Organic field‐effect transistors incorporating planar π‐conjugated metal‐free macrocycles and their metal derivatives are fabricated by vacuum deposition. The crystal structures of [H2(OX)] (H2OX=etioporphyrin‐I), [Cu(OX)], [Pt(OX)], and [Pt(TBP)] (H2TBP=tetra‐(n‐butyl)porphyrin) as determined by single crystal X‐ray diffraction (XRD), reveal the absence of occluded solvent molecules. The field‐effect transistors (FETs) made from thin films of all these metal‐free macrocycles and their metal derivatives show a p‐type semiconductor behavior with a charge mobility (μ) ranging from 10?6 to 10?1 cm2 V?1 s?1. Annealing the as‐deposited Pt(OX) film leads to the formation of a polycrystalline film that exhibits excellent overall charge transport properties with a charge mobility of up to 3.2×10?1 cm2 V?1 s?1, which is the best value reported for a metalloporphyrin. Compared with their metal derivatives, the field‐effect transistors made from thin films of metal‐free macrocycles (except tetra‐(n‐propyl)porphycene) have significantly lower μ values (3.0×10?6–3.7×10?5 cm2 V?1 s?1). 相似文献
Poly(hydroxyethylmethacrylate)‐based hydrogel membranes were applied to microfabricated, microdisk electrode arrays (MDEAs) of 50 μm (5184 disks), 100 μm (1296 disks) and 250 μm (207 disks) (d/r=4; A= 0.1 cm2) and studied by cyclic voltammetry (CV) in 1.0 mM ferrocene monocarboxylic acid (FcCO2H). The membrane produced an order of magnitude decrease in current densities and a shift to quasi reversibility due to a decrease in the Dappt of FcCO2H, from 4.51×10?6 cm2 s?1 to 1.42×10?8 cm2 s?1, (2.18×10?8 cm2 s?1 from release experiments). The MDEA050 (comprising 50 μm disks) maintained its enhanced current density attributes confirming its value as an effective electrode for biosensors. Finite element modeling (FEM) simulations successfully replicated the voltammograms of the MDEAs. 相似文献
We present a study of electrical and optical properties of nitrogen‐doped tin oxide thin films deposited on glass by the DC Magnetron Sputtering method. The deposition conditions to obtain p‐type thin films were a relative partial pressure between 7% and 11% (N2 and/or O2), a total working pressure of 1.8 mTorr and a plasma power of 30 W. The deposited thin films were oxidized after annealing at 250°C for 30 minutes. X‐ray diffraction results showed that the as‐deposited thin films exhibit a Sn tetragonal structure, and after annealing, they showed SnO tetragonal structure. X‐ray photoelectron spectroscopy results showed the presence of nitrogen in the samples before and after annealing. The measured physical parameters of the thin films were optical band gap between 1.92 and 2.68 eV, resistivity between 0.52 and 5.46 Ωcm, a concentration of p‐type carriers between 1018 and 1019 cm?3, and a Hall mobility between 0.1 and 1.94 cm2V?1s?1. These thin films were used to fabricate p‐type thin film transistors. 相似文献
Two‐dimensional (2D) AA′n?1MnX3n+1 type halide perovskites incorporating straight‐chain symmetric diammonium cations define a new type of structure, but their optoelectronic properties are largely unexplored. Reported here is the synthesis of a centimeter‐sized AA′n?1MnX3n+1 type perovskite, BDAPbI4 (BDA=NH3C4H8NH3), single crystal and its charge‐transport properties under X‐ray excitation. The crystal shows a staggered configuration of the [PbI6]4? layers, a band gap of 2.37 eV, and a low trap density of 3.1×109 cm?3. The single‐crystal X‐ray detector exhibits an excellent sensitivity of 242 μC Gyair?1 cm?2 under the 10 V bias (0.31 V μm?1), a detection limit as low as 430 nGyair s?1, ultrastable response current, a stable baseline with the lowest dark current drift of 6.06×10?9 nA cm?1 s?1 V?1, and rapid response time of τrise=7.3 ms and τfall=22.5 ms. These crystals are promising candidates for the next generation of optoelectronic devices. 相似文献
Photoresists are essential for the fabrication of flexible electronics through all-photolithographic processes. Single component semiconducting photoresist exhibits both semiconducting and photo-patterning properties, and as a result, the device fabrication process can be simplified. However, the design of semiconducting polymeric photoresist with ambipolar semiconducting property remains challenging. In this paper, we report a single component semiconducting photoresist (PFDPPF4T-N3) by incorporating azide groups and noncovalent conformation locks into the side alkyl chains and conjugated backbones of a diketopyrrolopyrrole-based conjugated polymer, respectively. The results reveal that PFDPP4FT-N3 exhibits ambipolar semiconducting property with hole and electron mobilities up to 1.12 and 1.17 cm2 V?1 s?1, respectively. Moreover, field effect transistors with the individual photo-patterned thin films of PFDPPF4T-N3 also show ambipolar semiconducting behavior with hole and electron mobilities up to 0.66 and 0.80 cm2 V?1 s?1, respectively. These results offer a simple yet effective design strategy for high-performance single component semiconducting photoresists, which hold great potential for flexible electronics processed by all photolithography.
