Energy Back Transfer Induced Color Controllable Upconversion Emissions in La2MoO6:Er3+/Yb3+ Nanocrystals for Versatile Applications. (12th January 2018)

• Record Type: Journal Article
• Authors: Du, Peng; Luo, Laihui; Yu, Jae Su
• Is Part Of: Particle and particle systems characterization. Volume 35:Number 3(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-01-12
• Subjects: luminescence -- nanocrystals -- thermometry -- upconversion; Particles -- Periodicals; 620.43
• DOI: 10.1002/ppsc.201700416
• Languages: English
• ISSNs: 0934-0866

Abstract

Abstract: Color controllable Er 3+ /Yb 3+ ‐codoped La2 MoO6 upconverting nanocrystals are successfully synthesized via a facile sol‐gel method. Under the irradiation of 980 nm light, the entire samples exhibit dazzling upconversion (UC) emissions arising from the intra‐4f transitions of Er 3+ ions and the UC emission intensity is strongly dependent on the Yb 3+ ion concentration. Moreover, by controlling the Yb 3+ ion concentration, the emission color is changed from green to yellow and finally to red as a result of the energy back transfer from Er 3+ to Yb 3+ ions, which is further verified by the theoretically discussion based on the steady‐state rate expressions. The optical thermometric properties of the prepared nanocrystals based on the ( 2 H11/2, 4 S3/2 ) thermally coupled levels of Er 3+ ions are systematically studied by analyzing the temperature‐dependent green UC emission spectra in the range of 303–663 K. The maximum sensor sensitivity of resultant nanocrystals is determined to be 0.0083 K −1 at 510 K. Furthermore, the emitting color of the synthesized nanocrystals relies on the temperature. In addition, the heating effect induced by the excitation pump power is also investigated and the host lattice temperature is enhanced from 319 to 404 K with raising the pump power from 159 to 757 mW. Abstract : Er 3+ /Yb 3+ ‐codoped La2 MoO6 upconversion nanocrystals are prepared by sol‐gel method. Owing to the energy back transfer process, multicolor emissions are observed in the resultant samples. The synthesized nanocrystals are found to be multifunctional materials for simultaneous optical thermometry, optical heater, and safety sign for high‐temperature environment.