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Enhanced Interfacial Binding and Electron Extraction Using Boron‐Doped TiO <sub/>2</sub> for Highly Efficient Hysteresis‐Free Perovskite Solar Cells
摘要： Perovskite solar cells (PSCs) have witnessed astonishing improvement in power conversion efficiency (PCE), more recently, with advances in long-term stability and scalable fabrication. However, the presence of an anomalous hysteresis behavior in the current density–voltage characteristic of these devices remains a key obstacle on the road to commercialization. Herein, sol–gel-processed mesoporous boron-doped TiO2 (B-TiO2) is demonstrated as an improved electron transport layer (ETL) for PSCs for the reduction of hysteresis. The incorporation of boron dopant in TiO2 ETL not only reduces the hysteresis behavior but also improves PCE of the perovskite device. The simultaneous improvements are mainly ascribed to the following two reasons. First, the substitution of under-coordinated titanium atom by boron species effectively passivates oxygen vacancy defects in the TiO2 ETL, leading to increased electron mobility and conductivity, thereby greatly facilitating electron transport. Second, the boron dopant upshifts the conduction band edge of TiO2, resulting in more efficient electron extraction with suppressed charge recombination. Consequently, a methylammonium lead iodide (MAPbI3) photovoltaic device based on B-TiO2 ETL achieves a higher efficiency of 20.51% than the 19.06% of the pure TiO2 ETL based device, and the hysteresis is reduced from 0.13% to 0.01% with the B-TiO2 based device showing negligible hysteresis behavior.
关键词： perovskite solar cells,hysteresis,interfacial binding,charge transport,titanium dioxide
更新于2025-09-19 17:13:59
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Investigation of polymera??based composites by laser desorption ionization Study of their photoa??oxidative aging
摘要： RATIONALE The polybutadiene (PB) is one of the most widely used polymers. Its aging occurs by reaction with oxygen under illumination and may modify its mechanical and/or aesthetic properties. To modify its properties, organic and/or inorganic compounds are generally added to the PB. The aging of such composite materials is poorly known. METHODS The PB and its mixtures with TiO2 and/or the Orange 13 pigment are subjected to an accelerated photo-oxidative aging step for one week. The analysis of PB and its composites with regard to their composition and the aging time, is carried out by 266 nm and/or 355 nm laser/desorption ionization Fourier transform ion cyclotron resonance mass spectrometry (LDI FT ICR–MS). RESULTS Both PB and its degradation products are detected by (+) LDI FT–ICR MS. The oxidation mechanism of the PB is not significantly affected by the used organic or inorganic fillers, which results from the cleavage of the polymer chain and the formation of carbonyl compounds. The crosslinking of the PB is significantly reduced by the two investigated fillers. The (–) LDI FT–ICR MS ensure the specific detection of the Orange 13 pigment. CONCLUSIONS LDI FT ICR - MS has demonstrated its ability to provide relevant information on the degradation of polymer-based composites. The main advantages of this approach are its ability to probe the surface, which is specifically affected by photo-oxidation aging processes, and to access the insoluble degradation compounds.
关键词： Orange 13 pigment,titanium dioxide,photo-aging,Polybutadiene
更新于2025-09-19 17:13:59
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Potential use of green TiO2 and recycled membrane in a photocatalytic membrane reactor for oil refinery wastewater polishing
摘要： Membrane bioreactors (MBRs) have been successfully used in oil refinery wastewater treatments. However, a polishing treatment of the MBR permeate is required to remove the recalcitrant organic compounds. In this study, the coupling of a photocatalytic membrane reactor (PMR) and MBR was investigated for the treatment of oil refinery wastewater. Titanium dioxide (TiO2) nanoparticles, synthesised by a cleaner route assisted by microwave radiation, and recycled membrane, an end-of-life reverse osmosis membrane converted to an ultrafiltration membrane by oxidation, were prepared for use as a PMR. The recycled membrane could completely retain the catalyst particles. The PMR exhibited higher efficiency and stability in the removal of organic matter than those of the individual photocatalysis and membrane processes. Adsorption of organic compounds was observed on the catalyst surface. These compounds were degraded releasing active sites for reaction/adsorption. A chemical oxygen demand analysis revealed that up to 60% of the organic matter in the MBR permeate was decomposed in the PMR, which also contributed to membrane fouling mitigation. The membrane fouling resistance in the PMR was 7.3 times lower than that in the system operated without the catalyst. In addition, membrane degradation was not observed upon the use of the catalyst. The results indicate that the PMR with the green TiO2 and recycled membrane is a highly active, stable, and promising system for the polishing of oil refinery wastewater previously treated by the MBR.
