Abstract
An all-in-one prism-free infrared sensor based on graphene surface plasmons is proposed for nanofluidic analysis. A conformal graphene-decorated nanofluidic sensor is employed to mimic the functions of a prism, sensing plate, and fluidic channel in the tradition setup. Simulation results show that the redshift of the resonant wavelength results in the improvement of sensitivity up to 4525 nm/RIU. To reshape the broadened spectral lines induced by the redshift of the resonant wavelength to be narrower and deeper, a reflection-type configuration is further introduced. By tuning the distance between the graphene and reflective layers, the figure of merit (FOM) of the device can be significantly improved and reaches a maximum value of 37.69 RIU−1, which is 2.6 times that of the former transmission-type configuration. Furthermore, the optimized sensor exhibits superior angle-insensitive property. Such a conformal graphene-decorated nanofluidic sensor offers a novel approach for graphene-based on-chip fluidic biosensing.
Highlights
Lab-on-chip systems combined with surface plasmon resonance (SPR) sensors provide a powerful technique to perform label-free biomolecular interaction measurements with high sensitivity [1,2,3]
The nanofluidic channel can contain the sample solution, and directly excite graphene surface plasmons (GSPs) without the need of an extra optical component, which significantly reduces the complexity of the device
A maximum figure of merit (FOM) of 37.69 RIU−1 can be achieved by adjusting the F–P cavity length, which is 2.6 times larger than that of the transmission-type sensor
Summary
Lab-on-chip systems combined with surface plasmon resonance (SPR) sensors provide a powerful technique to perform label-free biomolecular interaction measurements with high sensitivity [1,2,3]. The prism needs to be angled appropriately to ensure the optimum output of incident light, making the system more complicated and less portable To overcome these issues, a prism-free all-in-one setup is proposed, combining the SPR excitation item, sensing plate and flow channel in a single setup. In contrast to the metals, graphene [10] that emerged as a unique two-dimensional carbon atoms possesses a high surface-to-volume ratio and strong π-π stacking interaction with the carbon-based ring structures in biomolecules [11]. A new type of sensor that integrates nanofluidic channel with a flat graphene sheet is reported [18] In such a configuration, the nanofluidic channel can contain the sample solution, and directly excite graphene surface plasmons (GSPs) without the need of an extra optical component, which significantly reduces the complexity of the device. A reflection-type configuration is proposed to improve the FOM while maintaining the high sensitivity
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