Fluorine Co-doping Research Articles

Surface Charge Regulation of Graphene by Fluorine and Chlorine Co-Doping for Constructing Ultra-Stable and Large Energy Density Micro-Supercapacitors.

Settling the structure stacking of graphene (G) nanosheets to maintain the high dispersity has been an intense issue to facilitate their practical application in the microelectronics-related devices. Herein, the co-doping of the highest electronegative fluorine (F) and large atomic radius chlorine (Cl) into G via a one-step electrochemical exfoliation protocol isengineered to actualize the ultralong cycling stability for flexible micro-supercapacitors (MSCs). Density functional theoretical calculations unveiled that the F into G can form the "ionic" C─F bond to increase the repulsive force between nanosheets, and the introduction of Cl can enlarge the layer spacing of G as well as increase active sites by accumulating the charge on pore defects. The co-doping of F and Cl generates the strong synergy to achieve high reversible capacitance and sturdy structure stability for G. The as-constructed aqueous gel-based MSC exhibited the superb cycling stability for 500,000 cycles with no capacitance loss and structure stacking. Furthermore, the ionic liquid gel-based MSC demonstrated a high energy density of 113.9mWhcm-3 under high voltage of up to 3.5V. The current work enlightens deep insights into the design and scalable preparation of high-performance co-doped G electrode candidate in the field of flexible microelectronics.

Fluorine and Nitrogen Codoped Carbon Nanosheets In Situ Loaded CoFe2O4 Particles as High-Performance Anode Materials for Sodium Ion Hybrid Capacitors

Fluorine and Nitrogen Codoped Carbon Nanosheets In Situ Loaded CoFe₂O₄ Particles as High-Performance Anode Materials for Sodium Ion Hybrid Capacitors

Self-Powered Electrochemical CO2 Conversion Enabled by a Multifunctional Carbon-Based Electrocatalyst and a Rechargeable Zn-Air Battery.

Multifunctional electrocatalysts are required for diverse clean energy-related technologies (e.g., electrochemical CO2 reduction reaction (CO2RR) and metal-air batteries). Herein, a nitrogen and fluorine co-doped carbon nanotube (NFCNT) is reported to simultaneously achieve multifunctional catalytic activities for CO2RR, oxygen reduction reaction (ORR), and oxygen evolution reaction (OER). Theoretical calculations reveal that the superior multifunctional catalytic activities of NFCNT are attributed to the synergistic effect of nitrogen and fluorine co-doping to induce charge redistribution and decrease the energy barrier of rate-determining step for different electrocatalytic reactions. Furthermore, the rechargeable Zn-air battery (ZAB) with NFCNT electrode delivers a high peak power density of 230mWcm-2 and superior durability over 100 cycles, outperforming the ZAB with Pt/C+RuO2 based electrodes. More importantly, a self-driven CO2 electrolysis unit powered by the as-assembled ZABs is developed, which achieves 80% CO Faraday efficiency and 60% total energy efficiency. This work provides a new insight into the exploration of highly efficient multifunctional carbon-based electrocatalysts for novel energy-related applications.

Synthesis of selenium and fluorine co-doped graphitic carbon nitride for photodegradation of toxic organic pollutants and hydrogen peroxide photoproduction

Science is developing every day to race against the factual growth of industrial pollution in order to redeem the environment. In this study, modification of graphitic carbon nitride via selenium and fluoride doping was successfully conducted. Specifically, the process of co-calcination was conscripted using organic precursors, whilst the foreign elements were obtained from ammonium fluoride and selenium dioxide. The morphological assessment revealed the treated-graphitic carbon nitride possessed a flaky sheet form with high porosity and great crystalline uniformity. Photochemical investigation showed the co-doping of selenium and fluorine elevated the optical properties, including the decrement of bandgap and diminishing the recombination rate of electrons and holes. With interesting improvement in photocatalytic activity, the material was applied in persistent organic compound degradation and hydrogen peroxide production. The treatment improved the degradation percentage, in which the methylene blue removal achieved 99.96 % while the tetracycline removal reached 86.38 %. Moreover, high compatibility and great reusability over 4 cycles were also recorded. When applying the material for the generation of hydrogen peroxide, the co-doped material performance was observed to reach 3307 μM/g.h. The results concluded the advancement in material modification with great application in various aspects.

