SPR 和 FRET 对 ZnO 纳米棒异质结构光致发光的协同效应。

Synergistic effects of SPR and FRET on the photoluminescence of ZnO nanorod heterostructures.

机构信息

Department of Materials Science and Engineering, Korea University, Seoul 136-713, Korea.

出版信息

Nanotechnology. 2011 Oct 21;22(42):425708. doi: 10.1088/0957-4484/22/42/425708.

PMID:21946036

Abstract

Solution-grown ZnO nanorods (NRs) were successfully conjugated with CdSe/ZnS quantum dots (QDs) and Ag nanoparticles (NPs) to suppress intrinsic defect emission and to enhance band-edge emission at the same time. First, high-density and high-crystallinity ZnO NRs of diameter 80–90 nm and length 1.2–1.5 μm were grown on glass substrates using a low-temperature seed-assisted solution method. The as-synthesized ZnO NRs showed sharp photoluminescence (PL) band-edge emission centered at ∼377 nm together with broad defect emission in the range of ∼450–800 nm. The ZnO NRs were decorated with CdSe/ZnS QDs and Ag NPs, respectively, by sequential drop-coating. The PL of CdSe/ZnS QD||ZnO NR conjugates showed that ZnO band-edge emission decreased by 73.8% due to fluorescence resonance energy transfer (FRET) and charge separation between ZnO and CdSe/ZnS by type II energy band structure formation. On the other hand, Ag NP||CdSe/ZnS QD||ZnO NR conjugates showed increased band-edge emission (by 25.8%) and suppressed defect emission compared to bare ZnO NRs. A possible energy transfer mechanism to explain the improved PL properties of ZnO NRs was proposed based upon the combined effects of FRET and surface plasmon resonance (SPR).

摘要

溶液生长的 ZnO 纳米棒（NRs）成功地与 CdSe/ZnS 量子点（QDs）和 Ag 纳米颗粒（NPs）结合，同时抑制本征缺陷发射并增强带边发射。首先，使用低温种子辅助溶液法在玻璃衬底上生长出直径为 80-90nm、长度为 1.2-1.5μm 的高密度、高结晶度 ZnO NRs。所合成的 ZnO NRs 表现出尖锐的光致发光（PL）带边发射，中心位于 ∼377nm，同时在 ∼450-800nm 范围内具有宽的缺陷发射。分别通过顺序滴涂法将 CdSe/ZnS QDs 和 Ag NPs 修饰到 ZnO NRs 上。CdSe/ZnS QD||ZnO NR 复合物的 PL 表明，由于荧光共振能量转移（FRET）和 ZnO 与 CdSe/ZnS 之间的电荷分离，通过 II 型能带结构形成，ZnO 带边发射减少了 73.8%。另一方面，与裸 ZnO NRs 相比，Ag NP||CdSe/ZnS QD||ZnO NR 复合物表现出增强的带边发射（增加了 25.8%）和抑制的缺陷发射。基于 FRET 和表面等离子体共振（SPR）的综合效应，提出了一种解释 ZnO NRs 改善的 PL 性能的可能能量转移机制。