Enhanced ultraviolet emission and improved spatial distribution uniformity of ZnO nanorod array light-emitting diodes via Ag nanoparticles decoration
Enhanced ultraviolet emission and improved spatial distribution uniformity of ZnO nanorod array light-emitting diodes via Ag nanoparticles decoration
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通过Ag纳米颗粒修饰增强ZnO纳米棒阵列发光二极管的紫外发射并改善空间分布均匀性
DOI：
10.1039/c3nr02844e
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发表时间：
2013-01-01
期刊：
影响因子：
6.7
通讯作者：
Liu, Yi Chun
中科院分区：
文献类型：
--
作者：
Liu, Wei Zhen;Xu, Hai Yang;Liu, Yi Chun
将ZnO纳米棒阵列/p-GaN薄膜异质结构嵌入Ag纳米颗粒/PMMA复合材料中，制备了局域表面等离子体增强的紫外发光二极管（LED）。通过优化Ag纳米颗粒在PMMA中的浓度，观察到电致发光（EL）光谱的两个明显变化：（1）来自ZnO激子的UV EL分量被选择性地增强超过13倍，并且整个光谱线形被改变;（2）输出光子强度的空间均匀性被改善，并且角分布曲线的线宽增加了约2倍。这些观察结果可以归因于Ag LSP和ZnO激子之间的近场光学耦合。时间分辨发光测量和模型计算表明，光耦合导致银纳米颗粒修饰的ZnO纳米棒阵列的自发辐射率和内量子效率增加。此外，LSP-激子相互作用允许器件的EL耦合出纳米棒波导并各向同性地散射到每个方向，从而加宽EL强度的角分布。
Localized surface plasmon (LSP) enhanced ultraviolet (UV) light-emitting diodes (LEDs) were fabricated by embedding a ZnO nanorod array/p-GaN film heterostructure into a Ag-nanoparticles/PMMA composite. By optimizing the concentration of Ag nanoparticles in PMMA, two distinct changes in electroluminescence (EL) spectra were observed: (1) the UV EL component from ZnO excitons was selectively enhanced more than 13-fold and the entire spectral lineshape was changed and (2) the spatial uniformity of the output photon intensity was improved and the linewidth of an angular distribution curve was increased by similar to 2 times. These observations can be attributed to near-field optical coupling between Ag LSPs and ZnO excitons. Time-resolved luminescence measurements and a model calculation reveal that the optical coupling results in the increase of the spontaneous emission rate and internal quantum efficiency of Ag-nanoparticles-decorated ZnO nanorod arrays. Moreover, the LSP-exciton interaction allows the device's EL to be coupled out of the nanorod waveguide and to be isotropically scattered into every direction, thus broadening the angular distribution of the EL intensity.