Tungsten and fluorine co-doping induced morphology change and textured growth of spray-pyrolyzed SnO2 thin films viable for photocatalytic application

Physicochemical aspects of numerous metal oxide based thin films are crucial for various optoelectronic applications. Cationic (W) and anionic (F) co-doping strategy into SnO2 thin film has been adapted in order to tune the optoelectronic parameters. X-ray diffraction pattern reveals successful doping of ‘W’ and ‘F’ into the SnO2 lattice and textured growth along (111) plane direction at the expense of suppression of the (211) plane. X-ray photoelectron spectroscopy confirmed the charge states of Sn4+, W6+, O2− and F1− elements present in the films. Scanning electron microscopy shows that tetragonal morphology of pure and F-doped SnO2 changes to a network-like feature upon ‘W’ co-doping and the elemental composition is also ensured. The contact angle measurement gives the surface wettability nature, which indicates all the films are hydrophilic. The 10 wt.% F-doped SnO2 shows a maximum transmittance of 89.36 % at 550 nm with a direct band gap of 3.82 eV. Electrical transport parameters are measured using linear four-probe and Hall effect techniques. Photocatalytic activity of methylene blue dye degradation showing a maximum efficiency for pure and solely F-doped SnO2 thin films are explained based on the obtained optoelectronic parameters.

Anionic Fluorine and Cationic Niobium Codoped Tin Oxide Thin Films as Transparent Conducting Electrodes for Optoelectronic Applications

Exploration of alternatives for supplementing indium tin oxide electrode is currently trending due to scarcity of indium, leading to a steep increase in the cost of related optoelectronic components. Codoping of niobium (Nb) and fluorine (F) into SnO2 lattice as cationic and anionic dopants, respectively, is explored by spray deposition technique. A fixed 10 wt% F and varying Nb concentration from 0 to 5 wt% is incorporated into the SnO2 lattice. X‐ray diffraction reveals substitution of Nb and F into the SnO2 lattice without altering the structure. Optical transmittance is found to increase with Nb content up to 4% of Nb (77.59%), and it decreases thereafter. Scanning electron microscope and optical profiler imply a relatively smooth surface with sharp‐tipped particles which vary with Nb concentration. Sheet resistance decreases up to 3 wt% of Nb doping and increases thereafter. Contact angle measurement indicates that upon doping with Nb, the films turn hydrophilic. Among the deposited films, 4 wt% of Nb‐doped film shows the highest figure of merit of 5.01 × 10−3 Ω−1. The surface work function of the 4 wt% Nb‐doped SnO2 film is 4,687.85 meV. The optimal films are tested as electrodes in dye‐sensitized solar cells and are discussed in detail.

Boron and fluorine Co-doped laser-induced graphene towards high-performance micro-supercapacitors

Laser-induced graphene (LIG) has attracted extensive research as an electrode material for micro-supercapacitors (MSC). However, the low capacitive performance of LIG arising from both limited specific surface area and few active sites remains challenging. Herein, in situ doping of fluorine and boron atoms into laser-induced graphene was innovatively achieved via laser direct writing approach using boron-doped fluorinated polyimide (FB-PI) as the precursor. The porous fluorine and boron co-doped laser-induced graphene (FB-LIG) exhibits more active sites and improved wettability and significantly enhanced capacitive performance due to the synergistic effect of fluorine and boron co-doping. By tuning the weight ratio of boron to fluorine, the MSC utilizing FB-LIG as the electrode and poly(vinyl alcohol) (PVA)/H2SO4 as the gel electrolyte delivers a high areal capacitance of 49.81 mF/cm2 at a current density of 0.09 mA/cm2, 23 times higher that of MSC from commercial polyimide (PI)-based LIG, and 3 times that of MSC from fluorinated PI-based LIG. In addition, MSCs from FB-LIG possess excellent mechanical stability and flexibility, rendering them promising for flexible wearable microelectronics.

