Figure 2. (A) UV-vis absorption and (B) PL spectra of the AuNCs; shown are NCs grew using LA (black line), LA-PEGsso-OCH3(blue line), LA-PEG750-OCH3 (dark yellow line), and LA-ZW (crimson line). The inset image shows the corresponding (from left toright) photographs of AuNCs prepared using the above four ligands under room and UV light exposure (using a hand-held UVlamp, hex = 365 nm). The Au:NaBHa: ligand molar ratio used for the synthesis was 1:2:3. (C) The excitation spectrum of LA-ZW-capped AuNCs. (D) Time-resolved fluorescence decay curves of LA-, LA-PEGsso-OCH3-, LA-PEG750-OCHs-, and LA-ZW-cappedAuNCs and the corresponding fit using a three-exponential decay function (red line); additional details on the fit are providedin the Supporting Information. (E) TEM images of LA-PEG750-OCH3- and (F) LA-ZW-capped AuNCs. Fluorescence spectra weregenerated using hex =- 550 nm.