title: Huge enhancement of upconversion luminescence by broadband dye sensitization of core/shell nanocrystals.
abstract: Upconversion nanocrystals (UCNCs) hold promise for bioimaging, solar cells, photocatalysis and volumetric displays. However, their upconversion luminescence intensities are usually low due to the weak and narrowband near-infrared absorption of lanthanide ions. Herein, we introduce and validate a strategy to hugely enhance upconversion luminescence intensity by using an organic near-infrared dye as an antenna to sensitize core/shell UCNCs. The dye can increase absorptivity and broaden the absorption spectrum of the UCNCs. Such dye sensitization, in combination with a core/shell structure, can tremendously enhance the upconversion luminescence (UCL) intensity of the UCNCs. The UCL intensity of dye-sensitized UCNCs excited at 820 nm is 800-folds higher than that of pure UCNCs excited at 980 nm. Further enhancement can be obtained by optimization of the dye emission and UCNC absorption spectral overlap. Moreover, the proposed approach can be extended to cover any part of the solar spectrum by using a set of dyes. This work provides new insights into the efficient enhancement of upconversion luminescence of the UCNCs and facilitates their applications.
authors.affiliation: School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, P R China. ydg@shu.edu.cn zwchen@shu.edu.cn mhwu@shu.edu.cn.
authors.forename: Dongguang
authors.initials: D
authors.lastname: Yin
authors.forename: Yumin
authors.initials: Y
authors.lastname: Liu
authors.forename: Jingxiu
authors.initials: J
authors.lastname: Tang
authors.forename: Feifei
authors.initials: F
authors.lastname: Zhao
authors.forename: Zhiwen
authors.initials: Z
authors.lastname: Chen
authors.forename: Tingting
authors.initials: T
authors.lastname: Zhang
authors.forename: Xinyu
authors.initials: X
authors.lastname: Zhang
authors.forename: Na
authors.initials: N
authors.lastname: Chang
authors.forename: Chenglong
authors.initials: C
authors.lastname: Wu
authors.forename: Dongwei
authors.initials: D
authors.lastname: Chen
authors.forename: Minghong
authors.initials: M
authors.lastname: Wu