Visible range optical absorption, Urbach energy estimation and paramagnetic response in Cr-doped TiO2 nanocrystals derived by a sol-gel method

Tri-Step Water-Assisted Strategy for Suppressing Cs4PbBr6 Phase in Printable Carbon-Based CsPbBr3 Solar Cells to Achieve High Stability

Often deemed the "natural nemesis" of perovskites, water molecules have been largely circumvented by the majority of researchers in the field of perovskite solar cells. This has resulted in significant hurdles in investigating the beneficial impacts of water molecules on perovskite crystallization. Herein, it is found that by utilizing ethanol with minimal water content and subjecting all-inorganic perovskite to three distinct annealing temperatures within the same solvent, the residual CsBr can be effectively removed, and the formation of the Cs4PbBr6 phase can be curtailed. By selecting an optimal water content, substantial improvements are observed in the crystalline quality of CsPbBr3, the perovskite/carbon interface, and the mesoporous filling effect. The Urbach energy (Eu) is reduced from 38.96 to 35.59 meV, and the defect density decreased from 4.16 × 1014 to 3.39 × 1014 cm-3. As a result, the power conversion efficiency (PCE) improved from 7.55% in the control group to 9.37%. Under severe environmental conditions with a temperature (T) of 85 °C and a relative humidity (RH) of 40%, tracking tests over 1200 h retained 89.3% of the initial PCE. This research signifies a breakthrough in the fabrication of highly stable and efficient all-inorganic printable mesoscopic perovskite solar cells.

Optical and UV Shielding Properties of Inorganic Nanoparticles Embedded in Polymethyl Methacrylate Nanocomposite Freestanding Films

Polymethyl methacrylate (PMMA) is an interesting polymer employed in various applications due to its outstanding properties. However, its electrical and mechanical properties can be further improved by incorporating nanoparticles, and in particular, PMMA nanocomposite with nanoparticles provides various multifunctional properties. This work reports PMMA nanocomposite preparation and structural and optical characterizations incorporating carbon nanotubes (CNTs), TiO2 nanoparticles, and carbon quantum dots (CQDs). CNT/PMMA, TiO2/PMMA, and CQD/PMMA nanocomposite freestanding films were prepared using a simple solution method. Various properties of the prepared composite films were analyzed using scanning electron microscopy, X-ray diffraction, photoluminescence, Fourier transform infrared, and UV-Vis and Raman spectroscopy. Optical parameters and photocatalytic dye degradation for the films are reported, focusing on the properties of the materials. The CNT/PMMA, TiO2/PMMA, and CQD/PMMA films achieved, respectively, good electrical conductivity, photodegradation, and fluorescence compared with other composite films.

Peroxymonosulfate enhanced photocatalytic degradation of organic dye by metal-free TpTt-COF under visible light irradiation

Recently, the activation of persulfate (PDS) by non-metallic photocatalysts under visible light has attracted significant interest in applications in environmental remediation. This study presents a pioneering investigation into the combined application of the TpTt-COF and PMS for visible light degradation of organic dyes. Synthesized orange TpTt-COF monomers exhibit exceptional crystallinity, a 2D structure, and notable stability in harsh conditions. The broad visible light absorption around a wavelength of 708 nm. The TpTt-COF emerges as a promising candidate for photocatalytic dye degradation. The study addresses high charge recombination in the TpTt-COF, highlighting the crucial role of its electron donor and acceptor for the PMS activation. Comparative analyses against traditional photocatalytic materials, such as the metal-free carbon-based material g-C3N4 and transition metal-containing TiO2, demonstrate TpTt-COF's superior performance, generating diverse free radicals. In simulated experiments, the TpTt-COF's degradation rate surpasses PMS-combined g-C3N4 by 13.9 times. and 1.6 times higher than the TpTt-COF alone. Remarkably, the TpTt-COF maintains high activity under harsh environments. Investigations into the degradation mechanism and the TpTt-COF's reusability reveal its efficiency and stability. Under visible light, TpTt-COF facilitates efficient electron-hole separation. Combining the TpTt-COF with PMS produces various radicals, ensuring effective separation and a synergistic effect. Radical quenching experiments confirm the pivotal role of O2-· radicals, while ·OH and SO4-· radicals intensify the degradation. After five cycles, TpTt-COF maintains an impressive 83.2% degradation efficiency. This study introduces an efficient photocatalytic system mediated by PMS and valuable insights into governing mechanisms for organic pollutant degradation in water environments.

