Manipulating the optical properties of carbon dots via fine tuning their structural features

DOI: 10.1002/cssc.201901795

Authors: Hui Luo (Imperial College London; Queen Mary University of London) , Nikolaos Papaioannou (Queen Mary University of London) , Enrico Salvadori (Queen Mary University of London; University of Turin) , Maxie Roessler (Queen Mary University of London; University of Turin) , Gereon Ploenes (Radboud University) , Ernst R. H. Van Eck (Radboud University) , Liviu Tanase (National Institute of Materials Physics, Romania) , Jingyu Feng (Imperial College London) , Yiwei Sun (Mary University of London) , Yan Yang (Imperial College London) , Mohsen Danaie (Diamond Light Source) , Ana Jorge Sobrido (Queen Mary University of London) , Andrei Sapelkin (Queen Mary University of London) , James Durrant (Imperial College London) , Stoichko D. Dimitrov (Swansea University) , Maria-Magdalena Titirici (Queen Mary University of London)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Chemsuschem

State: Published (Approved)
Published: August 2019
Diamond Proposal Number(s): 17587

Abstract: As a new class of sustainable carbon material, the term “carbon dots” represents an “umbrella term” as there are many types of materials included. We employ a broad range of techniques to develop understanding on hydrothermally synthesized carbon dots and show how fine tuning the structural features using simple reduction/oxidation reactions can drastically affect their excited state properties. Structural and spectroscopic studies found that photoluminescence originates from direct excitation of localized fluorophores involving oxygen functional groups, while the excitation at graphene‐like features leads to ultrafast phonon‐assisted relaxation and largely quenches the fluorescent quantum yields. This is arguably the first to identify the dynamics of photoluminescence including Stokes’ shift formation, allowing us to fully resolve the relaxation pathways in these carbon dots. The comprehensive investigation sheds light on how understanding the excited state relaxation processes in different carbon structure is crucial for tuning the optical properties for any potential commercial applications.

Journal Keywords: carbon dots; Nanostructures; fluorescence; mechanism; laser spectroscopy

Subject Areas: Chemistry, Materials

Diamond Offline Facilities: Electron Physical Sciences Imaging Centre (ePSIC)
Instruments: E01-JEM ARM 200CF

Added On: 21/08/2019 14:39

Discipline Tags:

Physical Chemistry Chemistry Materials Science Chemical Engineering Engineering & Technology Nanoscience/Nanotechnology

Technical Tags:

Microscopy Electron Microscopy (EM) Transmission Electron Microscopy (TEM)