Degrees Of Doping Research Articles

Short Notice: Metal-insulator transition in single crystals Y1−zPrzBa2Cu3O7−δ

The aim was to conduct comparative studies of the evolution of conductivity along and across the base ab plane in Y1−zPrzBa2Cu3O7−δ single crystals at different degrees of praseodymium doping in a wide range of concentrations 0≤z≤0.5. It is established that the increase in the degree of praseodymium doping in samples Y1−zPrzBa2Cu3O7−δ leads to increased effects of localization and implementation in the system of metal–insulator type transition, which always precedes the superconducting transition. Increasing the concentration of praseodymium leads to a significant shift in the beginning of the metal–insulator transition at the low temperature region.

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The electrical characteristics of thin films formed from Si nanoparticles (nc-Si) with various degrees of doping are studied. To exclude the influence of ionic conductivity, the current parameters of the films were recorded in an ultrahigh vacuum (P ~ 3 – 5∙10–9 Torr) with preliminary high-temperature (9500C) annealing. An analysis of the temperature dependences of the conductivity showed that in nc-Si films formed from heavily doped nanoparticles (the concentration of free electrons ne is greater than 1019 cm-3), the transport is determined by variable-length hopping (VRH). In these samples, the Mott conductivity prevails at temperatures above 300C and at lower temperatures, the Efros-Shklovskii type variable range hopping conduction is dominate. In films with a medium level of doping of nanoparticles (ne <1019 cm-3), transport is realized by the Mott, Efros - Shklovskii and thermally activated conductivities. At the same time, thermally activated conductivity is dominated at temperatures above 560K. In nc-Si films formed from undoped nanoparticles, the transport parameters are determined by thermally activated conductivity and Mott's conductivity. Conductivity of Efros - Shklovskii is not observed in such films. From the analysis of the parameters corresponding to the Mott and Efros - Shklovsky conductivities, the localization lengths of wave functions, the density of states at the Fermi level (g (EF)), and average hopping lengths are found. The average hopping lengths in nc-Si films from nanoparticles pre-etched in HF are in the range 56 - 86 nm, which indicates that hopping in such films occurs via intermediate nanoparticles.

Прыжковая проводимость Мотта и Эфроса-Шкловского в пленках из наночастц Si, легированных фосфором и бором

The electrical characteristics of thin films formed from Si nanoparticles (nc-Si) with various degrees of doping are studied. To exclude the influence of ionic conductivity, the current parameters of the films were recorded in an ultrahigh vacuum (P ~ 3 – 5∙10–9 Torr) with preliminary high-temperature (9500C) annealing. An analysis of the temperature dependences of the conductivity showed that in nc-Si films formed from heavily doped nanoparticles (the concentration of free electrons ne is greater than 1019 cm-3), the transport is determined by variable-length hopping (VRH). In these samples, the Mott conductivity prevails at temperatures above 300C and at lower temperatures, the Efros-Shklovskii type variable range hopping conduction is dominate. In films with a medium level of doping of nanoparticles (ne <1019 cm-3), transport is realized by the Mott, Efros - Shklovskii and thermally activated conductivities. At the same time, thermally activated conductivity is dominated at temperatures above 560K. In nc-Si films formed from undoped nanoparticles, the transport parameters are determined by thermally activated conductivity and Mott's conductivity. Conductivity of Efros - Shklovskii is not observed in such films. From the analysis of the parameters corresponding to the Mott and Efros - Shklovsky conductivities, the localization lengths of wave functions, the density of states at the Fermi level (g (EF)), and average hopping lengths are found. The average hopping lengths in nc-Si films from nanoparticles pre-etched in HF are in the range 56 - 86 nm, which indicates that hopping in such films occurs via intermediate nanoparticles.

Thermodynamic and Structural Modelling of Non-Stoichiometric Ln-Doped UO2 Solid Solutions, Ln = {La, Pr, Nd, Gd}.