Scanning with Laser Beam over the TiO2 Nanotubes Covered with Thin Chromium Layers towards the Activation of the Material under the Visible Light

This work presents pulsed UV laser treatment (355 nm, 2 Hz) of TiO₂ nanotubes decorated with chromium oxides. The modification was performed in a system equipped with a beam homogenizer, and during the irradiation, the samples were mounted onto the moving motorized table. In such a system, both precisely selected areas and any large area of the sample can be modified. Photoelectrochemical tests revealed photoresponse of laser-treated samples up to 1.37- and 18-fold under the illumination with ultraviolet-visible and visible light, respectively, in comparison to bare titania. Optimal beam energy fluence regarding sample photoresponse has been established. Scanning electron microscopy images, X-ray diffraction patterns, along with Raman and X-ray photoelectron spectra, suggest that the enhanced photoresponse results from changes solely induced in the layer of chromium oxides. It is believed that the results of the present work will contribute to a wider interest in laser modification of semiconductors exhibiting improved photoelectrochemical activity.

Study of Structural and Optical Properties of Titanate Nanotubes with Erbium under Heat Treatment in Different Atmospheres

Titanate nanotubes were synthesized and subjected to an ion exchange reaction with erbium salt aqueous solution to obtain titanate nanotubes exchanged with erbium (3+) ions. In order to evaluate the effects of the thermal treatment atmosphere on the structural and optical properties of erbium titanate nanotubes, we subjected them to heat treatment in air and argon atmospheres. For comparison, titanate nanotubes were also treated in the same conditions. A complete structural and optical characterizations of the samples was performed. The characterizations evidenced the preservation of the morphology with the presence of phases of erbium oxides decorating the surface of the nanotubes. Variations in the dimensions of the samples (diameter and interlamellar space) were promoted by the replacement of Na⁺ by Er³⁺ and the thermal treatment in different atmospheres. In addition, the optical properties were investigated by UV-Vis absorption spectroscopy and photoluminescence spectroscopy. The results revealed that the band gap of the samples depends on the variation of diameter and sodium content caused by ion exchange and thermal treatment. Furthermore, the luminescence strongly depended on vacancies, evidenced mainly by the calcined erbium titanate nanotubes in argon atmosphere. The presence of these vacancies was confirmed by the determination of Urbach energy. The results suggest the use of thermal treated erbium titanate nanotubes in argon atmosphere in optoelectronics and photonics applications, such as photoluminescent devices, displays, and lasers.

Sunlight promoted self-fenton photodegradation and pathway of doxycycline: Interactive effects of nanomaterial on bean plant and its genotoxicity against Allium cepa

