High-performance and self-powered visible light photodetector using multiple coupled synergetic effects.

In this work, we demonstrate, for the first time, that coupling together the pyroelectric effect, the photovoltaic effect and the plasmonic effect is a novel method to significantly enhance the performance of self-powered photodetectors in the visible region. Photodetectors based on tri-layered heterojunction of n-Si/p-SnO/n-ZnO through the inclusion of silver (Ag) nanoparticles (NPs) at the SnO/ZnO interface were fabricated. The photo-response of the device, with excitation from a chopped 650 nm wavelength laser, was carefully investigated, and it was shown that the photodetector performance is enhanced the most with the inclusion of spheroidal Ag NPs with ∼70 nm diameter. The Al/Si/SnO/Ag NPs/ZnO/ITO device exhibited an optimum responsivity, detectivity and sensitivity of 210.2 mA W-1, 5.47 × 109 Jones and 15.0 × 104, respectively, together with a rise and fall time of 2.3 and 51.3 µs, respectively, at a laser power density of 317 mW cm-2 and at a chopper frequency of 10 Hz. The present photodetectors are more than twice as responsive as the current best-performing ZnO-based pyro-phototronic photodetectors and they also exhibit other competitive features, such as detectivity, and fall and rise times. Therefore, by exploiting the plasmonic effect of the Ag NPs together with the pyroelectric effect in a ZnO film, and the photovoltaic effect at a Si/SnO junction, all in a single device, photodetectors were developed with state-of-the-art performance for the visible region.

Cost-effective, high-performance Ni3Sn4 electrocatalysts for methanol oxidation reaction in acidic environments.

Methanol (CH3OH) oxidation offers a promising avenue for transitioning to clean energy, particularly in the field of direct methanol fuel cells (DMFCs). However, the development of efficient and cost-effective catalysts for the methanol oxidation reaction (MOR) remains a critical challenge. Herein, we report the exceptional electrocatalytic activity and stability of Ni3Sn4 toward MOR in acidic media, achieving a performance comparable to that of commercial Pt/C catalysts. Our catalyst design incorporates Earth-abundant Ni and Sn elements, resulting in a material that is 1800 times more cost-effective than Pt/C. Density functional theory (DFT) modeling substantiates our experimental findings, shedding light on the favorable reaction mechanisms and kinetics on the Ni3Sn4 surface. Additionally, the as-synthesized Ni3Sn4 electrocatalyst demonstrates commendable durability, maintaining its electrocatalytic activity even after prolonged exposure to harsh acidic conditions.

Ferroelectric Orthorhombic ZrO2 Thin Films Achieved Through Nanosecond Laser Annealing.

A new approach for the stabilization of the ferroelectric orthorhombic ZrO2 films is demonstrated through nanosecond laser annealing (NLA) of as-deposited Si/SiOx /W(14 nm)/ZrO2 (8 nm)/W(22 nm), grown by ion beam sputtering at low temperatures. The NLA process optimization is guided by COMSOL multiphysics simulations. The films annealed under the optimized conditions reveal the presence of the orthorhombic phase, as confirmed by X-ray diffraction, electron backscatter diffraction, and transmission electron microscopy. Macroscopic polarization-electric field hysteresis loops show ferroelectric behavior, with saturation polarization of 12.8 µC cm-2 , remnant polarization of 12.7 µC cm-2 and coercive field of 1.2 MV cm-1 . The films exhibit a wake-up effect that is attributed to the migration of point defects, such as oxygen vacancies, and/or a transition from nonferroelectric (monoclinic and tetragonal phase) to the ferroelectric orthorhombic phase. The capacitors demonstrate a stable polarization with an endurance of 6.0 × 105 cycles, demonstrating the potential of the NLA process for the fabrication of ferroelectric memory devices with high polarization, low coercive field, and high cycling stability.

Fermiology of Chiral Cadmium Diarsenide CdAs2, a Candidate for Hosting Kramers-Weyl Fermions.