Available data on the dependence of the equilibrium chemical potential of oxygen on degrees of doping, z, and non-stoichiometry, x, y, in U1-z Ln z O2+0.5(x-y) fluorite solid solutions and data on the dependence of the lattice parameter, a, on the same variables are combined within a unified structural-thermodynamic model. The thermodynamic model fits experimental isotherms of the oxygen potential under the assumptions of a non-ideal mixing of the endmembers, UO2, UO2.5, UO1.5, LnO1.5, and Ln 0.5U0.5O2, and of a significant reduction in the configurational entropy arising from short-range ordering (SRO) within cation-anion distributions. The structural model further investigates the SRO in terms of constraints on admissible values of cation coordination numbers and, building on these constraints, fits the lattice parameter as a function of z, y, and x. Linking together the thermodynamic and structural models allows predicting the lattice parameter as a function of z, T and the oxygen partial pressure. The model elucidates contrasting structural and thermodynamic changes due to the doping with LaO1.5, on the one hand, and with NdO1.5 and GdO1.5, on the other hand. An increased oxidation resistance in the case of Gd and Nd is attributed to strain effects caused by the lattice contraction due to the doping and to an increased thermodynamic cost of a further contraction required by the oxidation.

B/N-doped carbon sheets from a new ionic liquid with excellent sorption properties for methylene blue

The pyrolytic treatment of the novel ionic liquid 1-ethyl-3-methyl-imidazolium tetrakis-(1-imidazolyl)borate ([EMIM][BIm4]) allowed the preparation of B/N-doped carbonaceous materials with an exceptional performance in the adsorptive removal of the cationic dye methylene blue (MB) from wastewater. [EMIM][BIm4] was prepared via an easy and scalable synthesis protocol in very good yield. The carbon materials obtained after salt templated pyrolysis of the IL displayed high degrees of heteroatom doping (up to 22 wt% N, 3 wt% B) and high surface areas of up to 1860 m2 g−1. The materials were tested for their performance in the adsorptive removal of MB from contaminated water. Adsorption equilibrium experiments revealed an adsorption capacity exceeding500 mg g−1, which is, to the best of our knowledge, the highest value reported so far. Time-resolved adsorption experiments showed that the materials not only exhibit high capacity but also very fast adsorption kinetics. Complete decolorization of MB solutions in only 5 min at high MB concentrations of 100 mg L−1 was observed. These results demonstrate that [EMIM][BIm4] is an excellent precursor for the preparation of IL-derived B/N-doped carbon sorbents.

Nitrogen-Doped Carbon Nanotubes as an Effective Support of Heterogeneous Catalysts for Selective Alkene Oxidation

Nitrogen-doped carbon nanotubes (N-CNTs) with different degrees of nitrogen doping were synthesized. The effects of nitrogen in the N-CNTs on the hydrophilic–hydrophobic properties of carbon nanotubes and their activity in the decomposition of Н2О2 were studied. Various approaches to the surface modification of N-CNTs by alkyl groups were studied, and the high resistance of N-CNTs to alkylation was found. Heterogeneous catalysts based on the polyoxometallate [PO4{WO(O2)2}4]3– and N-CNTs with a low degree of nitrogen doping (≤1.8 at %) were successfully synthesized. The high efficiency of the catalysts in the liquid-phase reactions of selective oxidation of alkenes using H2O2 as a green oxidizer was found, and the heterogeneous nature of catalysis was confirmed.

(Invited) Exploring Sodium Layered Oxide Cathodes: Designing Tailored Materials

Interest in developing energy storage systems to meet a wide array of future challenges has driven research into a range of new battery technologies. Sodium-ion batteries (SIBs) have proven to be particularly popular due to their attractive properties and broad range of potential applications. However, before SIBs take their place in the pantheon of battery technologies, there still remain challenges to overcome - perhaps the most significant of which is the ongoing development of optimal cathode materials.Sodium Mn-rich layered oxides, i.e. NaxMn1-yMyO2 (y ≤ 0.33; M is one or more transition metals, such as Ni, Ti, Fe, etc.), have proven to be a promising family of SIB cathode materials with a low cost, highly tuneable, and environmentally friendly nature synergises well with the main advantages of SIBs.[1] Considerable research in this area, using a variety of conventional and specialised techniques, has led to an increased understanding of the nature and behaviour of these materials, and the key factors affecting their electrochemistry.[1-4]Performance of these materials is frequently governed by their structure, and in this work, we will highlight the importance of taking this into consideration. For example, while Manganese-rich layered oxides are particularly attractive due to their combination of low cost and low toxicity, their performances are often hindered by the effect of Jahn-Teller distortion (resulting from the presence of Mn3+).[5] We will not only discuss this in detail, but also highlight mitigation strategies – such as doping with electrochemically active (e.g. Fe) and inactive (e.g. Mg, Ti) elements, or synergetic P2/O3 combination effect.[5–8] This understanding has enabled the rapid investigation of not only suitable elements (selected with careful attention to electrochemical performance, cost, scarcity, etc.) but also appropriate degrees of doping and substitution.In this presentation, we will highlight some of the most significant Mn-rich materials and their properties, as well as examining and explaining the key parameters and factors which determine their performance. We will explain how this understanding has been used to develop a rational design approach, before summarising the trends in this area and areas of future exploitation.