Formation of Highly-Activated N-Type Shallow Junction in Germanium Using Nanosecond Laser Annealing and Fluorine Co-Doping

By employing a 355-nm nanosecond (ns) ultraviolet (UV) laser annealing, the impact of fluorine (F) co-doping on the formation of a highly activated N-type shallow junction in germanium (Ge) is investigated. Secondary ion mass spectrometry (SIMS) depth profiling of phosphorus (P) demonstrated that an ultra high P concentration of 9 × 1020 cm−3 at a shallow junction of 55 nm with less dopant diffusion can be obtained using ns laser annealing. F co-doping was confirmed to be an efficient way to improve the activation of the P dopants, but show less influence on the redistribution of P dopants within the NLA melted region. However, the activation level of the shallow junction could be increased to approximately 1 × 1020 cm−3 in the presence of F at an optimized concentration.

Ti, F Codoped Sodium Manganate of Layered P2-Na 0.7 MnO 2.05 Cathode for High Capacity and Long-Life Sodium-Ion Battery

Open AccessRenewablesRESEARCH ARTICLES14 Jan 2023Ti, F co-doped Sodium Manganate of Layered P2-Na0.7MnO2.05 Cathode for High Capacity and Long-life Sodium Ion Battery Pengchao Wen, Haodong Shi, Dandan Guo, Aimin Wang, Yan Yu and Zhong-Shuai Wu Pengchao Wen Google Scholar More articles by this author , Haodong Shi Google Scholar More articles by this author , Dandan Guo Google Scholar More articles by this author , Aimin Wang Google Scholar More articles by this author , Yan Yu Google Scholar More articles by this author and Zhong-Shuai Wu Google Scholar More articles by this author https://doi.org/10.31635/renewables.022.202200012 SectionsSupplemental MaterialAboutPDF ToolsAdd to favoritesDownload CitationsTrack Citations ShareFacebookTwitterLinked InEmail The development of layered sodium manganese oxides cathode materials with high capacity and structural stability is one of the keys to boost the performance of sodium-ion batteries (SIBs), but remains a great challenge. Herein, a titanium and fluorine co-doped P2 type sodium manganate of Na0.7MnO2.05 cathode material (NMO-0.1TF) is developed as high-capacity and long-durable cathode for high-performance SIBs. The titanium and fluorine co-doping could significantly reduce the structural deformation, synergistically improved structural stabilization, inhibit the formation of irreversible phases and enhance electrochemical kinetics. As a result, the NMO-0.1TF||Na battery working in the voltage ranges of 2.0-4.2 V exhibits a high specific capacity of 227 mAh g-1 at current density of 20 mA g-1, and excellent rate performance (76 mAh g-1 at a high current density of 3 A g-1). Such battery still delivers an outstanding cycle stability, shows a high initial discharge capacity of 133 mAh g-1 at 1 A g-1, and maintains the initial capacity of 96.2% after 200 cycles. More importantly, the assembled full battery of NMO-0.1TF||hard carbon validates high capacity and impressive cyclability. Therefore, this co-doped NMO-0.1TF cathode with high capacity and excellent stability presents brilliantly practical application for developing high energy density SIBs. Download figure Download PowerPoint Previous articleNext article FiguresReferencesRelatedDetails Issue AssignmentNot Yet AssignedSupporting Information Copyright & Permissions© 2023 Chinese Chemical Society Downloaded 7 times PDF downloadLoading ...