Nonmagnetic chiral crystals are a new class of systems hosting Kramers-Weyl Fermions, arising from the combination of structural chirality, spin-orbit coupling (SOC), and time-reversal symmetry. These materials exhibit nontrivial Fermi surfaces with SOC-induced Chern gaps over a wide energy range, leading to exotic transport and optical properties. In this study, we investigate the electronic structure and transport properties of CdAs2, a newly reported chiral material. We use synchrotron-based angle-resolved photoelectron spectroscopy (ARPES) and density functional theory (DFT) to determine the Fermiology of the (110)-terminated CdAs2 crystal. Our results, together with complementary magnetotransport measurements, suggest that CdAs2 is a promising candidate for novel topological properties protected by the structural chirality of the system. Our work sheds light on the details of the Fermi surface and topology for this chiral quantum material, providing useful information for engineering novel spintronic and optical devices based on quantized chiral charges, negative longitudinal magnetoresistance, and nontrivial Chern numbers.

Hydrogen Production Mechanism in Low-Temperature Methanol Decomposition Catalyzed by Ni3Sn4 Intermetallic Compound: A Combined Operando and Density Functional Theory Investigation.

Hydrogen production from methanol decomposition to syngas (H2 + CO) is a promising alternative route for clean energy transition. One major challenge is related to the quest for stable, cost-effective, and selective catalysts operating below 400 °C. We illustrate an investigation of the surface reactivity of a Ni3Sn4 catalyst working at 250 °C, by combining density functional theory, operando X-ray absorption spectroscopy, and high-resolution transmission electron microscopy. We discovered that the catalytic reaction is driven by surface tin-oxide phases, which protects the underlying Ni atoms from irreversible chemical modifications, increasing the catalyst durability. Moreover, we found that Sn content plays a key role in enhancing the H2 selectivity, with respect to secondary products such as CO2. These findings open new perspectives for the engineering of scalable and low-cost catalysts for hydrogen production.

Chitosan-Hyaluronan Nanoparticles for Vinblastine Sulfate Delivery: Characterization and Internalization Studies on K-562 Cells.

In the present study, we developed chitosan/hyaluronan nanoparticles (CS/HY NPs) for tumor targeting with vinblastine sulfate (VBL), that can be directed to the CD44 transmembrane receptor, over-expressed in cancer cells. NPs were prepared by coating with HY-preformed chitosan/tripolyphosphate (CS/TPP) NPs, or by polyelectrolyte complexation of CS with HY. NPs with a mean hydrodynamic radius (RH) of 110 nm, 12% polydispersity index and negative zeta potential values were obtained by a direct complexation process. Transmission Electron Microscopy (TEM) images showed spherical NPs with a non-homogeneous matrix, probably due to a random localization of CS and HY interacting chains. The intermolecular interactions occurring between CS and HY upon NPs formation were experimentally evidenced by micro-Raman (µ-Raman) spectroscopy, through the analysis of the spectral changes of characteristic vibrational bands of HY during NP formation, in order to reveal the involvement of specific chemical groups in the process. Optimized NP formulation efficiently encapsulated VBL, producing a drug sustained release for 20 h. In vitro studies demonstrated a fast internalization of labeled CS/HY NPs (within 6 h) on K-562 human myeloid leukemia cells. Pre-saturation of CD44 by free HY produced a slowing-down of NP uptake over 24 h, demonstrating the need of CD44 for the internalization of HY-based NPs.

3D Porous Collagen Matrices-A Reservoir for In Vitro Simultaneous Release of Tannic Acid and Chlorhexidine.

The treatment of wounds occurring accidentally or as a result of chronic diseases most frequently requires the use of appropriate dressings, mainly to ensure tissue regeneration/healing, at the same time as treating or preventing potential bacterial infections or superinfections. Collagen type I-based scaffolds in tandem with adequate antimicrobials can successfully fulfill these requirements. In this work, starting from the corresponding hydrogels, we prepared a series of freeze-dried atelocollagen type I-based matrices loaded with tannic acid (TA) and chlorhexidine digluconate (CHDG) as active agents with a broad spectrum of antimicrobial activity and also as crosslinkers for the collagen network. The primary aim of this study was to design an original and reliable algorithm to in vitro monitor and kinetically analyze the simultaneous release of TA and CHDG from the porous matrices into an aqueous solution of phosphate-buffered saline (PBS, pH 7.4, 37 °C) containing micellar carriers of a cationic surfactant (hexadecyltrimethylammonium bromide, HTAB) as a release environment that roughly mimics human extracellular fluids in living tissues. Around this central idea, a comprehensive investigation of the lyophilized matrices (morpho-structural characterization through FT-IR spectroscopy, scanning electron microscopy, swelling behavior, resistance against the collagenolytic action of collagenase type I) was carried out. The kinetic treatment of the release data displayed a preponderance of non-Fickian-Case II diffusion behavior, which led to a general anomalous transport mechanism for both TA and CHDG, irrespective of their concentrations. This is equivalent to saying that the release regime is not governed only by the gradient concentration of the releasing components inside and outside the matrix (like in ideal Fickian diffusion), but also, to a large extent, by the relaxation phenomena of the collagen network (determined, in turn, by its crosslinking degree induced by TA and CHDG) and the dynamic capacity of the HTAB micelles to solubilize the two antimicrobials. By controlling the degree of physical crosslinking of collagen with a proper content of TA and CHDG loaded in the matrix, a tunable, sustainable release profile can be obtained.

