Abstract: Spectral conversion of light radiation is essential for a variety of modern-day technologies including displays, photovoltaics, data storage, and cancer therapy. In the past decades, a variety of luminescent materials, including organic dyes and semiconductor quantum dots, were developed to realize photon energy conversion in the ultraviolet (UV) to near infrared (NIR) spectral range. However, practical application of these techniques is typically limited by constraints such as toxicity and/or poor stability. In this regard, lanthanide-doped upconversion nanoparticles have been developed as a promising alternative to conventional luminescent nanomaterials. By comparison, these nanoparticles offer low cytotoxicity, sharp emission peaks, long-lived excited electronic states, as well as high stability against photo bleaching and chemical degradation. In this talk, I focus on our recent efforts on lanthanide-doped core-shell nanoparticles that are generally composed of a layer-by-layer structure with a set of lanthanide ions incorporated into separate layer. Examples will be given to demonstrate how to tune the luminescence process and enhance multiphoton upconversion emission for exciting new technological applications.
References
[1] X. Chen, D. Peng, Q. Ju, F. Wang, Photon upconversion in core-shell nanoparticles. Chem. Soc. Rev. 2015, 44, 1318.
[2] Wen, H.; Zhu, H.; Chen, X.; Hung, T. F.; Wang, B.; Zhu, G.; Yu, S. F.; Wang, F. Upconverting near-infrared light through energy management in core–shell–shell nanoparticles, Angew. Chem. Int. Ed. 2013, 52, 13419.
[3] X. Chen, L. Jin, W. Kong, T. Sun, W. Zhang, X. Liu, J. Fan, S. F. Yu, Feng Wang, Confining energy migration in upconversion nanoparticles towards deep ultraviolet lasing, Nature Communications 2016, 7, 10304, doi: 10.1038/ncomms10304.
[4] Chen, B.; Liu, Y.; Xiao, Y.; Chen, X.; Li, Y.; Li, M.; Qiao, X.; Fan, X.; Wang, F. Amplifying Excitation-Power Sensitivity of Photon Upconversion in a NaYbF4:Ho Nanostructure for Direct Visualization of Electromagnetic Hotspots, J. Phys. Chem. Lett. 2016, 7, 4916.
Biography: Dr. Feng Wang received his BE (2001) and PhD (2006) degrees in Materials Science and Engineering from Zhejiang University. His PhD thesis was focused on the synthesis and characterization of lanthanide-doped fluoride nanomaterials under the supervision of Prof. Minquan Wang and Prof. Xianping Fan. He then carried out postdoctoral research work with Prof. Xiaogang Liu at the National University of Singapore and the Institute of Materials Research and Engineering in Singapore. He joined the faculty of City University of Hong Kong in 2012 as an Assistant Profess, and is promoted to Associated Professor in 2017. His research is focused on nano- and micro-structural materials comprising luminescent lanthanides for applications in biology and photonics.
