共查询到20条相似文献,搜索用时 15 毫秒
1.
Jia‐Zhao Wang Lin Lu Mustafa Lotya Jonathan N. Coleman Shu‐Lei Chou Hua‐Kun Liu Andrew I. Minett Jun Chen 《Liver Transplantation》2013,3(6):798-805
Layered MoS2 prepared by liquid‐phase exfoliation has been blended with single‐walled carbon nanotubes (SWNTs) to form novel composite thin films for lithium battery applications. The films were formed by vacuum filtration of blended dispersions onto nitrocellulose membranes. The resulting composite films were transferred onto Cu foil electrodes via a facile filtration/wet transfer technique from nitrocellulose membranes. The morphology of the film was characterised by field emission scanning electron microscopy, which suggests that the MoS2‐SWNT composite film shows good adherence to the Cu foil substrate. The MoS2‐SWNT composite thin films show strong electrochemical performance at different charge‐discharge rates. The capacity of a MoS2‐SWNT composite film with thickness of 1 μm is approximately 992 mAh g?1 after 100 cycles. The morphology study showed that the MoS2‐SWNT thin film retains structural integrity after 100 cycles, while the MoS2 thin film without SWNTs displays significant cracking. In addition, the novel composite thin film preparation and transfer protocols developed in this study could be extended to the preparation of various layered‐material‐based composite films, with the potential for new device designs for energy applications. 相似文献
2.
Conductive and Stable Magnesium Oxide Electron‐Selective Contacts for Efficient Silicon Solar Cells
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Yimao Wan Chris Samundsett James Bullock Mark Hettick Thomas Allen Di Yan Jun Peng Yiliang Wu Jie Cui Ali Javey Andres Cuevas 《Liver Transplantation》2017,7(5)
A high Schottky barrier (>0.65 eV) for electrons is typically found on lightly doped n‐type crystalline (c‐Si) wafers for a variety of contact metals. This behavior is commonly attributed to the Fermi‐level pinning effect and has hindered the development of n‐type c‐Si solar cells, while its p‐type counterparts have been commercialized for several decades, typically utilizing aluminium alloys in full‐area, and more recently, partial‐area rear contact configurations. Here the authors demonstrate a highly conductive and thermally stable electrode composed of a magnesium oxide/aluminium (MgOx/Al) contact, achieving moderately low resistivity Ohmic contacts on lightly doped n‐type c‐Si. The electrode, functionalized with nanoscale MgOx films, significantly enhances the performance of n‐type c‐Si solar cells to a power conversion efficiency of 20%, advancing n‐type c‐Si solar cells with full‐area dopant‐free rear contacts to a point of competitiveness with the standard p‐type architecture. The low thermal budget of the cathode formation, its dopant‐free nature, and the simplicity of the device structure enabled by the MgOx/Al contact open up new possibilities in designing and fabricating low‐cost optoelectronic devices, including solar cells, thin film transistors, or light emitting diodes. 相似文献
3.
Donor‐Acceptor Interfacial Interactions Dominate Device Performance in Hybrid P3HT‐ZnO Nanowire‐Array Solar Cells
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Luisa Whittaker‐Brooks William E. McClain Jeffrey Schwartz Yueh‐Lin Loo 《Liver Transplantation》2014,4(16)
The adsorption of self‐assembled monolayers (SAMs) on metal oxide surfaces is a promising route to control electronic characteristics and surface wettability. Here, arylphosphonic acid derivatives are used to modulate the surface properties of vertically oriented ZnO nanowire arrays. Arylphosphonate‐functionalized ZnO nanowires are incorporated into hybrid organic‐inorganic solar cells in which infiltrated poly(3‐hexylthiophene) (P3HT) serves as the polymer donor. Strong correlations between device short‐circuit current density (J sc) and power conversion efficiencies (PCEs) with ZnO surface functionalization species are observed and a weak correlation in the open‐circuit voltage (V oc) is observed. Inverted solar cells fabricated with these treated interfaces exhibit PCEs as high as 2.1%, primarily due to improvements in J sc. Analogous devices using untreated ZnO arrays having efficiencies of 1.6%. The enhancement in J sc is attributed to surface passivation of ZnO by SAMs and enhanced wettability from P3HT, which improve charge transfer and reduce carrier recombination at the organic‐inorganic interface in the solar cells. 相似文献
4.
