Molecular Insights of Carbon Nanodots Formation and Their Two‐Photon Emission Properties

Abstract

The structure formation of carbon nanodots (C‐dots) prepared from three different organic precursors is discussed at the molecular level. During microwave synthesis, organic chromophores associated with C‐dot structures are formed that exhibit distinct optical features. The molecular structure of these fluorophores is elucidated and their optical properties with and without the C‐dots are investigated. The emergence of two‐photon emission is observed and correlated with the hybridization state of the carbon atoms within the C‐dot as well as the formation of the fluorophores. Varying contents of sp2‐ and sp3‐hybridization in different C‐dots also affect their one‐photon and two‐photon emission characteristics. Understanding the molecular structure of the carbon nanocore and the organic fluorophores formed in C‐dots would enable rational design of C‐dots with improved optical features, which would be of great relevance for their applications, for example, in bioimaging.

Keywords

• carbon nanodots
• fluorescence lifetime imaging microscopy
• formation mechanism
• hybridization
• molecular fluorophores
• optical stability