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1.
Here, room‐temperature solution‐processed inorganic p‐type copper iodide (CuI) thin‐film transistors (TFTs) are reported for the first time. The spin‐coated 5 nm thick CuI film has average hole mobility (µFE) of 0.44 cm2 V?1 s?1 and on/off current ratio of 5 × 102. Furthermore, µFE increases to 1.93 cm2 V?1 s?1 and operating voltage significantly reduces from 60 to 5 V by using a high permittivity ZrO2 dielectric layer replacing traditional SiO2. Transparent complementary inverters composed of p‐type CuI and n‐type indium gallium zinc oxide TFTs are demonstrated with clear inverting characteristics and voltage gain over 4. These outcomes provide effective approaches for solution‐processed inorganic p‐type semiconductor inks and related electronics.  相似文献   

2.
In situ monitoring of hydrogen peroxide (H2O2) during its production process is needed. Here, an electrochemical H2O2 sensor with a wide linear current response range (concentration: 5 × 10?8 to 5 × 10?2 m ), a low detection limit (32.4 × 10?9 m ), and a high sensitivity (568.47 µA mm ?1 cm?2) is developed. The electrocatalyst of the sensor consists of cobalt nanoparticles and atomic Co‐Nx moieties anchored on nitrogen doped carbon nanotube arrays (Co‐N/CNT), which is obtained through the pyrolysis of the sandwich‐like urea@ZIF‐67 complex. More cobalt nanoparticles and atomic Co‐Nx as active sites are exposed during pyrolysis, contributing to higher electrocatalytic activity. Moreover, a portable screen‐printed electrode sensor is constructed and demonstrated for rapidly detecting (cost ≈40 s) H2O2 produced in microbial fuel cells with only 50 µL solution. Both the synthesis strategy and sensor design can be applied to other energy and environmental fields.  相似文献   

3.
The realization of spin‐crossover (SCO)‐based applications requires study of the spin‐state switching characteristics of SCO complex molecules within nanostructured environments, especially on surfaces. Except for a very few cases, the SCO of a surface‐bound thin molecular film is either quenched or heavily altered due to: (i) molecule–surface interactions and (ii) differing intermolecular interactions in films relative to the bulk. By fabricating SCO complexes on a weakly interacting surface, the interfacial quenching problem is tackled. However, engineering intermolecular interactions in thin SCO active films is rather difficult. Here, a molecular self‐assembly strategy is proposed to fabricate thin spin‐switchable surface‐bound films with programmable intermolecular interactions. Molecular engineering of the parent complex system [Fe(H2B(pz)2)2(bpy)] (pz = pyrazole, bpy = 2,2′‐bipyridine) with a dodecyl (C12) alkyl chain yields a classical amphiphile‐like functional and vacuum‐sublimable charge‐neutral FeII complex, [Fe(H2B(pz)2)2(C12‐bpy)] (C12‐bpy = dodecyl[2,2′‐bipyridine]‐5‐carboxylate). Both the bulk powder and 10 nm thin films sublimed onto either quartz glass or SiOx surfaces of the complex show comparable spin‐state switching characteristics mediated by similar lamellar bilayer like self‐assembly/molecular interactions. This unprecedented observation augurs well for the development of SCO‐based applications, especially in molecular spintronics.  相似文献   

4.
By fine‐tuning the crystal nucleation and growth process, a low‐temperature‐gradient crystallization method is developed to fabricate high‐quality perovskite CH3NH3PbBr3 single crystals with high carrier mobility of 81 ± 5 cm2 V?1 s?1 (>3 times larger than their thin film counterpart), long carrier lifetime of 899 ± 127 ns (>5 times larger than their thin film counterpart), and ultralow trap state density of 6.2 ± 2.7 × 109 cm?3 (even four orders of magnitude lower than that of single‐crystalline silicon wafers). In fact, they are better than perovskite single crystals reported in prior work: their application in photosensors gives superior detectivity as high as 6 × 1013 Jones, ≈10–100 times better than commercial sensors made of silicon and InGaAs. Meanwhile, the response speed is as fast as 40 µs, ≈3 orders of magnitude faster than their thin film devices. A large‐area (≈1300 mm2) imaging assembly composed of a 729‐pixel sensor array is further designed and constructed, showing excellent imaging capability thanks to its superior quality and uniformity. This opens a new possibility to use the high‐quality perovskite single‐crystal‐based devices for more advanced imaging sensors.  相似文献   

