A Photochemical Avenue to Photoluminescent N-Dots and their Upconversion Cell Imaging

Abstract

A photochemical avenue to synthesize nitrogen-rich quantum dots (N-dots) using 2-azido imidazole as the starting material was established for the first time. A production yield of up to 92.7% was obtained. The N-dots were then fully characterized by elemental analysis, IR, XPS, XRD, AFM and TEM. On the basis of the N2 production and in situ IR results, the underlying mechanism for the photochemical formation of N-dots was proposed. These N-dots showed promising optical properties including wavelength-dependent upconversion photoluminescence, and were successfully used in upconversion cell imaging.