The extension of in vivo optical imaging for disease screening and image-guided surgical interventions requires brightly-emitting, tissue-specific materials that optically transmit through living tissue and can be imaged with portable systems that display data in real-time. Recent work suggests that a new window across the short wavelength infrared region can improve in vivo imaging sensitivity over near infrared light. Here we report on the first evidence of multispectral, real-time short wavelength infrared imaging offering anatomical resolution using brightly-emitting rare-earth nanomaterials and demonstrate their applicability toward disease-targeted imaging. Inorganic-protein nanocomposites of rare-earth nanomaterials with human serum albumin facilitated systemic biodistribution of the rare-earth nanomaterials resulting in the increased accumulation and retention in tumor tissue that was visualized by the localized enhancement of infrared signal intensity. Our findings lay the groundwork for a new generation of versatile, biomedical nanomaterials that can advance disease monitoring based on a pioneering infrared imaging technique.

Conjugated polymer materials are at the forefront of many next-generation organic optoelectronic technologies including organic light-emitting diodes, photovoltaics and lasers. The photophysical properties of these materials can be controlled and optimized through the formation of nanoscaleconfined geometries such as nanoparticles, aggregates, nanofibers, or thin films. In this review, we discuss the photonic characteristics of conjugated polymer-based nanostructured materials and devices with a focus on how excitons and photons can be manipulated and managed though confinement of polymer chains and through interactions with inorganic nanostructures. We include case studies from the literature on how internal molecular morphology can be controlled in conjugated polymer thin-film optoelectronics, nanowires and nanofibers and, in turn, how internal morphology affects the photonic properties of these structures. Extrinsic approaches to controlling or modifying the photonic properties of conjugated polymer materials and devices through the addition of inorganic photonic nanostructures are also discussed.

Ln(SePh) 3 (Ln ) Ce, Pr, Nd) reacts with elemental Se in the presence of Na ions to give (py) 16 Ln 17 NaSe 18 (SePh) 16 , a spherical cluster with a 1 nm diameter. All three rare-earth metals form isostructural products. The molecular structure contains a central Ln ion surrounded by eight five-coordinate Se 2that are then surrounded by a group of 16 Ln that define the cluster surface, with additional µ 3 and µ 5 Se 2-, µ 3 and µ 4 SePh -, and pyridine donors saturating the vacant coordination sites of the surface Ln, and a Na ion coordinating to selenolates, a selenido, and pyridine ligands. NIR emission studies of the Nd compound reveal that this material has a 35% quantum efficiency, with four transitions from the excited state 4 F 3/2 ion to 4 I 9/2 , 4 I 11/2 , 4 I 13/2 , and 4 I 15/2 states clearly evident. The presence of Na + is key to the formation of these larger clusters, where reactions using identical concentrations of Nd(SePh) 3 and Se with either Li or K led only to the isolation of (py) 8 Nd 8 Se 6 (SePh) 12 .

Gold nanotube arrays are synthesized with a range of wall thicknesses (15 to >140 nm) and inner diameters of ∼200 nm using a hard-template method. A red spectral shift (>0.39 eV) with decreasing wall thickness is observed in dark-field spectra of nanotube arrays and single nanowire/nanotube heterostructures. Finite-difference-timedomain simulations show that nanotubes in this size regime support propagating surface plasmon modes as well as surface plasmon ring resonances at visible wavelengths (the latter is observed only for excitation directions normal to the nanotube long axis with transverse polarization). The energy of the surface plasmon modes decreases with decreasing wall thickness and is attributed to an increase in mode coupling between propagating modes in the nanotube core and outer surface and the circumference dependence of ring resonances. Surface plasmon mode propagation lengths for thicker-walled tubes increase by a factor of ∼2 at longer wavelengths (>700 nm), where ohmic losses in the metal are low, but thinner-walled tubes (30 nm) exhibit a more significant increase in surface plasmon propagation length (by a factor of more than four) at longer wavelengths. Additionally, nanotubes in this size regime support a photonic mode in their core, which does not change in energy with changing wall thickness. However, photonic mode propagation length is found to decrease for optically thin walls. Finally, correlations are made between the experimentally observed changes in dark-field spectra and the changes in surface plasmon mode properties observed in simulations for the various gold nanotube wall thicknesses and excitation conditions.