5.
All‐solution‐processed pure formamidinium‐based perovskite light‐emitting diodes (PeLEDs) with record performance are successfully realized. It is found that the FAPbBr3 device is hole dominant. To achieve charge carrier balance, on the anode side, PEDOT:PSS 8000 is employed as the hole injection layer, replacing PEDOT:PSS 4083 to suppress the hole current. On the cathode side, the solution‐processed ZnO nanoparticle (NP) is used as the electron injection layer in regular PeLEDs to improve the electron current. With the smallest ZnO NPs (2.9 nm) as electron injection layer (EIL), the solution‐processed PeLED exhibits a highest forward viewing power efficiency of 22.3 lm W?1, a peak current efficiency of 21.3 cd A?1, and an external quantum efficiency of 4.66%. The maximum brightness reaches a record 1.09 × 105 cd m?2. A record lifetime T50 of 436 s is achieved at the initial brightness of 10 000 cd m?2. Not only do PEDOT:PSS 8000 HIL and ZnO NPs EIL modulate the injected charge carriers to reach charge balance, but also they prevent the exciton quenching at the interface between the charge injection layer and the light emission layer. The subbandgap turn‐on voltage is attributed to Auger‐assisted energy up‐conversion process.  相似文献   

6.
Abstract: In this study, digital image correlation (DIC)‐based strain analysis software was successfully developed. Its strain resolution lies in the order of 2.3 × 10?4–3.1 × 10?4. Full‐strain field measurement was used to study indentation‐induced plastic patterns around the spherical indenter for a polycrystal and a single crystal of pure aluminium. During indentation, the pure aluminium specimen of the single crystal revealed a symmetric indentation pattern of von Mises strain. The piling‐up around the residual impression was successfully and directly characterised by examining the sign of strain ?X and ?Y in the X and Y directions. However, the inward, out‐of‐plane movement results in an error in calculating in‐plane strain referred to as a ‘distortion strain’ using two‐dimensional DIC.  相似文献   

7.
A novel droplet‐based surface‐enhanced Raman scattering (SERS) sensor for high‐throughput real‐time SERS monitoring is presented. The developed sensors are based on a droplet‐guiding‐track‐engraved superhydrophobic substrate covered with hierarchical SERS‐active Ag dendrites. The droplet‐guiding track with a droplet stopper is designed to manipulate the movement of a droplet on the superhydrophobic substrate. The superhydrophobic Ag dendritic substrates are fabricated through a galvanic displacement reaction and subsequent self‐assembled monolayer coating. The optimal galvanic reaction time to fabricate a SERS‐active Ag dendritic substrate for effective SERS detection is determined, with the optimized substrate exhibiting an enhancement factor of 6.3 × 105. The height of the droplet stopper is optimized to control droplet motion, including moving and stopping. Based on the manipulation of individual droplets, the optimized droplet‐based real‐time SERS sensor shows high resistance to surface contaminants, and droplets containing rhodamine 6G, Nile blue A, and malachite green are successively controlled and detected without spectral interference. This noble droplet‐based SERS sensor reduces sample preparation time to a few seconds and increased detection rate to 0.5 µ L s?1 through the simple operation mechanism of the sensor. Accordingly, our sensor enables high‐throughput real‐time molecular detection of various target analytes for real‐time chemical and biological monitoring.  相似文献   

