Ultrahigh current efficiency of light-emitting devices based on octadecylamine-graphene quantum dots. (February 2017)

• Record Type: Journal Article
• Authors: Kim, Dae Hun; Kim, Tae Whan
• Is Part Of: Nano energy. Volume 32(2017:Feb.)
• Page Start: 441
• Page End: 447
• Publication Date: 2017-02
• Subjects: Quantum dot -- Graphene -- Light-emitting device -- Graphene quantum dot -- Current efficiency; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2017.01.002
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: Graphene quantum dots (GQDs) have currently emerged as excellent candidates for applications in GQD-based LEDs because of their potential applications in next-generation multifunctional systems. However, the numerous oxygenous functional groups and defects existing in the GQDs restrict their florescence quantum yield, resulting in a decrease in the brightness of light-emitting devices (LEDs) based on GQDs. Here, we report on solution-processed and highly-efficient LEDs that have been developed based on octadecylamine (ODA)-GQDs. In contrast with the GQDs, the number of oxygen components in the ODA-GQDs is lower due to nucleophilic substitution between the amine and the epoxy functional groups. The current and the external quantum efficiency of an LED with ODA-GQDs are 6.51 cd/A and 2.67%, respectively, this current efficiency of 6.51 cd/A being the highest among the efficiencies reported for LEDs based on GQDs. The efficiency enhancement in the LEDs with ODA-GQDs is attributed to significant improvements in the optical properties of the ODA-GQDs. The successful demonstration of this efficiency enhancement for LEDs based on ODA-GQDs indicates a potential for applications of GQD-based LEDs as next-generation real optical sources. Graphical abstract: Highlights: ODA-GQDs formed by using a safe method of synthesis are cost-effective and have eco-friendly advantages. Oxygen content of the ODA-GQDs was smaller than that of the typical GQDs due to nucleophilic substitution. LED with ODA-GQDs have the highest current efficiency among the reported LEDs based on GQDs. Current efficiency of an LED with ODA-GQDs is 6.51 cd/A. External quantum efficiency of the LEDs with ODA-GQDs is 2.67%.