Quantum Dot Modification of Large Area Graphene Surfaces via Amide Bonding

Large-area graphene grown by chemical vapor deposition is functionalized by p-aminophenyl groups via the diazonium-route. Subsequently, carboxylic acid-modified CdSXSe1-X/ZnS dots (QDs) with maximum emission wavelengths of 540 nm and 630 nm are immobilized via amidation reaction to the amino-functionalized graphene on the copper growth substrate forming stable covalent bonds in all functionalization steps. After immobilization of the QDs, the functional QD/graphene stack is available for transfer from the growth substrate onto any other substrate. In this study, the QD-modified graphene is transferred to a Si wafer with surface oxide without losing the QD modification. The successful binding of the QDs onto the functionalized graphene is characterized by their vibrational signature using Raman backscattering and infrared-spectroscopic ellipsometry and by their specific light emission as measured by photoluminescence (PL) spectroscopy. Large-area graphene on Cu is functionalized with aminophenyl groups via the diazonium-route. Subsequently, carboxylic acid-modified photoluminescent quantum dots (QDs) are immobilized by forming stable covalent amide bonds on the aminophenyl groups. This layer stack is transferred to SiO2-coated c-Si without losing the optical properties of the QDs. image