Photocatalytic induction of electron/hole recombination, surface property and light response ability effectively enhance the photocatalytic activity of nanomaterial. In this work, the effective charge carrier separating Sn/Mn-ZnFe₂O₄-CdFe₂O₄-Ag₃PO₄ Quantum dots (M/SZFO-CFO-AP QDs) was fabricated for photocatalytic degradation of doxycycline (doxy) antibiotic. The result showed enhanced photocatalytic activity of doxy and the degradation efficiency of doxy was about 98.8% in short span of time. The calculated WH plot and urbach energy of prepared photocatalyst exhibited evidence for the prevalence of point defects and its contribution to efficient charge separation and transferability. The total organic carbon (TOC) removal was found to be 98.9%, which depicts the complete mineralization of doxy. The synergetic charge transfer of n-p-n heterojunction enables the effective removal of doxy under visible light irradiation. Further, the genotoxicity study was determined by interacting the SZFO-CFO-AP QDs with Allium Cepa. The results depict that SZFO-CFO-AP QDs show lower toxicity level and there were no trace of defective mitotic phases and micro nuclei. Further, the progression and development of bean plant was determined after treating with prepared nanomaterials and the result showed the enhanced growth in SZFO-CFO-AP QDs treated bean plant compared to the counterparts. Therefore, the prepared SZFO-CFO-AP QDs was can be used as an environmental friendly photocatalyst for effective treatment of antibiotic present in the water bodies.

Studies on Synthesis, Characterization, and Photocatalytic Activity of TiO2 and Cr-Doped TiO2 for the Degradation of p-Chlorophenol

TiO₂ and Cr-TiO₂ nanoparticles (NPs) have been synthesized by the sol-gel method using titanium isopropoxide as the precursor of Titania. The prepared samples were analyzed by employing scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Fourier transform infrared analyses. Under UV irradiation, the photocatalytic activities of TiO₂ and Cr-TiO₂ were observed by estimating the % degradation of p-chlorophenol (PCP) as a sample pollutant. The extent of degradation was investigated, varying the catalyst dosage, initial PCP concentration, irradiation time, and solution pH. The experimental results show that efficiency of catalysts initially increases but decreases later on, whereas the % degradation of PCP is the highest at its lowest initial concentration. For TiO₂ and Cr-TiO₂ NPs at their optimal catalyst dosage of 2.0 g/L, acidic pH, and with UV irradiation for 90 min, the observed % degradation of PCP is 50.23 ± 3.12 and 66.51 ± 2.14%, respectively. Thus, the prepared Cr-TiO₂ NPs have enhanced the degradation efficiency of PCP with an irradiation time which is four time less than those reported earlier. From the kinetics analysis, the degradation reaction of PCP is found to follow a pseudo-first-order model and the rate constants are 0.0075 and 0.0122 min^-1 for pure TiO₂ and Cr-TiO₂ NPs, respectively. The present study has further revealed that owing to the lower rate of electron-hole pair recombination, the photocatalytic activity of Cr-TiO₂ NPs becomes higher than that of TiO₂. Therefore, as viable photocatalytic agents, Cr-TiO₂ NPs are suggested to be used also for efficient degradation of other organic pollutants.

Angular orientation between the cores of iron oxide nanoclusters controls their magneto-optical properties and magnetic heating functions

Oriented attachment of nanobricks into hierarchical multi-scale structures such as inorganic nanoclusters is one of the crystallization mechanisms that has revolutionized the field of nano and materials science. Herein, we show that the mosaicity, which measures the misalignment of crystal plane orientation between the nanobricks, governs their magneto-optical properties as well as the magnetic heating functions of iron oxide nanoclusters. Thanks to high-temperature and time-resolved millifluidic, we were able to isolate and characterize (structure, properties, function) the different intermediates involved in the diverse steps of the nanocluster's formation, to propose a detailed dynamical mechanism of their formation and establish a clear correlation between changes in mosaicity at the nanoscale and their resulting physical properties. Finally, we demonstrate that their magneto-optical properties can be described using simple molecular theories.

