Size-controllable and uniform gold bumpy nanocubes for single-particle-level surface-enhanced Raman scattering sensitivityElectronic supplementary information (ESI) available: Growth conditions and size distributions of various samples, SEM images, extinction spectra, and polarization-dependent SERS spectra. See DOI: 10.1039/c9cp00138g

Gold nanocubes modified to form roughened structures, namely, gold bumpy nanocubes (Au BNCs), with very strong and uniform single-particle surface-enhanced Raman scattering (SERS) intensity were developed. The Au BNCs were synthesized by controlled regrowth, competing with 4-aminothiophenol during gold nanocube growth. Under controlled conditions, Au BNCs of various sizes were successfully generated while maintaining a cubic outline. As the bumpy surfaces of the Au BNCs increased the number of hot spots on a single cubic nanoparticle, these nanoparticles exhibited 15-times stronger SERS than normal cubic nanoparticles. We expect that this unique nanostructure will be applicable in versatile fields as an ultrasensitive SERS nanoprobe or nanoantenna owing to its cubic outline and high uniformity, as well as the ease of particle size adjustment. Gold nanocubes modified to form roughened structures with very strong and uniform single-particle surface-enhanced Raman scattering intensity were developed.