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Novel design strategy for GaAsa??based solar cell by application of singlea??walled carbon nanotubes topmost layer
摘要： Attempts to improve solar cells efficiency touch all its constituents and are directly related to their fabrication protocols. While the most promising material platform for high efficiency photovoltaic devices is still III-V semiconductors, introduction of novel materials like single-walled carbon nanotubes (SWCNTs), which are characterized by unique combination of conductivity and transparency, might greatly yield the device performance. Here, for the first time, we present the results of the fabrication and characterization of a thin-film GaAs solar cell with a SWCNT top contact. We examine the contact between the SWCNT film and the semiconductor structure by means of the optical and electron beam-induced current techniques. The fabricated device demonstrates better performance, that is, increased power conversion efficiency from 10.6% to 11.5% when compared to the cell with the traditional metal contact grid, stemming from the enhanced photocurrent collection efficiency and low parasitic light absorption in the emitter layer. We envision future prospects to exploit the multifunctionality of the SWCNTs in fabrication of highly efficient photovoltaic devices including flexible solar cells.
关键词： EBIC,EQE,solar cell,GaAs,SWCNT,OBIC
更新于2025-09-23 15:21:01
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Using Nonionic Surfactants for Production of Semiconductor-Type Carbon Nanotubes by Gel-Based Affinity Chromatography
摘要： Single-wall carbon nanotubes (SWCNTs) have remarkable properties based on their electronic properties, i.e., metallic or semiconducting types, but as-grown SWCNTs contain a mixture of both types. Presented here is an improved and detailed method for producing highly enriched semiconducting SWCNTs from a colloidal suspension of as-grown SWCNTs through agarose gel column-based affinity chromatography. After a 2 wt% sodium dodecyl sulphate (SDS) aqueous dispersion of SWCNTs is passed through the gel column, metal-type SWCNTs preferentially elute out using a 1.5 wt% SDS solution. Semiconductor-type SWCNTs are subsequently recovered from the column using a 2 wt% Pluronic F77 surfactant solution eluent. The semiconductor-enriched fraction purity is in the 90-95% range, based on detailed UV-vis-NIR absorption and resonant Raman spectroscopy characterization of the particulate suspension. Semiconductor-type SWCNTs are recovered in solid form by evaporating the suspension fluid, and heating the dried sample in air to a temperature just above the Pluronic decomposition temperature. Using Pluronic and other nonionic-type surfactants can aid the scalability of the chromatographic production of semiconducting SWCNT samples.
关键词： Carbon Nanotube,SWCNT,Semiconductor,Separation,Affinity Chromatography
更新于2025-09-23 15:21:01
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RETRACTED: A diode based on a chemically-doped SWCNT
摘要： Carbon nanotube p-n junction diodes are expected to be the building block of next generation integrated circuits. A p-i-n junction diode was prepared from a SWCNT with one end p-type doped, the other end n-type doped and the middle segment undoped. The p-type doping was performed using triethyloxonium hexachloroantimonate to form an air stable charge transfer complex (SWCNT+ -SbCl6-) while polyethylene imine was used as an electron donor for the n-type doping. The device showed an excellent performance with a high rectification ratio of 10^3 and a low reverse saturation current of 23 pA.
关键词： p-i-n junction diode,Rectification characteristic,Locally chemical doping,SWCNT
更新于2025-09-19 17:15:36
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Computation-led design of pollutant gas sensors with bare and carbon nanotube supported rhodium alloys
摘要： Quantum chemical study has been performed on finite-sized bi-metallic Rh3M alloys, M = Ag, Ir, Pd, Pt, Au, derived from magic cluster, Rh4. Bond length of C–O and N–O are noticed to be elongated in the presence of rhodium alloy clusters. CO2 and NO2 gases are found to be highly adsorbed on Rh3M clusters, which is confirmed by stretching frequency of C–O and N–O. DFT evaluated dipole moment and electronic charge redistribution suggests the sensing capability of CO2 and NO2 gases by Rh3M clusters which is further confirmed by the calculated HOMO–LUMO gap. Mixed rhodium alloy clusters supported on single-wall carbon nanotube (SWCNT) exhibits much higher ability to sense CO2 and NO2. On the other hand, SWCNT@Rh3M shows higher catalytic activity for the activation of CO2 and NO2 in comparison to bare Rh3M because of the higher electronic charge redistribution in the case of SWCNT@Rh3M. In case of SWCNT-supported gas adsorbed clusters, p electrons play a major role in bonding.
