Ulsan Metropolitan City, , Republic of Korea 3 School of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan Metropolitan City, , Republic of Korea 4 These authors contributed equally to this work. Correspondence: Prof. M.H. Song, School of Materials Science and Engineering and KIST- UNIST Ulsan Center for Convergent Materials, Ulsan National Institute of Science and Technology (UNIST), Ulsan Metropolitan City, , Republic of Korea or Prof. J.-U. Park, School of Materials Science and Engineering, Wearable Electronics Research Group, Smart Sensor Research Center, Ulsan National Institute of Science and Technology (UNIST), Ulsan Metropolitan City, , Republic of Korea mhsong@unist.ac.kr or jangung@unist.ac.kr 1

2 Figure S1. The characteristics of electrospun epoxy nanofibers (a) SEM image of electrospun epoxy nanofiber with average diameter of 420 nm. (b) Statistical diameter distributions of epoxy nanofibers. Scale bar, 5 µm. 2

3 Figure S2. SEM images of CNFs-epoxy hybrid as increasing in volume of sprayed CNFs solution. Volume of sprayed CNF solution was (a) 100 ml, (b) 200 ml, and (c) 300 ml, respectively. Scale bars, 1 µm. 3

4 Figure S3. (a) AFM images of the surface of a CNF hybrid film before hot pressing. Measured RMS roughness 64 nm. (b) AFM images of a hot pressed hybrid film. Measured RMS roughness 0.7 nm (left: 3D image, right: 2D image). 4

5 Figure S4. Thickness versus processing time curve of hybrid film (before hot pressing) and hybrid film (after hot pressing). The volume of sprayed CNF solution was 300 ml. 5

6 Figure S5. Optical haze versus wavelength for each film throughout the spectrum range from 400 nm to 1500 nm. 6

7 Figure S6. Plot of the sheet resistance versus time for graphene electrode onto hybrid film and PET film after exposure to humid and hot air conditions (temperature: 85 ºC, humidity: 85%) for 240 hr. 7

8 Figure S7. Thermogravimetric analysis (TGA) of (a) pristine CNF film, (b) pristine epoxy film, and (c) hybrid film, respectively. 8

9 Figure S8. Comparison of the contact angles of a water droplet on the (a) 42º for the pristine CNF film and (b) 86º for the hybrid film. t = 1 s. 9

10 Figure S9. Comparison of the thermal stability of the TSPs with different substrates (CNF hybrid films and PET films). Black scale bars are 2 cm and white scale bars are 30 µm. 10

11 Figure S10. Characterization curves of the TOLED onto glass and hybrid film. (a) The luminous efficiency versus the applied voltage (LE-V). (b) The power efficiency versus the applied voltage (PE-V). (c) The external quantum efficiency versus the applied voltage (EQE-V). (d) The normalized electroluminescence (EL) spectra of TOLED. 11

12 Captions of Supplementary Movies Supplementary Movie S1. This movie shows the operation of the transparent and flexible touch-screen panel fabricated on the hybrid substrates. 12

13 Supplementary Movie S2. This movie shows the stable operation of the TOLED fabricated on the hybrid film, emitting light through both top and bottom directions. 13

14 Calculation of the bending-induced strain (ε) The bending-induced strain (ε) at the top of the node (top axis of Figure 3c) is calculated by the simple equation (1), 1 εε (%) = tt ss+ tt ff 2rr cc 100% (1) where ts and tf are the thickness of the substrate (the CNF hybrid film) and the film (the AgNW electrode), respectively. Because the thickness of the substrate (20 µm) is much larger than that of AgNW electrodes (several tens of nanometers), equation (1) can be simplify into equation (2), 2 εε (%) = tt ss 2rr cc 100% (2) Therefore, the bending-induced strain (ε) at the bending radius of 100 µm is approximately 10%. 14

15 References 1. Suo, Z., Ma, E. Y., Gleskova, H. & Wagner, S. Mechanics of rollable and foldable film-onfoil electronics. Appl. Phys. Lett. 74, (1999). 2. Baca, A. J., Ahn, J.-H., Sun, Y., Meitl, M. A., Menard, E., Kim, H.-S., Choi, W. M., Kim, D.- H., Huang, Y. & Rogers, J. A. Semiconductor Wires and Ribbons for High- Performance Flexible Electronics. Angew. Chem. Int. Ed. 47, (2008). 15