8.
Molecularly engineered novel dopant‐free hole‐transporting materials for perovskite solar cells (PSCs) combined with mixed‐perovskite (FAPbI3)0.85(MAPbBr3)0.15 (MA: CH3NH3+, FA: NH=CHNH3+) that exhibit an excellent power conversion efficiency of 18.9% under AM 1.5 conditions are investigated. The mobilities of FA‐CN, and TPA‐CN are determined to be 1.2 × 10?4 cm2 V?1 s?1 and 1.1 × 10?4 cm2 V?1 s?1, respectively. Exceptional stability up to 500 h is measured with the PSC based on FA‐CN. Additionally, it is found that the maximum power output collected after 1300 h remained 65% of its initial value. This opens up new avenue for efficient and stable PSCs exploring new materials as alternatives to Spiro‐OMeTAD.  相似文献   

9.
Natural biomolecules have potential as proton‐conducting materials, in which the hydrogen‐bond networks can facilitate proton transportation. Herein, a biomolecule/metal–organic framework (MOF) approach to develop hybrid proton‐conductive membranes is reported. Single‐strand DNA molecules are introduced into DNA@ZIF‐8 membranes through a solid‐confined conversion process. The DNA‐threaded ZIF‐8 membrane exhibits high proton conductivity of 3.40 × 10?4 S cm?1 at 25 °C and the highest one ever reported of 0.17 S cm?1 at 75 °C, under 97% relatively humidity, attributed to the formed hydrogen‐bond networks between the DNA molecules and the water molecules inside the cavities of the ZIF‐8, but very low methanol permeability of 1.25 × 10?8 cm2 s?1 due to the small pore entrance of the DNA@ZIF‐8 membranes. The selectivity of the DNA@ZIF‐8 membrane is thus significantly higher than that of developed proton‐exchange membranes for fuel cells. After assembling the DNA@ZIF‐8 hybrid membrane into direct methanol fuel cells, it exhibits a power density of 9.87 mW cm?2 . This is the first MOF‐based proton‐conductivity membrane used for direct methanol fuel cells, providing bright promise for such hybrid membranes in this application.  相似文献   

10.
Narrow bandgap n‐type organic semiconductors (n‐OS) have attracted great attention in recent years as acceptors in organic solar cells (OSCs), due to their easily tuned absorption and electronic energy levels in comparison with fullerene acceptors. Herein, a new n‐OS acceptor, Y5, with an electron‐deficient‐core‐based fused structure is designed and synthesized, which exhibits a strong absorption in the 600–900 nm region with an extinction coefficient of 1.24 × 105 cm?1, and an electron mobility of 2.11 × 10?4 cm2 V?1 s?1. By blending Y5 with three types of common medium‐bandgap polymers (J61, PBDB‐T, and TTFQx‐T1) as donors, all devices exhibit high short‐circuit current densities over 20 mA cm?2. As a result, the power conversion efficiency of the Y5‐based OSCs with J61, TTFQx‐T1, and PBDB‐T reaches 11.0%, 13.1%, and 14.1%, respectively. This indicates that Y5 is a universal and highly efficient n‐OS acceptor for applications in organic solar cells.  相似文献   

11.
Large size of capacitors is the main hurdle in miniaturization of current electronic devices. Herein, a scalable solution‐based layer‐by‐layer engineering of metallic and high‐κ dielectric nanosheets into multilayer nanosheet capacitors (MNCs) with overall thickness of ≈20 nm is presented. The MNCs are built through neat tiling of 2D metallic Ru0.95O20.2? and high‐κ dielectric Ca2NaNb4O13? nanosheets via the Langmuir–Blodgett (LB) approach at room temperature which is verified by cross‐sectional high‐resolution transmission electron microscopy (HRTEM). The resultant MNCs demonstrate a high capacitance of 40–52 µF cm?2 and low leakage currents down to 10?5–10?6 A cm?2. Such MNCs also possess complimentary in situ robust dielectric properties under high‐temperature measurements up to 250 °C. Based on capacitance normalized by the thickness, the developed MNC outperforms state‐of‐the‐art multilayer ceramic capacitors (MLCC, ≈22 µF cm?2/5 × 104 nm) present in the market. The strategy is effective due to the advantages of facile, economical, and ambient temperature solution assembly.  相似文献   

