Enhancing Quantum Yield via Local Symmetry Distortion in Lanthanide-Based Upconverting Nanoparticles
Enhancing Quantum Yield via Local Symmetry Distortion in Lanthanide-Based Upconverting Nanoparticles
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DOI：
10.1021/acsphotonics.6b00166
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发表时间：
2016-07
期刊：
影响因子：
7
通讯作者：
Michael D. Wisser;S. Fischer;Peter C. Maurer;Noah D Bronstein;S. Chu;A. Alivisatos;A. Salleo;J. Di
中科院分区：
文献类型：
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作者：
Michael D. Wisser;S. Fischer;Peter C. Maurer;Noah D Bronstein;S. Chu;A. Alivisatos;A. Salleo;J. Di
基于镧系元素的上转换纳米颗粒在太阳能发电、生物成像和安全技术方面表现出了巨大的潜力，但由于目前材料的效率极低，尚未得到广泛采用。4f轨道之间的弱跃迁偶极矩阻碍了光子的吸收和发射。在这里，我们介绍了一种新的方法来提高辐射跃迁率的Yb，Er基上转换纳米粒子的基础上局部对称性畸变。从六方相（β）NaYF 4的基质开始，我们逐渐去除Y3+离子，并用Gd 3+和Lu 3+的1：1混合物代替它们。这两种离子的作用是分别膨胀和收缩晶格，在保持平均宿主结构的同时诱导局域能级畸变。我们合成了一系列β-NaY 0.8 - 2xGdxLuxF 4：Yb 0.18Er 0.02纳米颗粒，并通过实验证实了颗粒尺寸，相，全局结构以及Yb 3+和Er 3+浓度随x的变化而保持恒定。U...
Lanthanide-based upconverting nanoparticles exhibit significant promise for solar energy generation, biological imaging, and security technologies but have not seen widespread adoption due to the prohibitively low efficiencies of current materials. Weak transition dipole moments between 4f orbitals hinder both photon absorption and emission. Here, we introduce a novel way to increase the radiative transition rates in Yb,Er-based upconverting nanoparticles based on local symmetry distortion. Beginning from a host matrix of the well-studied hexagonal (β)-phase NaYF4, we incrementally remove Y3+ ions and cosubstitute for them a 1:1 mixture of Gd3+ and Lu3+. These two ions act to expand and contract the lattice, respectively, inducing local-level distortion while maintaining the average host structure. We synthesize a range of β-NaY0.8–2xGdxLuxF4:Yb0.18Er0.02 nanoparticles and experimentally confirm that particle size, phase, global structure, and Yb3+ and Er3+ concentrations remain constant as x is varied. U...