Carbon-coated Na3V2(PO4)3 (NVP) was prepared by a standard sol–gel procedure. The apparent diffusion coefficients of sodium ions in the rhombohedral NVP have been determined by different techniques such as galvanostatic intermittent titration technique (GITT) and cyclic voltammetry (CV). It was found that the apparent diffusion coefficients range from 6?×?10?13 cm2 s?1 to 2?×?10?15 cm2 s-1. These sodium ion apparent diffusion coefficients follow a similar trend as observed for lithium ions in the closely related monoclinic modification of Li3V2(PO4)3, demonstrating a minimum at the potential where the ion extraction/insertion occurs. 相似文献
A new single‐source precursor, [SnCl4{OC(H)OC2H5}2], prepared by treating tin tetrachloride with ethyl formate (1:2 ratio) was developed for the deposition of tin oxide thin films on glass substrates. The compound [SnCl4{OC(H)OC2H5}2] is highly volatile and provides very high growth rates (up to 100Å s?1 at 560 °C) in an atmospheric pressure chemical vapor deposition (APCVD) reactor. More significantly, the compound does not decompose to tin oxide below 320 °C, thereby minimizing the formation of particles in the vapor above the growing tin oxide film. To prepare highly conducting fluorine doped tin oxide (SnO2:F) films 2,2,2‐trifluoroethyl trifluoroacetate was used as the source of fluoride. High quality SnO2:F films were deposited at 560 °C with a flow rate of 2 mL fluoride reagent hr?1; typical film properties are resistivity of 5.9 X 10?4 Ω cm, Hall mobility of 27.3 cm2 V?1 s?1, carrier concentration of 3.9 X 1020 cm?3 and percent transmission ranging from 86 to 88 %. The best films of SnO2:F possess transparencies as high as 90 % (750 nm), sheet resistances as low as 7 Ω sq?1 and Haacke's figure of merit as high as 29 X 10?3 (750 nm). The newly developed APCVD reactor and the chemistry were optimized with respect to structural, electrical and optical properties of the films by adjusting the substrate temperature, gas flow rates and the amount of fluoride present in the vapor stream. Growth rates with respect to deposition time, substrate temperature and flow rates of precursors were found to be similar for both undoped (SnO2) and doped (SnO2:F) samples. The SnO2:F films possess larger grains than the SnO2 which may account for the lower resistivity and the higher mobility in the SnO2:F samples. 相似文献
Electron‐transporting organic semiconductors (n‐channel) for field‐effect transistors (FETs) that are processable in common organic solvents or exhibit air‐stable operation are rare. This investigation addresses both these challenges through rational molecular design and computational predictions of n‐channel FET air‐stability. A series of seven phenacyl–thiophene‐based materials are reported incorporating systematic variations in molecular structure and reduction potential. These compounds are as follows: 5,5′′′‐bis(perfluorophenylcarbonyl)‐2,2′:5′,‐ 2′′:5′′,2′′′‐quaterthiophene ( 1 ), 5,5′′′‐bis(phenacyl)‐2,2′:5′,2′′: 5′′,2′′′‐quaterthiophene ( 2 ), poly[5,5′′′‐(perfluorophenac‐2‐yl)‐4′,4′′‐dioctyl‐2,2′:5′,2′′:5′′,2′′′‐quaterthiophene) ( 3 ), 5,5′′′‐bis(perfluorophenacyl)‐4,4′′′‐dioctyl‐2,2′:5′,2′′:5′′,2′′′‐quaterthiophene ( 4 ), 2,7‐bis((5‐perfluorophenacyl)thiophen‐2‐yl)‐9,10‐phenanthrenequinone ( 5 ), 2,7‐bis[(5‐phenacyl)thiophen‐2‐yl]‐9,10‐phenanthrenequinone ( 6 ), and 2,7‐bis(thiophen‐2‐yl)‐9,10‐phenanthrenequinone, ( 7 ). Optical and electrochemical data reveal that phenacyl functionalization significantly depresses the LUMO energies, and introduction of the quinone fragment