Influence of Fluorine and Nitrogen Co-Doping on the Structural and Morphological Properties of Sol-Gel ZnO Films

The structural, vibrational, optical and morphological properties of ZnO:N:F films, obtained by the sol-gel method, were investigated. The effect of single (fluorine, nitrogen) and F, N co-doping and thermal treatments (300–600 °C) on the properties of ZnO films was analyzed. X-ray Diffraction (XRD) revealed that ZnO:N:F films crystallized in a polycrystalline wurtzite structure. F and N incorporation changed lattice parameters, crystallite sizes, texture coefficients (TC) and residual stress. TC (002) of ZnO:N:F films increased with annealing, reaching 1.94 at 600 °C lower than the TC (002) of ZnO and ZnO:N films. The shifting of the characteristic absorption bands and/or the appearance of new IR lines were detected for ZnO:N:F samples. The highest transmittance (90.98%) in the visible spectral region was found for ZnO:F films. ZnO:N:F films possessed optical transparency up to 88.18% and their transmittance decreased at the higher annealings. The optical band gap (Eg) values of ZnO:N:F films were changed with fluorine and nitrogen concentrations. The formation of the wrinkle-like structures on the surface of ZnO and ZnO:N films was depicted in Field Emission Scanning Electron Microscopy (FESEM) images. The F, N dual doping modified ZnO morphology and suppressed wrinkle formation.

Nitrogen and Fluorine Codoped Graphite Derived from Microcrystalline Graphite ore as a High-performance Anode Material for Potassium-Ion Batteries

Nitrogen and Fluorine Codoped Graphite Derived from Microcrystalline Graphite ore as a High-performance Anode Material for Potassium-Ion Batteries

Synthesis of Ti6Al4V/SrFHA Composites by Microwave-Assisted Liquid Phase Deposition and Calcination.

The feasibility of synthesis of Ti6Al4V/SrFHA (Ca9.37Sr0.63(PO4)6F2) composites via coating strontium and fluorine co-doped HA to Ti6Al4V substrate by microwave-assisted liquid phase deposition and calcination was evaluated, with a focus on the effect of the deposition temperature from 30 °C to 70 °C. The outcomes demonstrate that strontium and fluorine can be successfully doped into HA to form a SrFHA coating with modified micromorphology which is deposited on the alloy. When the deposition temperature was 50 °C, the coating with the largest uniform continuous SrFHA coverage was obtained. After calcination, the adhesion strength and Vickers microhardness of the Ti6Al4V/SrFHA composite increased from 0.68 MPa and 323 HV to 2.41 MPa and 329 HV, respectively, with a decrease in the water contact angle from 10.88° to 7.24°, exhibiting enhancement of both mechanical properties and wettability. Moreover, the composite obtained at the deposition temperature of 50 °C exhibited good bioactivity based on the simulate body fluid (SBF) test. On account of the above features primarily as a result of the combined effect of the co-doping of strontium and fluorine, high crystallinity of SrFHA, large surface roughness, and formation of the titanium oxide transition layer, the Ti6Al4V/SrFHA composite shows great potential in dental implantology.

Efficient charge transfers in hematite photoanode integrated by fluorine and zirconia co-doping for photoelectrochemical water splitting

Dual elemental doping strategies were employed in this study to fabricate fluorine and zirconia co-doped hematite (F–Zr:Fe2O3/FTO) photoanodes. Such F–Zr:Fe2O3/FTO photoanodes had a (110)-oriented structure with a remarkable photocurrent density of 1.91 mA cm−2 without any catalyst support at water oxidation potential of 1.23 VRHE. The enhancement in net photocurrent density was attributed to the synergistic effect between the two doping elements. When in situ doped Zr4+ ions were used to substitute iron ions, they increase photogenerated free electrons within the bulk hematite and resulted in lower bulk charge transfer resistance, and a minimal concentration of F was doped into hematite lattice, it would go into the oxygen site rather than the iron site, resulting in more positive charges on iron site. The charge compensation contributed to reduced recombination of free electron–hole pairs and improved surface charge injection efficiency at the semiconductor–electrolyte interface by promoting hole transfer via surface states.

