A new method for synthesizing doped semiconductor nanocrystals enables the introduction of dopants into host lattices without loss of kinetically trapped size distributions or morphologies. This process involves thermodynamically controlled deposition of dopants onto the surfaces of preformed nanocrystals followed by dopant diffusion through the host lattice. Unlike cation exchange processes, this diffusion doping method proceeds by addition of cation-anion pairs without loss of host cations, and excels at the introduction of relatively unreactive impurity ions. Diffusion doping enables the synthesis of Cd1-xMnxSe with very large magneto-optical effects and unprecedentedly large manganese concentrations (>20%) while maintaining the narrow size distribution of seed CdSe nanocrystals. Control of the solution and lattice chemical potentials of Cd2+, Mn2+, and Se2- allows for the tuning of the equilibrium composition of the resultant nanocrystals. Characterization by magneto-optical spectroscopy and inductively coupled plasma atomic emission spectrometry (ICP-AES) demonstrate precise thermodynamic control over large dopant concentrations in Cd1-xMnxSe (0=x=0.2).

Nanocrystal diffusion doping

248th National Meeting (2014)

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