Structure and Ultrafast Dynamics of White-Light-Emitting CdSe Nanocrystals

Citations Over TimeTop 10% of 2009 papers

Abstract

White-light emission from ultrasmall CdSe nanocrystals offers an alternative approach to the realization of solid-state lighting as an appealing technology for consumers. Unfortunately, their extremely small size limits the feasibility of traditional methods for nanocrystal characterization. This paper reports the first images of their structure, which were obtained using aberration-corrected atomic number contrast scanning transmission electron microscopy (Z-STEM). With subangstrom resolution, Z-STEM is one of the few available methods that can be used to directly image the nanocrystal's structure. The initial images suggest that they are crystalline and approximately four lattice planes in diameter. In addition to the structure, for the first time, the exciton dynamics were measured at different wavelengths of the white-light spectrum using ultrafast fluorescence upconversion spectroscopy. The data suggest that a myriad of trap states are responsible for the broad-spectrum emission. It is hoped that the information presented here will provide a foundation for the future development and improvement of white-light-emitting nanocrystals.

Related Papers

• → Photon upconversion: from two-photon absorption (TPA) to triplet–triplet annihilation (TTA)(2016)208 cited
• FREQUENCY UPCONVERSION FLUORESCENCE OF Er 3+ -DOPED TeO 2-WO3 GLASS(2005)
• → Cross-sectional HRTEM study of Si(5 5 12) reconstructed surface(2002)23 cited
• Energy transfer and frequency upconversion in Er~（3＋）-Yb~（3＋） codoped oxy-fluoro-tungstosilicate glasses(2012)
• → Model for efficient upconversion detection at mid-infrared(2019)