Effect of fluorine and niobium co-doping on boosting the NIR blocking performance of TiO2 nanoparticles for energy efficient window

Development of novel solar shielding materials is significantly important for energy efficient windows.In this work, F-Nb codoped TiO2 (NFTO) nanoparticles with enhanced infrared radiation blocking property were synthesized for energy efficient windows. The results indicated that the co-doping of F and Nb promoted the formation of spindle-like anatase TiO2 nanocrystals. XRD, Raman and XPS studies revealed that Nb and F were successfully codoped into TiO2. The co-doping of F and Nb generated more free electrons in TiO2 crystals, which was confirmed by the bandgap widening phenomenon. The electron concentration of F-Nb doped TiO2 was as high as 3.5 × 1020 cm−3. Due to the enhanced plasmon resonance, the infrared blocking property of the films was vastly boosted by co-doping with niobium and fluorine. The NIR blockage efficiency of the NFTO films with a thickness of 176 μm reached 68.5%. Furthermore, the visible transparency of NFTO films was higher than 76%. In the thermal tests, the NFTO films reduced the indoor temperature by 8.8℃. Our results show thatthe F-Nb doped TiO2 nanocrystals are promising for energy efficient windows applications.

Realization of UV-C absorption in ZnO nanostructures using fluorine and silver co-doping

In this study, we realized absorption in UV-C region using silver (Ag) and fluorine (F) co-doping in zinc oxide (ZnO). Also, the influence of Ag and F co-doping in ZnO on the morphological, compositional, structural, and optical properties using the hydrothermal method were investigated. The result shows that vertically aligned nanorods (NRs) of different dimensions were observed using field emission scanning electron microscopy (FESEM). Wurtzite hexagonal structure and polycrystalline nature of the samples were confirmed through X-ray diffraction (XRD) analysis. The crystallite size increased from 29.92 to 35.81 nm and microstrains values were decreased upon co-doping. Energy dispersive X-ray (EDX) analysis confirmed the existence of zinc, oxygen, silver, fluorine, and oxygen deficiency in all the studied samples. Ultra-violet (UV) visible analysis has shown a decrement in the optical energy bandgap from 3.273 to 3.179 eV upon co-doping with the appearance of two absorption edges. The additional optical characteristics comprising absorption coefficient (α), skin depth, optical density (OD), extinction coefficient (k) were also explained. Photoluminescence (PL) analysis has shown that the ZnO native visible defects were suppressed significantly upon co-doping, showing crystal quality improvement as revealed by XRD analysis.

Efficient Charge Transfers in Hematite Photoanode Integrated by Fluorine and Zirconia Co-Doping for Photoelectrochemical Water Splitting

Efficient Charge Transfers in Hematite Photoanode Integrated by Fluorine and Zirconia Co-Doping for Photoelectrochemical Water Splitting

Origins of radiation-induced attenuation in pure-silica-core and Ge-doped optical fibers under pulsed x-ray irradiation

We investigated the nature, optical properties, and decay kinetics of point defects causing large transient attenuation increase observed in silica-based optical fibers exposed to short duration and high-dose rate x-ray pulses. The transient radiation-induced attenuation (RIA) spectra of pure-silica-core (PSC), Ge-doped, F-doped, and Ge + F-doped optical fibers (OFs) were acquired after the ionizing pulse in the spectral range of [∼0.8–∼3.2] eV (∼1500–∼380 nm), from a few ms to several minutes after the pulse, at both room temperature (RT) and liquid nitrogen temperature (LNT). Comparing the fiber behavior at both temperatures better highlights the thermally unstable point defects contribution to the RIA. The transient RIA origin and decay kinetics are discussed on the basis of already-known defects absorbing in the investigated spectral range. These measurements reveal the importance of intrinsic metastable defects such as self-trapped holes (STHs), not only for PSC and F-doped fibers but also for germanosilicate optical fibers as clearly evidenced by our LNT measurements. Furthermore, our results show that fluorine co-doping seems to decrease the RIA related to the strain-assisted STHs absorption bands in both types of optical fibers. Regarding Ge-doped glasses, besides a description of the defects responsible of the RIA, highlighting the STHs' role in their transient response, we provide a clear correlation between the GeX and GeY centers’ kinetics. In conclusion, the presented results improve our understanding of the transient RIA origin in the ultraviolet and visible domains. The lack of knowledge about the defects causing the RIA in the near-infrared domain will require future studies.