Structural, optical and magnetic properties of pure and 3d metal dopant-incorporated SnO2 nanoparticles

Dilute magnetic oxide semiconductors doped with transition metals have attracted significant attention both theoretically and experimentally due to their interesting and debatable magnetic behavior. In this work, we investigated the influence of Fe, Co and Ni doping on the structural, optical and magnetic properties of SnO2 nanoparticles, which were produced via a simple sol-gel technique. Raman spectroscopy, XRD, XPS, TEM, FT-IR characterizations were performed to study the crystal structure and morphology of the pure and doped nanoparticles, which confirmed the tetragonal rutile structure of the SnO2 nanoparticles. The XPS analysis revealed the incorporation of divalent dopant ions in the host matrix. The Raman plots indicated the generation of the cassiterite crystal structure, structural disorder and oxygen vacancies in the pure and doped SnO2 nanoparticles. The UV-visible plots indicated a decrease in the bandgap for the doped SnO2 nanoparticles because doping introduced defect levels in the band gap. The photoluminescence study showed the creation of oxygen vacancies due to the doping of different charge states of dopants. The magnetic study based on varying the temperature and field of magnetization revealed the diamagnetic nature of SnO2 at 300 K and 5 K respectively, and the concurrence of ferromagnetic (FM) and paramagnetic (PM) nature in doped SnO2 nanoparticles. The bound polaron model was used to explain the co-existence of FM and PM behavior in all the doped SnO2 nanoparticles.

Internal Interactions between Mixed Bulky Organic Cations on Passivating Defects in Perovskite Solar Cells

In perovskite solar cells (PSCs), bulky organic cation halide salt additions play a significant role in suppressing nonradiative recombination by passivating intrinsic defects in perovskites. Herein, a passivation treatment is developed by applying mixed bulky cations [guanidinium cation (GA⁺) and phenylethylammonium cations (PEA⁺)] as the additive for perovskite thin films. The internal interactions between the two bulky cations could result in lower carrier trap-state densities, a sharper Urbach tail, and better carrier transport in perovskite films in comparison with a control film. As a result, in comparison to the control device, which has a power conversion efficiency (PCE) of 18.92%, the mixed-cation-based device exhibits a dramatic enhancement of PCE of 20.64%. Importantly, after 720 h of storage in an ambient atmosphere with a relative humidity (RH) of 60-80% at room temperature, the mixed-cation-based device retains 62.7% of its original performance, whereas the control devices decay to less than 40% of their original performance.

One-Step Aqueous Synthesis of Anionic and Cationic AgInS2 Quantum Dots and Their Utility in Improving the Efficacy of ALA-Based Photodynamic Therapy

Silver-indium-sulfide quantum dots (AIS QDs) have potential applications in many areas, including biomedicine. Their lack of regulated heavy metals, unlike many commercialized QDs, stands out as an advantage, but the necessity for alloyed or core-shell structures and related costly and sophisticated processes for the production of stable and high quantum yield aqueous AIS QDs are the current challenges. The present study demonstrates the one-step aqueous synthesis of simple AgInS2 QD compositions utilizing for the first time either a polyethyleneimine/2-mercaptopropionic acid (AIS-PEI/2MPA) mixture or only 2-mercaptopropionic acid (AIS-2MPA) as the stabilizing molecules, providing a AgInS2 portfolio consisting of cationic and anionic AIS QDs, respectively, and tuneable emission. Small AIS QDs with long-term stability and high quantum yields (19-23%) were achieved at a molar ratio of Ag/In/S 1/10/10 in water without any dopant or a semiconductor shell. The theranostic potential of these cationic and anionic AIS QDs was also evaluated in vitro. Non-toxic doses were determined, and fluorescence imaging potential was demonstrated. More importantly, these QDs were electrostatically loaded with zwitterionic 5-aminolevulinic acid (ALA) as a prodrug to enhance the tumor availability of ALA and to improve ALA-induced porphyrin photodynamic therapy (PDT). This is the first study investigating the influence of nanoparticle charge on ALA binding, release, and therapeutic efficacy. Surface charge was found to be more critical in cellular internalization and dark toxicity rather than drug loading and release. Both QDs provided enhanced ALA release at acidic pH but protected the prodrug at physiological pH, which is critical for tumor delivery of ALA, which suffers from low bioavailability. The PDT efficacy of the ALA-loaded AIS QDs was tested in 2D monolayers and 3D constructs of HT29 and SW480 human colon adenocarcinoma cancer cell lines. The incorporation of ALA delivery by the AIS QDs, which on their own do not cause phototoxicity, elicited significant cell death due to enhanced light-induced ROS generation and apoptotic/necrotic cell death, reducing the IC50 for ALA dramatically to about 0.1 and 0.01 mM in anionic and cationic AIS QDs, respectively. Combined with simple synthetic methods, the strong intracellular photoluminescence of AIS QDs, good biocompatibility of especially the anionic AIS QDs, and the ability to act as drug carriers for effective PDT signify that the AIS QDs, in particular AIS-2MPA, are highly promising theranostic QDs.

