Dual-Mode Luminescent Nanopaper Based on Ultrathin g–C3N4 Nanosheets Grafted with Rare-Earth Upconversion Nanoparticles

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• 作者：Yafei Zhao ; Ruoyan Wei ; Xin Feng ; Lining Sun ; Panpan Liu ; Yongxiang Su ; Liyi Shi
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：August 24, 2016
• 年：2016
• 卷：8
• 期：33
• 页码：21555-21562
• 全文大小：502K
• 年卷期：0
• ISSN：1944-8252

文摘

Ultrathin graphite-like carbon nitride (g–C<sub>3sub>N<sub>4sub>) nanosheets have attracted considerable attention due to the enhanced intrinsic photoabsorption and photoresponse with respect to bulk g–C<sub>3sub>N<sub>4sub>. For the first time, a dual-mode of down- and upconversion luminescent g–C<sub>3sub>N<sub>4sub> nanopaper with high optical transparency and mechanical robustness was successfully fabricated through a simple thermal evaporation process using chitosan as a green cross-linking agent. The dual-mode of down- and upconversion fluorescence emission originated from the amino terminated ultrathin g–C<sub>3sub>N<sub>4sub> nanosheets functionalized with carboxylic acid modified multicolored rare-earth upconversion nanoparticles (cit–UCNPs) via EDC/NHS coupling chemistry. The homogeneously distributed cit–UCNPs@g–C<sub>3sub>N<sub>4sub> nanoconjugates with excellent hydrophilicity displayed good film-forming ability and structural integrity; thus, the photoluminescence of each ingredient was substantially maintained. Results indicated that the freestanding chitosan cross-linked cit–UCNPs@g–C<sub>3sub>N<sub>4sub> luminescent nanopaper possessed high transmittance, excellent mechanical properties, and remarkable dual-mode emission. The smart design of high performance luminescent nanopaper based on ultrathin g–C<sub>3sub>N<sub>4sub> nanosheets grafted with multicolored UCNPs offers a potential strategy to immobilize other multifunctional luminescent materials for easily recognizable and hardly replicable anticounterfeiting fields.