共查询到20条相似文献,搜索用时 31 毫秒
1.
Yelin Hu Aswani Yella Stefan Guldin Marcel Schreier Francesco Stellacci Michael Grätzel Morgan Stefik 《Liver Transplantation》2014,4(14)
Cobalt‐based electrolytes are highly tunable and have pushed the limits of dye‐sensitized solar cells, enabling higher open‐circuit voltages and new record efficiencies. However, the performance of these electrolytes and a range of other electrolytes suffer from slow electron transfer at platinum counter electrodes. High surface area platinum would enhance catalysis, but pure platinum structures are too expensive in practice. Here, a material‐efficient host‐guest architecture is developed that uses an ultrathin layer of platinum deposited upon an electrically conductive scaffold, niobium‐doped tin oxide (NTO). This nanostructured composite enhances the counter electrode performance of dye‐sensitized solar cells (DSCs) using a Co(II/III)BPY3 electrolyte with an increased fill factor and power conversion efficiency (11.26%), compared to analogous flat films. The modular strategy is elaborated by integrating a light scattering layer onto the counter electrode to reflect unabsorbed light back to the photoanode to improve the short‐circuit current density and power conversion efficiency. 相似文献
2.
Mesoporous TiO2 Beads Offer Improved Mass Transport for Cobalt‐Based Redox Couples Leading to High Efficiency Dye‐Sensitized Solar Cells
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Leo‐Philipp Heiniger Fabrizio Giordano Thomas Moehl Michael Grätzel 《Liver Transplantation》2014,4(12)
Overcoming ionic diffusion limitations is essential for the development of high‐efficiency dye‐sensitized solar cells based on cobalt redox mediators. Here, improved mass transport is reported for photoanodes composed of mesoporous TiO2 beads of varying pore sizes and porosities in combination with the high extinction YD2‐o‐C8 porphyrin dye. Compared to a photoanode made of 20 nm‐sized TiO2 particles, electrolyte diffusion through these films is greatly improved due to the large interstitial pores between the TiO2 beads, resulting in up to 70% increase in diffusion‐limited current. Simultaneously, transient photocurrent measurements reveal no mass transport limitations for films of up to 10 μm thickness. In contrast, standard photoanodes made of 20 nm‐sized TiO2 particles show non‐linear behavior in photocurrent under 1 sun illumination for a film thickness as low as 7 μm. By including a transparent thin mesoporous TiO2 underlayer in order to reduce optical losses at the fluorine‐doped tin oxide (FTO)‐TiO2 interface, an efficiency of 11.4% under AM1.5G 1 sun illumination is achieved. The combination of high surface area, strong scattering behavior, and high porosity makes these mesoporous TiO2 beads particularly suitable for dye‐sensitized solar cells using bulky redox couples and/or viscous electrolytes. 相似文献
3.
Atomic Layer Deposition of Highly Transparent Platinum Counter Electrodes for Metal/Polymer Flexible Dye‐Sensitized Solar Cells
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Diana Garcia‐Alonso Valerio Zardetto Adriaan J. M. Mackus Francesca De Rossi Marcel A. Verheijen Thomas M. Brown Wilhelmus M. M. Kessels Mariadriana Creatore 《Liver Transplantation》2014,4(4)
Atomic layer deposition (ALD) is used to deposit Pt nanoparticles at low temperature (25–150 °C) to fabricate highly transparent counter electrodes (CEs) for flexible dye‐sensitized solar cells (DSCs). The Pt nanoparticles (NPs) are deposited for different number of ALD cycles on indium tin oxide (ITO)/polyethylene naphthalate (PEN) substrates. Rutherford backscattering spectroscopy (RBS) and transmission electron microscopy (TEM) are used to assess the Pt NP loading, density, and size. There is a trade‐off between transparency and catalytic activity of the CE, and the best cell performances of back‐side‐illuminated DSCs (≈3.7% efficiency) are achieved for Pt ALD at temperatures in the range of 100–150 °C, even though deposition at 25 °C is also viable. The best cell produced with ALD platinized CE (100 cycles at 100 °C) outperforms the reference cells fabricated with electrodeposited and sputtered Pt CEs, with relative improvements in efficiency of 19% and 29%, respectively. In addition, these parameters are used to fabricate a large area CE for a sub‐module (active area of 17.6 cm2), resulting in an efficiency of 3.1%, which demonstrates the scalability of the process. 相似文献
4.
