Nanophotonics Research Laboratory, Department of Physics, Academy of Maritime Education and Training, 135, East Coast Road, Kanathur, Chennai-603112, India.
Methods Appl Fluoresc. 2018 Apr 27;6(3):035009. doi: 10.1088/2050-6120/aabcf2.
In this article, we report on enhancement in photoluminescence and Raman line intensity of SnS quantum dots embedded in a mesh of Sn nanostructures. SnS nanoparticles synthesized by homogenous precipitation method show strong quantum confinement with a band gap of ∼2.7 eV (blue shift of ∼1 eV compared to bulk SnS particles). The optical band gap of SnS quantum dots is controlled by varying the pH (∼0 to 2.25), ageing time (24 to 144 h) and molarity (0 to 2 M) of the precursors. These SnS nanoparticles are embedded in a mesh of Sn nanostructures which are synthesized from tin chloride by using sodium borohydride as reducing agent. The Sn nanostructures have a morphology dependent, tunable surface plasmon resonance (SPR), ranging from UV (∼295 nm) to visible region (∼400 nm) of the electromagnetic spectrum. In the SnS-Sn nanohybrids, the excitons are strongly coupled with plasmons leading to a shift in the excitonic binding energy (∼400 meV). The pure SnS quantum dots have a very weak photoluminescence peak at ∼560 nm and Raman shift of low intensity at 853.08 cm, 1078.17 cm, 1255.60 cm, 1466.91 cm. The coupling of SnS nanoparticles with Sn nanoparticles results in strong exciton-plasmon interactions leading to enhanced photoluminescence and Raman line intensity. The nanohybrids formed using Sn nanosheets whose SPR matches with absorption onset of the SnS nanoparticles shows an enhancement of ∼10 times higher than pure SnS nanoparticles. Thus, Sn nanosheet with surface plasmon resonance in visible region (400 nm) like Au and Ag is a promising material for surface enhanced Raman spectroscopy, plasmon assisted fluorescence imaging and for enhancing the emission intensity of semiconductors with weak emission intensity.
本文报道了嵌入 Sn 纳米结构网格中的 SnS 量子点的光致发光和拉曼线强度增强。通过均匀沉淀法合成的 SnS 纳米粒子表现出强烈的量子限制，带隙约为 2.7eV（与体相 SnS 粒子相比约蓝移 1eV）。SnS 量子点的光学带隙通过改变 pH 值（约 0 至 2.25）、前体的老化时间（24 至 144 小时）和摩尔浓度（0 至 2M）来控制。这些 SnS 纳米粒子嵌入 Sn 纳米结构网格中，Sn 纳米结构由氯化锡通过使用硼氢化钠作为还原剂合成。Sn 纳米结构具有形态依赖性的可调谐表面等离子体共振（SPR），范围从电磁光谱的紫外区（约 295nm）到可见区（约 400nm）。在 SnS-Sn 纳米杂化中，激子与等离子体强烈耦合，导致激子结合能发生偏移（约 400meV）。纯 SnS 量子点在约 560nm 处具有非常弱的光致发光峰，拉曼位移的低强度峰在 853.08cm、1078.17cm、1255.60cm、1466.91cm 处。SnS 纳米粒子与 Sn 纳米粒子的耦合导致强烈的激子-等离子体相互作用，从而增强光致发光和拉曼线强度。与 SnS 纳米粒子的吸收起始匹配的 Sn 纳米片形成的纳米杂化物显示出比纯 SnS 纳米粒子高约 10 倍的增强。因此，具有与 Au 和 Ag 等可见光区表面等离子体共振的 Sn 纳米片是表面增强拉曼光谱、等离子体辅助荧光成像以及增强具有弱发射强度的半导体发射强度的有前途的材料。
