MOF-Templated Synthesis of Ultrasmall Photoluminescent Carbon-Nanodot Arrays for Optical Applications

Arrays of ultrasmall and uniform carbon nanodots (CDs) are of pronounced interest for applications in optical devices. Herein, we describe a low-temperature calcination approach with rather inexpensive reactants. After glucose molecules had been loaded into the pores of metal-organic frameworks (MOFs), well-defined CD arrays were produced by heating to 200 °C. The size and spacing of the CDs could be controlled by the choice of templating MOF: HKUST-1, ZIF-8, or MIL-101. The sizes of the obtained CDs were approximately 1.5, 2.0, and 3.2 nm, which are close to the corresponding MOF pores sizes. The CD arrays exhibited interesting photophysical properties, including photoluminescence with tunable emission and pronounced nonlinear optical (NLO) effects. The NLO properties of the obtained CD arrays were significantly different from those of a CD suspension, thus indicating the existence of collective phenomena.