Preparation of stable, bright luminescent nanoparticles having compositionally engineered properties

A method is provided for preparing luminescent semiconductor nanoparticles composed of a first component X, a second component A, and a third component B, wherein X, A, and B are different, by combining B with X and A in an amount such that the molar ratio B:(A+B) is in the range of approximately 0.001 to 0.20 and the molar ratio X:(A+B) is in the range of approximately 0.5:1.0 to 2:1. The characteristics of these nanoparticles can be substantially similar to those of nanoparticles containing only X and B while maintaining many useful properties characteristic of nanoparticles containing only X and A; and can additionally exhibit emergent properties such as a peak emission energy less than that characteristic of a particle composed of XA or XB alone. This method is particularly applicable to the preparation of stable, bright nanoparticles that emit in the red to infrared regions of the electromagnetic spectrum.