Valerio Zardetto Francesco Di Giacomo Diana Garcia‐Alonso Wytze Keuning Mariadriana Creatore Claudia Mazzuca Andrea Reale Aldo Di Carlo Thomas M. Brown 《Liver Transplantation》2013,3(10):1292-1298
The application of UV irradiation processes are successfully proposed for the first time in the fabrication of both of the two plastic electrodes in flexible dye solar cells (DSCs) and modules. For the realization of the photo‐electrode, a customized TiO2 paste formulation and UV processing method was developed which yields 134% (48%) performance enhancement with respect to the same (binder‐free) paste treated at 120 °C. UV treatment induces both complete removal of organic media and more efficient charge collection. Significantly, highly catalytic platinized flexible counter‐electrodes are also obtained via UV photo‐induced reduction of screen‐printed platinum precursor pastes based on hexachloroplatinic acid. Using both UV‐processed electrodes, a fully plastic DSC is fabricated with a conversion efficiency of 4.3% under 1 Sun (semitransparent) and 5.3% under 0.2 Sun (opaque). Performance is within 10% of the efficiency of a glass‐based DSC prepared with the same materials but with conventional high temperature processes. The material formulations and processes are simple, and easily up‐scaled over large areas, even directly and simultaneously applicable to the preparation of both the photo‐and counter‐electrode on the same substrate which enabled us to demonstrate the first module on plastic realized with a W series interconnection. 相似文献
5.
Hussein Melhem Pardis Simon Layla Beouch Fabrice Goubard Mourad Boucharef Catherine Di Bin Yann Leconte Bernard Ratier Nathalie Herlin‐Boime Johann Bouclé 《Liver Transplantation》2011,1(5):908-916
A crucial issue regarding emerging nanotechnologies remains the up‐scaling of new functional nanostructured materials towards their implementation in high performance applications on a large scale. In this context, we demonstrate high efficiency solid‐state dye‐sensitized solar cells prepared from new porous TiO2 photoanodes based on laser pyrolysis nanocrystals. This strategy exploits a reduced number of processing steps as well as non‐toxic chemical compounds to demonstrate highly porous TiO2 films. The possibility to easily tune the TiO2 nanocrystal physical properties allows us to demonstrate all solid‐state dye‐sensitized devices based on a commercial benchmark materials (organic indoline dye and molecular hole transporter) presenting state‐of‐the‐art performance comparable with reference devices based on a commercial TiO2 paste. In particular, a drastic improvement in pore infiltration, which is found to balance a relatively lower surface area compared to the reference electrode, is evidenced using laser‐synthesized nanocrystals resulting in an improved short‐circuit current density under full sunlight. Transient photovoltage decay measurements suggest that charge recombination kinetics still limit device performance. However, the proposed strategy emphasizes the potentialities of the laser pyrolysis technique for up‐scaling nanoporous TiO2 electrodes for various applications, especially for solar energy conversion. 相似文献
6.
Quantum‐Dot Sensitized Solar Cells Employing Hierarchical Cu2S Microspheres Wrapped by Reduced Graphene Oxide Nanosheets as Effective Counter Electrodes
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Hierarchical Cu2S microspheres wrapped by reduced graphene oxide (RGO) nanosheets are prepared via a one‐step solvothermal process. The amount of graphene oxide used in the synthesis process has a remarkable effect on the features of Cu2S microspheres. Compared to Pt and Cu2S electrodes, RGO‐Cu2S electrodes show better electrocatalytic activity, greater stability, lower charge‐transfer resistance, and higher exchange current density. As expected, RGO‐Cu2S electrodes exhibit superior performance when functioning as counter electrodes in CdS/CdSe quantum dot‐sensitized solar cells (QDSSCs) using a polysulfide electrolyte. A power conversion efficiency up to 3.85% is achieved for the QDSSC employing an optimized RGO‐Cu2S counter electrode, which is higher than those of the QDSSCs featuring Pt (2.14%) and Cu2S (3.39%) counter electrodes. 相似文献
7.
