Lanthanide-Doped Upconversion Nanoprobes
Lanthanide-doped upconversion nanoparticles (UCNPs) have attracted considerable interest due to their superior physicochemical features, such as large anti-Stokes shifts, low autofluorescence background, low toxicity, and high penetration depth, which mak
- PDF / 1,618,892 Bytes
- 51 Pages / 439.37 x 666.142 pts Page_size
- 105 Downloads / 234 Views
Lanthanide-Doped Upconversion Nanoprobes Datao Tu, Wei Zheng, Ping Huang and Xueyuan Chen
Abstract Lanthanide-doped upconversion nanoparticles (UCNPs) have attracted considerable interest due to their superior physicochemical features, such as large anti-Stokes shifts, low autofluorescence background, low toxicity, and high penetration depth, which make them extremely suitable for use as alternatives to conventional downshifting luminescence bioprobes such as organic dyes and quantum dots for various biological applications. Fundamental understanding the photophysics of lanthanide-doped UCNPs is of vital importance for discovering novel optical properties and exploring their new applications. In this chapter, we focus on the most recent advances in the development of lanthanide-doped UCNPs as potential luminescent nanobioprobes by means of our customized lanthanide photophysics measurement platforms specially designed for upconversion luminescence, which covers from their fundamental photophysics to bioapplications, including electronic structures (energy levels and local site symmetry of emitters), excited-state dynamics, UC luminescence enhancement strategies, and their promising applications for biodetection and bioimaging. Some future prospects and efforts toward this rapidly growing field are also envisioned.
8.1
Introduction
Lanthanide (Ln3+) activated upconversion (UC) materials, which are able to convert long-wavelength stimulation into short-wavelength emission, have been widely used in solid-state lasers, flat displays, optical communications, and other photonic devices. In comparison with the multiphoton absorption or second harmonic generation that require expensive ultrashort-pulse lasers (e.g., a femtosecond pulse D. Tu W. Zheng P. Huang X. Chen (&) Key Laboratory of Optoelectronic Materials Chemistry and Physics and State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, Fujian, China e-mail: [email protected] © Springer Science+Business Media Singapore 2016 R.S. Liu (ed.), Phosphors, Up Conversion Nano Particles, Quantum Dots and Their Applications, DOI 10.1007/978-981-10-1590-8_8
237
238
D. Tu et al.
laser) to perform the excitation, Ln3+-doped UC materials generally take advantage of a more efficient energy transfer UC process and thus can be excited by a low-cost continuous-wave (CW) near-infrared (NIR) diode laser (e.g., 808 nm or 980 nm laser). It is their unique electronic structures that enable the Ln3+ ions in crystals to effectively emit photons from high energy levels through successive photon absorptions and energy transfers from their low-lying energy levels. Thanks to the pioneering work by Auzel and others in theoretical and experimental studies on UC within 4fN electronic structure, much of the spectroscopy and mechanism involved in Ln3+-doped UC materials are well understood [1–3]. With the rapid advances in nanotechnology and biotechnology, particularly the development of new met
Data Loading...