Opto-Electronic Characterization of Photocatalysts Based on p,n-Junction Ternary and Quaternary Mixed Oxides Semiconductors (Cu2O-In2O3 and Cu2O-In2O3-TiO2)

Semiconductor materials are the basis of electronic devices employed in the communication and media industry. In the present work, we report the synthesis and characterization of mixed metal oxides (MOs) as p,n-junction photocatalysts, and demonstrate the correlation between the preparation technique and the properties of the materials. Solid-state UV-visible diffuse reflectance spectroscopy (UV-VIS DRS) allowed for the determination of the light absorption properties and the optical energy gap. X-ray photoelectron spectroscopy (XPS) allowed for the determination of the surface speciation and composition and for the determination of the valence band edge. The opto-electronic behavior was evaluated measuring the photocurrent generated after absorption of chopped visible light in a 3-electrode cell. Scanning electron microscopy (SEM) measurements allowed for auxiliary characterization of size and morphology, showing the formation of composites for the ternary Cu2O-In2O3 p,n-mixed oxide, and even more for the quaternary Cu2O-In2O3-TiO2 MO. Light absorption spectra and photocurrent-time curves mainly depend upon the composition of MOs, while the optical energy gap and defective absorption tail are closely related to the preparation methodology, time and thermal treatment. Qualitative electronic band structures of semiconductors are also presented.

Structure-Property-Function Relationships of Iron Oxide Multicore Nanoflowers in Magnetic Hyperthermia and Photothermia

Magnetite and maghemite multicore nanoflowers (NFs) synthesized using the modified polyol-mediated routes are to date among the most effective nanoheaters in magnetic hyperthermia (MHT). Recently, magnetite NFs have also shown high photothermal (PT) performances in the most desired second near-infrared (NIR-II) biological window, making them attractive in the field of nanoparticle-activated thermal therapies. However, what makes magnetic NFs efficient heating agents in both modalities still remains an open question. In this work, we investigate the role of many parameters of the polyol synthesis on the final NFs' size, shape, chemical composition, number of cores, and crystallinity. These nanofeatures are later correlated to the magnetic, optical, and electronic properties of the NFs as well as their collective macroscopic thermal properties in MHT and PT to find relationships between their structure, properties, and function. We evidence the critical role of iron(III) and heating ramps on the elaboration of well-defined NFs with a high number of multicores. While MHT efficiency is found to be proportional to the average number of magnetic cores within the assemblies, the optical responses of the NFs and their collective photothermal properties depend directly on the mean volume of the NFs (as supported by optical cross sections numerical simulations) and strongly on the structural disorder in the NFs, rather than the stoichiometry. The concentration of defects in the nanostructures, evaluated by photoluminescence and Urbach energy (E_U), evidence a switch in the optical behavior for a limit value of E_U = 0.4 eV where a discontinuous transition from high to poor PT efficiency is also observed.

