Suitable labels are at the core of Luminescence and fluorescence imaging and sensing. One of the most exciting, yet also controversial, advances in label technology is the emerging development of quantum dots (QDs)--inorganic nanocrystals with unique optical and chemical properties but complicated surface chemistry--as in vitro and in vivo fluorophores. Here we compare and evaluate the differences in physicochemical properties of common fluorescent labels, focusing on traditional organic dyes and QDs. Our aim is to provide a better understanding of the advantages and limitations of both classes of chromophores, to facilitate label choice and to address future challenges in the rational design and manipulation of QD labels.

International audienceElectrospinning is attracting close interest as a versatile fabrication method for one dimensional mesostructured organic, inorganic and hybrid nanomaterials of controlled dimensions prepared as randomly oriented or oriented continuous nanofibres that can present internal compositional organisation such as core-sheath, hollow or porous fibre, or even multichannel microtube arrangements. The dimensionality, directionality and compositional flexibility of electrospun nanofibres and mats are increasing being investigated for the targeted development of electrode and electrolyte materials. Specific properties associated with the nano-scale features such high surface to volume and aspect ratios, low density and high pore volume allow performance improvements in energy conversion and storage devices. We review here the application of electrospinning for designing architectured nanofibre materials for dye sensitised solar cells, fuel cells, lithium ion batteries and supercapacitors, with particular emphasis on improved energy and power density imparted by performance improvement to, inter alia, ionic conductivity, cyclability, reversibility, interfacial resistance and electrochemical stability, as well as mechanical strength, of electrospun electrode and electrolyte components

Niobium doped nanofibers elaborated by facile, single-step electrospinning present higher rate capability in electrochemical cycling experiments than non-doped materials. This is attributed to the reduction of Li + diffusion path lengths and enhanced intimate inter-particle contact, in combination with improved intra-particle conductivity. Niobium doping has a significant effect on the electronic structure and provokes a substantial decrease in particle size.