Jussila Henri, Albrow-Owen Tom, Yang He, Hu Guohua, Aksimsek Sinan, Granqvist Niko, Lipsanen Harri, Howe Richard C T, Sun Zhipei, Hasan Tawfique
Cambridge Graphene Centre, University of Cambridge, 9 JJ Thomson Avenue, Cambridge CB3 0FA, U.K.
Department of Electronics and Nanoengineering, Aalto University, Tietotie 3, 02150 Espoo, Finland.
ACS Omega. 2017 Jun 13;2(6):2630-2638. doi: 10.1021/acsomega.7b00336. eCollection 2017 Jun 30.
Solution processing-based fabrication techniques such as liquid phase exfoliation may enable economically feasible utilization of graphene and related nanomaterials in real-world devices in the near future. However, measurement of the thickness of the thin film structures fabricated by these approaches remains a significant challenge. By using surface plasmon resonance (SPR), a simple, accurate, and quick measurement of the deposited thickness for inkjet-printed graphene thin films is reported here. We show that the SPR technique is convenient and well-suited for the measurement of thin films formulated from nanomaterial inks, even at sub-10 nm thickness. We also demonstrate that the analysis required to obtain results from the SPR measurements is significantly reduced compared to that required for atomic force microscopy (AFM) or stylus profilometer, and much less open to interpretation. The gathered data implies that the film thickness increases linearly with increasing number of printing repetitions. In addition, SPR also reveals the complex refractive index of the printed thin films composed of exfoliated graphene flakes, providing a more rigorous explanation of the optical absorption than that provided by a combination of AFM/profilometer and the extinction coefficient of mechanically exfoliated graphene flakes. Our results suggest that the SPR method may provide a new pathway for the thickness measurement of thin films fabricated from any nanomaterial containing inks.
基于溶液处理的制造技术，如液相剥离，可能在不久的将来使石墨烯及相关纳米材料在实际设备中的经济可行利用成为现实。然而，通过这些方法制造的薄膜结构的厚度测量仍然是一个重大挑战。本文报道了利用表面等离子体共振（SPR）对喷墨打印石墨烯薄膜的沉积厚度进行简单、准确且快速的测量。我们表明，SPR技术方便且非常适合测量由纳米材料墨水制成的薄膜，即使在厚度低于10纳米时也是如此。我们还证明，与原子力显微镜（AFM）或触针轮廓仪相比，从SPR测量中获取结果所需的分析显著减少，且更不易产生歧义。收集到的数据表明，薄膜厚度随打印重复次数的增加呈线性增加。此外，SPR还揭示了由剥离的石墨烯薄片组成的打印薄膜的复折射率，比AFM/轮廓仪与机械剥离的石墨烯薄片的消光系数相结合所提供的光学吸收解释更为严谨。我们的结果表明，SPR方法可能为测量由任何含纳米材料墨水制成的薄膜厚度提供一条新途径。