Effects of Counter‐Ion Size on Delocalization of Carriers and Stability of Doped Semiconducting Polymers

AbstractSince doped polymers require a charge‐neutralizing counter‐ion to maintain charge neutrality, tailored and high degrees of doping in organic semiconductors requires an understanding of the coupling between ionic and electronic carrier motion. A method of counter‐ion exchange is utilized using the polymeric semiconductor poly[2,5‐bis(3‐tetradecylthiophen‐2‐yl)thieno[3,2‐b]thiophene] ‐C14 to deconvolute the effects of ionic/polaronic interactions with the electrical properties of doped semiconducting polymers. In particular, exchanging the counter‐ions of the dopant nitrosonium hexafluorophosphate enables investigation into the role of counter‐ion size from 5.2 to 8.2 Å in diameter. The orientational order of the polymeric crystallites is not affected with this exchange process while effectively modifying the counter‐ion distance to the charge carrier. Doped films have electrical conductivities of 320 S cm−1 and are not sensitive to an increased ion‐polaron distance. It is posited that other factors dominate the electrical properties at a device scale, such as the morphology and presence of domain boundaries. Interestingly, the temperature stability of the doped film can be drastically improved with the use of counter‐ions containing less labile bonds. This platform serves as a unique way to retain the morphology of polymeric thin films while studying charge interactions at the local scale.

Глубокая рентгеновская рефлектометрия сверхмногопериодных A3B5-структур с квантовыми ямами, выращиваемых методом молекулярно-пучковой эпитаксии

We studied the elastically strained AlGaAs/GaAs super-multiperiod (SMP – 100–1000 periods) superlattices with different degrees of doping and a small difference in the period thickness. The proposed characterization technique, consisting of the matched application of the deep X-ray reflectometry method, based on a rigorous calculation method, as well as the well-known high-resolution X-ray reflectometry method, made it possible to study 100-period structures with 2-nm wide Al0.3Ga0.7As barriers and 10-nm wide GaAs wells and to determine the layer thicknesses and the blurring of interfaces with high accuracy. It can be considered as the first step in the further analysis of thick structures using bright sources of synchrotron radiation. The difference between the expected and obtained, as a result of restoration by the proposed method, values of the layer thicknesses was several percent, including for samples with a high degree of doping (up to 10^18 cm^−3). All SMP structures are characterized by sharp interfaces with a standard deviation of the order of 0.1 nm. Based on the thickness data obtained, it is possible to accurately determine the composition of the layers using high-resolution X-ray diffractometry.

Microwave properties of aluminum-substituted barium hexaferrite BaFe12-xAlxO19 ceramics in the frequency range of 32–50 GHz

The paper describes the method for obtaining barium hexaferrite with different degrees of aluminum doping. Samples were obtained in the form of powder. The composition of the samples was confirmed by the X-ray test results. A method of measuring the electrodynamic parameters of material samples in the frequency range of 32–50 GHz using waveguide transmission line is described. The values of the real and imaginary parts of permittivity and permeability, based on the measured S-parameters, are obtained using the Nicolson-Ross-Weir method. The behavior of the calculated dependences of the electrodynamic parameters on frequency is explained by the influence of dipole, resonant, and electronic polarization.

