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A Wearable Skinlike Ultra-Sensitive Artificial Graphene Throat Yuhong Wei,†,§ Yancong Qiao,†,§ Guangya Jiang,‡,§ Yunfan Wang,‡,§ Fangwei Wang,† Mingrui Li,† Yunfei Zhao,† Ye Tian,† Guangyang Gou,† Songyao Tan,† He Tian,*,† Yi Yang,*,† and Tian-Ling Ren*,† Downloaded via UNIV OF SOUTHERN INDIANA on July 17, 2019 at 03:57:32 (UTC). See https://pubs.acs.org/sharingguidelines for options on how to legitimately share published articles.
†
Institute of Microelectronics & Beijing National Research Center for Information Science and Technology and ‡Department of Electronic Engineering, Tsinghua University, Beijing 100084, China S Supporting Information *
ABSTRACT: Most mute people cannot speak due to their vocal cord lesion. Herein, to assist mute people to “speak”, we proposed a wearable skinlike ultrasensitive artificial graphene throat (WAGT) that integrated both sound/ motion detection and sound emission in single device. In this work, the growth and patterning of graphene can be realized at the same time, and a thin poly(vinyl alcohol) film with laser-scribed graphene was obtained by a waterassisted transferring process. In virtue of the skinlike and low-resistant substrate, the WAGT has a high detection sensitivity (relative resistance changes up to 150% at 133 Ω) and an excellent sound-emitting ability (up to 75 dB at 0.38 W power and 2 mm distance). On the basis of the excellent mechanical-electrical performance of graphene structure, the sound detecting and emitting mechanisms of WAGT are realized and discussed. For sound detection, both the motion of larynx and vibration of vocal cord contribute to throat movements. For sound emission, a thermal acoustic model for WAGT was established to reveal the principle of sound emitting. More importantly, a homemade circuit board was fabricated to build a dual-mode system, combining the detection and emitting systems. Meanwhile, different human motions, such as strong and small throat movements, were also detected and transformed into different sounds like “OK” and “NO”. Therefore, the implementation of these sound/motion detection acoustic systems enable graphene to achieve device-level applications to system-level applications, and those graphene acoustic systems are wearable for its miniaturization and light weight. KEYWORDS: artificial graphene throat, piezoresistive effect, thermoacoustic effect, laser scribing process, thermal acoustic model, dual-mode system, motion detected system insulated.2,16,28 Correspondingly, previous thermal sound sources cannot detect sound for their relatively low sensitivity.35 Recently, a nanomembrane with orthogonal silver nanowire arrays has been successful working as a sound detector and emitter, respectively.9 However, directly transforming input sound signals into output sound signals has not been realized. Laser scribing technology, with high efficiency, programmable forming, and easier operation, is widely used to fabricate devices of laser-scribed graphene (LSG).35−44 In our previous work, a graphene epidermal electronic skin was fabricated to monitor physical health signals,17 but its sound-emitting performance has not been realized. Recently, the prototype of graphene artificial device has been demonstrated,45 but
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coustic devices consist of sound/motion detectors and sound emitters. Sound/motion detectors, working under the same principles as strain sensors, can measure human pulse and heart beat for health monitoring,1,2 while sound emitters work as audios or loudspeakers.3 Compared with the materials used before in acoustic devices like carbon nanotubes,4−6 aluminum nanowires,7 and silver nanowires,8,9 graphene is a two-dimensional (2D) material that is well-known for its high electromobility, high flexibility, and low heat capacity.10−14 Therefore, graphene has been widely applied in strain sensors15−24 and thermoacoustic sound sources.25−34 There is an urgent need for acoustic devices with a multifunctional integration and a minimal size, but few devices have realized both sound detecting and sound emitting in audio sound range in a single device. Sound detectors are usually separated from thermoacoustic sound sources, because the ductile substrates used for packaging sound detector are © XXXX American Chemical Society
Received: April 26, 2019 Accepted: July 3, 2019 Published: July 3, 2019 A
DOI: 10.1021/acsnano.9b03218 ACS Nano XXXX, XXX, XXX−XXX
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Figure 1. Schematic illustration of the fabrication process and characterization of LSG. (a) The fabrication process of WAGT. (b) Schematic of artificial graphene throat when attached to throat. (c) The working mechanism diagram of WAGT. (d) Six LSG samples generated by different laser intensity ranging from 0.68 to 6.0 mW. The SEM images show the morphology and cross-section of two LSG samples generated by lasers at 4.7 and 5.3 mW, respectively.
