Exciton diffusion in semiconducting single-wall carbon nanotubes studied by transient absorption microscopy

Spatiotemporal dynamics of excitons in isolated semiconducting single-walled carbon nanotubes are studied using transient absorption microscopy. Differential reflection and transmission of an 810-nm probe pulse after excitation by a 750-nm pump pulse are measured. We observe a bi-exponentially decaying signal with a fast time constant of 0.66 ps and a slower time constant of 2.8 ps. Both constants are independent of the pump fluence. By spatially and temporally resolving the differential reflection, we are able to observe a diffusion of excitons, and measure a diffusion coefficient of 200 cm2/s at room temperature and 300 cm2/s at lower temperatures of 10 K and 150 K.Comment: 6 pages, 4 figure

The renaissance of hybrid solar cells: progresses, challenges, and perspectives

This is the publisher's version, also available electronically from http://pubs.rsc.org/en/Content/ArticleLanding/2013/EE/c3ee23666h#!divAbstractSolution-processed hybrid solar cells, a blend of conjugated polymers and semiconducting nanocrystals, are a promising candidate for next-generation energy-conversion devices. The renaissance of this field in recent years has yielded a much deeper understanding of optoelectronic interactions in organic–inorganic hybrid systems. In this article, we review the state-of-the-art progress in hybrid bulk heterojunction solar cells, covering new materials design, interfacial interaction, and processing control. Furthermore, critical challenges that determine photovoltaic performance and prospects for future directions are discussed

Exciton diffusion in semiconducting single-walled carbon nanotubes studied by transient absorption microscopy

This is the publisher's version, also available electronically from http://journals.aps.org/prb/abstract/10.1103/PhysRevB.86.205417.Spatiotemporal dynamics of excitons in isolated semiconducting single-walled carbon nanotubes are studied using transient absorption microscopy. Differential reflection and transmission of an 810-nm probe pulse after excitation by a 750-nm pump pulse are measured. We observe a biexponentially decaying signal with a fast time constant of 0.66 ps and a slower time constant of 2.8 ps. Both constants are independent of the pump fluence. By spatially and temporally resolving the differential reflection, we are able to observe a diffusion of excitons, and measure a diffusion coefficient of 200±10 cm2/s at room temperature and 300±10 cm2/s at lower temperatures of 10 K and 150 K

Surface-passivated plasmonic nano-pyramids for bulk heterojunction solar cell photocurrent enhancement

This is the published version. ©Copyright 2012 Royal Society of ChemistryWe report that self-assembled gold (Au) nanopyramid arrays can greatly enhance the photocurrent of narrow bandgap organic solar cells using their plasmonic near-field effect. The plasmonic enhanced power conversion efficiency exhibited up to 200% increase under the AM 1.5 solar illumination

Effects of cage vs. net-floor mixed rearing system on goose spleen histomorphology and gene expression profiles

Due to the demands for both environmental protection and modernization of the goose industry in China, the traditional goose waterside rearing systems have been gradually transitioning to the modern intensive dryland rearing ones, such as the net-floor mixed rearing system (MRS) and cage rearing system (CRS). However, the goose immune responses to different dryland rearing systems remain poorly understood. This study aimed to investigate and compare the age-dependent effects of MRS and CRS on the splenic histomorphological characteristics and immune-related genes expression profiles among three economically important goose breeds, including Sichuan White goose (SW), Gang goose (GE), and Landes goose (LD). Morphological analysis revealed that the splenic weight and organ index of SW were higher under CRS than under MRS (p < 0.05). Histological observations showed that for SW and LD, the splenic corpuscle diameter and area as well as trabecular artery diameter were larger under MRS than under CRS at 30 or 43 weeks of age (p < 0.05), while the splenic red pulp area of GE was larger under CRS than under MRS at 43 weeks of age (p < 0.05). Besides, at 43 weeks of age, higher mRNA expression levels of NGF, SPI1, and VEGFA in spleens of SW were observed under MRS than under CRS (p < 0.05), while higher levels of HSPA2 and NGF in spleens of LD were observed under MRS than under CRS (p < 0.05). For GE, there were higher mRNA expression levels of MYD88 in spleens under CRS at 30 weeks of age (p < 0.05). Moreover, our correlation analysis showed that there appeared to be more pronounced positive associations between the splenic histological parameters and expression levels of several key immune-related genes under MRS than under CRS. Therefore, it is speculated that the geese reared under MRS might exhibit enhanced immune functions than those under CRS, particularly for SW and LD. Although these phenotypic differences are assumed to be associated with the age-dependent differential expression profiles of HSPA2, MYD88, NGF, SPI1, and VEGFA in the goose spleen, the underlying regulatory mechanisms await further investigations

Identification of stable reference genes for quantitative gene expression analysis in the duodenum of meat-type ducks

Quantitative polymerase chain reaction (qPCR) is an important method to detect gene expression at the molecular level. The selection of appropriate housekeeping genes is the key to accurately calculating the expression level of target genes and conducting gene function studies. In this study, the expression of eight candidate reference genes, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), beta-actin (β-actin), 18S ribosomal RNA (18S rRNA), hydroxymethylbilane synthase (HMBS), hypoxanthine phosphoribosyltransferase 1 (HPRT1), TATA box binding protein (TBP), ribosomal protein L13 (RPL13), and tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein (YWHAZ), in the duodenal epithelial tissue of 42-day-old meat-type ducks were detected using qPCR. Furthermore, their expression stability was analyzed using the geNorm, NormFinder, and BestKeeper programs. The results indicated that HMBS and YWHAZ were the most stably expressed genes. All three programs indicated that the expression of 18S rRNA was the least stable, making it unsuitable for the study of gene expression in meat-type duck tissues. This study provides stable reference genes for gene expression analysis and contributes to further studies on the gene function of meat-type ducks

Ultrathin Gold Nanowire-Functionalized Carbon Nanotubes for Hybrid Molecular Sensing

Carbon nanotubes (CNTs) have shown great potential as sensing component in the electrochemical, field effect transistor and optical sensors, because of their extraordinary onedimensional electronic structure, thermal conductivity, tunable and stable near-infrared emission. However, the insolubility of CNTs due to strong van der Waals interactions limits their use in the field of nanotechnology. In this study, we demonstrate that non-covalent ultrathin gold nanowires functionalized multi-walled carbon nanotube (GNW-CNT) hybrid sensing agents show highly efficient and selective immune molecular sensing in electrochemical and near-infrared photoacoustic imaging methods. A detection limit of 0.01 ng/mL for the Alpha-Fetoprotein (AFP) antigen with high selectivity is shown. The extraordinary optical absorption, thermal and electric conductivity of hybrid GNW-CNTs presented in this study could be an effective tactic to integrate imaging, sensing and treatment functionalities

The renaissance of hybrid solar cells : progresses, challenges, and perspectives

Solution-processed hybrid solar cells, a blend of conjugated polymers and semiconducting nanocrystals, are a promising candidate for next-generation energy-conversion devices. The renaissance of this field in recent years has yielded a much deeper understanding of optoelectronic interactions in organic–inorganic hybrid systems. In this article, we review the state-of-the-art progress in hybrid bulk heterojunction solar cells, covering new materials design, interfacial interaction, and processing control. Furthermore, critical challenges that determine photovoltaic performance and prospects for future directions are discussed