Lewis‐Adduct Mediated Grain‐Boundary Functionalization for Efficient Ideal‐Bandgap Perovskite Solar Cells with Superior Stability
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Yingxia Zong Zhongmin Zhou Min Chen Nitin P. Padture Yuanyuan Zhou 《Liver Transplantation》2018,8(27)
State‐of‐the‐art perovskite solar cells (PSCs) have bandgaps that are invariably larger than 1.45 eV, which limits their theoretically attainable power conversion efficiency. The emergent mixed‐(Pb, Sn) perovskites with bandgaps of 1.2–1.3 eV are ideal for single‐junction solar cells according to the Shockley–Queisser limit, and they have the potential to deliver higher efficiency. Nevertheless, the high chemical activity of Sn(II) in these perovskites makes it extremely challenging to control their physical properties and chemical stability, thereby leading to PSCs with relatively low PCE and stability. In this work, the authors employ the Lewis‐adduct SnF2·3FACl additive in the solution‐processing of ideal‐bandgap halide perovskites (IBHPs), and prepare uniform large‐grain perovskite thin films containing continuously functionalized grain boundaries with the stable SnF2 phase. Such Sn(II)‐rich grain‐boundary networks significantly enhance the physical properties and chemical stability of the IBHP thin films. Based on this approach, PSCs with an ideal bandgap of 1.3 eV are fabricated with a promising efficiency of 15.8%, as well as enhanced stability. The concept of Lewis‐adduct‐mediated grain‐boundary functionalization in IBHPs presented here points to a new chemical route for approaching the Shockley–Queisser limit in future stable PSCs. 相似文献
5.
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
6.
Wenjing Xu Shiting Wu Xinming Li Mingchu Zou Liusi Yang Zelin Zhang Jinquan Wei Song Hu Yanhui Li Anyuan Cao 《Liver Transplantation》2016,6(12)
Currently studied carbon nanotube‐silicon (CNT‐Si) solar cells are based on relatively small active areas (typically <0.15 cm2); increasing the active area generally leads to reduced power conversion efficiencies. This study reports CNT‐Si solar cells with active areas of more than 2 cm2 for single cells, yet still achieving cell efficiencies of about 10%, which is the first time for CNT‐Si solar cells with an active area more than 1 cm2 to reach the level for real applications. In this work, a controlled number of flattened highly conductive CNT strips is added, in simple arrangement, to form a CNT‐Si solar cell with CNT strips in which the middle film makes heterojunctions with Si while the top strips act as self‐similar top electrodes, like conventional metal grids. The CNT strips, directly condensed from as‐grown CNT films, not only improve the CNT‐Si junctions, but also enhance the conductivity of top electrodes without introducing contact barrier when the CNT strips are added onto the film. This property may facilitate the development of large‐area high‐performance CNT or graphene‐Si solar cells. 相似文献
7.
