Dye-sensitized TiO nanotube membranes act as a visible-light switchable diffusion gate.

Here we report that both-end open anodic TiO nanotube membranes, after sensitization with a Ru(ii)-based dye, exhibit visible-light switching properties for flow-through the nanotube channels. Under illumination, the gate is in an open state providing ∼four-times faster permeation of small molecules through the membrane compared to a dark state. Switching is reversible with no apparent dye degradation being observed.

Synthesis of free-standing TaN nanotube membranes and flow-through visible light photocatalytic applications.

We report on free-standing TaN nanotubular membranes with open top and bottom, used as visible-light-active, flow-through photocatalytic micro-reactors. We grow first a robust anodic TaO layer, lift-off a membrane and convert to TaN. Such membranes can easily, in a flow-through mode, degrade methylene blue under visible light (wavelength >400 nm) or solar illumination.

Fabrication of PEDOT Nanocone Arrays with Electrochemically Modulated Broadband Antireflective Properties.

Ordered nanocone arrays of the electroactive polymer poly(3,4-ethylenedioxythiophene) (PEDOT) were fabricated by the simultaneous oxygen plasma etching of an electrodeposited PEDOT thin film coated with a hexagonally closed packed polystyrene bead monolayer. PEDOT nanocone arrays with an intercone spacing of 200 nm and an average nanocone height of 350 nm exhibited a low broadband reflectivity of <1.5% from 550 to 800 nm.

Aligned metal oxide nanotube arrays: key-aspects of anodic TiO nanotube formation and properties.

Over the past ten years, self-aligned TiO nanotubes have attracted tremendous scientific and technological interest due to their anticipated impact on energy conversion, environment remediation and biocompatibility. In the present manuscript, we review fundamental principles that govern the self-organized initiation of anodic TiO nanotubes. We start with the fundamental question: why is self-organization taking place? We illustrate the inherent key mechanistic aspects that lead to tube growth in various different morphologies, such as ripple-walled tubes, smooth tubes, stacks and bamboo-type tubes, and importantly the formation of double-walled TiO nanotubes versus single-walled tubes, and the drastic difference in their physical and chemical properties.

Single-Walled TiO2 Nanotubes: Enhanced Carrier-Transport Properties by TiCl4 Treatment.

In the present work we report significant enhancement of the photoelectrochemical properties of self- organized TiO2 nanotubes by a combined "de-coring" of classic nanotubes followed by an appropiate TiCl4 treatment. We show that, except for the expected particle decoration, a key effect of the TiCl4 treatment is that the electron transport characteristics in TiO2 nanotubes can be drastically improved, for example, we observe an enhancement of up to 70 % in electron-transport times.

NH₃ treatment of TiO₂ nanotubes: from N-doping to semimetallic conductivity.

In the present work we show that a suitable high temperature ammonia treatment allows for the conversion of single-walled TiO2 nanotube arrays not only to a N-doped photoactive anatase material (which is already well established), but even further into fully functional titanium nitride (TiN) tubular structures that exhibit semimetallic conductivity.

Ultrafast growth of highly ordered anodic TiO2 nanotubes in lactic acid electrolytes.

In the present work, we show that fully functional self-organized TiO(2) nanotube layers can be electrochemically grown with an unprecedented growth rate if lactic acid (LA) is used as an additive during anodization. The main effect of LA addition is that it allows performing nanotube growth at significantly higher anodization voltage than in the LA free case, and this without dielectric oxide breakdown ("burning"). As a result, for example, 15 μm tube thick nanotube layers, suitable for a use in dye-sensitized solar cells (DSSCs) can be grown in 45 s and 7 μm tubes suitable for water splitting can be grown in 25 s.

Efficient and stable panchromatic squaraine dyes for dye-sensitized solar cells.

A new series of stable, unsymmetrical squaraine near-IR sensitizers (JK-216 and JK-217), which are assembled using both thiophenyl pyrrolyl and indolium groups, exhibit a panchromatic light harvesting up to 780 nm. The JK-216 based cell exhibited a record efficiency of 6.29% for near-IR DSSCs.