关键词： SWCNT,Rhodium,DFT,Alloy,CO2,NO2
更新于2025-09-16 10:30:52
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Effect of Carboxyl-Functionalized Single Walled Carbon Nanotubes on the Interfacial Barrier Height of Malachite Green Dye Based Organic Device
摘要： In this study, we have estimated the interfacial barrier height ((cid:1)b) of Indium Tin Oxide (ITO) coated glass/Malachite Green (MG) dye/Aluminium (Al) based organic device and subsequently we have also observed the effect of carboxylfunctionalized SWCNT (COOH-SWCNT) on the (cid:1)b. Presence of COOH-SWCNT reduces the interfacial barrier height as SWCNT acts as filler and provides easy path for charge percolation. We have used ITO coated glass and aluminium as front electrode and back electrode respectively to form the organic device. This organic device has been prepared with and without COOH-SWCNT by using spin coating technique. We have measured the steady state current-Voltage (I-V) characteristics of the device to estimate the interfacial barrier height ((cid:1)b) of the device. (cid:1)b is reduced from 0.67 eV to 0.59 eV in the presence of COOH-SWCNT. We have also estimated the (cid:1)b by using Norde’s Method. This method also shows a reduction of interfacial barrier height from 0.72 eV to 0.64 eV due to incorporation of COOH-SWCNT. Both the methods show good consistency with each other. Reduction of the interfacial barrier height in presence of COOH-SWCNT indicates the enhancement of charge injection through the metal-organic dye interface. By suitable doping or addition of COOH-SWCNT within the MG dye it is possible to reduce the barrier height and enhance the current injection through metal-organic dye interface.
关键词： Interfacial Barrier Height,Malachite Green Dye,Metal-Organic Dye Interface,COOH-SWCNT
更新于2025-09-12 10:27:22
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The State of HiPco Single-Walled Carbon Nanotubes in 2019
摘要： High-pressure carbon monoxide (HiPco)-synthesized single-walled carbon nanotubes (SWCNTs) have been a widely studied carbon nanomaterial for nearly two decades. It has been the de facto standard for SWCNT research, be it functionalization, separation and purification, or composites, as a result of the consistent, high-quality material that was made available at an affordable price to researchers worldwide. The recent shutdown of the HiPco reactor at Rice University has resulted in a scarcity of HiPco material available to the research community, and a new source of similar SWCNTs is desperately needed. Continued research and development on the design, materials used, and the overall process have led to a new HiPco material, referred to as NoPo HiPCO?, as an alternative to the erstwhile Rice HiPco SWCNTs. In this work, we have compared the two HiPco materials, and aim to provide more clarity for researchers globally on the state of HiPco SWCNTs for research and applications alike in 2019.
关键词： SWCNT,carbon nanotube,carbon,NoPo HiPCO?,HiPco
更新于2025-09-11 14:15:04
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I–V characteristics and conductance of strained SWCNTs
摘要： We present a new procedure to investigate the I–V characteristics and the conductance for strained SWCNTs. These electronic transport properties have been studied theoretically at zero temperature for zig-zag, armchair and chiral SWCNTs under the effect of the uniaxial tension and torsional strain. The analytical expression of the energy spectrum in the tight binding approximation has been used to calculate the induced current and the conductance through Landauer–Büttiker formalism. It is shown that the conductance for unstrained CNTs at initial values of the voltage can take discrete values which are equal to zero and 4 (e2/h) for semiconducting and conducting SWCNTs respectively. The emergence of the kinks in the I–V characteristics is due to the discrete electronic spectrum in the SWCNTs. The location and number of kinks are changeable under the effect of strain process. The conductance in a strained armchair (5, 5) CNT decreases to zero under torsional strain, consequently, it will transform the conducting SWCNTs at a threshold value of strain to a semiconducting SWCNT. In contrast, by applying the uniaxial tension on the armchair (5, 5) CNT, the conductance does not change absolutely. There is a different behavior can be observed by applying the strain on zig-zag (10, 0) CNT, where the conductance decreases rapidly and slightly under the in?uence of uniaxial tension and torsional strain, respectively. We found that the conductance of chiral (10, 9) CNT is not signi?cantly affected by applying the strain under consideration. More interestingly, the band structure of chiral (10, 9) CNT under uniaxial tension and torsional strain have been investigated within the tight binding approximation.
关键词： I–V characteristics,Mechanical strain,Tight binding approximation,SWCNT,Conductance
更新于2025-09-10 09:29:36
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Low-Voltage Operating Single-Wall Carbon Nanotube Thin-Film Transistors Using High Work Function Contacts on Flexible Substrates
摘要： There have been constant attempts as regards high-performance thin-film transistors (TFTs) by improving the charge injection between the source/drain electrode (S/D) and the channel. In this paper, we investigate the effect of the electric contact on the device performance of single-wall carbon nanotube (SWCNT) TFTs employing the suitable work function material. In order to realize the electric contacts for the dominant hole injection between the S/D and the SWCNT active channel, a high work function material of molybdenum trioxide (MoOx) fabricated by an optimized process are utilized. The contact resistance is extracted by plotting the width-normalized resistance of SWCNT-TFT with Pd and MoOx contacts as a function of channel length. We also demonstrate low-voltage operating SWCNT TFTs on flexible polyimide substrates with the reduced electric contacts. Without a buffer film which has been widely used to improve the device performance of TFT on a flexible substrate, high-performance low-voltage operating SWCNT-TFTs were achieved.
关键词： Flexible Substrate,Charge Injection,Device Performance,High Work Function Contacts,SWCNT TFTs
更新于2025-09-04 15:30:14