▎ 摘　　要

2D carbon nanomaterials such as graphene and its oxide counterpart have sought good research attention for their application as well as fundamental interest. Especially the versatility of graphene oxide establishes its elite candidature in every field because of diverse application potential. Here we are reporting a greener, eco-friendly and cost effective one step hydrothermal route for the synthesis of potassium doped graphene oxide (K-doped GO) from agricultural waste i.e. Quercus ilex Fruit. The elemental analysis and XPS study showed the high percentage (6.81%) of natural doping of potassium. The K-doped GO is specific and demonstrates bright blue photoluminescence (PL) under UV-light (lambda ex = 365 nm). Low toxicity, intracellular localization, good biocompatibility and strong PL properties of the synthesized K-doped GOs portray it as an excellent bio-imaging agent holding great promise in analytical and biological fields.