neither is its graphene/polyimide (PI) structure thin enough to realize adequate sound detection ability nor did it possesses enough comfortability as a wearable electronic device, since it needs to be taped. Some strain sensors of thin film like tattoo have been extensively researched recently, but those tattoolike sensors have not been applied in acoustic field.46−53 Therefore, a thinner skinlike film artificial throatlike tattoo with good adhesion is a huge need to be fabricated. In this work, we proposed a thin 1.5 cm × 1.5 cm squareshaped wearable skinlike ultrasensitive artificial graphene throat (WAGT), which integrated both sound/motion detection and sound emission. As a sound/motion detector, WAGT transformed mechanical signal to electrical signal based on the piezoresistive effect. In application, the WAGT was transferred onto the throat to receive sound signals, and throat movements led to strain deformation of WAGT. Furthermore, the sound-detecting mechanism of WAGT was studied more thoroughly. We distinguished the contribution of larynx mechanical movement and vibration of vocal cord from sound transmission when normally speaking, both of which composed throat movements. The thin substrate of WAGT enables the device with a high sensitivity to sound signals, so that words can be recognized and recorded through waveforms of resistance change precisely and in real time. As a sound emitter, WAGT applied to electrical signal produces joule heat and releases it to the air, generating sound based on the thermoacoustic effect. The low-resistant (∼50 Ω) artificial graphene throat is available to achieve the high sound pressure level (SPL) up to 75 dB. Moreover, a dual-mode system is built to transform sound input into sound output, and the human motions include different meanings can be converted
into corresponding sounds. On the basis of that, the WAGT device is able to detect different throat movements of mute people and translates them into audible sound. At last, the WAGT shows a great performance on stability and durability, as the sample has no attenuation after emitting for 120 min and being bent at least 20 000 times. After it worked continuously, the maximum temperature of WAGT only increases to 28.2 °C with an input power of 0.025 W, which is acceptable for human skin. In addition, the WAGT can remain on human throat with good adhesion after 11 h.
RESULTS Figure 1a shows the fabrication processes of WAGT, containing graphene oxide (GO) drop-casting, laser scribing, lift-off, and electrode-connecting processes. The water-transfer paper consists of a paper substrate, a sacrificial layer, and a thin poly(vinyl alcohol) (PVA) film (support layer). The Young’s modulus of this PVA film substrate (∼24 MPa) is close to the Young’s modulus of human skin (20−80 MPa),54 promising a good adhesion of the film to the skin. After the laser scribing process, the device was immersed into water, a few minutes before the sacrificial layer was dissolved in water, and unreduced GO mixture was separated with LSG.17 Finally, a thin LSG film with high flexibility and adhesion property was gained. After the electrodes were connected, the LSG was divided into two regions, working as sound/motion detector and sound emitter, respectively. These two divided regions can avoid short circuit, guarantee normal systems operation without disturbing each other, and detect or emit sound simultaneously. Some samples with different programed patterns were attached to the skin, with more details shown B
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Figure 2. The signal collections of sound/motion by LSG. (a) Schematic diagram of LSG attached to throat working as a sound/motion detector. (b) Frame diagram of how different throat movements were transformed to different sound signals. (c) The relative resistance changes of LSG transferred onto throat of a tester who makes different motions. (d) The tester says “Happy” normally with throat movements and with larynx movement voicelessly. (e) The response of attached LSG toward sound, “Happy New Year”. One wave curve is magnified to be showed. (f) The waveform of resistance change of LSG after the sample is transferred onto an audio, which plays the same recorded sound, “Happy New Year”. One wave curve is magnified to be showed.
LSG thickness increased from 13 to 20 μm when laser intensity power increased from 4.7 to 5.3 mW. Figure S2 shows the schematic illustration of characterization of LSG samples under SEM. At lower intensity, such as P = 0.68 mW, only a small amount of GO was reduced, and it cannot form a conductive layer. At higher intensity, such as P = 0.8 mW, the surface of GO was broken into fragments, decreasing the conducting ability (Figure S2a−d). The thickness of LSG samples increased when laser scribing number increased from 1 to 3, due to the incomplete reduction of GO. However, after excessive scanning numbers, the structure of surface graphene is destroyed, reducing the thickness (Figure S2e−h). The Raman spectra of GO, LSG, and water transfer paper are shown in Figure S3. The GO and LSG spectra present similar characteristic with D peak at 1350 cm−1 and G peak at 1580 cm−1, respectively. Moreover, 2D peak of LSG, at 2700 cm−1, proved that part of GO is transformed into LSG by laser. The
in Figure S1. From Figure 1b, the WAGT was attached to the throat to detect signal and emit sound. The working mechanism diagram in the detailed introduction was shown in Figure 1c. The throat movements were generated by vibration of vocal cord and stretching and contraction movement of muscle at larynx, leading to the corresponding strain of sound/motion detector. Subsequently, those strain signals were transmitted to sound emitter and then generated sound. More details will be discussed later to explain the mechanism of detecting and emitting sound. The morphology and cross-section view of LSG device under scanning electron microscope (SEM) are shown in Figure 1d. These SEM images show that LSG has a porous surface. The thickness of LSG is mainly controlled by laser intensity, laser scribing numbers, and GO drop-casting thickness. For instance, two LSG devices were fabricated at different generated laser intensity P = 4.7 and 5.3 mW, respectively. Their cross-section views show that C
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Figure 3. The emitting sound signal performance of LSG. (a) The output sound pressure (SP) of LSG on paper is measured using commercial microphone. (b) The experimental and theoretical SP vs input power. (c) The SPL vs frequency of LSG generated by laser at different power. (d) The output SP vs measuring distance of LSG at 7.5 and 15 kHz. The circle is the experimental result, and the dashed line is the theoretical result. (e) The plot of the SP vs the thickness of LSG at 7.5 and 15 kHz. The square is the experimental result, and the line is the theoretical result. (f) The thermal acoustic model for LSG on paper in this study. (g) The plot of directivity shows a highly directional acoustic wave. (h) SPL vs frequency from theoretical model (red) and experimental results (black), which shows agreement with each other.
