Due to the inherent heterogeneity of even the most monodisperse samples of semiconducting, colloidal quantum dots (QDs), determination of their structures with atomic precision has been a major challenge. Recently, we developed a synthetic method that yields four cadmium selenide QDs with uniform compositions (Cd35Se20(X)30(L)30, Cd56Se35(X)42(L)42, Cd84Se56(X)56(L)56, and Cd120Se84(X)72(L)n; X = O2CPh, L = H2N-C4H9 or H2N-C5H11) and atomically precise structures. Using a combination of single-crystal X-ray diffraction and atomic pair distribution function analysis, we determine the structures of their inorganic cores revealing a series of pyramidal nanostuctures with cadmium terminated {111} facets. Knowledge of their structures has allowed us to study the structural origins of their optoelectronic properties in great detail using a combination of computational and experimental techniques including Raman and optical spectroscopies. These materials will open the door to a deeper fundamental understanding of structure-property relationships in quantum-confined semiconductors.

Structural origins of optoelectronic properties in quantum dots: Studies of atomically precise cadmium selenide

249th National Meeting (2015)

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