Photoluminescence-Based Bioassay With Cysteamine-Capped TiO2 Nanoparticles for the Selective Recognition of N-Acyl Homoserine Lactones

Currently available diagnostic procedures for infections are laborious and time-consuming, resulting in a substantial financial burden by increasing morbidity, increased costs of hospitalization, and mortality. Therefore, innovative approaches to design diagnostic biomarkers are imperative to assist in the rapid and sensitive diagnosis of microbial infections. Acyl homoserine lactones (AHLs) are ubiquitous bacterial signaling molecules that are found to be significantly upregulated in infected sites. In this pioneering work, we have developed a simple photoluminescence-based assay using cysteamine-capped titanium oxide (TiO2) nanoparticles for AHL detection. The PL intensity variation of the oxygen defect state of TiO2 was used for the biosensing measurements. The bioassays were validated using two well-studied AHL molecules (C4-HSL and 3-oxo-C12 HSL) of an important human pathogen, Pseudomonas aeruginosa. The developed system has a maximum relative response of 98%. Furthermore, the efficacy of the system in simulated host urine using an artificial urine medium showed a linear detection range of 10-160 nM. Also, we confirmed the relative response and specificity of the system in detecting AHLs produced by P. aeruginosa in a temporal manner.

Memristive Behavior of Mixed Oxide Nanocrystal Assemblies

Recent advances in memristive nanocrystal assemblies leverage controllable colloidal chemistry to induce a broad range of defect-mediated electrochemical reactions, switching phenomena, and modulate active parameters. The sample geometry of virtually all resistive switching studies involves thin film layers comprising monomodal diameter nanocrystals. Here we explore the evolution of bipolar and threshold resistive switching across highly ordered, solution-processed nanoribbon assemblies and mixtures comprising BaZrO₃ (BZO) and SrZrO₃ (SZO) nanocrystals. The effects of nanocrystal size, packing density, and A-site substitution on operating voltage (V_SET and V_TH) and switching mechanism were studied through a systematic comparison of nanoribbon heterogeneity (i.e., BZO-BZO vs BZO-SZO) and monomodal vs bimodal size distributions (i.e., small-small and small-large). Analysis of the current-voltage response confirms that tip-induced, trap-mediated space-charge-limited current and trap-assisted tunneling processes drive the low- and high-resistance states, respectively. Our results demonstrate that both smaller nanocrystals and heavier alkaline earth substitution decrease the onset voltage and improve stability and state retention of monomodal assemblies and bimodal nanocrystal mixtures, thus providing a base correlation that informs fabrication of solution-processed, memristive nanocrystal assemblies.

Understanding the structure, bonding and reactions of nanocrystalline semiconductors: a novel high-resolution instrumental method of solid-state synchronous luminescence spectroscopy

This Perspective Article describes the recent advancements in studies of nanocrystalline metal oxides using a novel ultra-high resolution method, solid-state synchronous luminescence spectroscopy (SS-SLS). Semiconductors notably include titanium dioxide and these studies shed light on the detailed electronic structure, composition, and their reactions. First, we critically discuss the limitations of the major existing non-spectroscopic and spectroscopic methods of characterization of electronic structure of nanocrystalline semiconductors and insulators. Second, we describe the foundations and the setup of SS-SLS as an enhanced-resolution, facile, non-contact, non-destructive, and highly capable method of studies of nanomaterials. Third, the following insights are featured which are obtained by SS-SLS, but are not available by other methods: (a) detection of traps of electric charge (specific mid-gap states); (b) discrimination between "surface" and "bulk" sites; (c) in situ studies of composite nanomaterials and mechanisms of reactions, (d) the derivative SS-SLS for accurate determination of energies of absorption and emission. The specific advantages of SS-SLS versus other methods and in direct comparison with "conventional" photoluminescence spectroscopy are highlighted. Finally, new opportunities and challenges of SS-SLS are presented. SS-SLS is an advanced spectroscopic method with significant potential to aid academia and industry in studies of chemo-sensing, photocatalysis, optoelectronic materials, applied surface science, development of instrumental analysis, and studies of mechanisms of surface and "bulk" chemical reactions.