results of the X-ray photoelectron spectroscopy (XPS) of GO and LSG can also confirm this conclusion (Figure S4). Sound/motion detection properties of LSG are investigated after transferred onto human throat (Figure 2a). As shown in Figure 2b, the mechanism of sound/motion detection is discussed, and two different throat movements are transformed to different sound signals. One of throat movements is named throat movement I. Spoken sound propagates through human body and generates the vibration of vocal cord, leading to strain of LSG at a higher speed. Thus, a higher-frequency sound signal is detected (named sound signal I). At the same time, throat movement II is caused by normal stretching and contraction of muscle at throat without voice, leading to strain of LSG at a lower speed. Thus, a lower-frequency sound signal is detected (named sound signal II). Either part of the sound signal can be analyzed independently when the other part is recognized and filtered out. Figure S5a shows the frequency test result by holding a microphone close to the throat of a tester who speaks normally or has only larynx movement in dynamic fast Fourier transform (FFT) mode. The SPL of voice signal is higher than larynx movement signal at the frequency
ranges from 200 to 800 Hz, which confirms the function of higher frequency of voice signal. When it worked as a sound/motion detector, the resistance of LSG device varied correspondingly depending on its strain, and exhibited great repeatability. As far as we know, most mute people can emit sounds like “cough” that convey specific meanings. The waveform of resistance change generated by each motion has its own shape (Figure 2c). Useful signals can be collected, and interferences like “hiccup” can also be recognized and filtered. After mute people get trained, they can generate meaningful signals, which can be translated into sound later through LSG, to express themselves. In this study, the waveform shape of resistance change is mainly influenced by throat movement I, while the value of resistance change is mainly determined by throat movement II. As shown in Figure 2d, the tester speaks “Happy” (“Student” in Figure S5b) voicelessly with only throat movement (throat movement II) or normally with throat movement (throat movements I and II), respectively, proving the effect of throat movement II. In further research, the tester speakers “OK” five times with LSG attached in a quiet environment and in a noisy environment, where music is played aloud (Figure S5c). It shows that the D
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Figure 4. WAGT: the sound-detection system and motion-detection system. (a) The sound-detection system. The WAGT is connected by a homemade circuit board. The microphone and Agilent 35670 are used to collect sound; the oscillography is used to display resistance change waveforms of LSG sound/motion detector. (b) The response of the graphene sound-detection system of (a). The waveforms displayed by oscillography in real time when the WAGT is attached to throat to detect sound/motion signals of (c) no speaking, (d) normal speaking, (e) larynx movement voicelessly, and (f) opening and closing mouth. The spoken words in (d, e) are the same. (g) WAGT is transferred onto throat to translate different human motions into corresponding sounds. (h) The working mechanism of the motiondetection system of (g). All scale bars represent 1 cm.
resistance change of LSG is due to the deformation of sample, so the background noise does not have an effect on LSG. Moreover, the relative resistance of LSG change increases when tester increases sound intensity (Figure S5d), which is because speaking louder can gain larger resistant variation; when the sound intensities increase from 59 to 70 dB, the resistant variations of the sample increase from 4.5% to 7%. Figure 2e,f shows the waveforms generated by samples attached to a throat and an audio, respectively. The strain of LSG caused by audio vibration is treated as the strain caused by throat movement I. Test sounds are recorded and played by the audio. As we can see, the shape of waveforms generated by the tester is similar to that generated by the audio. Besides, waveforms generated by the vocal of “Happy New Year” are made up of waveforms of three single words, and each individual waveform is made up of specific syllables,17 proving the effect of throat movement I. Vocal of a whole sentence is also tested (Figure S6a−f). In Figure S6g,h, the sample is attached to two different testers. Similar wave curves can be recognized as the characteristic of the specific words, and the detailed difference can be recognized as individual difference of person, which shows promising prospects for development of voice recognition. Waveforms generated by the audio are more
isolated due to the lack of throat movement, and the relative resistance can change up to 150% during the tests, showing its high detection sensitivity and flexibility (Figure S6i). The LSG is also tested as a thermoacoustic sound source after water-transferred onto a paper substrate, as shown in Figure 3a. There is no obvious degradation of SPL after watertransferring process (Figure S7a). The measuring distance is 2 mm. The applied bias voltage sets the quiescent operation point, and the applied alternating voltage generates periodic joule heat, causing the periodic vibration of air, which generates sound. Three samples are fabricated by different laser powers at 4.7, 5.3, and 6.0 mW, and the corresponding average thickness for the thin PVA film with LSG is 13, 20, and 38 μm, respectively. From Figure 3b, the output sound pressure (SP) increases linearly with the input power, and the LSG has a higher efficiency at 15 kHz than at 7.5 kHz. The SPL decreases from 75 to 65 dB by increasing of LSG synthesis laser power from 4.7 to 6.3 mW (Figure 3c). The experimental results are normalized with the same input power (1 W) and same area (1 cm × 1 cm). The output SP is inversely proportional to the measured distance (Figure 3d), as well as the thickness of LSG (Figure 3e). Normalized results show that, with the decrease of the LSG thickness, the leakage of E
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Figure 5. The integration of sound- and motion-detection systems. (a) The artificial throat system is worn by a tester. (b) The comparison chart of detected sensitivity between WAGT and other devices. All scale bars represent 2 cm.
