Thermodynamic Analysis of Multiply Twinned Particles: Surface Stress Effects

In nanoparticle technologies, such as SERS, fuel cell catalysis and data storage, icosahedral and decahedral nanoparticles, owing to their defect structure, provide higher functionality than their single-crystal Wulff counterparts. However, precise control on the yield of multiply twinned structures during solution synthesis has been challenging. In particular, it is difficult to synthesize icosahedral structures due to the high volumetric strain energy associated with the disclination defects and the transition to decahedral morphologies. In this Letter, we elucidate the role of surface stresses in influencing the thermodynamic stability of multiply twinned particles. Increasing the surface stresses inhibits the formation of decahedral structures and increases the likelihood of synthesizing, metastable, icosahedral particles. Analogously, large decahedral particles may be stabilized by decreasing the surface stresses. Therefore, by tailoring the solution chemistry to influence the surface stresses, greater control over the synthesis of multiply twinned structures can be achieved.