Dual State Emissive AIE Active Carbon Dots with Matrix-Free Room Temperature Phosphorescence

Long-lived triplet excitons are kingmakers to generate high efficiency optoelectronic OLEDs. However, it is difficult to produce matrix-free solid state emissive room temperature phosphorescence (RTP) from carbon dots (CDs). In the present work, limited rotation of the two naphthol rings in (R)-1,1-Bi-2-naphthol (R-Binol) has been used to synthesize CDs aimed to obtain emission in the aggregated and RTP states. The R-Binol-derived CDs were prepared using an easy one-pot solvothermal treatment of the precursor. In-depth structural analysis reveals the presence of twisted naphthalene moiety that resists π-π stacking to make it dual emissive. These CDs are prone to accumulate producing spherical aggregates with 32-fold enhanced emission in binary THF-water mixture. Nevertheless, for the first time, we harvested triplet excitons from matrix free CDs generating 23 % PLQY. A phosphor converted light emitting diode (pc-LED) was also fabricated with the CDs.