US Patent 9227846 Purification of nanocrystals for thermoelectric, solar, and electronic applications

Disclosed herein is a method of purifying and doping a population of semiconductor nanocrystals. The method includes mixing the population of semiconductor nanocrystals having a first material system and a first ligand with a set of particles in the presence of a first solvent, the set of particles having a second material system which is different from the first material system and a second ligand which is different from the first ligand, to form a mixture. The method also includes facilitating a ligand exchange and an ionic exchange in the mixture, altering the first material system of the population of semiconductor nanocrystals to a third material system, different from the first material system and the second material system. The method includes sonicating the mixture and isolating the population of semiconductor nanocrystals having the third material system and the second ligand from the mixture.