Supplementary Information for

Transparent-Flexible-Multimodal Triboelectric Nanogenerators for

Mechanical Energy Harvesting and Self-powered Sensor

Applications

Qitao Zhou1†, Jun Gyu Park1†, Kyeong Nam Kim2, Ashish Kumar Thokchom1, Juyeol Bae1, Jeong Min Baik2* and Taesung Kim1,3*

1Department of Mechanical Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulsan 44919, Republic of Korea.

2School of Materials Science and Engineering, KIST-UNIST Ulsan Center for Convergent Materials, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea

3Department of Biomedical Engineering, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulsan 44919, Republic of Korea

*CORRESPONDENCE:

Taesung KimDepartment of Mechanical EngineeringUlsan National Institute of Science and Technology (UNIST)50 UNIST-gil, Ulsan 44919, Republic of KoreaE-mail: tskim@unist.ac.krTel: +82-52-217-2313; Fax: +82-52-217-2409

Jeong Min BaikSchool of Materials Science and Engineering, KIST-UNIST-Ulsan Center for Convergent MaterialsUlsan National Institute of Science and Technology (UNIST)Ulsan 689-798, KoreaE-mail: jbaik@unist.ac.krTel: +82-52-217-2324; Fax: +82-52-217-2309

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Supplementary Table

Table S1. Comparison of the key properties among FTCEs fabricated by various materials and

methods.

Materials Sheet resistanceRs (Ω/sq)

Transmittance at550 nm [%]

Reference

Reduced graphene oxide films 1800 81 [1]Graphene Films 230 72 [2]Carbon nanotube films 160 87 [3]Pt nanobelt network 16 83 [4]Ag nanowire network 71.2 87.7 [5]Ag grid 30 85 [6]Cu film with hole arrays 17.48 83 [7]Ag film with pore arrays 18.5 93.1 This workBare Ag film (15 nm) 7.4 67.2 This work

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Table S2. Comparison of the key properties among TENGs fabricated by various PDMS based structures.

Structure Material Open-circuit voltage

Output current

densities

Reference

Microneedle-StructuredPDMS

Al–PDMS/Al 102.8 V 1.5 µA cm2 [8]

Cicada wing replicated PDMS structures

Cu–PDMS/Au 210 V 3.68 μA/cm2 [9]

PDMS nano-pillar Al/PDMS–Ni ～100 V[10]

Pyramid-featured PDMS

Indium tin oxide (ITO)/PET–PDMS/PET/ITO

18 V ∼0.13 μA/cm2

[11]

PDMS with hierarchical surfacemorphology

Al–PDMS/Al 207 V 14.1 μA/cm2 [12]

PDMS pyramid patterns

Electrode/Kapton/PDMS–Al with cubic patterns

230 V 15.5 μ A/cm2 [13]

PDMS porous Pyramid patterns

Ag/PET–PDMS/Ag/PET 80.8 V 28.4 μ A/cm2 This work

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Supplementary Figures

Fig. S1. SEM images of PMMA patterns printed on the PET substrate with different voltage. (a) 23 V, (b) 35 V. The corresponding center-to-center spacing distances set as 100 μm. Scale bars are 100 μm.

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Fig. S2. SEM images of PMMA patterns printed on the PET substrate with different center to center distances between the printing drops. (a-c) The corresponding center-to-center spacing distances set as 110 μm, 100 μm and 90 μm. Scale bars are 100 μm.

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Fig. S3. (a) Schematic of fabrication process for transparent denticulate Ag microwire arrays, and corresponding SEM image (b). (c) and (d) are photographs of FTCEs consisted of denticulate Ag microwires before and after removing the PMMA patterns.

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Fig. S4. SEM images of the Ag film with pore patterns fabricated on PDMS and the close-up view.

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Fig. S5. Schematic illustration of the structure of the four-wire touch screen fabricated in this work. The right lower picture shows the connection between the TSP and controller board. The controller board connect with a computer by a USB cable.

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Fig. S6. (a-c) SEM images of the photoresist grids after slide coating PS particles with concentrations of 2.6 wt%, 5.2 wt% and 10.4 wt%, respectively. (d-f) The SEM images of corresponding PDMS replicas. The depth of the photoresist is 10 μm. Scale bars are 10 μm.

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Fig. S7. UV-vis spectra of bare PDMS interlayer, the PDMS interlayers with porous pyramid pattern, the TENG device with a porous pyramid patterned PDMS interlayer between the top and bottom FTCEs and Ag film with a thickness of 15 nm.

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Fig. S8. (a) Open-circuit voltage, and (b) output current densities of the porous pyramid based TENG under working frequencies of 2 Hz and force of 10 N.

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Fig. S9. (a) Open-circuit voltage, and (b) output current densities of from the non-transparent electrode and PDMS pair under working frequencies of 10 Hz and force of 22 N.

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Fig. S10. The measured voltage of a commercial capacitor (1000 μF) charged with AC to DC signal converting circuit.

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Fig. S11. Optical transmittance of the transparence of the single-electrode-based TENG.

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Reference

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