New Phenotype and Mineralization of Biogenic Iron Oxide in Magnetotactic Bacteria.

Many magnetotactic bacteria (MTB) biomineralize magnetite crystals that nucleate and grow inside intracellular membranous vesicles originating from invaginations of the cytoplasmic membrane. The crystals together with their surrounding membranes are referred to as magnetosomes. Magnetosome magnetite crystals nucleate and grow using iron transported inside the vesicle by specific proteins. Here, we tackle the question of the organization of magnetosomes, which are always described as constituted by linear chains of nanocrystals. In addition, it is commonly accepted that the iron oxide nanocrystals are in the magnetite-based phase. We show, in the case of a wild species of coccus-type bacterium, that there is a double organization of the magnetosomes, relatively perpendicular to each other, and that the nanocrystals are in fact maghemite. These findings were obtained, respectively, by using electron tomography of whole mounts of cells directly from the environment and high-resolution transmission electron microscopy and diffraction. Structure simulations were performed with the MacTempas software. This study opens new perspectives on the diversity of phenotypes within MTBs and allows to envisage other mechanisms of nucleation and formation of biogenic iron oxide crystals.

Wake-up Free Ferroelectric Rhombohedral Phase in Epitaxially Strained ZrO2 Thin Films.

Zirconia- and hafnia-based thin films have attracted tremendous attention in the past decade because of their unexpected ferroelectric behavior at the nanoscale, which enables the downscaling of ferroelectric devices. The present work reports an unprecedented ferroelectric rhombohedral phase of ZrO2 that can be achieved in thin films grown directly on (111)-Nb:SrTiO3 substrates by ion-beam sputtering. Structural and ferroelectric characterizations reveal (111)-oriented ZrO2 films under epitaxial compressive strain exhibiting switchable ferroelectric polarization of about 20.2 µC/cm2 with a coercive field of 1.5 MV/cm. Moreover, the time-dependent polarization reversal characteristics of Nb:SrTiO3/ZrO2/Au film capacitors exhibit typical bell-shaped curve features associated with the ferroelectric domain reversal and agree well with the nucleation limited switching (NLS) model. The polarization-electric field hysteresis loops point to an activation field comparable to the coercive field. Interestingly, the studied films show ferroelectric behavior per se, without the need to apply the wake-up cycle found in the orthorhombic phase of ZrO2. Overall, the rhombohedral ferroelectric ZrO2 films present technological advantages over the previously studied zirconia- and hafnia-based thin films and may be attractive for nanoscale ferroelectric devices.

All-Oxide p-n Junction Thermoelectric Generator Based on SnOx and ZnO Thin Films.

Achieving thermoelectric devices with high performance based on low-cost and nontoxic materials is extremely challenging. Moreover, as we move toward an Internet-of-Things society, a miniaturized local power source such as a thermoelectric generator (TEG) is desired to power increasing numbers of wireless sensors. Therefore, in this work, an all-oxide p-n junction TEG composed of low-cost, abundant, and nontoxic materials, such as n-type ZnO and p-type SnOx thin films, deposited on borosilicate glass substrate is proposed. A type II heterojunction between SnOx and ZnO films was predicted by density functional theory (DFT) calculations and confirmed experimentally by X-ray photoelectron spectroscopy (XPS). Moreover, scanning transmission electron microscopy (STEM) combined with energy-dispersive X-ray spectroscopy (EDS) show a sharp interface between the SnOx and ZnO layers, confirming the high quality of the p-n junction even after annealing at 523 K. ZnO and SnOx thin films exhibit Seebeck coefficients (α) of ∼121 and ∼258 µV/K, respectively, at 298 K, resulting in power factors (PF) of 180 µW/m K2 (for ZnO) and 37 µW/m K2 (for SnOx). Moreover, the thermal conductivities of ZnO and SnOx films are 8.7 and 1.24 W/m K, respectively, at 298 K, with no significant changes until 575 K. The four pairs all-oxide TEG generated a maximum power output (Pout) of 1.8 nW (≈126 µW/cm2) at a temperature difference of 160 K. The output voltage (Vout) and output current (Iout) at the maximum power output of the TEG are 124 mV and 0.0146 µA, respectively. This work paves the way for achieving a high-performance TEG device based on oxide thin films.

