Synthesis and photoluminescence properties of orange-red carbon dots from the paper tissues as the precursor

Abstract

In recent years, stable and photoluminescence (PL) tunable fluorescent materials known as carbon dots (CDs) have seen rapid development. Here, a simple, low-cost, and environmentally friendly approach has been developed to synthesize the orange-red CDs (OR-CDs) with paper tissues as the precursor in the presence of ethanol and concentrated sulfuric acid. The average diameter of the OR-CDs was measured at around 1.25 nm. The as-prepared OR-CDs are composed of carbon cores with the graphite structure distributed in the middle and wrapped or entangled by polymers for the outside. Moreover, the PL characteristics of the OR-CDs under the dilute solution state and the concentrated solution state, respectively, were explored. The former with the blue light showed prominent excitation-dependent characteristics in the range from 365 to 420 nm; the latter rendered the excitation-independent property with distinguished orange-red fluorescence emission. With an increase in the concentration, the emission fluorescence intensities gradually increased under the excitation wavelength of 540 nm, which can be attributed to the aggregation-induced emission property of the OR-CDs. By virtue of their excellent PL properties and low toxicity, we believe that the OR-CDs have potential applications in various optoelectronic areas, especially in white LED fields.