Enhanced optical and thermoelectric properties of ZnO by tin and fluorine codoping: First-principles DFT calculations

Ab initio density functional calculations of the structural, optoelectronic, thermoelectric and thermodynamic properties of ZnO codoped with tin and fluorine with possible application as Transparent Conductive Oxides (TCO’s), are reported in this work. This study shows that incorporation of Sn and F into the ZnO matrix converts it to a degenerate semiconductor. The calculated optical absorption coefficients show that the four compounds ZnO, Sn:ZnO, F:ZnO and Sn:F:ZnO have transparent properties in the visible range. At 900[Formula: see text]K, the Seebeck coefficient of Sn:F:ZnO is greatly improved with respect to the undoped ZnO. A maximum electrical conductivity value of [Formula: see text]S cm[Formula: see text]s[Formula: see text] is predicted for Sn-doped ZnO. ZT increases with temperature to a maximum value of 0.13 at 900[Formula: see text]K for tin and fluorine codoped ZnO.

Novel Sponge-like Structure of a High-Capacity Nitrogen–Fluorine Codoped Reduced Graphene (N, F-rGO) Film Electrode and Electrochemical Performance in Lithium-Ion Batteries

The nitrogen–fluorine-codoped reduced GO film (N, F-rGO film) is prepared by a simple one-step pyrolysis process. The as-prepared N, F-rGO film displays a loose porous structure between layers, and the N- and F-doping contents of the resulting N, F-rGO film were 4 and 1.3%, respectively. As a negative electrode for lithium-ion batteries (LIBs), the as-prepared N, F-rGO film exhibits high reversible capacity and good cycle stability. It delivers an initial discharge capacity of 2133 mA h g–1 and a high reversible specific discharge capacity of 878 mA h g–1 at the current density of 200 mA g–1. Even at the current density of 2 A g–1, the reversible specific capacity could be 344 mA h g–1 after 500 cycles. The N, F-double doping and the high-surface area mesoporous structure of rGO provide efficient ionic diffusion path, offering sufficient active sites for lithium-ion storage, resulting in excellent electrochemical performance.

The synergistic effect of nitrogen and fluorine co-doping in graphene quantum dot catalysts for full water splitting and supercapacitor

Development of efficient electrochemical catalysts is crucial for clean energy technologies such as water splitting, and batteries, etc. Despite large amounts of electrocatalyst research, it remains a challenge to eco-friendly non-metal catalyst showing high performance as much as novel metal. To achieve high performance as much as noble-metal, carbon nanomaterials (CNMs) have been attracted as a candidate to the widespread application using electrochemical reaction. Herein, we report nitrogen, and fluorine co-doped graphene quantum dot (N,F-GQDs) synthesized by two-step functionalizing method for highly efficient overall water splitting. N,F-GQDs demonstrate electrocatalytic effect toward HER, and OER, and is fabricated as two-electrode full-water splitting showing good stability at various potential points. Furthermore, due to fluorine treatment, prepared N,F-GQDs exhibits enhanced electrochemical reaction property, which can induce capacitance due to the large difference of electronegativity between fluorine and carbon. N,F-GQDs is applied for the anode of super capacitance in the three-electrode system and reveal specific capacitance of 270 F g−1 at 1 mV s−1 from CV curves, and GCD capacitance of 244 F g−1 at 3 mA cm−2. This work provides a new avenue for enhancing both activities of the electrocatalytic and electrochemical reaction.