Premium
Photo‐and Electroluminescence from Nitrogen‐Doped and Nitrogen–Sulfur Codoped Graphene Quantum Dots
Author(s) -
Hasan Md Tanvir,
GonzalezRodriguez Roberto,
Ryan Conor,
Faerber Nicolas,
Coffer Jeffery L.,
Naumov Anton V.
Publication year - 2018
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201804337
Subject(s) - materials science , quantum dot , graphene , photoluminescence , quantum yield , photochemistry , fourier transform infrared spectroscopy , fluorescence , nanotechnology , optoelectronics , chemical engineering , chemistry , optics , physics , engineering
Abstract As opposed to inorganic counterparts, organic quantum dots often exhibit lower fluorescence efficiencies and are complex to synthesize. Here we develop nitrogen‐doped (N‐GQDs) and nitrogen–sulfur codoped (NS‐GQDs) graphene quantum dots exhibiting high‐yield visible and near‐IR emission that are synthesized via a single‐step microwave‐assisted hydrothermal technique with a single glucosamine‐HCl starting material (thiourea precursor used for NS‐GQDs). As‐synthesized N‐GQDs and NS‐GQDs are well‐dispersed (average sizes of 5.50 and 3.90 nm) with high crystallinity and pronounced G‐band. Formed by the bottom‐up assembly of glucosamine, they contain amine linkage and a variety of oxygen‐containing functional groups assessed by Fourier‐transform infrared spectroscopy with ≈2% sulfur for NS‐GQDs. The synthetic procedure allows varying their size and the bandgap. Unlike other graphene‐based quantum dots, these GQDs exhibit bright, stable fluorescence both in the visible and near‐IR with high quantum yields of up to 60%. Excitation‐dependent visible fluorescence is attributed to size‐dependent bandgaps, with near‐IR emission potentially arising from the emissive defect states/their arrangements. Advantageous properties of these GQDs are utilized to develop exciton recombination layer for organic light‐emitting devices exhibiting both photoluminescence and electroluminescence in the visible. Produced by ecofriendly one‐step scalable synthesis brightly‐emissive N‐GQDs and NS‐GQDs become a promising material for novel organic optoelectronics.