Gas-Responsive Photoluminescence of YVO4:Eu3+ Nanoparticles Dispersed in an Ultralight, Three-Dimensional Nanofiber Network
Gas-Responsive Photoluminescence of YVO4:Eu3+ Nanoparticles Dispersed in an Ultralight, Three-Dimensional Nanofiber Network
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分散在超轻三维纳米纤维网络中的YVO4:Eu3+纳米颗粒的气体响应光致发光
DOI：
10.1021/acs.chemmater.6b04160
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发表时间：
2016-11
影响因子：
8.6
通讯作者：
Satoru Takeshita;Y. Takebayashi;Hiroyuki Nakamura;Satoshi Yoda
中科院分区：
文献类型：
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作者：
Satoru Takeshita;Y. Takebayashi;Hiroyuki Nakamura;Satoshi Yoda
纳米荧光粉是一种无机发光纳米材料，由于其潜在的工业应用和基础科学研究价值，在近几十年来引起了人们的广泛关注。1，2将磷光体颗粒纳米化诱导了一些在块状材料中未观察到的有趣特征，例如光学透明度、量子效应和由于其高表面积而引起的表面活性。3 - 5特别是，在纳米荧光粉表面发生的动态物理化学现象导致环境响应的光致发光（PL），例如，周围介质的PL增强和猝灭，6，7与表面物质的荧光共振能量转移（称为FRET），8 - 10和表面氧化还原反应的PL开关。11，12这些相互作用的PL行为为成像和传感开辟了新的方法。然而，大多数先前的研究都集中在生物医学应用上，因为它们主要使用胶体纳米荧光粉，其在体外和体内与溶质物种有效地相互作用，但在干燥环境中不与气体相互作用。为了实现与气体分子的有效相互作用，纳米荧光粉需要均匀地分散并固定在透明且高度透气的基质中，而不会失去表面活性，就像它们“独立于空气中”一样。在这项研究中，我们已经成功地合成了一种结构新的单片纳米复合材料接近这个虚构的结构，通过固定Eu 3+掺杂的YVO 4（YVO 4：Eu 3+）纳米粒子在超轻的三维网络的壳聚糖纳米纤维。为了制造含有功能性纳米颗粒的独立式整料，支撑基质作为物理支架实际上是必不可少的。迄今为止报道的大多数纳米颗粒复合材料由嵌入致密聚合物树脂中的无机纳米颗粒组成，其不仅提供机械韧性和可加工性，而且还提供物理化学稳定性。换句话说，纳米颗粒表面的动态化学活性被周围的树脂阻挡。例如，我们以前发现的YVO 4：Bi 3+，Eu 3+纳米荧光粉/聚氨酯复合材料的光漂白行为：纳米荧光粉表面表现出与树脂的光氧化还原反应，导致树脂的氧化分解伴随着纳米荧光粉的还原光漂白。16− 18这种效应可以应用于交互式PL器件，例如，结合传感功能的污染气体光氧化清洁剂，但前提是我们可以利用纳米颗粒表面，而不会被周围的树脂阻挡。
Nanophosphors, inorganic luminescent nanoparticles, have attracted much attention in recent decades for their potential industrial uses and fundamental scientific interest. 1, 2 Nanosizing the phosphor particles induces some interesting features that are not observed in bulk materials, such as optical transparency, quantum effects, and surface activities due to their high surface areas. 3− 5 In particular, dynamic physicochemical phenomena occurring at nanophosphor surfaces lead to environmentally responsive photoluminescence (PL), eg, PL enhancement and quenching by the surrounding media, 6, 7 fluorescent resonance energy transfer (known as FRET) with surface species, 8− 10 and PL switching by surface redox reactions. 11, 12 These interactive PL behaviors have opened up new methodologies for imaging and sensing. 13, 14 However, most of the previous studies have focused on biomedical applications because they mainly used colloidal nanophosphors, which interact efficiently with solute species in vitro and in vivo but not with gases in a dry environment. To realize an efficient interaction with gas molecules, nanophosphors need to be homogeneously dispersed and fixed in a transparent and highly gas permeable matrix without losing surface activities, as if they were “free-standing in the air.” In this study, we have succeeded in synthesizing a structurally new monolithic nanocomposite close to this imaginary structure by fixing Eu3+-doped YVO4 (YVO4: Eu3+) nanoparticles in an ultralight three-dimensional network of chitosan nanofibers. To fabricate a free-standing monolith containing functional nanoparticles, a supporting matrix is practically essential as a physical scaffold. Most of the nanoparticle composites reported so far are composed of inorganic nanoparticles embedded in a dense polymer resin, which provides not only mechanical toughness and processability, but also physicochemical stability. 15 In other words, the dynamic chemical activities of nanoparticle surfaces are blocked by the surrounding resin. For example, we previously discovered photobleaching behavior of a YVO4: Bi3+, Eu3+ nanophosphor/polyurethane composite: The nanophosphor surface exhibited photoredox reactions with the resin, resulting in oxidative decomposition of the resin accompanied by reductive photobleaching of the nanophosphor. 16− 18 This effect can be applied to interactive PL devices, eg, a photooxidative cleaner for pollutant gases combined with a sensing function, but only if we can utilize the nanoparticle surfaces without them being blocked by the surrounding resin.