A multiphase BiVO4 with the potential of being an environmental photocatalyst

Novel Y3+ and Mo6+ dual-doped, multiphased BiVO4 nanoparticles (NPs) were synthesised using a modified hydrothermal method through a gradient doping method. Yttrium (III) was used as a phase-stabilising agent for the tetragonal phase, while Mo6+ was used to control the volume of the crystals. The NPs were characterised using SEM, TEM, PL, FTIR, XRD, and BET to determine crystal phase, morphology, and surface area. It was found that the introduction of the dopants and formation of the phase junction lead to diminished PL spectra indicative of reduced electron–hole recombination. The 10% (m–m) Y–Mo dual-doped multiphased BiVO4 NPs have the highest electron–hole separation efficiency. However, 15% (m–m) Y–Mo had the least charge separation due to the formation of recombination centres at high degrees of metal doping. The multiphased systems also showed a red shift in the UV–Vis absorption spectrum. The Mott–Schottky plot obtained from electroimpedance spectroscopy confirmed the formation of a phase junction in the multiphased systems which resulted in an improvement of the photocurrent to twice that of the intrinsic BiVO4 NPs for the 10% Y–Mo BiVO4 NPs. The photocurrent for 10% Y–Mo was 0.025 A cm−2, while that of the intrinsic BiVO4 NPs was about 0.014 A cm−2. This increase in photocurrent proves the improvement of charge separation. BET results showed that surface area increased with an increase in the degree of doping and that the 10% Y–Mo dual-doped BiVO4 nanomaterials had a surface area of 9.009 m2/g. The 10% Y–Mo dual-doped BiVO4 reached 99.1% Cr6+ removal in 60 min.

Low‐Cost Catalysts for the Water Gas Shift Reaction Based on Cu–Ni on La‐Promoted Ceria

Proton‐exchange membrane fuel cells are of great interest for vehicular applications. A highly pure, sustainably obtained H2 stream is desirable to use as the cell feed. In the water gas shift (WGS) process, large amounts of CO, which is a poison for the cell anode, are removed from a bioalcohol‐derived H2 stream before it enters the cell. In this study, Cu–Ni catalysts supported on La‐doped ceria were analyzed and studied in the WGS reaction. The supports were prepared by the urea thermal decomposition method with different percentages of La as a promoter of ceria. The metal phase was incorporated by incipient wet impregnation. Many characterization techniques were employed in this work (BET, XRD, SEM, ICP, TPR, OSC), and the relationship between the resulting properties and catalytic performance was investigated to determine the effect of La. A mixture of Cu and Ni was found to be the most effective active phase, having considerable activity and selectivity towards the desired reaction. Low degrees of La doping in ceria enhance oxygen mobility in the lattice. A commercial Ce salt containing La as its main impurity (ca. 2 %) is a convenient precursor, given its good performance and low cost compared to a high‐purity salt.

Directing the Aggregation of Native Polythiophene during in Situ Polymerization.

The performance of semiconducting polymers strongly depends on their intra- and intermolecular electronic interactions. Therefore, the morphology and particularly crystallinity and crystal structure play a crucial role in enabling a sufficient overlap between the orbitals of neighboring polymers. A new solution-based in situ polymerization for the fabrication of native polythiophene thin films is presented, which exploits the film formation process to influence the polymer crystal structure in the resulting thin films. The synthesis of the insoluble polythiophene is based on an oxidative reaction in which the oxidizing agent, iron(III) p-toluenesulfonate (FeTos), initially oxidizes the monomers to enable the polymer chain growth and secondly the final polymers, thereby chemically doping the polythiophene. To exploit the fact that the doped polythiophene has a different crystal packing structure compared to the undoped polythiophene, we investigate the structural effect of this inherent doping process by varying the amounts of FeTos in the reaction mixture, creating polythiophene thin films with different degrees of doping. The structural investigation performed by means of grazing incidence wide-angle X-ray scattering (GIWAXS) suggests that the strongly doped polymer chains aggregate in a π-stacked manner in the film formation process. Moreover, this π-stacking can be maintained after the removal of the dopant molecules. GIWAXS measurements, molecular dynamics simulations, and spectroscopic analysis suggest the presence of polythiophene in a novel and stable crystal structure with an enhanced intermolecular interaction.