Humberto Rodriguez‐Alvarez Alfons Weber Jakob Lauche Christian Alexander Kaufmann Thorsten Rissom Dieter Greiner Manuela Klaus Thomas Unold Christoph Genzel Hans‐Werner Schock Roland Mainz 《Liver Transplantation》2013,3(10):1381-1387
Thin film solar cells based on co‐evaporated Cu(In,Ga)Se2 absorber films present the highest efficiencies among current polycrystalline thin‐film technologies. Thanks to the development of a novel experimental setup for in situ growth studies, it was possible to follow the formation of the crystalline phases during such deposition processes for the first time. This synchrotron‐based energy‐dispersive X‐ray diffraction and fluorescence setup is suited for real‐time studies of thin film vapor deposition processes. Focusing on the growth of CuInSe2 and CuGaSe2 fabricated by three‐stage processing, we find that the phase transitions in the Cu‐In‐Se system follow the reported pseudo‐binary In2Se3‐Cu2Se phase diagram. This requires a transformation of the Se sublattice during the incorporation of Cu‐Se into the In2Se3 precursor film from the first process stage. In the Cu‐Ga‐Se system, besides an increase in the lattice spacings, we observe no transformation of the Se sublattice. Furthermore, the structural defects of the Ga‐Se precursor film are preserved until the CuGaSe2 stoichiometry is reached. By means of model calculations of the fluorescence signals, we confirm in both systems the segregation of Cu2Se at the surface near a concentration of 25 at.% Cu shortly after the recrystallization of the films. The modeling also reveals that Cu2Se penetrates into the CuInSe2 film, whereas it remains at the surface of the CuGaSe2 film. 相似文献
8.
HyeonOh Shin Byung‐Man Kim Taehyung Jang Kwang Min Kim Deok‐Ho Roh Jung Seung Nam Jeong Soo Kim Un‐Young Kim Byunghong Lee Yoonsoo Pang Tae‐Hyuk Kwon 《Liver Transplantation》2019,9(3)
A vacancy‐ordered double perovskite, Cs2SnI6, has emerged as a promising lead‐free perovskite in the optoelectronic field. However, the charge transfer kinetics mediated by its surface state remains unclear. Here, the charge transfer mechanism of Cs2SnI6 is reported and the role of its surface state in the presence of a redox mediator is clarified. Specifically, charge transfer through the surface state of Cs2SnI6 and its subsequent surface state charging are demonstrated by cyclic voltammetry and Mott–Schottky measurements, respectively. Because it is expected that the surface state of Cs2SnI6 is capable of regenerating oxidized organic dyes, a Cs2SnI6‐based regenerator is developed for a dye‐sensitized solar cell composed of fluorine‐doped tin oxide (FTO)/dyed mesoporous TiO2/regenerator/poly(3,4‐ethylenedioxythiophene)/FTO. As expected, the performance of the Cs2SnI6‐based regenerator is strongly dependent on the highest occupied molecular orbital of the dyes. Consequently, Cs2SnI6 shows efficient charge transfer with a thermodynamically favorable charge acceptor level, achieving a 79% enhancement in the photocurrent density (14.1 mA cm?2) compared with that of a conventional liquid electrolyte (7.9 mA cm?2). The results suggest that the surface state of Cs2SnI6 is the main charge transfer pathway in the presence of a redox mediator and should be considered in future designs of Cs2SnI6‐based devices. 相似文献
9.
Hamed Azimi Thomas Heumüller Andreas Gerl Gebhard Matt Peter Kubis Monica Distaso Rameez Ahmad Tugce Akdas Moses Richter Wolfgang Peukert Christoph J. Brabec 《Liver Transplantation》2013,3(12):1589-1596
The understanding and control of nanostructures with regard to transport and recombination mechanisms is of key importance in the optimization of the power conversion efficiency (PCE) of solar cells based on inorganic nanocrystals. Here, the transport properties of solution‐processed solar cells are investigated using photo‐CELIV (photogenerated charge carrier extraction by linearly increasing voltage) and transient photovoltage techniques; the solar cells are prepared by an in‐situ formation of CuInS2 nanocrystals (CIS NCs) at the low temperature of 270 °C. Structural and morphological analyses reveal the presence of a metastable CuIn5S8 phase and a disordered morphology in the CuInS2 nanocrytalline films consisting of polycrystalline grains at the nanoscale range. Consistent with the disordered morphology of the CIS NC thin films, the CIS NC devices are characterized by a low carrier mobility. The carrier density dynamic indicates that the recombination kinetics in these devices follows the dispersive bimolecular recombination model and does not fully behave in a diffusion‐controlled manner, as expected by Langevin‐type recombination. The mobility–lifetime product of the charge carriers properly explains the performance of the thin (200 nm) CIS NC solar cell with a high fill‐factor of 64% and a PCE of over 3.5%. 相似文献
10.