A Hierarchically Organized Photoelectrode Architecture for Highly Efficient CdS/CdSe‐Sensitized Solar Cells
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Jong Hoon Park Dong Hoe Kim Seong Sik Shin Hyun Soo Han Myeong Hwan Lee Hyun Suk Jung Jun Hong Noh Kug Sun Hong 《Liver Transplantation》2014,4(3)
A form of photoelectrode architecture suitable for inorganic semiconductor solar cells is reported. The developed architecture consists of hierarchically organized TiO2 nanostructures with several tens of nanometer‐sized particles that have a large surface area and open channels with several hundred‐nanometer‐gaps perpendicular to the substrate. These are tailored by controlling the kinetic energy of the ablated species during pulsed laser deposition (PLD). To fabricate the solar cells, CdS and CdSe inorganic sensitizers are assembled onto the architecture by successive ionic layer adsorption and reaction and polysulfide solution is used as an electrolyte with lead sulfide counter‐electrodes. The inorganic semiconductor solar cells using the developed architecture (PLD‐TiO2) show high energy conversion efficiencies of 5.57% compared to a conventional mesoporous TiO2 film(NP‐TiO2) (3.84%) with an optical mask at 1 sun of illumination. The improved cell performance of PLD‐TiO2 is attributed to greater light‐harvesting ability, which results in the enhancement of the Jsc value. PLD‐TiO2 absorbs more CdS/CdSe because of its larger surface area and excellent adhesion properties with fluorine‐doped tin oxide (FTO) substrates. Additionally, due to its unique channel‐shaped architecture, PLD‐TiO2 has a longer electron lifetime compared to NP‐TiO2. 相似文献
8.
Taking Temperature Processing Out of Dye‐Sensitized Solar Cell Fabrication: Fully Laser‐Manufactured Devices
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Girolamo Mincuzzi Luigi Vesce Malte Schulz‐Ruhtenberg Elmar Gehlen Andrea Reale Aldo Di Carlo Thomas M. Brown 《Liver Transplantation》2014,4(14)
Novel approaches for the fabrication of dye‐sensitized solar cells (DSCs) are reported in which all the main constituent materials are processed by laser radiation. In addition to laser sintering of the nanocrystalline TiO2 film it is shown that lasers can be successfully utilized for nc‐TiO2 film patterning, platinization of the counter‐electrode, and efficient gasket sealing. All the mentioned processes are optimized and utilized for the fabrication of the first efficient and durable all‐laser‐based DSCs. Under one sun A.M. 1.5 illumination the power conversion efficiency (PCE) is 5.3% (6.2% unmasked) and also greater than or equal to the PCE of the cell fabricated with the same materials set but processed using conventional procedures (5.2%). These results open up a new scenario for DSC technology, i.e., that of setting up an entire, laser‐based, three‐step DSC pilot production line with tangible advantages in terms of effective processing, automation, large area scalability, and embedded energy. 相似文献
9.