tester speaks the same words, “Skinlike ultra-sensitive intelligent graphene throat” normally and with only larynx movement, respectively (Figure 4d,e). When tester just opens and closes mouth, the sound signal is also detected (Figure 4f). Those displays prove that the signals of both throat movements I and II and mouth motions of mute people are able to be collected as useful signals, which provide the possibility for mute people to “talk” with others. The frequency bandpass of fabricated circuit board ranges from 16 Hz to 16 kHz, filtering the waveforms generated by useless muscle movement like hiccup, and other high-frequency sounds not generated by tester. From the movie, the resistance change waveforms is displayed continuously in high precision, good repeatability, and real time. The WAGT succeeds in transforming different human motions to different sounds (Figure 4g), after the WAGT is attached to throat of tester, who makes strong or small throat movements. The motion detector can detect different degrees of larynx movements and transfer signal input to microcomputer (MCU); the MCU transforms different resistance changes of LSG caused by different human motions into different voltages, respectively. The buttons of decoder are controlled by different voltages by pins, and then, the sound emitter can play different sounds through different buttons “selected”. Thus, the sound emitter speaks “OK” after tester making strong movement and speaks “NO” after tester making a small movement (Movie S2). What’s more, after connected with a decoder and a power amplifier, the sound emitter is able to work as an audio to play music (Movie S3). The audio file in secure digital memory card (SD) storage can be read and loaded, and then the artificial throat sample can play music when connected and switched on. The integrated artificial throat system is worn by a tester showing its excellent miniaturization, light weight, and versatility (Figure 5a). A broader development is expected in the future, if the high technology including bluetooth transmission, voice recognition, and machine learning are added. The comparison chart of sensitivity detection shows the ultrasensitive detection of WAGT compared with some other existing graphene strain sensors (Figure 5b). For better contrast, graphene sensors with similar 2D structure are selected for comparison. The sound-emitting stability and durability of sound emitter are also tested (Figure S8); it shows that the SPL has no obvious damping after 120 min (Figure S8a). The sound-
thermal energy will reduce, and more thermal energy will be diffused into the air, indicating a higher SP. Figure S7b−d indicates that fast laser scribing speed, low thermal conductivity substrate, and large area of LSG are essential during the manufacturing process. The thickness of LSG decreases when the laser scribing speed increases; low thermal conductivity55−57 substrate and large area of LSG are beneficial to the heat loss in the air. Figure 3f sketches the theoretical model of thermal acoustic for LSG on paper substrate. Note that the equation depicts the upper bounded SP generated by a point source.4,58 For the square LSG presented, the directivity D(θ,φ) needs to be deduced.7 At 20 kHz, directivity of the LSG sound source in (|D(θ,0)|2) is plotted in Figure 3g, indicating a highly directional acoustic field. In this study, the output SP is the multiple of the directivity N(0,0) = N0, and the upper bounded SP generates by a point source (see Thermal acoustic model analysis methods for LSG on paper in the Supporting Information): Prms =
f N0Q̇ air 2 CpT0r
(1)
Note that N0 was deduced under quasi-spherical wave assumption not necessarily far field assumption. Figure 3h shows an agreement between the theoretical curves and the experimental results. Here, the sample has the thickness of 20 μm, and the input power is 176 mW. In this work, the WAGT includes a sound/motion detector and a sound emitter in system performing as an artificial graphene throat. As shown in Figure 4a, a circuit board with high gain is fabricated to amplify and transform signals. The resistance change signal is gained by the sound detector. The signal is then amplified and transformed to voltage change signal to drive sound emitter to generate sound. A wireless transmission module was used to prevent the sound source from interfering with the result of detecting sound by microphone. The bias voltage applied by an operational amplifier in circuit board can be adjusted within ±5 V. An oscillography is used to display real-time resistance change waveforms of sound detector (Movie S1). Figure 4b shows the sound response of graphene sound-detection system; the sound signals are detected by microphone in dynamic FFT mode. After WAGT is transferred onto throat, there is no sound signal detected when not speaking (Figure 4c). In further research, the sound signals I and II are detected when F
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ACS Nano emitting ability of device has almost no weakening after 20 000 times bending (8 h), showing excellent durability (Figure S8b). The bending radius is 1 cm, the stress is 0.06 N, and the bending degree of sample is higher than that attached to throat. Figure S9 shows the device maximum temperature increases from 25.3 to 28.2 °C when the input power increases from 0 to 0.025 W, which is acceptable for human skin. In addition, the WAGT can remain on human throat with good stability for more than 11 h (Figure S10).
The waveform displayed in real time when WAGT attached onto throat to detect sound and motion signals of throat movements (MP4) The WAGT motion detected system generates different sounds controlled by different human motions (MP4) The LSG working as a sound emitter can play music (MP4)
AUTHOR INFORMATION Corresponding Authors
CONCLUSION In conclusion, the WAGT system that integrates sound/ motion detector and thermoacoustic sound source in single device is proposed. First, as a sound detector, the WAGT device shows a maximum of 150% strain range, an excellent skin adhesion ability, with an ultrathin thickness. It can recognize sound signal with the collected specific waveforms corresponding to every word. Moreover, the sound-detecting mechanism of WAGT is realized and distinguished. The strain of WAGT is caused by throat movements, consisting of vibration of vocal cord and motion of larynx. The wave shape is dominantly precisely controlled by vibration of vocal cord, and wave value is dominantly controlled by movement of larynx. Second, as a sound emitter, the device generates up to 75 dB SPL at frequency ranges from 100 Hz to 20 kHz. Finally, a circuit board with the function of transforming sound signals is fabricated and applied to the sound-detection system. As a motion detector, the WAGT motion-detected system can transform different human motions to different sounds. In all, the WAGT can detect the throat movement signals of mute people sensitively and then speak out on behalf of them precisely, which is very meaningful for helping mute people to “speak” in the future.
