Colloid & Nanoscience Journal

Colloid & Nanoscience Journal

Diphenylamine-based colloidal graphene quantum dots with enhanced blue-emission

Document Type : Original Article

Authors
Reza Sahraei 1
Leila Omidi 1
Ehsan Soheyli 2
1 Department of Chemistry, Faculty of Science, Ilam University, Ilam 69315-516, Iran
2 Department of Physics, Faculty of Science, Ilam University, Ilam 69315-516, Iran
Abstract
Representing new precursors to achieve enhanced emission properties in carbon-based quantum dots is a promising academic task. In the present study, deep-blue emissive graphene quantum dots (GQDs) were successfully synthesized through a facile one-step solvothermal treatment using diphenylamine and formamide as precursors, demonstrating an efficient molecular-carbonization strategy for producing highly luminescent carbon nanomaterials. In this approach, diphenylamine served mainly as the carbon source, while formamide plays the role of dopant precursor, enabling controlled heteroatom incorporation during the nucleation and growth of sp²-dominated graphene domains. The solvothermal reaction promoted oxidative dehydrogenation and polymerization of the aromatic precursor, followed by gradual carbonization to yield GQDs with broad emission signal located at around 398 nm. Structural characterization revealed the presence of carbon/oxygen/ and nitrogen elements, along with abundant surface functional groups, including amine, hydroxyl, and carboxyl moieties that ensured excellent water dispersibility and contributed to bright photoluminescent behavior. The combined simplicity of the synthetic process, the use of an inexpensive aromatic precursor, and the favorable optical characteristics with emission quantum efficiency of 56.6% underscore the potential of diphenylamine-derived GQDs as versatile nanophotonic materials for sensing, light-emitting devices, and fluorescence-based diagnostics.

Graphical Abstract

Diphenylamine-based colloidal graphene quantum dots with enhanced blue-emission
Keywords
Graphene quantum dots
Diphenylamine
Solvothermal
Blue emission
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Colloid & Nanoscience Journal
Volume 3, Issue 4
Autumn 2025

  • Receive Date 28 December 2025
  • Revise Date 14 April 2026
  • Accept Date 26 April 2026