Enhanced Lanthanide Luminescence Using Silver Nanostructures: Opportunities for a New Class of Probes with Exceptional Spectral Characteristics

The photophysical effects of europium tetracycline immobilized in thin polyvinyl alcohol films coated onto silver nanostructures have been investigated. Complimentary to recent reports from our laboratories that the close proximity of luorophores to silver nanostructures can enhance their intrinsic radiative decay rate, we show that up to a 16-fold enhancement in lanthanide luminescence is possible, accompanied by a notable reduction in luminescence lifetime. These results suggest the potential future development of a new class of significantly brighter lanthanide based probes with exceptional spectral properties, which can probably undergo significantly more excitation–emission event cycles due to the reduced lifetime, substantially increasing detectability.     

保护中国山东沿海岛屿山茶(Camellia japonica)群落(英文)

山茶(Camellia japonica)为常绿灌木或小乔木,主产于亚热带常绿阔叶林区域,是我国著名的观赏花卉。山东省青岛市属于暖温带落叶阔叶林区域,由于气候上稍具冬暖夏凉的特点,所以采些亚热带常绿植物得以生存。青岛崂山原有多处分布着野生的山茶,目前已消失殆尽。但在沿海各岛屿上却甚普遍,特别是长门岩岛数量最多,是这一亚热带植物在我国自然分布的最北界线。该岛现尚有593株野生山茶,多与其它常绿树木形成群落。山茶是孑遗植物,第三纪时胶州湾地区的森林是由落叶阔叶和常绿阔叶树木组成。第四纪冰期后,只在一些水热条件较好的岛屿和陆地的某些小地形上才有残存。从岛屿上山茶分布的现状,可以为研究植物地理,特别是历史植物地理提供丰富的论据。在研究我国植物区系和作为植物资源基因库上,山茶及其群落组成种类也具有重大意义。为繁荣冬季的旅游,野生的山茶群落在一片景色焦枯的北方提供了郁郁葱葱和百花争艳的生态环境。所以保护山东沿海岛屿的野生山茶不仅对于植物科学的研究,而且在改善大地面貌和提高人们的精神生活上,都是很有价值的。     

等离子体增强InAs单量子点荧光辐射的研究

通过测量光致发光(PL)谱、PL时间分辨光谱及不同激发功率下PL发光强度,研究了低温(5 K)下等离子体对InAs单量子点PL光谱的增强效应.采用电子束蒸发镀膜技术在InAs量子点样品表面淀积了5 nm厚度的金膜,形成纳米金岛膜结构.实验发现,金岛膜有利于量子点样品发光强度的增加,最大PL强度增加了约5倍,其主要物理机理是金岛膜纳米结构提高了量子点PL光谱的收集效率.     

Surface‐enhanced Raman scattering from polystyrene on gold clusters

Surface‐enhanced Raman scattering (SERS) constitutes a spectroscopic method of rapidly growing importance, and polystyrene is a widely used compound of great industrial importance. In this work, SERS data were obtained from polystyrene samples prepared by vapor deposition of gold and plasma‐induced polymerization of styrene gas. A thorough examination of this data is presented. The relationships between sample preparation parameters, gold‐cluster morphology, and SERS intensity were elucidated. Using Wilson's notation, vibrations were assigned to all bands between 250 and 1750 cm⁻¹ in the ordinary Raman and SERS spectra of polystyrene. The correct assignment of these bands would be a significant achievement because they have been controversial in the literature for ∼30 years. Our assignments were made by reviewing the literature and comparing the assignments found there to spectral data acquired during this study; they were confirmed using density functional theory (DFT) calculations performed on the styrene monomer. The orientation of polystyrene's phenyl ring, relative to the gold surface, was determined. It has been suggested that reactions involving silver catalyze polystyrene degradation during SERS, but we found that silver is not necessary for the degradation to occur. Copyright © 2009 John Wiley & Sons, Ltd.