12.
Exploring novel multifunctional rare earth materials is very important because these materials have fundamental interests, such as new structural facts and connecting modes, as well as potential technological applications, including optics, magnetic properties, sorption, and catalytic behaviors. Especially, employing these nanomaterials for sensing or catalytic reactions is still very challenging. Herein, a new superstable, anionic terbium‐metal–organic‐framework, [H2N(CH3)2][Tb(cppa)2(H2O)2], (China Three Gorges University ( CTGU‐1 ), H2cppa = 5‐(4‐carboxyphenyl)picolinic acid), is successfully prepared, which can be used as a turn‐on, highly‐sensitive fluorescent sensor to detect Eu3+ and Dy3+, with a detection limitation of 5 × 10?8 and 1 × 10?4m in dimethylformamide, respectively. This result represents the first example of lanthanide‐metal–organic‐frameworks (Ln‐MOF) that can be employed as a discriminative fluorescent probe to recognize Eu3+ and Dy3+. In addition, through ion exchanging at room temperature, Ag(I) can be readily reduced in situ and embedded in the anionic framework, which leads to the formation of nanometal‐particle@Ln‐MOF composite with uniform size and distribution. The as‐prepared Ag@ CTGU‐1 shows remarkable catalytic performance to reduce 4‐nitrophenol, with a reduction rate constant κ as large as 2.57 × 10?2 s?1; almost the highest value among all reported noble‐metal‐nanoparticle@MOF composites.  相似文献   

13.
Designing ultrasensitive detectors often requires complex architectures, high‐voltage operations, and sophisticated low‐noise measurements. In this work, it is shown that simple low‐bias two‐terminal DC‐conductance values of graphene and single‐walled carbon nanotubes are extremely sensitive to ionized gas molecules. Incident ions form an electrode‐free, dielectric‐ or electrolyte‐free, bias‐free vapor‐phase top‐gate that can efficiently modulate carrier densities up to ≈0.6 × 1013 cm?2. Surprisingly, the resulting current changes are several orders of magnitude larger than that expected from conventional electrostatic gating, suggesting the possible role of a current‐gain inducing mechanism similar to those seen in photodetectors. These miniature detectors demonstrate charge–current amplification factor values exceeding 108 A C?1 in vacuum with undiminished responses in open air, and clearly distinguish between positive and negative ions sources. At extremely low rates of ion incidence, detector currents show stepwise changes with time, and calculations suggest that these stepwise changes can result from arrival of individual ions. These sensitive ion detectors are used to demonstrate a proof‐of‐concept low‐cost, amplifier‐free, light‐emitting‐diode‐based low‐power ion‐indicator.  相似文献   

14.
A novel surface‐enhanced Raman scattering (SERS) sensor is developed for real‐time and highly repeatable detection of trace chemical and biological indicators. The sensor consists of a polydimethylsiloxane (PDMS) microchannel cap and a nanopillar forest‐based open SERS‐active substrate. The nanopillar forests are fabricated based on a new oxygen‐plasma‐stripping‐of‐photoresist technique. The enhancement factor (EF) of the SERS‐active substrate reaches 6.06 × 106, and the EF of the SERS sensor is about 4 times lower due to the influence of the PDMS cap. However, the sensor shows much higher measurement repeatability than the open substrate, and it reduces the sample preparation time from several hours to a few minutes, which makes the device more reliable and facile for trace chemical and biological analysis.  相似文献   

