Diethylenetriamine-Doped Graphene Oxide Quantum Dots with Tunable Photoluminescence for Optoelectronic Applications

Modulation of the photoluminescence (PL) properties in graphene oxide quantum dots (GOQDs) is important for fundamental research and applications in bioimaging and optoelectronic devices. Herein, the synthesis of GOQDs doped with diethylenetriamine (DETA) was implemented by one-pot synthesis via oil bath heating. The PL intensity in the GOQDs was increased by an enhancement factor of ∼13.2 following the DETA doping. The band gap of the GOQDs increased with the increase in DETA doping, producing tunable PL from red to blue emission with a wavelength change of ∼265 nm. The significant tuning of the PL wavelength in the GOQDs was attributed to the variation of pyrrolic and/or graphitic N in the C–N bonding configuration. The synthesized GOQDs were found to inject carriers into the gallium nitride (GaN) epilayer in the GOQD/GaN composite, which in turn enhance the PL in the GaN epilayer. Our observations provide effective approaches for tuning the PL wavelength in GOQDs and enhancing the PL intensity in GaN; these are promising developments for applications in optoelectronic devices such as light-emitting diodes and solar cells.