Abstract The coupling of rare-earth ions doped upconversion nanoparticles (UCNPs) with localized surface plasmon resonance (LSPR) of noble metal has attracted more interest because of improving luminescent efficiency of UCNPs. The nonstoichiometric semiconductor tungsten oxides can provide a possibility for the achievement of effective upconversion luminescence enhancement owning to concentrating and transferring the NIR-plasmonic energy in upconversion system. In this work, Yb3+/Tm3+-doped NaYF4 nanoparticles (NaYF4:Yb-Tm NPs)/ W18O49 nanowires (NWs) composite film which can tremendously improve the upconversion luminescence of Tm3+ as high as 140-fold has been fabricated. Investigations show that the LSPR-induced plasmonic energy transfer process produced by W18O49 NWs is the primary reason for enhancing the upconversion luminescence of NaYF4:Yb-Tm NPs, originating from much more intense excitation electric-field to generate more electrons on the excited state energy-levels of Tm3+ ions. It is anticipated that the development of non-metallic plasmon-sensitized upconversion luminescence materials may provide a platform for widely exploring application in biomedical imaging, therapeutics, and energy conversion.

中文翻译：

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非金属等离子体促进Tm3+的1G4-3H6电子跃迁过程

摘要 稀土离子掺杂的上转换纳米粒子（UCNPs）与贵金属局域表面等离子体共振（LSPR）的耦合由于提高了UCNPs的发光效率而引起了越来越多的关注。非化学计量的半导体氧化钨可以通过在上转换系统中聚集和转移近红外等离子体能量来实现有效的上转换发光增强。在这项工作中，Yb3+/Tm3+ 掺杂的 NaYF4 纳米粒子 (NaYF4:Yb-Tm NPs)/W18O49 纳米线 (NWs) 复合薄膜可以极大地提高 Tm3+ 的上转换发光高达 140 倍。研究表明，由 W18O49 NWs 产生的 LSPR 诱导的等离子体能量转移过程是增强 NaYF4 上转换发光的主要原因：Yb-Tm NPs，源自更强烈的激发电场，以在 Tm3+ 离子的激发态能级上产生更多电子。预计非金属等离子体敏化上转换发光材料的发展可以为广泛探索在生物医学成像、治疗和能量转换中的应用提供平台。