Nanocluster growth: Via "graft-onto": Effects on geometric structures and optical properties

Abstract

Atomically precise engineering on the nanocluster surface remains highly desirable for the fundamental understanding of how surface structures of a nanocluster contribute to its overall properties. In this paper, the concept of "graft-onto" has been exploited to facilitate nanocluster growth on surface structures. Specifically, the Ag2(DPPM)Cl2 complex is used for re-constructing the surface structure of Pt1Ag28(SR)18(PPh3)4 (Pt1Ag28, SR = 1-adamantanethiolate) and producing a size-growth nanocluster-Pt1Ag31(SR)16(DPPM)3Cl3 (Pt1Ag31). The grafting effect of Ag2(DPPM)Cl2 induces both direct changes on the surface structure (e.g., size growth, structural transformation, and surface rotation) and indirect changes on the kernel structure (from a fcc configuration to an icosahedral configuration). Remarkable differences have been observed by comparing optical properties between Pt1Ag28 and Pt1Ag31. Significantly, Pt1Ag31 exhibits high photo-luminescent intensity with a quantum yield of 29.3%, which is six times that of the Pt1Ag28. Overall, this work presents a new approach (i.e., graft-onto) for the precise dictation of nanocluster surface structures at the atomic level.