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  • Tuning Fermi Energy of Graphene Using Platinum Nanoparticles and Ultraviolet Irradiation to Increase Charge Transfer for Surface-Enhanced Raman Spectroscopy
Title: Tuning Fermi Energy of Graphene Using Platinum Nanoparticles and Ultraviolet Irradiation to Increase Charge Transfer for Surface-Enhanced Raman Spectroscopy
Surface-enhanced Raman spectroscopy (SERS) is an important analytical tool with ultrahigh sensitivity that depends on electromagnetic mechanism (EM) and chemical mechanism (CM). The CM relies on efficient charge transfer between the probe molecules and SERS substrates, which means engineering the molecule attachment and the energy level alignment at the molecule/substrate interface is critical to optimal CM enhancement. Herein, we report enhanced CM of Rhodamine 6G (R6G) on graphene SERS substrates using combined C-band ultraviolet (UVC) irradiation and Pt nanoparticle (Pt-NPs) decoration using atomic layer deposition (ALD). An enhancement of 270% was obtained in the former, which is ascribed to the graphene surface activation and p-doping on graphene for improved R6G molecule attachment and charge transfer by its surface change from hydrophobic to hydrophilic and the down-shift of the Fermi energy (p-doping) after UVC exposure. The Pt-NPs decoration adds an additional enhancement of 250% by further p-doping graphene, which shifts the graphene’s Fermi energy to promote charge (hole) transfer at the R6G/graphene interface. Remarkably, the combination of the UVC irradiation and Pt-NPs decoration has led to enhanced R6G SERS sensitivity of 5 × 10−9 M, which represents a two-orders of magnitude enhancement over that on the pristine graphene and illustrates the importance of graphene engineering for optimal probe molecule attachment and the energy level alignment at the molecule/graphene interface toward achieving high-performance SERS biosensing.  more » « less
Award ID(s):
2314401 1909292
PAR ID:
10521260
Author(s) / Creator(s):
; ; ;
Publisher / Repository:
ACS
Date Published:
Journal Name:
ACS Applied Nano Materials
Volume:
6
Issue:
23
ISSN:
2574-0970
Page Range / eLocation ID:
21626 to 21633
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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