Fig. 1: TEM and HRTEM images and optical properties of nGQD nanocomposites.

a TEM image of nGQDs. b HRTEM image showing localized lattice fringes of nGQDs. c Comparison of SPR reflectivity curves obtained with a conventional SPR (bare Au) chip and different CA:UR ratios of nGQD-based SPR chips. Inset: Photograph of the bare Au and nGQD-based SPR chips. d UV-Vis absorption spectra of nGQD nanocomposites in different CA:UR ratios. e PL spectra under excitation at 405 nm in different CA:UR ratios. f PL spectra of the nGQDs under different synthesis times showing shifts in fluorescence.