Fig. 4
From: Biocompatible Fluorescent Core-Shell Nanoconjugates Based on Chitosan/Bi2S3 Quantum Dots
XPS spectra of Bi2S3 nanoconjugate (QD_CHI0.67_3.5): Bi 4f region (a) before and (c) after Ar+ etching and S 2s region (b) before and (d) after Ar+ etching. A two-column figure