Lee Do Hoon, Miyashita Takuma, Xuan Yan, Takei Kuniharu
Graduate School of Information Science and Technology, Hokkaido University, Sapporo, Hokkaido 060-0814, Japan.
ACS Nano. 2024 Nov 19;18(46):32255-32265. doi: 10.1021/acsnano.4c13156. Epub 2024 Nov 4.
Laser-induced graphene (LIG) has attracted considerable attention for its use in flexible and stretchable sensors, owing to its electrical/mechanical properties and scalable fabrication processes. Although laser scanning facilitates the formation of LIG and its strain sensor, the strain-sensing sensitivity enhancement of LIG remains limited by the material's properties and structural design. In this study, we demonstrate a substantial improvement in sensitivity that was achieved by fabricating a LIG using ZnO nanoparticle (NP)-assisted photothermal enhancement. The results show that ZnO NPs selectively reduce the threshold fluence needed to convert polyimide (PI) into LIG. By transferring the LIG formed on PI to poly(dimethylsiloxane), we fabricate a stretchable strain sensor with ultrahigh sensitivity and a gauge factor of 1214 at 10% strain, which is approximately 60 times higher than the gauge factor without ZnO NPs. Using the selective graphenization properties of LIG, a flexible, dual-sided integrated sensor sheet that is equipped with flexible strain and ultraviolet (UV) sensors is demonstrated. This sheet enables simultaneous monitoring of UV intensity and joint bending angles of sports wearable devices. We validated the developed sensors by attaching them to a runner's body to monitor and simulate forefoot and heel strikes, demonstrating the sensor's ultrahigh sensitivity and long-term stability without the need for a camera. These findings highlight the potential of the proposed method for developing multifunctional sensor applications with ultrahigh sensitivity and stability.
激光诱导石墨烯（LIG）因其电学/力学性能以及可扩展的制造工艺，在柔性和可拉伸传感器中的应用备受关注。尽管激光扫描有助于LIG及其应变传感器的形成，但LIG的应变传感灵敏度提升仍受材料性能和结构设计的限制。在本研究中，我们展示了通过使用氧化锌纳米颗粒（NP）辅助光热增强制备LIG实现的灵敏度大幅提高。结果表明，氧化锌纳米颗粒选择性地降低了将聚酰亚胺（PI）转化为LIG所需的阈值能量密度。通过将在PI上形成的LIG转移到聚二甲基硅氧烷上，我们制备了一种可拉伸应变传感器，其在10%应变下具有超高灵敏度和1214的应变系数，这比没有氧化锌纳米颗粒时的应变系数高出约60倍。利用LIG的选择性石墨化特性，展示了一种配备柔性应变和紫外线（UV）传感器的柔性双面集成传感器片。该片能够同时监测运动可穿戴设备的紫外线强度和关节弯曲角度。我们通过将开发的传感器附着在跑步者身体上以监测和模拟前脚掌和后脚跟撞击来验证这些传感器，证明了该传感器无需相机即可具有超高灵敏度和长期稳定性。这些发现突出了所提出方法在开发具有超高灵敏度和稳定性的多功能传感器应用方面的潜力。
