Graphene Quantum Rings Doped PEDOT:PSS Based Composite Layer for Efficient Performance of Optoelectronic Devices

Abstract

The method of synthesis has a profound influence on the properties of carbon nanostructures endowed with quantum confinement. Here, we report synthesis method of the graphene quantum rings (GQRs) from pitch carbon fiber by a thermal hydrolysis process and their application in optoelectronic devices. Synthesized GQRs with excitation-dependent photoluminescence and excellent electrical conducting properties have a work function of -4.16 eV suitable for optoelectronic applications. The electrical properties of the GQRs are studied by metal-semiconductor-metal (MSM), field-effect transistor (FET), and hybrid (inorganic and organic) solar cell devices comprising the GQRs as the p-type channel and hole transporting material, respectively. The current-voltage (I-V) characteristic from a diode-type MSM device shows a conductance of 1.5 mA at 3.5 V in the dark. Under an illumination of 1.5 AM the current increases to 5.28 mA at 3.5 V, showing that these GQRs are very good candidates for photodiodes and other optoelectronic properties. The GQRs doped poly(3,4-ethylenedioxythiophene) :polystyrenesulfonate (PEDOT:PSS) composite layer served as an efficient hole extraction layer in hybrid solar cells, which shows excellent power conversion efficiency as maximum as 7.4%. Such performances of the devices are attributed to the unique electrical properties and hole extraction applicability of the GQRs. These results demonstrate the great potential of GQRs for future electronic and other optoelectronic devices.