Ultrafast exciton quenching by energy and electron transfer in colloidal CdSe nanosheet–Pt heterostructures†

• Type of Material: Article
• Authors: Kaifeng Wu, Emory University; Qiuyang Li, Emory University; Yongling Du, Emory University; Zheyuan Chen, Emory University; Tianquan Lian, Emory University
• Language: English
• Date: 2015-02-01
• Publisher: Royal Society of Chemistry: Open Access
• Publication Version: Final Published Version
• Copyright Statement: © The Royal Society of Chemistry 2015.
• License: Creative Commons Attribution 3.0 Unported
• Final Published Version (URL): http://dx.doi.org/10.1039/c4sc02994a
• Title of Journal or Parent Work: Chemical Science
• ISSN: 2041-6520
• Volume: 6
• Issue: 2
• Start Page: 1049
• End Page: 1054
• Grant/Funding Information: We gratefully acknowledge the financial support from the National Science Foundation (CHE-1309817).
• Research Categories: Chemistry, General

Abstract

Two-dimensional (2-D) semiconductor nanomaterials are receiving tremendous research interests due in part to their attractive light absorption and charge transport properties. Integration of catalytic metal nanoparticles with these 2-D semiconductors can potentially lead to new photocatalytic nanoheterostructures for efficient solar-to-fuel conversion. Here we report the synthesis and transient absorption study of colloidal quantum confined CdSe nanosheets with a Pt nanoparticle at the edge or vertex. Due to the large in-plane exciton mobility, ∼86.6 ± 0.5% of excitons generated in CdSe sheets can be transported to NS-Pt interface and quenched by energy transfer to Pt (with a half-life < 150 fs). The remaining excitons (13.4 ± 0.5%) become localized due to fast hole trapping and can be dissociated by interfacial electron transfer to Pt (with a half life of ∼9.4 ± 0.7 ps). The resulting charge-separated states (with electrons in Pt and trapped holes in CdSe) are long-lived (half life of ∼75 ± 14 ns), suggesting possible applications for solar driven H 2 generation.