*E-mail:
[email protected]. (T.-L.R.) *E-mail:
[email protected]. (Y.Y.) *E-mail:
[email protected]. (H.T.) ORCID
Yuhong Wei: 0000-0002-7316-0262 Yancong Qiao: 0000-0003-0979-6853 Ye Tian: 0000-0002-3278-1126 He Tian: 0000-0001-7328-2182 Author Contributions §
Y.W., Y.Q., G.J., and Y.W. contributed equally to this work.
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS This work was supported by the National Key R&D Program (2016YFA0200400), National Natural Science Foundation (61434001, 61574083, 61874065, 51861145202), and National Basic Research Program (2015CB352101) of China. The authors are also thankful for the support of the Research Fund from Beijing Innovation Center for Future Chip, Beijing Natural Science Foundation (4184091), and Shenzhen Science and Technology Program (JCYJ20150831192224146). He Tian thanks for the support from Young Elite Scientists Sponsorship Program by CAST (2018QNRC001).
EXPERIMENTAL METHODS Material Preparation. A 2 mg mL−1 GO dispersion was mixed with tetrahydrofuran (THF) at a volume ratio of 1:5; the GO dispersion was provided by Nanjing/Jiangsu XFNANO Materials Tech Co. Ltd. Then the mixture was stirred well by glass rod and dropped on water-transfer paper. After the structure was dried at room temperature for 2−3 d, the water-transfer paper with thin GO thin PVA film was fabricated. Fabrication Process of WAGT. A laser scribing platform with the 450 nm wavelength and 28.1 mW/cm2 power density is used to reduce the GO to laser scribed graphene, then the water-transfer paper with programmable patterns is immersed in deionized (DI) water for a few minutes, the GO unreduced by laser falls off into DI water, and the thin PVA film with LSG is separated with paper structure. Finally, this thin PVA film with LSG can be transferred onto throat to detect sound. Characterization. The surface morphology of the LSG was observed by a Quanta FEG 450 SEM (FEI Inc.). Raman spectroscopy was performed using a laser with a wavelength of 532 nm (HORIBA Inc.). XPS (PHI Quantro SXM) was performed using monochromatic aluminum Kα X-rays. The electrical signals of the strain sensor were recorded by a digital source-meter (DM 3068). The Young’s modulus of thin PVA film was measured by atomic force microscopy (Bruker).
REFERENCES (1) Kang, D.; Pikhitsa, P. V.; Choi, Y. W.; Lee, C.; Shin, S. S.; Piao, L.; Park, B.; Suh, K. Y.; Kim, T. I.; Choi, M. Ultrasensitive Mechanical Crack-Based Sensor Inspired by the Spider Sensory System. Nature 2014, 516, 222−226. (2) Wang, C.; Li, X.; Gao, E.; Jian, M.; Xia, K.; Wang, Q.; Xu, Z.; Ren, T.; Zhang, Y. Carbonized Silk Fabric for Ultrastretchable, Highly Sensitive, and Wearable Strain Sensors. Adv. Mater. 2016, 28, 6640− 6648. (3) Zhou, Q.; Zettl, A. Electrostatic Graphene Loudspeaker. Appl. Phys. Lett. 2013, 102, 223109. (4) Asadzadeh, S. S.; Moosavi, A.; Huynh, C.; Saleki, O. Thermo Acoustic Study of Carbon Nanotubes in Near and Far field: Theory, Simulation, and Experiment. J. Appl. Phys. 2015, 117, 095101. (5) Xiao, L.; Chen, Z.; Feng, C.; Liu, L.; Bai, Z.-Q.; Wang, Y.; Qian, L.; Zhang, Y.; Li, Q.; Jiang, K. J. N. l.; et al. Flexible, Stretchable, Transparent Carbon Nanotube Thin Film Loudspeakers. Nano Lett. 2008, 8, 4539−4545. (6) Mason, B. J.; Chang, S.-W.; Chen, J.; Cronin, S. B.; Bushmaker, A. W. J. A. n. Thermoacoustic Transduction in Individual Suspended Carbon Nanotubes. ACS Nano 2015, 9, 5372−5376. (7) Xie, Q. Y.; Ju, Z. Y.; Tian, H.; Xue, Q. T.; Chen, Y. Q.; Tao, L. Q.; Mohammad, M. A.; Zhang, X. Y.; Yang, Y.; Ren, T. L. A Point Acoustic Device Based on Aluminum Nanowires. Nanoscale 2016, 8, 5516−5525. (8) Tian, H.; Xie, D.; Yang, Y.; Ren, T.-L.; Lin, Y.-X.; Chen, Y.; Wang, Y.-F.; Zhou, C.-J.; Peng, P.-G.; Wang, L.-G.; Liu, L.-T. Flexible, Ultrathin, and Transparent Sound-Emitting Devices Using Silver Nanowires Film. Appl. Phys. Lett. 2011, 99, 253507.