Huanping Zhou Tze‐Bin Song Choong‐Heui Chung Bao Lei Brion Bob Rui Zhu Hsin‐Sheng Duan Chia‐Jung Hsu Yang Yang 《Liver Transplantation》2012,2(11):1368-1374
As a wide‐bandgap semiconductor, titanium dioxide (TiO2) with a porous structure has proven useful in dye‐sensitized solar cells, but its application in low‐cost, high‐efficiency inorganic photovoltaic devices based on materials such as Cu(InGa)Se2 or Cu2ZnSnS4 is limited. Here, a thin film made from solution‐processed TiO2 nanocrystals is demonstrated as an alternative to intrinsic zinc oxide (i‐ZnO) as the window layer of CuInSxSe1?x solar cells. The as‐synthesized, well‐dispersed, 6 nm TiO2 nanocrystals are assembled into thin films with controllable thicknesses of 40, 80, and 160 nm. The TiO2 nanocrystal films with thicknesses of 40 and 80 nm exhibit conversion efficiencies (6.2% and 6.33%, respectively) that are comparable to that of a layer of the typical sputtered i‐ZnO (6.42%). The conversion efficiency of the devices with a TiO2 thickness of 160 nm decreases to 2.2%, owing to the large series resistance. A 9‐hour reaction time leads to aggregated nanoparticles with a much‐lower efficiency (2%) than that of the well‐dispersed TiO2 nanoparticles prepared using a 15‐hour reaction time. Under optimized conditions, the champion TiO2 nanocrystal‐film‐based device shows even higher efficiency (9.2%) than a control device employing a typical i‐ZnO film (8.6%). 相似文献
10.
Andreas Kunzmann Silvia Valero Ángel E. Sepúlveda Marisa Rico‐Santacruz Elena Lalinde Jesús R. Berenguer Javier García‐Martínez Dirk M. Guldi Elena Serrano Rubén D. Costa 《Liver Transplantation》2018,8(12)
In this work, a new strategy to design low‐temperature (≤200 °C) sintered dye‐sensitized solar cells (lt‐DSSC) is reported to enhance charge collection efficiencies (ηcoll), photoconversion efficiencies (η), and stabilities under continuous operation conditions. Realization of lt‐DSSC is enabled by the integration of hybrid nanoparticles based on TiO2‐Ru(II) complex (TiO2_Ru_IS)—obtained by in situ bottom‐up construction of Ru(II) N3 dye‐sensitized titania—into the photoelectrode. Incentives for the use of TiO2_Ru_IS are i) dye stability due to its integration into the TiO2 anatase network and ii) enhanced charge collection yield due to its significant resistance toward electron recombination with electrolytes. It is demonstrated that devices with single‐layer photoelectrodes featuring blends of P25 and TiO2_Ru_IS give rise to a 60% ηcoll relative to a 46% ηcoll for devices with P25‐based photoelectrodes. Responsible for this trend is a better charge transport and a reduced electron recombination. When using a multilayered photoelectrode architecture with a top layer based only on TiO2_Ru_IS, devices with an even higher ηcoll (74%) featuring a η of around 8.75% and stabilities of 600 h are achieved. This represents the highest values reported for lt‐DSSC to date. 相似文献
11.
Titanium Dioxide Mesoporous Electrodes for Solid‐State Dye‐Sensitized Solar Cells: Cross‐Analysis of the Critical Parameters
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Silvia Colella Emanuele Orgiu Ingmar Bruder Andrea Liscio Vincenzo Palermo Bernd Bruchmann Paolo Samorì Peter Erk 《Liver Transplantation》2014,4(9)
We report a comparative study on the use of four different mesoporous titanium dioxide (TiO2) photo‐electrodes for the fabrication of solid‐state dye‐sensitized solar cells (sDSSCs). The photovoltaic parameters of the device correlate with several intrinsic properties of the film, based not only on its morphological features, as commonly considered in standard characterizations, but also on the transport and the electronic properties of the photo‐electrode. These properties differ significantly for TiO2 electrodes processed using different colloidal pastes, and are decisive for the photovoltaic efficiency, ranging from 3.7% up to 5.1%. In particular, the dielectric permittivity of each mesoporous layer (εeff) and the number of traps (Nt) determined by the space‐charge‐limited current (SCLC) theory are found to be a bottle‐neck for the charge transport, greatly influencing the fill factor (FF) and open circuit voltage (Voc) of the cells. In addition, a direct correlation between TiO2 surface potential with the Voc was established. Cross‐analysis of key macroscopic parameters of the films prior to integration in the devices, in particular focusing on the determination of the capacitance and surface potential shift of the TiO2 mesoporous anode, represents a straightforward yet powerful method to screen and select the most suitable TiO2 for applications in sDSSCs. 相似文献
12.
