【用户成果】基于印刷石墨烯油墨的可拉伸热声器件
文摘
2024-07-31 10:02
上海
可拉伸电子器件突破了刚性无机电子材料的机械限制，打破了半导体、人工智能和临床医学等各行各业的技术障碍。可拉伸传感器，包括 LED 阵列、晶体二极管或医疗贴片在各个领域都表现出卓越的灵活性和应用潜力。尽管取得了重大进展，但可拉伸电子器件的固有可拉伸元件仍存在一些局限性，如稳定性差、在施加机械应变时电气性能下降等，这些都阻碍了器件实现高性能、高可靠性和高集成度。静电扬声器需要传统的金属材料，如电容器和弹簧，因为它们的发声过程依赖于静电迫使振膜振动，导致面积大、质量重。因此，它们无法适用于可穿戴设备。目前，可拉伸声学设备仍未问世，因此研究工作主要集中在提高设备的性能和稳定性上。由于石墨烯具有超强的断裂强度(42N m-1)和杨氏模量(1 TPa)、出色的导热性以及极佳的声学特性，它是一种理想的声学材料；因此，目前正在开发许多基于石墨烯的声学设备。此外，有关可拉伸声学设备的研究也在进行之中。热声器件作为柔性超薄声源具有巨大潜力。然而，基于热声机制的可拉伸声源仍然难以实现因为在合理范围内实现稳定的阻力具有挑战性。清华大学任天令&田禾教授团队在编织物上制造了基于石墨烯墨水的可拉伸热声器件。在优化石墨烯油墨浓度后，该器件在非拉伸状态下运行 4000 次时，电阻变化了 8.94%。经过多次弯曲、折、挤压和水洗后，该装置的声压级(SPL)变化不超过10%。此外，在特定范围内，声压级随应变的增加而增加，显示出一种类似负微分电阻(NDR)效应的现象。这项研究为电子皮肤和可穿戴电子设备使用可拉伸热声器件提供了启示。相关研究以“Stretchable Ink Printed Graphene Device with Weft-Knitted Fabric Substrate Based on Thermal-Acoustic Effect”为题发表在ACS Applied Materials & Interfaces期刊上。Figure 1. (a) Concept for SGTAD sounding in stretched and nonplanar states and the SEM results of device surface and textile fabric substrate. (b)The SPL versus frequency including five tests for verifying wearability. (c) SPL distribution under different sweep tests containing original states and stretched, bending, prodded, folded, and washed states.Figure 2. (a) Schematic of the SGTAD. (b) Fabrication of the SGTAD. (c) Process exploration for the ratio of deionized water/water-based graphene slurry and printing layers. Green frame: The sample being stretched printed two layers with the ink deionized water/water-based graphene scale factor of 1:2. Blue frame: The sample after being stretched printed two layers with the ink deionized water/water-based graphene scale factor of 1:1. Dark red frame: The resistance change rate for first three times (upper frame) and photoshoot (lower frame) of the sample printed two layers with the ink deionized water/water-based graphene scale factor of 1:2. (d,e) The normalized average resistance response for the SGTAD under 50% relative strain in one cycle of X-direction and Y-direction stretching, respectively. (f,g) The normalized average resistance response for the SGTAD under 50% relative strain in five consecutive cycles of X-direction and Y-direction stretching, respectively.Figure 3. (a) Digital operation system schematic of the SGTAD. The drive circuit consisted of SSM2377 and OPA2674. (b) The spectrum in PC of acoustic signal driven by the circuit scheme and the SGTAD optical picture in the 1000th releasing cycle. (c,d) Change of SPL vs frequency with repeated stretching under 50% uniaxial strain in the Y-direction and X-direction, respectively. (e,f) Change of SPL vs frequency with repeated folding to 180 deg and prodding to a height of 3 mm for 1000 times, respectively. (g) Change of SPL vs frequency with repeated washing. (h)Change of SPL vs frequency with different heights of bending.Figure 4. (a) SPL of the last 10 cycles of each 100 in 1000 stretching cycles and first 10 cycles. (b) The SEM results of textile fabric substrate under different strain conditions (0, 20, 30, 50%). (c−g) The comparison for SPL vs strain between experiment and simulation based on the tensile[1]sounding model at different cycles (100th, 300th, 500th, 700th, 1000th).Figure 5. Radar chart of the performance of stretchable devices. Evaluation from six dimensions; our devices have advantages in comprehensive characteristics.总之，作者通过使用二维材料打印机在预拉伸织物基底上直接打印石墨烯/去离子水混合墨水提出了 SGTAD。该制备技术简单实用，有望应用于图案绘制和自动化批量生产。实验结果表明，SGTAD 经过多次拉伸、戳穿、折、水洗和弯曲后仍能输出稳定的声音，不同频段的平均性能衰减率分别为 8.94%、9.2%、9.4%、9.8%和 6%。在可拉伸性、性能稳定性、抗破坏性、易制备性、可弯曲性和声音性能这六个关键方面，拟议的设备都优于以前的设备。这表明拟议的设备在可穿戴电子设备领域大有可为。此外，还首次观察到声压级随应变而增加。现有的石墨烯织物器件 NDR 模型被扩展到声学领域。模拟结果与实验结果完全吻合。这项工作将激励声学设备的开发，预计这些设备将用于检测人类活动中的微小变化。Stretchable Ink Printed Graphene Device with Weft-Knitted Fabric Substrate Based on Thermal-Acoustic Effecthttps://doi.org/10.1021/acsami.3c00072*本文来源：作者团队，感谢作者团队对本公众号的大力支持！如有侵权，请联系删除，如有冒犯之处敬请见谅!
