Ultra-narrow-bandwidth graphene quantum dots for superresolved spectral and spatial sensing

Abstract

Narrow-bandwidth luminescent materials are already used in optoelectronic devices, superresolution, lasers, imaging, and sensing. The new-generation carbon fluorescence nanomaterials—carbon dots—have attracted considerable attention due to their advantages, such as simple operation, environmental friendliness, and good photoelectric performance. In this work, two narrower-bandwidth (21 and 30 nm) emission graphene quantum dots with long-wavelength fluorescence were successfully prepared by a one-step method, and their photoluminescence (PL) peaks were at 683 and 667 nm, respectively. These red-emitting graphene quantum dots were characterized by excitation wavelength dependence of the fluorescence lifetimes, and they were successfully applied to spectral and spatial superresolved sensing. Here, we proposed to develop an infrared spectroscopic sensing configuration based on two narrow-bandwidth-emission graphene quantum dots. The advantage of the method used is that spectroscopic information was extracted without using a spectrometer, and two narrow-bandwidth-emission graphene quantum dots were simultaneously excited to achieve spatial separation through the unique temporal “signatures” of the two types of graphene quantum dots. The spatial separation localization errors of the graphene quantum dots (GQDs-Sn and GQDs-OH) were 1 pixel (10 nm) and 3 pixels (30 nm), respectively. The method could also be adjusted for nanoscope-related applications in which spatial superresolved sensing was achieved.