Bo Ding Bong Jae Lee Mengjin Yang Hyun Suk Jung Jung‐Kun Lee 《Liver Transplantation》2011,1(3):415-421
In this study, the effect of plasmonic core‐shell structures, consisting of dielectric cores and metallic nanoshells, on energy conversion in dye‐sensitized solar cells (DSSCs) is investigated. The structure of the core‐shell particles is controlled to couple with visible light so that the visible component of the solar spectrum is amplified near the core‐shell particles. In core‐shell particle – TiO2 nanoparticle films, the local field intensity and light pathways are increased due to the surface plasmons and light scattering. This, in turn, enlarges the optical cross‐section of dye sensitizers coated onto the mixed films. When 22 vol% of core‐shell particles are added to a 5 μm thick TiO2 film, the energy conversion efficiency of DSSCs increases from 2.7% to 4.0%, in spite of a more than 20% decrease in the amount of dyes adsorbed on the composite films. The correlation between core‐shell particle content and energy conversion efficiency in DSSCs is explained by the balance among near‐field effects, light scattering efficiency, and surface area in the composite films. 相似文献
13.
MoS2‐Based All‐Purpose Fibrous Electrode and Self‐Powering Energy Fiber for Efficient Energy Harvesting and Storage
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Jia Liang Guoyin Zhu Caixing Wang Yanrong Wang Hongfei Zhu Yi Hu Hongling Lv Renpeng Chen Lianbo Ma Tao Chen Zhong Jin Jie Liu 《Liver Transplantation》2017,7(3)
Here an all‐purpose fibrous electrode based on MoS2 is demonstrated, which can be employed for versatile energy harvesting and storage applications. In this coaxial electrode, ultrathin MoS2 nanofilms are grown on TiO2 nanoparticles coated carbon fiber. The high electrochemical activity of MoS2 and good conductivity of carbon fiber synergistically lead to the remarkable performances of this novel composite electrode in fibrous dye‐sensitized solar cells (showing a record‐breaking conversion efficiency of 9.5%) and high‐capacity fibrous supercapacitors. Furthermore, a self‐powering energy fiber is fabricated by combining a fibrous dye‐sensitized solar cell and a fibrous supercapacitor into a single device, showing very fast charging capability (charging in 7 s under AM1.5G solar illumination) and an overall photochemical‐electricity energy conversion efficiency as high as 1.8%. In addition, this wire‐shaped electrode can also be used for fibrous Li‐ion batteries and electrocatalytic hydrogen evolution reactions. These applications indicate that the MoS2‐based all‐purpose fibrous electrode has great potential for the construction of high‐performance flexible and wearable energy devices. 相似文献
14.
Nitrogen‐Doped CNx/CNTs Heteroelectrocatalysts for Highly Efficient Dye‐Sensitized Solar Cells
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Aabhash Shrestha Munkhbayar Batmunkh Cameron J. Shearer Yanting Yin Gunther G. Andersson Joseph G. Shapter Shizhang Qiao Sheng Dai 《Liver Transplantation》2017,7(8)
The use of polydopamine as a nitrogen containing precursor to generate catalytically active nitrogen‐doped carbon (CNx) materials on carbon nanotubes (CNTs) is reported. These N‐doped CNx/CNT materials display excellent electrocatalytic activity toward the reduction of triiodide electrolyte in dye‐sensitized solar cells (DSSCs). Further, the influence of various synthesis parameters on the catalytic performance of CNx/CNTs is investigated in detail. The best performing device fabricated with the CNx/CNTs material delivers power conversion efficiency of 7.3%, which is comparable or slightly higher than that of Pt (7.1%) counter electrode‐based DSSC. These CNx/CNTs materials show great potential to address the issues associated with the Pt electrocatalyst including the high cost and scarcity. 相似文献
15.
