Transformation from Silver Nanoprisms to Nanodecahedra in a Temperature-Controlled Photomediated Synthesis

The photomediated transformation of silver nanoparticles is both synthetically useful and mechanistically intriguing. Temperature effects on photochemical synthesis of silver nanoparticles are investigated. The morphology of final products is strongly dependent on the reaction temperature: nanodecahedra are formed at a low temperature of 20 degrees C; nanoprisms are formed at a higher temperature of 40 degrees C; and a mixture of shapes results at 30 degrees C. An interesting transformation process is observed at a lower temperature of 20 degrees C: silver nanoprisms are grown first and then transformed into nanodecahedra completely. We propose that silver seeds in a type of multitwinning are more stable than the platelike structure at lower temperature during the photochemical growth process. The transformed silver nanodecahedra exhibit greatly superior enhancement of Raman scattering compared to silver nanoprisms. These findings may provide a new insight on photomediated synthesis of silver nanostructures and suggest a new way of thinking about control over the morphology of nanoparticles.