ASSOCIATED CONTENT S Supporting Information *
The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acsnano.9b03218. Additional figures as described in the text (PDF) G
DOI: 10.1021/acsnano.9b03218 ACS Nano XXXX, XXX, XXX−XXX
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ACS Nano (9) Kang, S.; Cho, S.; Shanker, R.; Lee, H.; Park, J.; Um, D.-S.; Lee, Y.; Ko, H. J. S. a. Transparent and Conductive Nanomembranes with Orthogonal Silver Nanowire Arrays for Skin-Attachable Loudspeakers and Microphones. Sci. Adv. 2018, 4, No. eaas8772. (10) Novoselov, K. S.; Geim, A. K.; Morozov, S. V.; Jiang, D.; Zhang, Y.; Dubonos, S. V.; Grigorieva, I. V.; Firsov, A. A. J. s. Electric Field Effect in Atomically Thin Carbon Films. Science 2004, 306, 666−669. (11) Castro Neto, A. H.; Guinea, F.; Peres, N. M.; Novoselov, K. S.; Geim, A. K. The Electronic Properties of Graphene. Rev. Mod. Phys. 2009, 81, 109−162. (12) Geim, A. K. J. s. Graphene: Status and Prospects. Science 2009, 324, 1530−1534. (13) Allen, M. J.; Tung, V. C.; Kaner, R. B. J. C. r. Honeycomb Carbon: A Review of Graphene. Chem. Rev. 2010, 110, 132−145. (14) Ferrari, A. C.; Bonaccorso, F.; Fal’Ko, V.; Novoselov, K. S.; Roche, S.; Bøggild, P.; Borini, S.; Koppens, F. H.; Palermo, V.; Pugno, N. J. N.; et al. Science and Technology Roadmap for Graphene, Related Two-Dimensional Crystals, and Hybrid Systems. Nanoscale 2015, 7, 4598−4810. (15) Cheng, Y.; Wang, R.; Sun, J.; Gao, L. A Stretchable and Highly Sensitive Graphene-Based Fiber for Sensing Tensile Strain, Bending, and Torsion. Adv. Mater. 2015, 27, 7365−7371. (16) Park, J. J.; Hyun, W. J.; Mun, S. C.; Park, Y. T.; Park, O. O. Highly Stretchable and Wearable Graphene Strain Sensors with Controllable Sensitivity for Human Motion Monitoring. ACS Appl. Mater. Interfaces 2015, 7, 6317−6324. (17) Qiao, Y.; Wang, Y.; Tian, H.; Li, M.; Jian, J.; Wei, Y.; Tian, Y.; Wang, D. Y.; Pang, Y.; Geng, X.; Wang, X.; Zhao, Y.; Wang, H.; Deng, N.; Jian, M.; Zhang, Y.; Liang, R.; Yang, Y.; Ren, T. L. Multilayer Graphene Epidermal Electronic Skin. ACS Nano 2018, 12, 8839− 8846. (18) Tao, L. Q.; Wang, D. Y.; Tian, H.; Ju, Z. Y.; Liu, Y.; Pang, Y.; Chen, Y. Q.; Yang, Y.; Ren, T. L. Self-Adapted and Tunable Graphene Strain Sensors for Detecting both Subtle and Large Human Motions. Nanoscale 2017, 9, 8266−8273. (19) Wang, Y.; Wang, L.; Yang, T.; Li, X.; Zang, X.; Zhu, M.; Wang, K.; Wu, D.; Zhu, H. Wearable and Highly Sensitive Graphene Strain Sensors for Human Motion Monitoring. Adv. Funct. Mater. 2014, 24, 4666−4670. (20) Wang, Y.; Yang, T.; Lao, J.; Zhang, R.; Zhang, Y.; Zhu, M.; Li, X.; Zang, X.; Wang, K.; Yu, W.; Jin, H.; Wang, L.; Zhu, H. UltraSensitive Graphene Strain Sensor for Sound Signal Acquisition and Recognition. Nano Res. 2015, 8, 1627−1636. (21) Yang, T.; Wang, W.; Zhang, H.; Li, X.; Shi, J.; He, Y.; Zheng, Q.-s.; Li, Z.; Zhu, H. J. A. n. Tactile Sensing System Based on Arrays of Graphene Woven Microfabrics: Electromechanical Behavior and Electronic Skin Application. ACS Nano 2015, 9, 10867−10875. (22) Tian, H.; Shu, Y.; Cui, Y. L.; Mi, W. T.; Yang, Y.; Xie, D.; Ren, T. L. Scalable Fabrication of High-Performance and Flexible Graphene Strain Sensors. Nanoscale 2014, 6, 699−705. (23) Yin, B.; Wen, Y.; Hong, T.; Xie, Z.; Yuan, G.; Ji, Q.; Jia, H. Highly Stretchable, Ultrasensitive, and Wearable Strain Sensors Based on Facilely Prepared Reduced Graphene Oxide Woven Fabrics in an Ethanol Flame. ACS Appl. Mater. Interfaces 2017, 9, 32054−32064. (24) Liu, Q.; Chen, J.; Li, Y.; Shi, G. High-Performance Strain Sensors with Fish-Scale-Like Graphene-Sensing Layers for Full-Range Detection of Human Motions. ACS Nano 2016, 10, 7901−7906. (25) Suk, J. W.; Kirk, K.; Hao, Y.; Hall, N. A.; Ruoff, R. S. Thermoacoustic Sound Generation from Monolayer Graphene for Transparent and Flexible Sound Sources. Adv. Mater. 2012, 24, 6342−6347. (26) Tian, H.; Xie, D.; Yang, Y.; Ren, T. L.; Wang, Y. F.; Zhou, C. J.; Peng, P. G.; Wang, L. G.; Liu, L. T. Static Behavior of A GrapheneBased Sound-Emitting Device. Nanoscale 2012, 4, 3345−3349. (27) Tian, H.; Yang, Y.; Li, C.; Mi, W.-T.; Mohammad, M. A.; Ren, T.-L. A Flexible, Transparent and Ultrathin Single-Layer Graphene Earphone. RSC Adv. 2015, 5, 17366−17371.