15.
In this study, a highly sensitive and self‐driven near‐infrared (NIR) light photodetector based on PdSe2/pyramid Si heterojunction arrays, which are fabricated through simple selenization of predeposited Pd nanofilm on black Si, is demonstrated. The as‐fabricated hybrid device exhibits excellent photoresponse performance in terms of a large on/off ratio of 1.6 × 105, a responsivity of 456 mA W?1, and a high specific detectivity of up to 9.97 × 1013 Jones under 980 nm illumination at zero bias. Such a relatively high sensitivity can be ascribed to the light trapping effect of the pyramid microstructure, which is confirmed by numerical modeling based on finite‐difference time domain. On the other hand, thanks to the broad optical absorption properties of PdSe2, the as‐fabricated device also exhibits obvious sensitivity to other NIR illuminations with wavelengths of 1300, 1550, and 1650 nm, which is beyond the photoresponse range of Si‐based devices. It is also found that the PdSe2/pyramid Si heterojunction device can also function as an NIR light sensor, which can readily record both “tree” and “house” images produced by 980 and 1300 nm illumination, respectively.  相似文献   

16.
A side‐chain conjugation strategy in the design of nonfullerene electron acceptors is proposed, with the design and synthesis of a side‐chain‐conjugated acceptor (ITIC2) based on a 4,8‐bis(5‐(2‐ethylhexyl)thiophen‐2‐yl)benzo[1,2‐b :4,5‐b′ ]di(cyclopenta‐dithiophene) electron‐donating core and 1,1‐dicyanomethylene‐3‐indanone electron‐withdrawing end groups. ITIC2 with the conjugated side chains exhibits an absorption peak at 714 nm, which redshifts 12 nm relative to ITIC1. The absorption extinction coefficient of ITIC2 is 2.7 × 105m ?1 cm?1, higher than that of ITIC1 (1.5 × 105m ?1 cm?1). ITIC2 exhibits slightly higher highest occupied molecular orbital (HOMO) (?5.43 eV) and lowest unoccupied molecular orbital (LUMO) (?3.80 eV) energy levels relative to ITIC1 (HOMO: ?5.48 eV; LUMO: ?3.84 eV), and higher electron mobility (1.3 × 10?3 cm2 V?1 s?1) than that of ITIC1 (9.6 × 10?4 cm2 V?1 s?1). The power conversion efficiency of ITIC2‐based organic solar cells is 11.0%, much higher than that of ITIC1‐based control devices (8.54%). Our results demonstrate that side‐chain conjugation can tune energy levels, enhance absorption, and electron mobility, and finally enhance photovoltaic performance of nonfullerene acceptors.  相似文献   

17.
Experimental studies on magneto‐photoluminescence based on two‐photon excitation in up‐conversion Y2O2S:Er, Yb crystal particles are reported. It is found that the up‐conversion photoluminescence generated by two‐photon excitation exhibits magnetic field effects at room temperature, leading to a two‐photon excitation‐induced magneto‐photoluminescence, when the two‐photon excitation exceeds the critical intensity. By considering the spin selection rule in electronic transitions, it is proposed that spin‐antiparallel and spin‐parallel transition dipoles with spin mixing are accountable for the observed magneto‐photoluminescence. Specifically, the two‐photon excitation generates spin‐antiparallel electric dipoles between 4S3/24I15/2 in Er3+ ions. The antiparallel spins are conserved by exchange interaction within dipoles. When the photoexcitation exceeds the critical intensity, the Coulomb screening can decrease the exchange interaction. Consequently, the spin–orbital coupling can partially convert the antiparallel dipoles into parallel dipoles, generating a spin mixing. Eventually, the populations between antiparallel and parallel dipoles reach an equilibrium established by the competition between exchange interaction and spin–orbital coupling. Applying a magnetic field can break the equilibrium by disturbing spin mixing through introducing spin precessions, changing the spin populations on antiparallel and parallel dipoles and leading to the magneto‐photoluminescence. Therefore, spin‐dependent transition dipoles present a convenient mechanism to realize magneto‐photoluminescence in multiphoton up‐conversion crystal particles.  相似文献   

