Key Laboratory of Photosensitive Material and Device of Liaoning Province, Key Laboratory of New Energy and Rare Earth Resource Utilization of State Ethnic Affairs Commission & School of Physics and Materials Engineering, Dalian Minzu University, Dalian 116600, P. R. China.
Nanoscale. 2018 Jan 3;10(2):726-732. doi: 10.1039/c7nr07241d.
Up-conversion luminescence (UCL) from rare-earth doped oxide (RE) films has great potential for application in fields such as solar cells, bioanalysis, or display technologies. However, the relatively high phonon energy of oxide matrices usually facilitates nonradiative relaxation leading to low UCL efficiency. Herein, we report a three-layer hierarchical structure of Ag/ZnO nanowires (nw-ZnO)/RE composite films, which enhances the UCL of rare-earth doped oxide films. An optimization of the geometric structure of the composite films demonstrated an increase of UCL by up to almost two orders of magnitude in Er and Tm doped YbMoO films. This UCL enhancement is attributed to the formation of a very strong electric field in the tips of the nw-ZnO creating a highly effective electric field at the composite films, combined with reflection at the silver layer. Furthermore, we use the UCL properties of these novel Ag/nw-ZnO/RE composite films to demonstrate their possible use in ZnO-based photocatalytic processes to enhance the utilization of near-infrared sunlight in these devices.
上转换发光（UCL）在掺稀土的氧化物（RE）薄膜中具有很大的应用潜力，可应用于太阳能电池、生物分析或显示技术等领域。然而，氧化物基质中相对较高的声子能量通常会促进非辐射弛豫，从而导致 UCL 效率低下。在此，我们报告了一种 Ag/氧化锌纳米线（nw-ZnO）/RE 复合薄膜的三层分层结构，该结构增强了掺稀土的氧化物薄膜的 UCL。对复合薄膜的几何结构进行优化，结果表明，掺铒和掺铥的 YbMoO 薄膜的 UCL 增强了近两个数量级。这种 UCL 增强归因于 nw-ZnO 尖端形成的非常强的电场，在复合薄膜中产生了非常有效的电场，再加上银层的反射。此外，我们利用这些新型 Ag/nw-ZnO/RE 复合薄膜的 UCL 特性，证明了它们在基于 ZnO 的光催化过程中的潜在应用，以提高这些器件中近红外太阳光的利用率。