Solvothermal phase change induced morphology transformation in CdS/CoFe2O4@Fe2O3 hierarchical nanosphere arrays as ternary heterojunction photoanodes for solar water splitting

The design of efficient heterojunction photoanodes with appropriate band alignment and ease of charge separation has been one of the most highly focused research areas in photoelectrodes.

Superior light absorbing CdS/vanadium sulphide nanowalls@TiO2 nanorod ternary heterojunction photoanodes for solar water splitting

Vanadium sulphide is an emerging infrared active photocatalyst that has not been utilized to its maximum potential.

Controlled Size Growth of Thermally Stable Organometallic Halide Perovskite Microrods: Synergistic Effect of Dual-Doping, Lattice Strain Engineering, Antisolvent Crystallization, and Band Gap Tuning Properties

Organometallic halide perovskites, as the light-harvesting material, have been extensively used for cost-effective energy production in high-performance perovskite solar cells, despite their poor stability in the ambient atmosphere. In this work, methylammonium lead iodide, CH₃NH₃PbI₃, perovskite was successfully doped with KMnO₄ using antisolvent crystallization to develop micrometer-length perovskite microrods. Thus, the obtained KMnO₄-doped perovskite microrods have exhibited sharp, narrow, and red-shifted photoluminescence band, as well as high lattice strain with improved thermal stability compared to undoped CH₃NH₃PbI₃. During the synthesis of the KMnO₄-doped perovskite microrods, a low boiling point solvent, anhydrous chloroform, was employed as an antisolvent to facilitate the emergence of controlled-size perovskite microrods. The as-synthesized KMnO₄-doped perovskite microrods retained the pristine perovskite crystalline phases and lowered energy band gap (∼1.57 eV) because of improved light absorption and narrow fluorescence emission bands (fwhm < 10 nm) with improved lattice strain (∼4.42 × 10^-5), Goldsmith tolerance factor (∼0.89), and high dislocation density (∼5.82 × 10^-4), as estimated by Williamson-Hall plots. Thus, the obtained results might enhance the optical properties with reduced energy band gap and high thermal stability of doped-perovskite nanomaterials in ambient air for diverse optoelectronic applications. This study paves the way for new insights into chemical doping and interaction possibilities in methylamine-based perovskite materials with various metal dopants for further applications.

Cellulose Acetate Incorporating Organically Functionalized CeO2 NPs: Efficient Materials for UV Filtering Applications

One of the major issues faced when constructing various materials incorporating inorganic nanoparticles (NPs) is aggregation leading to loss of their final activity. In our work, cellulose acetate (CA) has been used to serve as matrix for the synthesis of UV-shielding and transparent films containing various amounts (1-5 wt.%) of cerium oxide (CeO2) NPs. In order to attain an improved dispersion and a better connectivity between NPs and the cellulose matrix, the surface of CeO2 NPs have been previously functionalized by the reaction with 3-aminopropyl(diethoxy)methylsilane (APDMS). The uniform dispersion of the NPs in the homogeneous thin films has been evidenced by using Transmission Electron Microscopy (TEM) and Fourier Transformation Infrared Spectroscopy (FTIR) characterization. The investigation of the optical properties for the hybrid films through UV-Vis spectroscopy revealed that the presence of CeO2 NPs in the CA matrix determined the appearance of strong UV absorption bands in the region 312-317 nm, which supports their use as efficient UV absorbers. This study has shown that UV shielding ability of the nanocomposites can be easily tuned by adjusting the numberof inorganic NPs in the CA template.

Highly efficient hydrogen evolution reaction, plasmon-enhanced by AuNP-l-TiO2NP photocatalysts

A set of AuNPs-l-TiO₂NPs nanoaggregates which showed efficient covering of the semiconductor's surface by AuNPs, as well as suitable AuNP sizes for LSPR-sensibilization were used as highly efficient photocatalysts for photoinduced HER.