Improved photovoltaic performance of quantum dot-sensitized solar cells based on highly electrocatalytic Ca-doped CuS counter electrodes

Herein we report the fabrication of highly efficient Ca-doped CuS counter electrodes (CEs) in order to modify the photovoltaic characteristics of quantum dot-sensitized solar cells (QDSSCs). CuS CEs with different degrees of Ca doping are deposited on fluorine-doped tin oxide (FTO) coated glass surfaces via the widely adopted chemical bath deposition (CBD) method and used directly as CEs for TiO2/CdS/CdSe/ZnS photoelectrode based QDSSCs. The results indicate that the QDSSCs incorporating 20% Ca-doped CuS CEs exhibit an excellent conversion efficiency (η) of 4.92%, short circuit current density (Jsc) of 15.47 mA cm−2, open circuit photovoltage (Voc) of 0.611 V, and fill factor (FF) of 0.521 under illumination of one sun (AM 1.5, 100 mW cm−2). These values are significantly higher than those obtained for QDSSCs incorporating bare CuS CEs (η = 3.51%, Jsc = 12.03 mA cm−2, Voc = 0.596 V, FF = 0.490) under similar conditions. The improved surface morphology of Ca-doped CuS materials offers more active sites for the catalytic reactions and an improved pathway for fast charge transport and a lower electron recombination rate for the electrolyte redox couple. The film thickness, elemental composition, crystallographic phase, surface topography, and chemical bond configurations of Ca-doped CuS CEs were characterized by scanning electron microscopy, inductively coupled plasma – atomic emission spectrometry, energy dispersive X-ray analysis, X-ray diffraction, atomic force microscopy, and X-ray photoelectron spectroscopy analysis. More importantly, impedance spectroscopy analysis and Tafel polarization curves indicate that Ca-doping on CuS CEs reduces charge transfer resistance and leads to high and consistent catalytic activity for the reduction of polysulfide electrolyte. This study demonstrates that an appropriate amount of Ca-doping of CuS CEs is an effective method of enhancing the performance of QDSSCs.

Scattering of Electromagnetic Radiation by ITO Nanoparticles with Various Doping Levels

The process of scattering of radiation by indium‒tin oxide (ITO) nanoparticles is theoretically studied at various degrees of doping and for different radii of nanoparticles. Qualitative conclusions are made about the character of the dependence of the scattering cross section on the frequency with variation of the particle size and the percentage content of tin. The prospects of using ITO nanoparticles as an active substance in optical sensors are estimated.

Numerical modelling of doped graphane superconducting and normal properties

The normal properties of graphane with various degrees of doping are calculated with the help of the generalized Eliashberg theory. Within the theory of strong electron-phonon interaction, a superconducting order parameter of the doped graphane has been found. The critical temperature of superconductivity of graphane has been calculated as a function of the doping degree taking into account the renormalization of the electron mass, the chemical potential, and the density of electronic states.

Regularities of oxygen and water thermal desorption from barium cerate doped by neodymium, samarium, and gadolinium

Processes of thermal desorption of oxygen molecules and water from BaCe1–x M x O3–δ, where M= Nd, Sm, and Gd, presintered in air at the temperature of 650°C are studied. It is found that oxygen is desorbed only from neodymium–doped barium cerate and is almost not evolved from barium cerate doped by samarium and gadolinium. The amount of desorbed oxygen features a square dependence on cationic doping by neodymium. At similar degrees of cationic doping, the amount of water desorbed from neodymium–doped barium cerate is always lower than that from the cerate doped by samarium and gadolinium. The obtained experimental data on thermal desorption and analysis of literature data served as a basis for the conclusion as to the mixed valency of neodymium Nd(III)–Nd(IV) in BaCe1–x Nd x O3–δ. In this case, at similar doping degrees x, the hydration degree of BaCe1–x Nd x O3–δ is lower and the oxygen index is higher than in BaCe1–x (Sm,Gd) x O3–δ. The differences become more pronounced at high degrees of cationic doping and must decrease at an increase in temperature.

Novel nitrogen-doped anatase TiO2 mesoporous bead photocatalysts for enhanced visible light response

Abstract This work reports the synthesis and characterization of a novel, high surface area N-doped anatase TiO 2 mesoporous bead as a photocatalyst for visible light photodegradation. The beads were prepared using a two-cycle microwave-assisted hydrothermal method using three different types of nitrogen dopants: diaminohexane, triethylamine, and urea. In the first cycle, TiO 2 mesoporous beads with controlled structures were synthesized at 200 °C without further calcination. The obtained beads were then subjected to a second cycle of microwave -assisted hydrothermal process for nitrogen doping. The photocatalytic activity of the N-doped mesoporous TiO 2 beads was determined by measuring the decomposition of a methyl blue aqueous solution under UV and visible light. It was found that different precursors lead to different degrees of doping which enhances the light absorption primarily in the visible light region. We demonstrate that the photocatalytic activity or photodegradation is enhanced in the visible light region.

