Color-Tunable Organic Nano-Dots: Synthesis and Applications in Color Conversion and Security Inks

Abstract

This study explores the synthesis of water-based color-tunable organic nanodots (CTONDs) capable of emitting multiple colors, including white light, by adjusting the molar ratio of blue, green, and red emissive fluorophores in the particles. Spectroscopic analyses reveal that the emissions are due to Forster resonance energy transfer (FRET) between the energy donor and acceptor nanoparticles. The energy transfer efficiencies are high, reaching over 90% in the film state due to the close packing of NDs while in their film state. Various molar ratios produced different colors in both liquid dispersions and in the solid state. These CTONDs demonstrate over 60% color conversion efficiency (CCE) when applied as color conversion layers (CCLs) in light-emitting devices, maintaining photostability for over four months under ambient conditions. Additionally, their aqueous processability and multicolor tunability make them attractive for environmentally friendly display technologies, flexible optoelectronics, and anti-counterfeiting applications such as security inks. This work offers a scalable and sustainable approach to fabricating tunable, solution-processed fluorescent organic nanomaterials and underscores their promise as a versatile platform for next-generation photonic and optoelectronic applications.