Engineering interfacial structure in "Giant" PbS/CdS quantum dots for photoelectrochemical solar energy conversion. (December 2016)

• Record Type: Journal Article
• Authors: Jin, Lei; Sirigu, Gianluca; Tong, Xin; Camellini, Andrea; Parisini, Andrea; Nicotra, Giuseppe; Spinella, Corrado; Zhao, Haiguang; Sun, Shuhui; Morandi, Vittorio; Zavelani-Rossi, Margherita; Rosei, Federico; Vomiero, Alberto
• Is Part Of: Nano energy. Volume 30(2016:Dec.)
• Page Start: 531
• Page End: 541
• Publication Date: 2016-12
• Subjects: Photoelectrochemical -- Giant quantum dot -- PbS -- CdS -- Core/shell; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2016.10.029
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: The interfacial structure in "giant" PbS/CdS quantum dots (QDs) was engineered by modulating the Cd:S molar ratio during in situ growth. The control of the gradient interfacial layer could facilitate hole transfer, regulate the transition from double- to single-color emission, as a consequence. These QDs are optically active close-to-the near-infrared (NIR) spectral region and are candidates as absorber materials in solar energy conversion. Photoinduced charge transfer from "giant" QDs to electron scavenger can still take place despite the ultra-thick (~5 nm) shell. The hybrid architecture based on a TiO2 mesoporous framework sensitized by the "giant" QDs with alloyed interface can produce a saturated photocurrent density as high as ~5.3 mA/cm 2 in a photoelectrochemical (PEC) cell under 1 Sun illumination, which is around 2 times higher than that of bare PbS and core/thin-shell PbS/CdS QDs sensitizer. The as-prepared PEC device presented very good stability thanks to the "giant" core/shell QDs architecture with tailored interfacial layer and a further coating of the ZnS shell. 78% of the initial current density is kept after 2-h irradiation at 1 Sun. Engineering of electronic band structure plays a key role in boosting the functional properties of these composite systems, which hold great potential for H2 production in PEC devices. Graphical abstract: Highlights: The interfacial structure in giant quantum dots (QDs) was engineered. The gradient interfacial layer facilitates hole transfer and regulates emission. Photoinduced charge can transfer from QDs to scavenger despite the ultra-thick shell (~5 nm). Close-to-NIR giant QDs produced saturated photocurrent density of ~5.3 mA/cm 2 .