关键词： oil refinery wastewater,titanium dioxide nanoparticle,recycled membrane,photocatalytic membrane reactor,recalcitrant compound
更新于2025-09-19 17:13:59
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Preparation of Plasmonic Au-TiO2 Thin Films on a Transparent Polymer Substrate
摘要： In this work, plasmonic thin films composed of Au nanoparticles embedded in a TiO2 matrix were prepared in a transparent polymer substrate of poly(dimethylsiloxane) (PDMS). The thin films were deposited by reactive DC magnetron sputtering, and then subjected to heat treatment up to 150 °C in order to promote the growth of the Au nanoparticles throughout the TiO2 matrix. The transmittance spectrum of the thin films was monitored in situ during the heat treatment, and the minimum time required to have a defined localized surface plasmon resonance (LSPR) band was about 10 min. The average size of Au nanoparticles was estimated to be about 21 nm—the majority of them are sized in the range 10‐40 nm, but also extend to larger sizes, with irregular shapes. The refractive index sensitivity of the films was estimated by using two test fluids (H2O and DMSO), and the average value reached in the assays was 37.3 ± 1.5 nm/RIU, resulting from an average shift of 5.4 ± 0.2 nm. The results show that it is possible to produce sensitive plasmonic Au‐TiO2 thin films in transparent polymer substrates such as PDMS, the base material to develop microfluidic channels to be incorporated in LSPR sensing systems.
关键词： localized surface plasmon resonance,gold nanoparticles,thin films,poly(dimethylsiloxane) substrate,reactive magnetron sputtering,titanium dioxide
更新于2025-09-19 17:13:59
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Photoexcitation Processes in Oligomethine Cyanine Dyes for Dye-Sensitized Solar Cellsa??Synthesis and Computational Study
摘要： We report density functional theory (DFT) calculations of three newly synthesized oligomethine cyanine-based dyes as potential TiO2-sensitizers in dye-sensitized solar cells. The three dyes have π-symmetry and the same acceptor side, terminating in the carboxylic anchor, but they differ through the π-bridge and the donor groups. We perform DFT and time-dependent DFT studies and present the electronic structure and optical properties of the dyes alone as well as adsorbed to the TiO2 nanocluster, to provide some predictions on the photovoltaic performance of the system. We analyze theoretically the factors that can influence the short circuit current and the open circuit voltage of the dye-sensitized solar cells. We examine the matching of the absorption spectra of the dye and dye-nanocluster system with the solar irradiation spectrum. We display the energy level diagrams and discuss the alignment between the excited state of the dyes and the conduction band edge of the oxide as well as between the redox level of the electrolyte and the ground state of the dyes. We determine the electron density of the key molecular orbitals and analyze comparatively the electron transfer from the dye to the semiconducting substrate. To put our findings in the right perspective we compare the results of our calculations with those obtained for a coumarin-based dye used in fabricating and testing actual devices, for which experimental data regarding the photovoltaic performance are available.
关键词： optical spectra,titanium dioxide cluster,dye-sensitized solar cells,oligomethine cyanine-based dyes,density functional theory
更新于2025-09-19 17:13:59
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Erythrocyte membrane nano-capsules: biomimetic delivery and controlled release of photothermala??photochemical coupling agents for cancer cell therapy
摘要： Photothermal therapy (PTT), which involves an increase in temperature triggered only by light signals at tumor sites to remove cancer cells, has been considered an attractive strategy in cancer therapy. Nevertheless, the in vivo applications of photosensitizer-based PTT are limited due to the poor biocompatibility of photothermal agents. Employing red blood cell (RBC) membranes to encapsulate photothermal agents can solve this issue, but the extra surface coating will suppress heat dissipation, which is unfavorable for the subsequent treatment. Herein, biomimetic nano-capsules have been fabricated for light signal-activated cancer therapy by encapsulating photocatalyst titanium dioxide colloid and photothermal agent gold nanorods (Au NRs) in erythrocyte membrane vesicles. The fabricated Au/TiO2@RBC nano-capsules can achieve the controlled release of Au NRs upon the photocatalytic degradation of their surface cell membrane coatings, and generate therapeutic signals after the released Au NRs are irradiated by an NIR laser. Meanwhile, the reactive oxygen species (ROS) produced by photocatalysis are helpful for killing tumor cells photodynamically. Thus, the biomimetic nano-capsules prepared herein will contribute to the research and development in cancer cell therapy.
关键词： cancer therapy,titanium dioxide,red blood cell membranes,biomimetic nano-capsules,gold nanorods,Photothermal therapy
更新于2025-09-19 17:13:59
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Engineering black titanium dioxide by femtosecond laser filament
摘要： We propose an approach, by utilizing the propagation of femtosecond laser pulses in the filamentation region in air, to achieve black titanium dioxide (TiO2), a promising material for efficient photocatalysis. It is found that the black TiO2 engineered by femtosecond laser filament in both solution and air environments shows significantly improved absorption in a broad spectral range from 400 to 2500 nm. In addition, the engineered black TiO2 shows a certain degree of enhanced absorption in the microwave range. The structural and elemental analysis of the processed TiO2 suggest that the absorption enhancement is mainly ascribed to the filament-induced disorder and dopant impurity in the surface layer of crystalline TiO2. Our technique provides an alternative way to engineer black TiO2 with the capability of absorbing the solar energy across a broad spectrum that can be useful for various applications in optoelectronics and photochemistry.