Phase Control in Hafnia: New Synthesis Approach and Convergence of Average and Local Structure Properties.

Technologically relevant tetragonal/cubic phases of HfO2 can be stabilized at room temperature by doping with trivalent rare earths using various approaches denoted generically as bulk coprecipitation. Using in situ/ex situ X-ray diffraction (XRD), Raman spectroscopy, high-resolution transmission electron microscopy, and in situ/ex situ site-selective, time-gated luminescence spectroscopy, we show that wet impregnation of hafnia nanoparticles with 10% Eu oxide followed by mild calcination in air at 500 °C produces an efficient stabilization of the cubic phase, comparable to that obtained by bulk precipitation. The physical reasons behind the apparently conflictual data concerning the actual crystallographic phase and the local symmetry around the Eu stabilizer and how these can be mediated by luminescence analysis are also discussed. Apparently, the cubic crystal structure symmetry determined by XRD results in a pseudocubic/tetragonal local structure around Eu determined by luminescence. Considering the recent findings on wet impregnated CeO2 and ZrO2, it is concluded that CeO2, ZrO2, and HfO2 represent a unique case of a family of oxides that is extremely tolerant to heavy doping by wet impregnation. In this way, the same batch of preformed nanoparticles can be doped with different lanthanide concentrations or with various lanthanides at a fixed concentration, allowing a systematic and reliable investigation of the effect of doping, lanthanide type, and lanthanide concentration on the various functionalities of these technologically relevant oxides.

Tailoring the Dopant Distribution in ZnO:Mn Nanocrystals.

The synthesis of semiconductor nanocrystals with controlled doping is highly challenging, as often a significant part of the doping ions are found segregated at nanocrystals surface, even forming secondary phases, rather than incorporated in the core. We have investigated the dopant distribution dynamics under slight changes in the preparation procedure of nanocrystalline ZnO doped with manganese in low concentration by electron paramagnetic resonance spectroscopy, paying attention to the formation of transient secondary phases and their transformation into doped ZnO. The acidification of the starting solution in the co-precipitation synthesis from nitrate precursors lead to the decrease of the Mn2+ ions concentration in the core of the ZnO nanocrystals and their accumulation in minority phases, until ~79% of the Mn2+ ions were localized in a thin disordered shell of zinc hydroxynitrate (ZHN). A lower synthesis temperature resulted in polycrystalline Mn-doped ZHN. Under isochronal annealing up to 250 °C the bulk ZHN and the minority phases from the ZnO samples decomposed into ZnO. The Mn2+ ions distribution in the annealed nanocrystals was significantly altered, varying from a uniform volume distribution to a preferential localization in the outer layers of the nanocrystals. Our results provide a synthesis strategy for tailoring the dopant distribution in ZnO nanocrystals for applications ranging from surface based to ones involving core properties.

Full Tetragonal Phase Stabilization in ZrO2 Nanoparticles Using Wet Impregnation: Interplay of Host Structure, Dopant Concentration and Sensitivity of Characterization Technique.

Here, we show that wet impregnation of ZrO2 nanoparticles with 10% and 20% Eu oxide followed by thermal anneal in air above 500 °C produces full stabilization of the tetragonal phase of ZrO2 without evidencing any phase separation. The bare ZrO2 nanoparticles were obtained using three synthetic methods: oil in water microemulsion, rapid hydrothermal, and citrate complexation methods. The homogeneity of the solid solutions was assessed using X-ray diffraction, Raman spectroscopy, high resolution transmission electron microscopy, and advanced luminescence spectroscopy. Our findings show that wet impregnation, which is a recognized method for obtaining surface doped oxides, can be successfully used for obtaining doped oxides in the bulk with good homogeneity at the atomic scale. The limits of characterization technique in detecting minor phases and the roles of dopant concentration and host structure in formation of phase stabilized solid solutions are also analyzed and discussed.

Ambiguous Role of Growth-Induced Defects on the Semiconductor-to-Metal Characteristics in Epitaxial VO2/TiO2 Thin Films.

