Chen Qiang, Wang Zhe, Jin Huihui, Zhao Xin, Feng Hao, Li Peng, He Daping
Hubei Engineering Research Center of RF-Microwave Technology and Application, Wuhan University of Technology, Wuhan 430070, China.
State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China.
Materials (Basel). 2023 Jan 5;16(2):526. doi: 10.3390/ma16020526.
Graphene and graphene-based materials gifted with high electrical conductivity are potential alternatives in various related fields. However, the electrical conductivity of the macro-graphene materials is much lower than their metal counterparts. Herein, we improved the electrical conductivity of reduced graphene oxide (rGO) based graphene assembled films (GAFs) by applying a series of compressive stress and systematically investigated the relationship between the compressive stress and the electrical conductivity. The result indicates that with increasing applied compressive stress, the sheet resistance increased as well, while the thickness decreased. Under the combined effect of these two competing factors, the number of charge carriers per unit volume increased dramatically, and the conductivity of compressed GAFs (c-GAFs) showed an initial increasing trend as we applied higher pressure and reached a maximum of 5.37 × 10 S/m at the optimal stress of 450 MPa with a subsequent decrease with stress at 550 MPa. Furthermore, the c-GAFs were fabricated into strain sensors and showed better stability and sensitivity compared with GAF-based sensors. This work revealed the mechanism of the tunable conductivity and presented a facile and universal method for improving the electrical conductivity of macro-graphene materials in a controllable manner and proved the potential applications of such materials in flexible electronics like antennas, sensors, and wearable devices.
具有高电导率的石墨烯及基于石墨烯的材料在各个相关领域都是潜在的替代材料。然而，宏观石墨烯材料的电导率远低于其金属同类材料。在此，我们通过施加一系列压缩应力提高了基于还原氧化石墨烯（rGO）的石墨烯组装薄膜（GAFs）的电导率，并系统地研究了压缩应力与电导率之间的关系。结果表明，随着施加的压缩应力增加，薄层电阻也增加，而厚度减小。在这两个相互竞争因素的共同作用下，单位体积内的电荷载流子数量急剧增加，压缩后的GAFs（c-GAFs）的电导率在我们施加更高压力时呈现出初始增加趋势，并在450 MPa的最佳应力下达到最大值5.37×10 S/m，随后在550 MPa应力下随应力降低。此外，将c-GAFs制成应变传感器，与基于GAFs的传感器相比，显示出更好的稳定性和灵敏度。这项工作揭示了可调电导率的机制，提出了一种简便通用的方法来可控地提高宏观石墨烯材料的电导率，并证明了此类材料在天线、传感器和可穿戴设备等柔性电子器件中的潜在应用。