关键词： femtosecond laser filamentation,disordered surface,solar energy,titanium dioxide,absorption enhancement,laser processing
更新于2025-09-19 17:13:59
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Improved perovskite solar cell with 2H–TaS2 nanosheets as an electron transport layer using microwave irradiation
摘要： In addition to the absorber ingredient of the perovskite, electron- and hole-transport materials deposited on each side of a perovskite active layer can play essential roles in the stability and overall power conversion efficiency (PCE) of a device. Herein, we developed and used a novel, stable, and efficient electron transport layer (ETL) as a Tantalum (IV) sulfide (2H-TaS2) nanosheets for perovskite solar cells (PSCs) which up to now not investigated in PSC. Synthesis of 2H-TaS2 transparent thin films was performed directly on the fluorine-doped tin oxide (FTO) substrate, using microwave irradiation. The electrical characteristics of 2H-TaS2 thin film with state-of-the-art efficient electron transporting materials such as SnO2 and TiO2 are measured and compared. Device structure based on 2H-TaS2 in our work being: Glass/FTO/2H-TaS2/perovskite/P3HT/Gold, indicate power photoelectric conversion efficiency (PCE) of 15.23% which is close to the obtained PCEs of compact SnO2 and TiO2 electron transport layer based PSCs. The results showed, high electrical conductivity, the better property of charge transfer, and good transparency layer in the visible region (400-900 nm) with 2H-TaS2 thin film. So, theses reasons included a process of low-temperature synthesis, beneficial for energy harvesting and other optoelectronic applications for 2H-TaS2 thin film.
关键词： Perovskite solar cells,Tantalum (IV) sulfide,Tin (IV) Oxide,Titanium dioxide
更新于2025-09-19 17:13:59
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MODIFIED ABSORPTION FEATURES OF TITANIA-ERBIUM INCORPORATED PLASMONIC TELLURITE GLASS SYSTEM
摘要： Achieving efficient lasing glass materials with enhanced absorption and emission cross-section by reducing the Rare Earth (RE) concentration quenching is a challenging issue. Metal nanoparticles (NPs) together with RE ions in the glass matrix are thought as a suitable alternative to overcome the limitations of concentration quenching and weak absorption of inorganic glasses. We prepare a series of Titania-Erbium doped Tellurite glass system with the form (69-x)TeO2-20ZnO-10Na2O-1Er2O3-(x)TiO2, where 0 ≤ x≤ 1.0 mol% via melt-quenching method with optimum erbium contents and varying TiO2 NPs concentrations. The NPs concentration dependent modifications in the absorption characteristics are scrutinized. Glasses are characterized via UV-Vis-NIR and XRD measurements. XRD pattern verifies the amorphous nature of prepared samples. The incorporation of TiO2 NPs is demonstrated to enhance the absorption intensity significantly. This augmentation is attributed to the effect of Surface Plasmon Resonance (SPR) mediated strong local electric field that is swallowed by neighboring Er3+ ions. The observed modification in optical energy band gap and Urbach energy are ascribed to the strong electric field around NPs that interact with the ligand of glass network to transform weak bond into defects. This observation is useful for the development of plasmonic nanoglass materials applicable for photonic devices.
关键词： absorption spectra,Tellurite glass,titanium dioxide nanoparticle
更新于2025-09-19 17:13:59
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Performance improvement of inverted perovskite solar cells using TiO2 nanorod array and mesoporous structure
摘要： In view of the low carrier mobility of organic materials, the carrier collection ability was suffered from the short transport length before carriers were recombined. To improve performances by enhancing carrier collection ability, the optimal period was 1.5 μm which was obtained by changing the period of titanium dioxide (TiO2) nanorod array in the inverted perovskite solar cells (IPSCs). The power conversion efficiency was improved to 11.96% from the 7.66% of the standard planar IPSCs. Besides, due to the inherent properties of high absorption surface area and high light scattering ability, the 150-nm-thick TiO2 mesoporous layer was embedded in the TiO2 electron transport layer. By changing the annealing temperature, the optimal crystallinity of anatase phase and the optimal porous distribution were obtained in the TiO2 mesoporous layers annealed at 500 °C for 30 min. Using the optimal annealed TiO2 mesoporous layers in the IPSCs, the power conversion efficiency was improved to 12.73%. The power conversion efficiency of 14.47% was obtained for the IPSCs embedded with the optimal 1.5-μm-periodic TiO2 nanorod array and the optimal 500 °C-annealed TiO2 mesoporous layer in the electron transport layer, simultaneously.
关键词： Nanorod array,Laser interference lithography system,Titanium dioxide material,Mesoporous layer,Inverted perovskite solar cells
更新于2025-09-16 10:30:52