Title: Interparticledistance as a key factor for controlling the dual-emission properties of carbondots

Author: Hyo Jeong Yoo,Byeong Eun Kwak and Do Hyun Kim

Journal: Phys. Chem.Chem. Phys., 2020, 22, 20227-20237

Abstract: Due to theirdistinct and useful features, multi-color-emissive carbon dots (CDs) havegained much attention, however, their lack of red emission has so far limitedtheir practical use for various applications, thus understanding of theiremission origins is required. Concentration-dependent photoluminescence (PL) isa unique feature of CDs and is regarded as one way to realize tunable PL,providing information on their PL mechanism. In this work, we synthesizedconcentration-dependent blue/red dual-color-emissive CDs under singleexcitation at 365 nm. With the increase in concentration, the blue emissionband showed a large red-shift from 431 to 500 nm, while the red emission bandat around 650 nm showed only a relative intensity change, without a significantspectral shift. We performed spectroscopic analysis by changing the solutionenvironment including the solvent type and pH to investigate the origins of thetwo emission bands. These results, combined with the zeta potential andfluorescence microscopy results, confirmed that the interparticle distance ofCDs is a key factor for their dual-emissive PL behavior. With the advantage of uniquePL features, we showed the potential of the CDs for white light-emitting diode(WLED) and ratiometric pH sensing applications.