Design and Fabrication of a Precious Metal‐Free Tandem Core–Shell p+n Si/W‐Doped BiVO4 Photoanode for Unassisted Water Splitting
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Pongkarn Chakthranont Thomas R. Hellstern Joshua M. McEnaney Thomas F. Jaramillo 《Liver Transplantation》2017,7(22)
Tandem photoelectrochemical water splitting cells utilizing crystalline Si and metal oxide photoabsorbers are promising for low‐cost solar hydrogen production. This study presents a device design and a scalable fabrication scheme for a tandem heterostructure photoanode: p+n black silicon (Si)/SnO2 interface/W‐doped bismuth vanadate (BiVO4)/cobalt phosphate (CoPi) catalyst. The black‐Si not only provides a substantial photovoltage of 550 mV, but it also serves as a conductive scaffold to decrease charge transport pathlengths within the W‐doped BiVO4 shell. When coupled with cobalt phosphide (CoP) nanoparticles as hydrogen evolution catalysts, the device demonstrates spontaneous water splitting without employing any precious metals, achieving an average solar‐to‐hydrogen efficiency of 0.45% over the course of an hour at pH 7. This fabrication scheme offers the modularity to optimize individual cell components, e.g., Si nanowire dimensions and metal oxide film thickness, involving steps that are compatible with fabricating monolithic devices. This design is general in nature and can be readily adapted to novel, higher performance semiconducting materials beyond BiVO4 as they become available, which will accelerate the process of device realization. 相似文献
11.
Atomic‐Scale Observation of Oxygen Substitution and Its Correlation with Hole‐Transport Barriers in Cu2ZnSnSe4 Thin‐Film Solar Cells
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Jin Hyun Kim Si‐Young Choi Minseok Choi Talia Gershon Yun Seog Lee Wei Wang Byungha Shin Sung‐Yoon Chung 《Liver Transplantation》2016,6(6)
Kesterite‐type Cu2ZnSn(S,Se)4 has been extensively studied over the past several years, with researchers searching for promising candidates for indium‐ and gallium‐free inexpensive absorbers in high‐efficiency thin‐film solar cells. Many notable experimental and theoretical studies have dealt with the effects of intrinsic point defects, Cu/Zn/Sn nonstoichiometry, and cation impurities on cell performance. However, there have been few systematic investigations elucidating the distribution of oxygen at an atomic scale and the correlation between oxygen substitution and charge transport despite unavoidable incorporation of oxygen from the ambient atmosphere during thin‐film fabrication. Using energy‐dispersive X‐ray spectroscopy, scanning transmission electron microscopy, and electron energy‐loss spectroscopy, the presence of nanoscale layers is directly demonstrated in which oxygen is substantially substituted for Se, near grain boundaries in polycrystalline Cu2ZnSnSe4 films. Density‐functional theory calculations also show that oxygen substitution remarkably lowers the valence band maximum and subsequently widens the overall bandgap. Consequently, anion modification by oxygen can make a major contribution to the formation of a robust barrier blocking the holes from bulk grains into grain boundaries, thereby efficiently attaining electron?hole separation. The findings provide crucial insights into achieving better energy conversion efficiency in kesterite‐based thin‐film solar cells through optimum control of oxidation during the fabrication process. 相似文献
12.
