Markedly Enhanced Photoluminescence of Carbon Dots Dispersed in Deuterium Oxide

In this work, we report some surprisingly interesting results in our pursuit to improve the photoluminescent emission of Carbon Dots (CDs) prepared from various precursors. By simply replacing the regular water with deuterium oxide (D2O) as a dispersion medium, the emission intensity and the subsequent quantum efficiency of the radiative processes could be markedly enhanced. The present study was performed on our previous reported works related to CDs; in each case, the preparation path was maintained accordingly. For each type of CD, the emission intensity and the absolute photoluminescence quantum yield (PLQY) were highly improved, with, in certain cases, more-than-doubled values being recorded and the gain in performance being easily noticeable with the naked eye even in plain daylight. For each type of CD dispersed in regular water and heavy water, respectively, the photoluminescent properties were thoroughly investigated through Steady State, lifetime, and absolute PLQY. To further elucidate the mechanism involved in the photoluminescence intensity enhancement, samples of D2O and H2O dispersed CDs were embedded in a crosslinked Poly(acrylic acid) polymer matrix. The investigations revealed the major influence of the deuterium oxide dispersion medium over the PL emission properties of the investigated CDs.