The researchers combined and heated gold and copper precursors with other chemicals to produce highly crystalline, homogeneous, perfect nanocubes with abundant yield. To study the formation process, they removed samples at 1 hour, 1.5 hours, 5 hours, and 24 hours and found that just five hours were needed to produce perfectly cubic nanoparticles of uniform size. By adjusting the ratios of the chemicals in the original solution and the reaction time, they were able to precisely control the size, shape and composition of the nanocubes.