Van der Waals Quantum Dots: Synthesis, Characterization, and Applications

Abstract

Boron nitride quantum dots (BNQDs) have gained increasing attention for their versatile fluorescent, optoelectronic, chemical, and biochemical properties. During the past few years, significant progress has been demonstrated, started from theoretical modeling to actual application. Many interesting properties and applications have been reported, such as excitation-dependent emission (and in some cases, non-excitation dependent), chemical functionalization, bioimaging, phototherapy, photocatalysis, chemical, and biological sensing. An overview of these early-stage research development of BNQDs will be discussed in this dissertation. Next, the origin of excitation-dependent fluorescence from BNQDs synthesized in an organic solvent is explored and explained with the support of theoretical modeling. Also, we have developed a series of calibration plots by using UV-Vis and fluorescent spectroscopy for the quantification of BNQDs. We demonstrated that these calibration plots are more than 90% accurate for estimating the concentration of BNQDs in solutions. Finally, the use of van der Waals QDs including BNQDs and MoS2 in thin films solar cells is explored. Our ZnO-based solar cell devices allow us to obtain a record high efficiency of 14.7% using commercial CdSe/ZnS QDs. Preliminary photovoltaic data based on van der Waals QDs will be discussed.