Department of Materials Science and Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Republic of Korea.
Nanotechnology. 2017 Jun 2;28(22):225502. doi: 10.1088/1361-6528/aa6ce0. Epub 2017 Apr 12.
In this study, plasmonic silver (Ag) nanoparticle-(NP) anchored ZnO nanorods (NRs) and nanotube-(NT) based UV photodetectors are demonstrated. Here, Ag NPs are synthesized and anchored by using a room-temperature photochemical method by exposing the precursor solution in UV radiation. In order to achieve a stronger surface plasmon resonance (SPR) and minimum agglomeration, the photochemical method is optimized with a precursor concentration of 5 mmol, a UV intensity of 0.4 mW · cm, and an exposure time of 30 min. An asymmetry around 380 nm in the absorption spectra of the NP solution indicates the presence of plasmonic resonance in that region. Upon anchoring the Ag NPs, ZnO NRs show enhanced band edge emission (380-400 nm) and the emission is further significantly increased in Ag NP-anchored ZnO NTs. The on/off ratio and photoresponse properties of the UV photodetectors are enhanced significantly after anchoring Ag NPs on the ZnO nanostructures. It is believed that the near-field coupling of SPR causes an optical enhancement of ZnO, whereas the bridging effect and hot-electron transfer to the conduction band of ZnO by plasmonic Ag NPs, anchored in close proximity, gives rise to a faster response of the photodetectors.
在这项研究中，展示了基于等离子体银（Ag）纳米粒子（NP）锚定的氧化锌纳米棒（NR）和纳米管（NT）的紫外光探测器。在这里，Ag NPs 是通过在紫外辐射下暴露前驱体溶液，利用室温光化学方法合成并锚定的。为了实现更强的表面等离子体共振（SPR）和最小的聚集，通过优化前驱体浓度为 5 mmol、UV 强度为 0.4 mW·cm 和暴露时间为 30 min 来优化光化学方法。NP 溶液吸收光谱中 380nm 左右的不对称性表明该区域存在等离子体共振。在 Ag NPs 锚定后，ZnO NRs 显示出增强的带边发射（380-400nm），并且在 Ag NP 锚定的 ZnO NTs 中，发射进一步显著增强。在 ZnO 纳米结构上锚定 Ag NPs 后，紫外光探测器的开关比和光响应特性得到了显著增强。据信，SPR 的近场耦合导致 ZnO 的光学增强，而紧密接近的等离子体 Ag NPs 的桥接效应和热电子向 ZnO 导带的转移导致光探测器的更快响应。
