Cadmium selenide: Surface and nanoparticle energetics

Cadmium selenide (CdSe) belongs to a class of important II-VI semiconductors widely used in optical, sensor, and laser materials and quantum-dot light-emitting diodes. Here we present the first direct calorimetric measurement of the surface energy of wurtzite CdSe. CdSe nanoparticles with particle size between 20 and 60 nm were prepared by a hydrothermal method without additives to control morphology, and the surface energy was derived from the drop solution enthalpies in molten sodium molybdate and from water adsorption calorimetry. The surface energy of the hydrated surface is 1.31 ± 0.26 J/m², whereas that of the anhydrous surface is 1.65 ± 0.27 J/m². These values are significantly lower than those for ZnO and many other oxides.