results in even greater LUMO stabilization. FET measurements reveal that the films of materials 1 , 3 , 5 , and 6 exhibit n‐channel activity. Notably, oligomer 1 exhibits one of the highest μe (up to ≈0.3 cm2 V?1 s?1) values reported to date for a solution‐cast organic semiconductor; one of the first n‐channel polymers, 3 , exhibits μe≈10?6 cm2 V?1 s?1 in spin‐cast films (μe=0.02 cm2 V?1 s?1 for drop‐cast 1 : 3 blend films); and rare air‐stable n‐channel material 5 exhibits n‐channel FET operation with μe=0.015 cm2 V?1 s?1, while maintaining a large Ion:off=106 for a period greater than one year in air. The crystal structures of 1 and 2 reveal close herringbone interplanar π‐stacking distances (3.50 and 3.43 Å, respectively), whereas the structure of the model quinone compound, 7 , exhibits 3.48 Å cofacial π‐stacking in a slipped, donor‐acceptor motif. 相似文献
The vanadium pentoxide (V2O5) films were deposited on silicon wafer by DC magnetron sputtering. By Raman scattering measurements, the microstructure properties of the V2O5 films prepared with different O2–Ar gas flow ratios and annealed at different temperatures were studied, respectively. The results revealed that the increase of O2–Ar gas flow ratio during sputtering was of advantage to prepare the V2O5 film with desired layer structure. A high post-annealing temperature (below 500 °C) induced the crystallization and the formation of the integrated structure of V2O5 film. However, it was found that both intensities of Raman scattering peaks at 146 cm?1 and 994 cm?1, respectively, decreased for samples annealed at a temperature of 550 °C. The peak at 146 cm?1 was attributed to skeleton bent vibration and that at 994 cm?1 was due to the stretching vibration of vanadyl V=OA bond. It showed that the high-temperature annealing was believed to have distorted the microstructure of V2O5 films. The oxygen vacancies were, therefore, induced, which benefited the formation of V-OA-V bonds between layers. The result of X-ray diffraction measurements was in good agreement with that of Raman scattering spectra. 相似文献
Transparent conductive tungsten-doped tin oxide (SnO2:W) thin films were synthesized on quartz glass substrates by sol–gel dip-coating method. It was found that the films were highly transparent and the average optical transmission was about 90% in the visible and near infrared region from 400 to 2,500 nm. The optical band gap is about 4.1 eV. The lowest resistivity of 5.8 × 10?3 ohm cm was obtained, with the carrier mobility of 14.2 cm2 V?1 s?1 and carrier concentration of 7.6 × 1019 cm?3 in 3 at.% W-doping films annealed at 850 °C in air. The structural properties, surface morphology and chemical states for the films were investigated. 相似文献
A new coordination polymer of terbium tartrate [Tb(H2O)3(C4H5O6)(C4H4O6)] has been synthesized and crystallizes in the polar space group P41 with cell constants a = 6.0415(9), b = 6.0415(9), c = 36.516(7) Å, V = 1332.8(4) Å3, Z = 4. The terbium(III) ion of title complex is nine-coordinate through oxygen donors. Four different coordination modes of tartrate occur. This Tb(III) complex exhibits a characteristic luminescence in the visible region upon excitation at 353 nm. The temperature-dependent magnetic properties of the Tb(III) complex were investigated in the temperature range of 2–300 K. Title compound exhibits significant ferroelectric properties at room temperature (remnant polarization 2Pr = 0.160 μC cm?2, coercive field 2Ec = 44.5 kV cm?1, saturation of the spontaneous polarization Ps = 0.176 μC cm?2). 相似文献