Shiyao Cao Zhuo Kang Yanhao Yu Junli Du Lazarus German Jun Li Xiaoqin Yan Xudong Wang Yue Zhang 《Liver Transplantation》2020,10(9)
Group III–V compound semiconductors are a promising group of materials for photoelectrochemical (PEC) applications. In this work, a metal assisted wet etching approach is adapted to acquiring a large‐area patterned microdome structure on p‐GaAs surface. In addition, atomic layer deposition is used to deposit a TiO2 protection layer with controlled thickness and crystallinity. Based on a PEC photocathode design, the optimal configuration achieves a photocurrent of ?5 mA cm?2 under ?0.8 V versus Ag/AgCl in a neutral pH electrolyte. The TiO2 coating with a particular degree of crystallization deposited via controlled temperature demonstrates a superior stability over amorphous coating, enabling a remarkably stable operation, for as long as 60 h. The enhanced charge separation induced by favorable band alignment between GaAs and TiO2 contributes simultaneously to the elevated solar conversion efficiency. This approach provides a promising solution to further development of group III–V compounds and other photoelectrodes with high efficiency and excellent durability for solar fuel generation. 相似文献
16.
Two Channels of Charge Generation in Perylene Monoimide Solid‐State Dye‐Sensitized Solar Cells
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Ian A. Howard Michael Meister Björn Baumeier Henrike Wonneberger Neil Pschirer Rüdiger Sens Ingmar Bruder Chen Li Klaus Müllen Denis Andrienko Frédéric Laquai 《Liver Transplantation》2014,4(2)
The mechanism of charge generation in solid‐state dye‐sensitized solar cells using triarylamine‐substituted perylene monoimide dyes is studied by vis‐NIR broadband pump‐probe transient absorption spectroscopy. The experiments demonstrate that photoinduced electron injection into the TiO2 can only occur in regions where Li+, from the commonly used Li‐TFSI additive salt, is present on the TiO2 surface. Incomplete surface coverage by Li+ means that some dye excitons cannot inject their electron into the TiO2. However it is observed in the solar cell structure that some of the dye excitons that cannot directly inject an electron still contribute to free charge generation by the previously hypothesized reductive quenching mechanism (hole transfer to the solid‐state hole transporter followed by electron injection from the dye anion into the TiO2). The contribution of reductive quenching to the quantum efficiency of charge generation is significant, raising it from 68% to over 80%. Optimization of this reductive quenching pathway could be exploited to maintain high quantum efficiency in dyes with greater NIR absorption to achieve overall enhancements in device performance. It is demonstrated that broadband NIR transient spectroscopy is necessary to obtain population kinetics in these systems, as strong Stark effects distort the population kinetics in the visible region. 相似文献
17.
Michelle P. Browne Jan Plutnar Amir Masoud Pourrahimi Zdenek Sofer Martin Pumera 《Liver Transplantation》2019,9(26)
3D‐printing technologies have begun to revolutionize many manufacturing processes, however, there are still significant limitations that are yet to be overcome. In particular, the material from which the products are fabricated is limited by the 3D‐printing material precursor. Particularly, for photoelectrochemical (PEC) energy applications, the as‐printed electrodes can be used as is, or modified by postfabrication processes, e.g., electrochemical deposition or anodization, to create active layers on the 3D‐printed electrodes. However, the as‐printed electrodes are relatively inert for various PEC energy applications, and the aforementioned postfabrication processing techniques do not offer layer conformity or control at the Ångström/nano level. Herein, for the first time, atomic layer deposition (ALD) is utilized in conjunction with metal 3D‐printing to create active electrodes. To illustrate the proof‐of‐concept, TiO2 is deposited by ALD onto stainless steel 3D‐printed electrodes and subsequently investigated as a photoanode for PEC water oxidation. Furthermore, by tuning the TiO2 thickness by ALD, the activity can be optimized. By combining 3D‐printing and ALD, instead of other metal deposition techniques, i.e., sputtering, rapid prototyping of electrodes with controllable thickness of the desired material onto an as‐printed electrodes with any porosity can be achieved that can benefit a multitude of energy applications. 相似文献
18.