18.
Self‐powered flexible photodetectors without an external power source can meet the demands of next‐generation portable and wearable nanodevices; however, the performance is far from satisfactory becuase of the limited match of flexible substrates and light‐sensitive materials with proper energy levels. Herein, a novel self‐powered flexible fiber‐shaped photodetector based on double‐twisted perovskite–TiO2–carbon fiber and CuO–Cu2O–Cu wire is designed and fabricated. The device shows an ultrahigh detectivity of 2.15 × 1013 Jones under the illumination of 800 nm light at zero bias. CuO–Cu2O electron block bilayer extends response range of perovskite from 850 to 1050 nm and suppresses dark current down to 10?11 A. The fast response speed of less than 200 ms is nearly invariable after dozens of cycles of bending at the extremely 90 bending angle, demonstrating excellent flexibility and bending stability. These parameters are comparable and even better than reported flexible and even rigid photodetectors. The present results suggest a promising strategy to design photodetectors with integrated function of self‐power, flexibility, and broadband response.  相似文献   

19.
Naphtho[1,2‐b:5,6‐b′]dithiophene is extended to a fused octacyclic building block, which is end capped by strong electron‐withdrawing 2‐(5,6‐difluoro‐3‐oxo‐2,3‐dihydro‐1H‐inden‐1‐ylidene)malononitrile to yield a fused‐ring electron acceptor (IOIC2) for organic solar cells (OSCs). Relative to naphthalene‐based IHIC2, naphthodithiophene‐based IOIC2 with a larger π‐conjugation and a stronger electron‐donating core shows a higher lowest unoccupied molecular orbital energy level (IOIC2: ?3.78 eV vs IHIC2: ?3.86 eV), broader absorption with a smaller optical bandgap (IOIC2: 1.55 eV vs IHIC2: 1.66 eV), and a higher electron mobility (IOIC2: 1.0 × 10?3 cm2 V?1 s?1 vs IHIC2: 5.0 × 10?4 cm2 V?1 s?1). Thus, IOIC2‐based OSCs show higher values in open‐circuit voltage, short‐circuit current density, fill factor, and thereby much higher power conversion efficiency (PCE) values than those of the IHIC2‐based counterpart. In particular, as‐cast OSCs based on FTAZ: IOIC2 yield PCEs of up to 11.2%, higher than that of the control devices based on FTAZ: IHIC2 (7.45%). Furthermore, by using 0.2% 1,8‐diiodooctane as the processing additive, a PCE of 12.3% is achieved from the FTAZ:IOIC2 ‐ based devices, higher than that of the FTAZ:IHIC2 ‐ based devices (7.31%). These results indicate that incorporating extended conjugation into the electron‐donating fused‐ring units in nonfullerene acceptors is a promising strategy for designing high‐performance electron acceptors.  相似文献   

20.
Bulk‐magnetoelectric (ME) composites consisting of various piezoelectric and piezomagnetic materials with (3‐0), (3‐1), (2‐2), and (2‐1) connectivity are proposed in a bid to realize strong ME coupling for next‐generation electronic‐device applications. Here, 1D (1‐1) connectivity ME composites consisting of a [011]‐oriented Pb(Mg,Nb)O3‐PbTiO3 (PMN‐PT) single‐crystal fiber laminated with laser‐treated amorphous FeBSi alloy (Metglas) and operating in L‐T mode (longitudinally magnetized and transversely poled) are reported, which exhibit an enhanced resonant ME coupling coefficient of ≈7000 V cm?1 Oe?1, which is nearly seven times higher than the best result published previously, and also a superhigh magnetic sensitivity of 1.35 × 10?13 T (directly detected) at resonance at room temperature, representing a significant advance in bulk magnetoelectric materials. The theoretical analyses based on magnetic‐circuit and equivalent‐circuit methods show that the enhancement in ME coupling can be attributed to the reduction in resonance loss of laser‐treated Metglas alloy due to nanocrystallization and the strong magnetic‐flux‐concentration effect in (1‐1) configuration composites.  相似文献   

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