Controlling the semiconductor-to-metal transition temperature in epitaxial VO2 thin films remains an unresolved question both at the fundamental as well as the application level. Within the scope of this work, the effects of growth temperature on the structure, chemical composition, interface coherency and electrical characteristics of rutile VO2 epitaxial thin films grown on TiO2 substrates are investigated. It is hereby deduced that the transition temperature is lower than the bulk value of 340 K. However, it is found to approach this value as a function of increased growth temperature even though it is accompanied by a contraction along the V4+-V4+ bond direction, the crystallographic c-axis lattice parameter. Additionally, it is demonstrated that films grown at low substrate temperatures exhibit a relaxed state and a strongly reduced transition temperature. It is suggested that, besides thermal and epitaxial strain, growth-induced defects may strongly affect the electronic phase transition. The results of this work reveal the difficulty in extracting the intrinsic material response to strain, when the exact contribution of all strain sources cannot be effectively determined. The findings also bear implications on the limitations in obtaining the recently predicted novel semi-Dirac point phase in VO2/TiO2 multilayer structures.

Impact of thickness variation on structural, dielectric and piezoelectric properties of (Ba,Ca)(Ti,Zr)O3 epitaxial thin films.

It is shown that the dielectric and piezoelectric properties of Ba(Ti0.8Zr0.2)O3-x(Ba0.7Ca0.3)TiO3 (x = 0.45) (BCTZ 45) epitaxial thin films have a nontrivial dependence on film thickness. BCTZ 45 epitaxial films with different thicknesses (up to 400 nm) have been deposited on SrTiO3 by pulsed laser deposition and investigated by different combined techniques: conventional and off-axis X-ray diffraction, high resolution transmission electron microscopy and dielectric and piezoforce microscopy. The changes occurring in epitaxial films when their thickness increases have been attributed to a partial relaxation of misfit strain, driving the induced tetragonal symmetry in very thin films to the original rhombohedral symmetry of the bulk material in the thickest film, which influences directly and indirectly the dielectric and piezoelectric properties.

Lipoic Acid Gold Nanoparticles Functionalized with Organic Compounds as Bioactive Materials.

Water soluble gold nanoparticles protected by lipoic acid were obtained and further functionalized by standard coupling reaction with 1-naphtylamine, 4-aminoantipyrine, and 4'-aminobenzo-15-crown-5 ether. Derivatives of lipoic acid with 1-naphtylamine, 4-aminoantipyrine, and 4'-aminobenzo-15-crown-5 ether were also obtained and characterized. All these were tested for their antimicrobial activity, as well as for their influence on mammalian cell viability and cellular cycle. In all cases a decreased antimicrobial activity of the obtained bioactive nanoparticles was observed as compared with the organic compounds, proving that a possible inactivation of the bioactive groups could occur during functionalization. However, both the gold nanoparticles as well as the functionalized bioactive nanosystems proved to be biocompatible at concentrations lower than 50 µg/mL, as revealed by the cellular viability and cell cycle assay, demonstrating their potential for the development of novel antimicrobial agents.

Structural, magnetic and magnetocaloric effects in epitaxial La0.67Ba0.33Ti0.02Mn0.98O3 ferromagnetic thin films grown on 001-oriented SrTiO3 substrates.

Epitaxial La0.67Ba0.33Ti0.02Mn0.98O3 (denoted as LBTMO hereafter) thin films of approximately 95 nm thickness were deposited by a pulsed laser deposition technique onto SrTiO3 (STO) (001) substrates. High-resolution X-ray diffraction (HRXRD) and transmission electron microscopy (TEM) investigations revealed that the films are epilayers with a four-fold symmetry around the [001] direction. Cross-sectional TEM and the presence of Pendellosung fringes in the XRD profiles demonstrate smooth interfaces. The STO substrate induces an in-plane compressive strain, which leads to a slight tetragonality of the film structure. The epilayers exhibit paramagnetic-to-ferromagnetic phase transitions at the Curie temperature TC (286 K), close to room temperature. The magnetization easy axis lies in the film plane along the [100] direction of the (001) substrate. The magnetic entropy change (ΔSM) associated with the second-order magnetic phase transition was determined via magnetization measurements in the temperature range between 210 and 350 K under different magnetic fields. The relative cooling power (RCP) of this film is about 220 J kg-1, somewhat lower than that of bulk Gd (410 J kg-1) for a 50 kOe field change, making the LBTMO ferromagnetic thin films a promising candidate for micro/nanomagnetic refrigeration around room temperature. The proposed universal curve provides a simple method for extrapolating ΔSM in a wide range of fields and temperatures, thus confirming the order of the magnetic transition in this system. The magnetic entropy (ΔSM)max around TC is proportional to (µ0H/TC)2/3 in agreement with the mean-field theory, indicating the existence of long-range ferromagnetic interactions in epitaxial LBTMO thin films.

