Assembly-promoted photocatalysis: Three-dimensional assembly of CdSxSe1-x (x = 0-1) quantum dots into nanospheres with enhanced photocatalytic performance

In this paper, through an emulsion-based bottom-up self-assembly method, monodisperse CdSxSe(1-x) (x-0-1) quantum dots (QDs) with tailoring compositions have been three-dimensionally assembled into spherical architectures in sub-micrometer sizes. UV-Vis absorption measurements revealed the enhanced light harvesting abilities of the assembled CdSxSe(1-x) spheres relative to their constituting QDs. HRTEM characterizations over the CdSxSe(1-x) assemblies suggested the existence of localized oriented adjoining of the CdSxSe(1-x) QDs and the resulting nano-twin structures that are favorable for photogenerated electron-hole separation. The quenching of photoluminescence and the improvement in IPCE after the assembly of CdSxSe(1-x) QDs provided a clue to the likely suppressed electron-hole recombination brought about by the unique architectures and interfaces derived from self-assembly. The above findings were coincided with the remarkably improved H-2 evolution activities observed for the well-assembled CdSxSe(1-x) nanospheres in photocatalytic water splitting, underpinning the importance of the alternative strategy to design advanced semiconductor photocatalysts based on architectural engineering. (C) 2017 The Chinese Ceramic Society. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.