摘要： White luminescent materials have been generating much excitement because of their wide-ranging potential applications. However, challenging synthesis, cytotoxicity and performance of current reported white luminescent materials still hinder their potential applications. Owing to their non-toxicity, excellent optical properties, and amenability to surface modification, white-light-emitting graphene quantum dots (WGQDs) are considered to be a next-generation white luminescent material to replace these above-mentioned conventional materials. The inherent challenge in WGQDs is their massive defects are known to give poor white optical properties. In the proof-of-concept, we designed and synthesized a novel WGQDs via a solvothermal molecular fusion route. The modulation of chlorine doping amount and reaction temperature gives the WGQDs a single-crystalline structure, bright white fluorescence and novel white phosphorescence performance for the first time. An optimum fluorescence quantum yield of WGQDs is 34%, which exceeds the majority of reported WGQDs and other white luminescent materials. The WGQDs display broad-spectrum absorption within almost the entire visible light region, broad full width at half maximum and extend their phosphorescence emission to the entire white long-wavelength region. This unique dual-mode optical characteristic of the WGQDs enlarges their applications in white light emission devices, cell nuclei imaging, and information encryption.