Nitrogen‐Doped Graphene Nanoribbons with Surface Enriched Active Sites and Enhanced Performance for Dye‐Sensitized Solar Cells
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Xiangtong Meng Chang Yu Xuedan Song Yang Liu Suxia Liang Zhiqiang Liu Ce Hao Jieshan Qiu 《Liver Transplantation》2015,5(11)
Superior electrocatalytic activities and excellent electrochemical stabilities of inexpensive counter electrodes (CEs) are crucial to the large‐scale practical application of dye‐sensitized solar cells (DSSCs). Herein, an efficient strategy for fabricating nitrogen‐doped graphene nanoribbons (N‐GNRs) via chemical unzipping of carbon nanotubes coupled with nitrogen doping process is reported, where abundant edge sites are produced and fully exposed basal planes of GNRs are activated by the N atoms within GNRs backbone. Benefiting from such unique characteristics, when first applied as CEs for DSSCs with triiodide/iodide electrolyte, a power conversion efficiency of 8.57% is delivered, outperforming GNRs (8.01%) and being superb to that of Pt (7.84%), and outstanding electrochemical stabilities of N‐GNRs are also demonstrated. Density functional theory calculations reveal that the N species within GNRs matrix, especially the predominant quaternary ones, could remarkably decrease the ionization energy of GNRs, which is instrumental to transfer electrons rapidly from external circuit to triiodide, and reduce charge‐transfer resistance, thus contributing to the enhanced photovoltaic performance. The present work has an insight into the unique role of N species on GNRs to the triiodide reduction, and provides an efficient strategy for design of high‐efficiency carbon electrodes with fully exposed active sites in energy conversion/storage devices. 相似文献
19.
Silvia Franz Hamed Arab Gian Luca Chiarello Massimiliano Bestetti Elena Selli 《Liver Transplantation》2020,10(23)
The fast, single‐step and easily scalable production by plasma electrolytic oxidation (PEO) of large area TiO2 electrodes with excellent photoactivity in water splitting under simulated solar light is systematically investigated here. In particular, the effects that the cell voltage (100–180 V) and the processing time (0.5–15 min) have on the electrode properties are studied. The PEO‐produced oxide layers are porous, the predominant crystalline structure shifting from anatase, to an anatase‐rutile mixture, and finally to rutile by rising the cell voltage. The electrodes show a double‐layered structure, with a more compact layer at the interface with the titanium substrate and a thick porous layer on the external surface. The photocurrent density versus wavelength reflects the phase composition, with a maximum incident photon‐to‐current efficiency of 90% at 320 nm. The highest H2 production rate is attained with the mixed anatase‐rutile electrode prepared by 300 s‐long PEO at 150 V. 相似文献
20.
Yongzhen Wu Xi Zhang Wenqin Li Zhong‐Sheng Wang He Tian Weihong Zhu 《Liver Transplantation》2012,2(1):149-156
For a sensitizer with a strong π‐conjugation system, a coadsorbent is needed to hinder dye aggregation. However, coadsorption always brings a decrease in dye coverage on the TiO2 surface. Organic ‘‘D–A–π–A’’ dyes, WS‐6 and WS‐11, are designed and synthesized based on the known WS‐2 material for coadsorbent‐free, dye‐sensitized solar cells (DSSCs). Compared with the traditional D–π–A structure, these D–A–π–A indoline dyes, with the additional incorporated acceptor unit of benzothiadiazole in the π‐conjugation, exhibit a broad photoresponse, high redox stability, and convenient energy‐level tuning. The attached n‐hexyl chains in both dyes are effective to suppress charge recombination, resulting in a decreased dark current and enhanced open‐circuit voltage. Electrochemical impedance spectroscopy studies indicate that both the resistance for charge recombination and the electron lifetime are increased after the introduction of alkyl chains to the dye molecules. Without deoxycholic acid coadsorption, the power‐conversion efficiency of WS‐6 (7.76%) on a 16 μm‐thick TiO2 film device is 45% higher than that of WS‐2 (5.31%) under the same conditions. The additional n‐hexylthiophene in WS‐11 extends the photoresponse to a panchromatic spectrum but causes a low incident photon‐to‐current conversion efficiency. 相似文献