(28) Tian, H.; Yang, Y.; Xie, D.; Ge, J.; Ren, T.-L. A Reduced Graphene Oxide Sound-Emitting Device: A New Use for Joule Heating. RSC Adv. 2013, 3, 17672−17676. (29) Tian, H.; Li, C.; Mohammad, M. A.; Cui, Y.-L.; Mi, W.-T.; Yang, Y.; Xie, D.; Ren, T.-L. J. A. n. Graphene Earphones: Entertainment for both Humans and Animals. ACS Nano 2014, 8, 5883−5890. (30) Tian, H.; Ren, T.-L.; Xie, D.; Wang, Y.-F.; Zhou, C.-J.; Feng, T.-T.; Fu, D.; Yang, Y.; Peng, P.-G.; Wang, L.-G. J. A. n.; et al. Graphene-on-Paper Sound Source Devices. ACS Nano 2011, 5, 4878−4885. (31) Tian, H.; Xie, D.; Yang, Y.; Ren, T. L.; Wang, Y. F.; Zhou, C. J.; Peng, P. G.; Wang, L. G.; Liu, L. T. Single-Layer Graphene SoundEmitting Devices: Experiments and Modeling. Nanoscale 2012, 4, 2272−2277. (32) Tao, L.-Q.; Sun, H.; Liu, Y.; Ju, Z.-Y.; Yang, Y.; Ren, T.-L. Flexible Graphene Sound Device Based on Laser Reduced Graphene. Appl. Phys. Lett. 2017, 111, 103104. (33) Kim, C. S.; Hong, S. K.; Lee, J. M.; Kang, D. S.; Cho, B. J.; Choi, J. W. Free-Standing Graphene Thermophone on A PolymerMesh Substrate. Small 2016, 12, 185−189. (34) Tao, L. Q.; Liu, Y.; Ju, Z. Y.; Tian, H.; Xie, Q. Y.; Yang, Y.; Ren, T. L. A Flexible 360-Degree Thermal Sound Source Based on Laser Induced Graphene. Nanomaterials 2016, 6, 112. (35) El-Kady, M. F.; Kaner, R. B. Scalable Fabrication of HighPower Graphene Micro-Supercapacitors for Flexible and On-Chip Energy Storage. Nat. Commun. 2013, 4, 1475. (36) Deng, N.-Q.; Tian, H.; Ju, Z.-Y.; Zhao, H.-M.; Li, C.; Mohammad, M. A.; Tao, L.-Q.; Pang, Y.; Wang, X.-F.; Zhang, T.-Y.; Yang, Y.; Ren, T.-L. Tunable Graphene Oxide Reduction and Graphene Patterning at Room Temperature on Arbitrary Substrates. Carbon 2016, 109, 173−181. (37) Lin, J.; Peng, Z.; Liu, Y.; Ruiz-Zepeda, F.; Ye, R.; Samuel, E. L.; Yacaman, M. J.; Yakobson, B. I.; Tour, J. M. Laser-Induced Porous Graphene Films from Commercial Polymers. Nat. Commun. 2014, 5, 5714. (38) Tao, L.; Wang, D.; Jiang, S.; Liu, Y.; Xie, Q.; Tian, H.; Deng, N.; Wang, X.; Yang, Y.; Ren, T.-L. Fabrication Techniques and Applications of Flexible Graphene-Based Electronic Devices. J. Semicond. 2016, 37, 041001. (39) Tian, H.; Yang, Y.; Xie, D.; Cui, Y. L.; Mi, W. T.; Zhang, Y.; Ren, T. L. Wafer-Scale Integration of Graphene-Based Electronic, Optoelectronic and Electroacoustic Devices. Sci. Rep. 2015, 4, 3598. (40) Xie, B.; Wang, Y.; Lai, W.; Lin, W.; Lin, Z.; Zhang, Z.; Zou, P.; Xu, Y.; Zhou, S.; Yang, C.; Kang, F.; Wong, C.-P. Laser-Processed Graphene Gased Micro-Mupercapacitors for Ultrathin, Rollable, Compact and Designable Energy Storage Components. Nano Energy 2016, 26, 276−285. (41) Zhang, Y.; Guo, L.; Wei, S.; He, Y.; Xia, H.; Chen, Q.; Sun, H.B.; Xiao, F.-S. Direct Imprinting of Microcircuits on Graphene Oxides Film by Femtosecond Laser Reduction. Nano Today 2010, 5, 15−20. (42) El-Kady, M. F.; Kaner, R. B. J. A. n. Direct Laser Writing of Graphene Electronics. ACS Nano 2014, 8, 8725−8729. (43) El-Kady, M. F.; Strong, V.; Dubin, S.; Kaner, R. B. J. S. Laser Scribing of High-Performance and Flexible Graphene-Based Electrochemical Capacitors. Science 2012, 335, 1326−1330. (44) Strong, V.; Dubin, S.; El-Kady, M. F.; Lech, A.; Wang, Y.; Weiller, B. H.; Kaner, R. B. J. A. n. Patterning and Electronic Tuning of Laser Scribed Graphene for Flexible All-Carbon Devices. ACS Nano 2012, 6, 1395−1403. (45) Tao, L. Q.; Tian, H.; Liu, Y.; Ju, Z. Y.; Pang, Y.; Chen, Y. Q.; Wang, D. Y.; Tian, X. G.; Yan, J. C.; Deng, N. Q.; Yang, Y.; Ren, T. L. An Intelligent Artificial Throat with Sound-Sensing Ability Based on Laser Induced Graphene. Nat. Commun. 