Erratum: Highly efficient blue photoluminescence from colloidal lead-iodide nanoparticles:(Journal of Physics D: Applied Physics (2006) 39 (1477-80))

In a recent paper (Finlayson C E and Sazio P J A 2006 J. Phys. D: Appl. Phys. 39 1477–80) we reported on the properties of colloidal lead (II) iodide nanoparticles, synthesized via a route using coordinating solvents. Our samples were characterized as having highly efficient and photostable photoluminescence in the blue region of the visible spectrum. Subsequent experiments show the observed behaviour of these nanoparticles during nucleation and ripening to be more complicated than originally reported and we believe that the observed photoluminescence may be related to extraneous factors, beyond the experimental methods as previously described

Highly efficient blue photoluminescence from colloidal lead-iodide nanoparticles

We report the synthesis of solvent-stabilized lead-iodide nanoparticles, using a convenient route involving coordinating solvents. The resultant colloids show strong absorption features in the ultraviolet region of the optical spectrum, which are consistent with the formation of semiconducting nanocrystals of lead (II) iodide. An effective-mass approximation model of quantum-confined states is in good agreement with the observed transition energies, giving strong indications of the particle morphologies and dimensions. Intense photoluminescence is also observed, with some spectral tuning possible with ripening time, giving a range of emission photon energies approximately spanning from 2.5 to 3.0 eV. We measure photo-stable luminescence quantum efficiencies of around 20% in solution, increasing to up to 30% if the coordinating ligand is exchanged for a Lewis-base capping layer. This demonstrates the potential for the utilization of lead-iodide nanocrystals in visible optoelectronics applications

Whispering gallery mode emission at telecommunications-window wavelengths using PbSe nanocrystals attached to photonic beads

We report the selective chemical attachment of infrared emitting PbSe nanocrystal quantum dots onto micron-scale glass photonic beads. Upon optical excitation, photoluminescence from the shell of nanocrystals is seen to couple into the high-Q 'whispering gallery' modes of the bead via the evanescent optical field, resulting in a series of sharp peaks being observed at wavelengths of around 1550 nm. Theoretical modelling gives a close agreement with the data for angular modes corresponding to l ~ 120. This work demonstrates the potential of narrow-bandgap II–VI semiconductor nanocrystals for use in a wide range of telecommunications-window photonics applications

Combining photocatalysis and optical fibre technology towards improved microreactor design for hydrogen generation with metallic nanoparticles

The use of solar energy to activate chemical pathways in a sustainable manner drives the development in photocatalysis. While catalyst optimization is a major theme in this pursuit, the development of novel photocatalytic reactors to enhance productivity is also imperative. In this work we combine, for the first time, microstructured optical fiber technology with photocatalysis, creating a photocatalytic microreactor coated with TiO2, decorated with palladium nanoparticles. In doing so, we create a system capable of effectively combining photons, liquids, and gases within a monolithic, highly confined, transparent silica geometry. We utilize a range of characterization techniques to selectively focus on the photocatalyst, that resides exclusively within the internal capillaries of this system. In doing so, we validate our design approach and demonstrate the ability to simultaneously control both nanoparticle size and metal content. Further, we justify our unique design, showing its activity in photocatalytic hydrogen generation from water. In doing so highlights the importance in developing light propagation properties from optical fibers and the significant potential of this technology in the expansive photocatalysis landscape. </p

Microstructured optical fibre semiconductor metamaterials

Microstructured optical fibres are single material optical fibres in which air-holes define the transverse structural profile. MOFs demonstrate a number of key properties when compared with conventional silica fibres, including broad band single mode guidance, nonlinear properties, and photonic band gap effects. The inclusion of materials such as semiconductors, metals or polymers within the microscale or nanoscale holes of MOFs presents radically novel electronic, photonic and plasmonic degrees of freedom for the exploration of new directions in metamaterials technology. This allows the design of complex optical fibre devices with exceptional tuneable properties. Furthermore, the inclusion of semiconductors to nanoscale MOFs holes will bring together fibre optics technology with the growing field of ultra small semiconductor nanowires for the generation and manipulation of light

Fabrication of extreme aspect ratio wires within photonic crystal fibers

We have recently fabricated continuous semiconducting micro and nanowires within the empty spaces of highly ordered microstructured (e.g., photonic crystal or holey) optical fibers (MOFs). These systems contain the highest aspect ratio semiconductor micro- and nanowires yet produced by any method: centimeters long and ~100 nm in diameter. These structures combine the flexible light guiding capabilities of an optical fiber with the electronic and optical functionalities of semiconductors and have many potential applications for in-fiber sensing, including in-fiber detection, modulation, and generation of light