High Permittivity (1 - x)Ba(Zr(0.2)Ti(0.8))O3 - x(Ba(0.7)Ca(0.3))TiO3 (x = 0.45) Epitaxial Thin Films with Nanoscale Phase Fluctuations.

Epitaxial (1 - x)Ba(Ti0.8Zr0.2)TiO3 - x(Ba0.7Ca0.3)TiO3, x = 0.45 (BCZT 45), thin films have been deposited on (001) SrTiO3 (STO) and (001/100) SrLaAlO4 (SLAO) substrates by pulsed laser deposition. X-ray diffraction and high-resolution transmission electron microscopy (HRTEM) confirmed the epitaxial growth of the films. A high structural quality has been evidenced for the BCZT/STO films. Geometric phase analysis (GPA) associated with the HRTEM enabled us to obtain microstrain analysis and the in-plane and out-of-plane lattice parameter variation on different areas. Tetragonality ratio fluctuations at nanoscale level which are relevant for the existence of nanodomains have been evidenced on the BCZT/STO films. The in-plane dielectric constant has been measured on interdigital electrodes deposited by lift-off technique on the top of the films. High values of dielectric permittivity (>3000) combined with low dielectric loss (<0.01) are obtained for BCZT 45 film deposited on STO substrate, showing nearly constant values between 1 kHz and 10 MHz. The high dielectric permittivity of BCZT thin films was attributed to their high structural quality and to the loss of rotation stability of the polarization associated with the presence of nanodomains. This results into a divergence of fluctuations of polarization direction and a peak of dielectric susceptibility. The enhanced switching of such nanodomain configuration was probed by piezoforce microscopy, by writing and reading domains during topography scanning.

Polarization induced self-doping in epitaxial Pb(Zr0.20Ti0.80)O3 thin films.

The compensation of the depolarization field in ferroelectric layers requires the presence of a suitable amount of charges able to follow any variation of the ferroelectric polarization. These can be free carriers or charged defects located in the ferroelectric material or free carriers coming from the electrodes. Here we show that a self-doping phenomenon occurs in epitaxial, tetragonal ferroelectric films of Pb(Zr0.2Ti0.8)O3, consisting in generation of point defects (vacancies) acting as donors/acceptors. These are introducing free carriers that partly compensate the depolarization field occurring in the film. It is found that the concentration of the free carriers introduced by self-doping increases with decreasing the thickness of the ferroelectric layer, reaching values of the order of 10(26) m(-3) for 10 nm thick films. One the other hand, microscopic investigations show that, for thicknesses higher than 50 nm, the 2O/(Ti+Zr+Pb) atomic ratio increases with the thickness of the layers. These results suggest that the ratio between the oxygen and cation vacancies varies with the thickness of the layer in such a way that the net free carrier density is sufficient to efficiently compensate the depolarization field and to preserve the outward direction of the polarization.

"Crystallographic" holes: new insights for a beneficial structural feature for photocatalytic applications.

One of the most fundamental aspects of the heterogeneous catalysis field is the manipulation of the catalysts' activity. In photocatalysis this is carried out by maximizing the right crystal plane of a semiconductor oxide. Until now, most of the papers have achieved this by a combination of different oxides, with noble metals and sometimes with carbon nanomaterials. In this work MWCNTs (multiwalled carbon nanotubes) were applied as "crystallization promoters" in a very simple, safe, one-step hydrothermal method. By this method TiO2 nano/micro crystals with exposed {001} facets were obtained in the first step. The next episode in the crystal manipulation "saga" was the modification of the (001) crystallographic plane's structure by creating ordered/own faceted "crystallographic holes". These elements are capable of further enhancing the obtained activity of titania microcrystals to a higher extent, as shown by the UV driven photocatalytic phenol degradation experiments. The appearance of the holes was "provoked" by simple calcination and their presence and influence were demonstrated by XPS and HRTEM.