Supporting Information Transparent Stretchable Self-Powered Patchable Sensor Platform with Ultrasensitive Recognition of Human Activities Byeong-Ung Hwang,, Ju-Hyuck Lee,, Tran Quang Trung,, Eun Roh, Do-Il Kim, Sang-Woo Kim,,,* and Nae-Eung Lee,,,* School of Advanced Materials Science & Engineering, Sungkyunkwan University, Suwon, Kyunggi-do 440-746, Republic of Korea SKKU Advanced Institute of Nano Technology (SAINT), Sungkyunkwan University, Suwon, Kyunggi-do 440-746, Republic of Korea Samsung Advanced Institute for Health Sciences & Technology (SAIHST), Sungkyunkwan University, Suwon, Kyunggi-do 440-746, Republic of Korea B.-U. Hwang, J.-H. Lee, and T. Q. Trung contributed equally to this work. Correspondence and requests for materials should be addressed to S.-W.Kim (email: kimsw1@skku.edu) or N.-E. Lee (email: nelee@skku.edu).
Material Stretchability Transmittance Sensitivity (GF) Table S1. Comparison of the performance with the data from other previous works on stretchable strain sensors. 1-11 Durability test Power consumption Reference Graphene 7% 75~80% 14 X Not shown Ref. 1 10% Non transparent 9.49 - Ref. 2 Cracked graphene 0.2% - 1,000,000 X - Ref. 3 Cracked Pt film 2% - > 2,000 - Ref. 4 CNT 280% - 0.82 - Ref. 5 300% - < 1 - Ref. 6 AgNP 20% - 7 - Ref. 7 Graphene/rubber 800% - 35 - Ref. 8 ZnO NW/polystyrene 50% < 20% 116 - Ref. 9 AgNW/PDMS 70% - 14 - Ref. 10 CNT/PDMS 27.8 (0-40%) (Interlocked microdome arrays) 120% - AgNWs/PEDOT:PSS/PU 100% 75.3% 1084 (40-90%) 9617 (90-120%) 12.4 (Low strain, <6%) X - Ref. 11 5µWcm -2 Our work
Figure S1. Schematic illustration of AgNW/PEDOT:PSS/PU nanocomposite strain sensor. (a) Fabrication process of the strain sensor. (b) Photographs of the nanocomposite strain sensor before and after stretching at strain ε = 0 and 100 %.
Figure S2. Stretching test of the AgNW/PEDOT:PSS/PU nanocomposites with different PEDOT:PSS/PU concentrations. Relative resistance changes ( R/R 0 ) versus strain of the samples with the PEDOT:PSS/PU ratio (a) 40/60 %, (b) 28/72 %, and (c) 14/86 % were replotted in a linear scale. (d) Comparison of the above samples in the smaller range of 0-30 % strain. (e) Reproducibility in the resistance changes of four different nanoscomposite films with the same concentration of AgNWs/PEDOT:PSS/PU at 14/86 %.
Figure S3. Electrical and optical properties of strain sensors. (a) Relative resistance change ( R/R 0 ) versus strain of the AgNW/PEDOT:PSS/PU nanocomposite film with different density of AgNWs. (b) Optical transmittance with different density of AgNWs in the nanocomposites.
Figure S4. Cyclic stretching tests on the PEDOT:PSS/PU (14/86 %) nanocomposite films without and with AgNWs. (a) Change in transient resistance of the film without AgNWs during 10,000 cycles of stretching-releasing at 0-40 % strain. (b) Change in transient resistance of the film with AgNWs during 10,000 cycles of stretching-releasing at 0-40 % strain.
Figure S5. Surface images of PEDOT:PSS/PU (14/86 %) nanocomposite films after cyclical stretching. (a, b) FE-SEM images of the nanocomposite films without (left) and with AgNWs (right). (c, d) AFM images of those films without (left) and with AgNWs (right). Scale bar, 2 µm.
Figure S6. Systematic straining tests of the AgNW/PEDOT:PSS/PU (14/86 %) nanocomposite resistive strain sensors. (a, c) Resistance change ( R/R 0 ) versus time of the nanocomposite strain sensor under progressively increasing stretch from 10 to 60 % (high tensile strain) with 50 cycles per pulse before and after 500 cycles of stretching, respectively. (b, d) Resistance change ( R/R 0 ) versus high strain before and after 500 cycles of stretching, respectively.
Figure S7. Systematic straining tests of the two-component PEDOT:PSS/PU and AgNW/PU composites. (a, b) Resistance change ( R/R 0 ) versus time of the PEDOT:PSS/PU (14/86 %) composite strain sensor under progressively increasing strain from 1.5 % to 6 % (low strain) in tensile and compressive cyclic bending modes (50 cycles per pulse), respectively. (c, d) Resistance change ( R/R 0 ) versus time of the PEDOT:PSS/PU (14/86 %) and AgNWs/PU composite strain sensor under progressively increasing stretching (high tensile strain) with 50 cycles per pulse, respectively.
Figure S8. Recognition of human activities based on AgNW/PEDOT:PSS/PU nanocomposite strain sensors. (a) Photographs of the sensor attached to the forearm. (b, c) Resistance change ( R/R 0 ) of the sensor attached on forearm skin to muscle motions of fist clenching with holding times of 2 s and 0.5 s (10 cycles per pulse), respectively. (d, e) R/R 0 response to strain on forearm skin to muscle motions of wrist bending and turning, respectively. (f) R/R 0 response of the sensor attached to the index finger during joint motion of the index finger.
Figure S9. Investigation on the performance of the transparent and stretchable TENG. (a) Electric peak voltage (left axis) and peak current (right axis) as a function of load resistance. The dots are experimentally measured values, while the lines are the fitted results. (b) Instantaneous electric peak power as a function of load resistance. The dots are experimentally measured values, while the line is a fitted result. (c) Output voltages as a function of load resistance: (i) at 10 kω, (ii) at 100 kω (iii) at 1 MΩ, (iv) at 10 MΩ, (v) at 50 MΩ (vi) at 100 MΩ, (vii) at 500 MΩ, and (viii) at 1 GΩ. (d) Output current as a function of load resistance: (i) at 10 kω, (ii) at 100 kω (iii) at 1 MΩ, (iv) at 10 MΩ, (v) at 50 MΩ, (vi) at 100 MΩ, (vii) at 500 MΩ, and (viii) at 1 GΩ. (e) Optical transmittance of the fabricated TENG.
Figure S10. Electrochemical characterizations of the AgNW/PEDOT:PSS/PU nanocomposite-based transparent and stretchable SC. (a) C-V curves at different scan rates. (b) Charge-discharge curves at different current densities. (c) Areal capacitance as a function of scan rate. (d) Areal capacitance as a function of current density. (e) Optical transmittance of the fabricated SC.
Figure S11. C-V curves before and after stretching at a scan rate of 100 mv/s. There is no significant deviation in the C-V curves of the stretchable SC before and after 5,000 stretching cycles at 30 % strain.
Figure S12. Charging property of the transparent and stretchable SC charged by a TENG. (a) Schematic of the rectifying circuit and SC. (b) Charging curve of the SC charged by the power generated by the TENG, and charging steps of the SC (inset). (c) Rectified output voltages of the TENG. (d) Rectified output currents of the TENG.
Figure S13. Electrical performances of integrated devices under mechanical stretching with 10% strain. (a) Generated voltage in TENG, (b) C-V curve of SC, and (c) resistance change in strain sensor.
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