2017, 8, 14579. (46) Kabiri Ameri, S.; Ho, R.; Jang, H.; Tao, L.; Wang, Y.; Wang, L.; Schnyer, D. M.; Akinwande, D.; Lu, N. Graphene Electronic Tattoo Sensors. ACS Nano 2017, 11, 7634−7641. (47) Windmiller, J. R.; Bandodkar, A. J.; Valdes-Ramirez, G.; Parkhomovsky, S.; Martinez, A. G.; Wang, J. Electrochemical Sensing H
DOI: 10.1021/acsnano.9b03218 ACS Nano XXXX, XXX, XXX−XXX
Article
ACS Nano Based on Printable Temporary Transfer Tattoos. Chem. Commun. 2012, 48, 6794−6796. (48) Bandodkar, A. J.; Molinnus, D.; Mirza, O.; Guinovart, T.; Windmiller, J. R.; Valdés-Ramírez, G.; Andrade, F. J.; Schöning, M. J.; Wang, J. J. B. Epidermal Tattoo Potentiometric Sodium Sensors with Wireless Signal Transduction for Continuous Non-Invasive Sweat Monitoring. Biosens. Bioelectron. 2014, 54, 603−609. (49) Berchmans, S.; Bandodkar, A. J.; Jia, W.; Ramírez, J.; Meng, Y. S.; Wang, J. An Epidermal Alkaline Rechargeable Ag−Zn Printable Tattoo Battery for Wearable Electronics. J. Mater. Chem. A 2014, 2, 15788−15795. (50) Guinovart, T.; Bandodkar, A. J.; Windmiller, J. R.; Andrade, F. J.; Wang, J. J. A. A Potentiometric Tattoo Sensor for Monitoring Ammonium In Sweat. Analyst 2013, 138, 7031−7038. (51) Bandodkar, A. J.; Hung, V. W.; Jia, W.; Valdés-Ramírez, G.; Windmiller, J. R.; Martinez, A. G.; Ramírez, J.; Chan, G.; Kerman, K.; Wang, J. J. A. Tattoo-Based Potentiometric Ion-Selective Sensors for Epidermal PH Monitoring. Analyst 2013, 138, 123−128. (52) Jia, W.; Valdés-Ramírez, G.; Bandodkar, A. J.; Windmiller, J. R.; Wang, J. J. A. C. I. E. Epidermal Biofuel Cells: Energy Harvesting from Human Perspiration. Angew. Chem., Int. Ed. 2013, 52, 7233− 7236. (53) Bandodkar, A. J.; Jia, W.; Wang, J. Tattoo-Based Wearable Electrochemical Devices: A Review. Electroanalysis 2015, 27, 562− 572. (54) Dąbrowska, A.; Rotaru, G. M.; Spano, F.; Affolter, C.; Fortunato, G.; Lehmann, S.; Derler, S.; Spencer, N. D.; Rossi, R. M. A Water-Responsive, Gelatine-Based Human Skin Model. Tribol. Int. 2017, 113, 316−322. (55) Morin, S. A.; Shepherd, R. F.; Kwok, S. W.; Stokes, A. A.; Nemiroski, A.; Whitesides, G. M. Camouflage and Display for Soft Machines. Science 2012, 337, 828−832. (56) Malekpour, H.; Chang, K. H.; Chen, J. C.; Lu, C. Y.; Nika, D. L.; Novoselov, K. S.; Balandin, A. A. Thermal Conductivity of Graphene Laminate. Nano Lett. 2014, 14, 5155−5161. (57) Jiajun, W.; Xiao-Su, Y. Effects of Interfacial Thermal Barrier Resistance and Particle Shape and Size on the Thermal Conductivity of AlN/PI Composites. Compos. Sci. Technol. 2004, 64, 1623−1628. (58) Vesterinen, V.; Niskanen, A. O.; Hassel, J.; Helisto, P. Fundamental Efficiency of Nanothermophones: Modeling and Experiments. Nano Lett. 2010, 10, 5020−5024.
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DOI: 10.1021/acsnano.9b03218 ACS Nano XXXX, XXX, XXX−XXX