The mass transport and charge transfer kinetics of ozone reduction at Nafion coated Au electrodes were studied in 0.5 mol/L H2SO4 and highly resistive solutions such as distilled water and tap water. The diffusion coefficient and partition coefficient of ozone in Nafion coating are 1.78×10-6 cm2·s-1 and 2.75 at 25℃ (based on dry state thickness), respectively. The heterogeneous rate constants and Tafel slopes for ozone reduction at bare Au are 4.1×10-6 cm·s-1, 1.0×10-6 cm·s-1 and 181 mV, 207 mV in 0.5 mol/L H2SO4 and distilled water respectively and the corresponding values for Nafion coated Au are 5.5×10-6 cm·s-1, 1.1×10-6 cm·s-1 and 182 mV, 168 mV respectively. The Au microelectrode with 3 μm Nafion coating shows good linearity over the range 0-10 mmol/L ozone in distilled water with sensitivity 61 μA·ppm-1 ·cm-2, detection limit 10 ppb and 95% response time below 5 s at 25℃. The temperature coefficient in range of 11-30℃ is 1.3%. 相似文献
A series of three thiophene–naphthalene‐based asymmetric oligomers—5‐decyl‐2,2′:5′,2′′:5′′,2′′′‐quaterthiophene (DtT), 5‐decyl‐5′′‐(naphthalen‐2‐yl)‐2,2′:5′,2′′‐terthiophene (D3TN), and 5‐(4‐decylphenyl)‐5′‐(naphthalen‐2‐yl)‐2,2′‐bithiophene (DP2TN)—was synthesized by Suzuki cross‐coupling reactions. The long alkyl side chains improved both the solubility of the oligomers in solvents and their tendency to self‐assemble. UV/Vis absorption measurements suggested that DtT, D3TN, and DP2TN form H‐type aggregates with a face‐to‐face packing structure. In addition, the three oligomers were found to adopt vertically aligned crystalline structures in films deposited on substrates, as revealed by grazing‐incidence wide‐angle X‐ray scattering. These oligomers were used as the active layers of p‐type organic field‐effect transistors, and the resulting devices showed field‐effect mobilities of 3.3×10?3 cm2 V?1 s?1 for DtT, 1.6×10?2 cm2 V?1 s?1 for D3TN, and 3.7×10?2 cm2 V?1 s?1 for DP2TN. The differences in transistor performances were attributed to the degree of π overlap and the morphological differences determined by the molecular structures. 相似文献
Monomeric and Dimeric Chromium(III) Phthalocyanines: Synthesis and Properties of Hydroxopyridinophthalocyaninatochromium(III) and μ-Oxodi(pyridinophthalocyaninatochromium(III)) Heating of ?[Cr(OH)Pc2?]”? in pyridine (Py) gives the paramagnetic (T = 273 K) complexes [Cr(OH)(Py)Pc2?] (μCr = 3.84 μB) and [(Cr(Py)Pc2?)2O] (μCr = 1.24 μB) by consecutive substitution and condensation reactions. The UV-VIS spectra are characterized by the typical B, Q, and N regions of the Pc2? ligand being shifted hypsochromically for the dimer with respect to the monomer due to excitonic coupling (1.5 kK). Regions of weak absorbance between 8 and 13 resp. 19 kK are assigned to trip-quartet transitions for both complexes. A weak band at 870 cm?1 in the FIR/MIR spectra is assigned to vas(Cr? O? Cr). In the resonance Raman(RR) spectra v(Cr? O) at 514 cm?1 resp. vs(Cr? O? Cr) at 426 cm?1 is selectively enhanced. Further strong RR-lines of the μ-Oxo dimer at 110 and 631 cm?1 are assigned to a (Py? Cr? O)- resp. internal pyridine deformation of a1g symmetry. An assignment as 2vas(Cr? O? Cr) is proposed for the remarkable RR line at 1740 cm?1. 相似文献