First-Principles Analysis of Oxygen Incorporation into Sr(Ti1-xFex)O3-D : Using External Dopants to Tune the Incorporation Mechanism

Although solid oxide fuel cells have been under intensive investigation for several decades, their practical development is hindered still by several fundamental challenges. One in particular is related to the kinetics of the electrode reactions, especially with respect to oxygen exchange at the cathode. Oxygen exchange requires chemisorption, dissociation, and incorporation, and can involve a complicated set of competing processes: for example, it may occur through directly via gas phase oxygen interaction with a surface vacancy through an active site-mediated mechanism, or it may occur directly onto a pristine surface with vacancies in the interior serving only as the final sink for the incorporated oxygen species. Often, resolving the rates of the relevant processes is challenging. The material Sr(Ti1-xFex)O3- d(STF) is a model system for the study of oxygen exchange mechanisms on electrodes of solid oxide electrodes. The perovskite material is stable in a wide range of oxygen partial pressures, and exhibits a flexible defect chemistry and electronic structure. The B-site substitution of Ti for Fe results in fast oxygen exchange kinetics. Even so, there remain several questions about the rate limiting steps to oxygen exchange in these materials, with contradictory suggestions that oxygen incorporation is limited by either electron transfer to the adsorbed molecules at the electrode surface or by the vacancy concentration at the surface. In this work, we will present the results of our first-principles calculations to provide some clues to the nature of oxygen incorporation in STF. We use density functional theory to consider several incorporation mechanisms under different environmental conditions. In particular, we consider how the presence of external dopants (eg A-site doping with La) might allow access to different ranges of oxygen vacancy concentrations and carrier concentrations in the material. We will show (i) the results of a defect chemistry equilibrium model to calculate the equilibrium defect concentrations and carrier concentrations in different chemical environments and under different degrees of extrinsic doping, and (ii) the reaction mechanism for oxygen molecule adsorption at the surface for different degrees of doping. The defect chemistry model shows that the concentration of oxygen vacancies and the Fermi level of the material can be tuned by the incorporation of external dopants. Further, according to our simulations, we predict that the most favorable pathway for oxygen incorporation can be controllably changed from an active-site mediated mechanism to a direct adsorption mechanism by appropriately tuning the dopant concentration.

Hydrazine-based synergistic Ti(III)/N doping of surfactant-templated TiO2 thin films for enhanced visible light photocatalysis

This study reports the preparation of titanium (Ti3+) and nitrogen co-doped cubic ordered mesoporous TiO2 thin films using N2H4 treatment. The resulting co-doped TiO2 (Ti3+-N-TiO2) thin films show significant enhancements in visible light absorption and photocatalytic activity. Cubic ordered mesoporous TiO2 thin films were prepared via a sol-gel method with Pluronic F127 as the pore template. After brief calcination, the TiO2 films were dipped into hydrazine hydrate which acts both as a nitrogen source and as a reducing agent, followed by heating at low temperature (90 °C). The hydrazine treatment period was varied from 5 to 20 h to obtain different degrees of reduction and nitrogen doping. X-ray photoelectron spectroscopy (XPS) analyses and UV–vis absorbance spectra of Ti3+-N-TiO2 films indicate that the incorporated N atoms and Ti3+ reduce the band gap of TiO2 and thus enhance the absorption of visible light. The corresponding visible light photocatalytic activity of Ti3+-N-TiO2 films was determined from the photocatalytic degradation of methylene blue under visible light illumination (at 455 nm). The Ti3+-N-TiO2 films prepared with 10 h of treatment show the optimum photocatalytic activity, with a pseudo-first order rate coefficient of 0.12 h−1, which is 3 times greater than that of undoped TiO2 films. Calcination temperature and time were varied prior to hydrazine treatment to confirm that a brief calcination at low temperature (10 min at 350 °C) gave the best photochemical activity. In photoelectrochemical water oxidation using a 455 nm LED, the Ti3+-N-TiO2 films prepared with 10 h of N2H4 treatment show about 4 times the photocurrent compared to undoped TiO2 films. The present study suggests that hydrazine induced doping is a promising approach to enable synergistic incorporation of N and Ti3+ into the lattice of surfactant-templated TiO2 films and enhanced visible light photoactivity, but that the benefits are limited by gradual mesostructure deterioration.