The photophysical properties and applications of semiconducting quantum dots (QDs) remains an active and growing area of research. The development of new QDs made of novel materials and of various core/shell structures has been fervently pursued over that past twenty years, while an understanding of the mechanisms responsible for their properties, specifically their colloidal growth and formation, has lagged behind. A widely studied class of QDs is cadmium selenide (CdSe). CdSe QDs have generated remarkable interest in the past decade because of their applications in biological fluorescence imaging, medical imaging, quantum dot solar cells, quantum dot lasers, and even military tracking devices. Reaction schemes have been developed to synthesize CdSe QDs of many different shapes such as rods, tetrapods, teardrops, arrows, and spheres. However, despite all of these advances, the growth dynamics for CdSe QDs are still largely unknown. Here, we present a novel semi-empirical atomistic QD growth model (algorithm) for CdSe QDs in which reaction parameters can be adjusted (such as temperature, pressure, growth solution components, precursor oxidation state, etc.) independently from one another. This approach can be used to systematically test synthetic schemes to provide growth statistics. These growth statistics can then be tested experimentally using an in situ technique to provide insight into the accuracies of the modeling program. Modeling aspects, including the use of charge equilibration techniques, as well as the effect of surface chemistries and QD symmetry, provide atomistic insight into the parameters most relevant to quantum dot growth. Using experimentally realized CdSe QD "magic sizes" as a basis for comparison, this new model provides new insight at a fraction of the computational cost of traditional ab initio or DFT approaches.

New algorithm to model quantum growth dot dynamics

253rd National Meeting (2017)

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