Conjugated molecules with low lying LUMO levels are demanding for the development of air stable n‐type organic semiconductors. In this paper, we report a new A‐D‐A′‐D‐A conjugated molecule ( DAPDCV ) entailing diazapentalene (DAP) and dicyanovinylene groups as electron accepting units. Both theoretical and electrochemical studies manifest that the incorporation of DAP unit in the conjugated molecule can effectively lower the LUMO energy level. Accordingly, thin film of DAPDCV shows n‐type semiconducting behavior with electron mobility up to 0.16 cm2?V?1?s?1 after thermal annealing under N2 atmosphere. Moreover, thin film of DAPDCV also shows stable n‐type transporting property in air with mobility reaching 0.078 cm2?V?1?s?1. 相似文献
Stable water films covered by arachidic acid monolayers were prepared on vertically arranged glass/Ag/SiO2-substrates, which were partially pulled out of a film balance trough. The thickness profiles were recorded by on-line-measurement, using the thickness dependence of the dispersion of surface plasmon polaritons. The surface plasmon imaging technique allows for a thickness resolution of 0.2 nm and a height resolution of ca. 20 μm. Variations of these profiles as a function of the lateral pressure of the horizontal arachidate layer on the film balance were observed. For the first time Raman studies were made on asymmetric soap films. The intensity ratio of the Δηa = 2800 cm−1 to the Δηs = 2850 cm−1 line in the CH-stretching vibration range shows a dependence on the lateral pressure in the monolayer. 相似文献
Two new electron‐rich molecules based on 3,4‐phenylenedioxythiophene (PheDOT) were synthesized and successfully adopted as hole‐transporting materials (HTMs) in perovskite solar cells (PSCs). X‐ray diffraction, absorption spectra, photoluminescence spectra, electrochemical properties, thermal stabilities, hole mobilities, conductivities, and photovoltaic parameters of PSCs based on these two HTMs were compared with each other. By introducing methoxy substituents into the main skeleton, the energy levels of PheDOT‐core HTM were tuned to match with the perovskite, and its hole mobility was also improved (1.33×10?4 cm2 V?1 s?1, being higher than that of spiro‐OMeTAD, 2.34×10?5 cm2 V?1 s?1). The PSC based on MeO‐PheDOT as HTM exhibits a short‐circuit current density (Jsc) of 18.31 mA cm?2, an open‐circuit potential (Voc) of 0.914 V, and a fill factor (FF) of 0.636, yielding an encouraging power conversion efficiency (PCE) of 10.64 % under AM 1.5G illumination. These results give some insight into how the molecular structures of HTMs affect their performances and pave the way for developing high‐efficiency and low‐cost HTMs for PSCs. 相似文献
A novel composite material of copper (I) oxide at manganese (IV) oxide (Cu2O@MnO2), was synthesized and applied for modification on the glassy carbon electrode (GCE) surface (Cu2O@MnO2/GCE) as a hydrogen peroxide (H2O2) sensor. The composite material was characterized regarding its structural and morphological properties, using field emission scanning electron microscopy (FE‐SEM), energy‐dispersive X‐ray spectroscopy (EDX), X‐ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The Cu2O@MnO2/GCE showed an excellent electrocatalytic response to the oxidation of H2O2 which provided a 0.56 s?1 charge transfer rate constant (Ks), 1.65×10?5 cm2 s?1 diffusion coefficient value (D), 0.12 mm2 electroactive surface area (Ae) and 1.04×10?8 mol cm?2 surface concentration ( ). At the optimal condition, the constructed sensor exhibited a wide linear range from 0.5 μM to 20 mM with a low limit of detection (63 nM, (S/N=3) and a good sensitivity of 256.33 μA mM?1 cm?2. It also presented high stability (ΔIresponse±15 %, n=100), repeatability (1.25 %RSD, n=10) and reproducibility (3.55 %RSD, n=10). The results indicated that the synthesized Cu2O@MnO2 was successfully used as a new platform for H2O2 sensing. 相似文献