Interface Pattern Engineering in Core‐Shell Upconverting Nanocrystals: Shedding Light on Critical Parameters and Consequences for the Photoluminescence Properties. Issue 47 (25th October 2021)

• Record Type: Journal Article
• Authors: Hudry, Damien; De Backer, Annick; Popescu, Radian; Busko, Dmitry; Howard, Ian A.; Bals, Sara; Zhang, Yang; Pedrazo‐Tardajos, Adrian; Van Aert, Sandra; Gerthsen, Dagmar; Altantzis, Thomas; Richards, Bryce S.
• Is Part Of: Small. Volume 17:Issue 47(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-10-25
• Subjects: core‐shell -- electron microscopy -- interface -- nanocrystals -- upconversion; Nanotechnology -- Periodicals; Nanoparticles -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1002/smll.202104441
• Languages: English
• ISSNs: 1613-6810

Abstract

Abstract: Advances in controlling energy migration pathways in core‐shell lanthanide (Ln)‐based hetero‐nanocrystals (HNCs) have relied heavily on assumptions about how optically active centers are distributed within individual HNCs. In this article, it is demonstrated that different types of interface patterns can be formed depending on shell growth conditions. Such interface patterns are not only identified but also characterized with spatial resolution ranging from the nanometer‐ to the atomic‐scale. In the most favorable cases, atomic‐scale resolved maps of individual particles are obtained. It is also demonstrated that, for the same type of core‐shell architecture, the interface pattern can be engineered with thicknesses of just 1 nm up to several tens of nanometers. Total alloying between the core and shell domains is also possible when using ultra‐small particles as seeds. Finally, with different types of interface patterns (same architecture and chemical composition of the core and shell domains) it is possible to modify the output color (yellow, red, and green‐yellow) or change (improvement or degradation) the absolute upconversion quantum yield. The results presented in this article introduce an important paradigm shift and pave the way toward the emergence of a new generation of core‐shell Ln‐based HNCs with better control over their atomic‐scale organization. Abstract : Parameters governing the formation of various interface patterns in core‐shell lanthanide‐based hetero‐nanocrystals are revealed. Interface patterns of individual particles can be visualized with atomic‐scale resolution. For a given type of architecture (fixed geometry and chemical composition), the alteration of the interface pattern leads to the modification of fundamental photoluminescence characteristics such as the emission spectrum and absolute upconversion quantum yield.