Hamed Azimi Alessia Senes Markus C. Scharber Kurt Hingerl Christoph J. Brabec 《Liver Transplantation》2011,1(6):1162-1168
Charge transport and recombination are studied for organic solar cells fabricated using blends of polymer poly[(4,4′‐bis(2‐ethylhexyl)dithieno[3,2‐b:2′,3′‐d]silole)‐2,6‐diyl‐alt‐(4,7‐bis(2‐thienyl)‐2,1,3‐benzothiadiazole)‐5,5′‐diyl] (Si‐PCPDTBT) with [6,6]‐phenyl‐C61‐butyric acid methyl ester (mono‐PCBM) and the bis‐adduct analogue of mono‐PCBM (bis‐PCBM). The photocurrent of Si‐PCPDTBT:bis‐PCBM devices shows a strong square root dependence on the effective applied voltage. From the relationship between the photocurrent and the light intensity, we found that the square‐root dependence of the photocurrent is governed by the mobility‐lifetime (μτ) product of charge carriers while space‐charge field effects are insignificant. The fill factor (FF) and short circuit current density (Jsc) of bis‐PCBM solar cells show a considerable increase with temperature as compared to mono‐PCBM solar cells. SCLC analysis of single carrier devices proofs that the mobility of both electrons and holes is significantly lowered when replacing mono‐PCBM with bis‐PCBM. The increased recombination in Si‐PCPDTBT:bis‐PCBM solar cells is therefore attributed to the low carrier mobilities, as the transient photovoltage measurements show that the carrier lifetime of devices are not significantly altered by using bis‐PCBM instead of mono‐PCBM. 相似文献
13.
Metal‐Free Artificial Photosynthesis of Carbon Monoxide Using N‐Doped ZnTe Nanorod Photocathode Decorated with N‐Doped Carbon Electrocatalyst Layer
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Youn Jeong Jang Mahesh Datt Bhatt Jaehyuk Lee Sun Hee Choi Byeong Jun Lee Jae Sung Lee 《Liver Transplantation》2018,8(20)
An artificial photosynthesis system based on N‐doped ZnTe nanorods decorated with an N‐doped carbon electrocatalyst layer is fabricated via an all‐solution process for the selective conversion of CO2 to CO. Substitutional N‐doping into the ZnTe lattice decreases the bandgap slightly and improves the charge transfer characteristics, leading to enhanced photoelectrochemical activity. Remarkable N‐doping effects are also demonstrated by the N‐doped carbon layer that promotes selective CO2‐to‐CO conversion instead of undesired water‐to‐H2 reduction by providing active sites for CO2 adsorption and activation, even in the absence of metallic redox centers. The photocathode shows promising performance in photocurrent generation (?1.21 mA cm?2 at ?0.11 VRHE), CO selectivity (dominant CO production of ≈72%), minor H2 reduction (≈20%), and stability (corrosion suppression). The metal‐free electrocatalyst/photocatalyst combination prepared via a cost‐effective solution process exhibits high performance due to synergistic effects between them, and thus may find application in practical solar fuel production. 相似文献
14.
Jun Hong Noh Hyun Soo Han Sangwook Lee Jin Young Kim Kug Sun Hong Gil‐Sang Han Hyunjung Shin Hyun Suk Jung 《Liver Transplantation》2011,1(5):829-835
A 3D transparent conducting oxide (3D‐TCO) has been fabricated by growing Sn‐doped indium oxide (ITO) nanowire arrays on glass substrates via a vapor transport method. The 3D TCO charge‐collection properties have been compared to those of conventional two‐dimensional TCO (2D‐TCO) thin films. For use as a photoelectrode in dye‐sensitized solar cells, ITO‐TiO2 core‐shell nanowire arrays were prepared by depositing a 45 nm‐thick mesoporous TiO2 shell layer consisting of ~6 nm anatase nanoparticles using TiCl4 treatments. Dye‐sensitized solar cells fabricated using these ITO‐TiO2 core‐shell nanowire arrays show extremely fast charge collection owing to the shorter electron paths across the 45 nm‐thick TiO2 shell compared to the 2D TCO. Interestingly, the charge‐collection time does not increase with the overall electrode thickness, which is counterintuitive to conventional diffusion models. This result implies that, in principle, maximum light harvesting can be achieved without hindering the charge collection. The proposed new 3D TCO should also be attractive for other photovoltaic applications where the active layer thickness is limited by poor charge collection. 相似文献
15.
Bahram Abdollahi Nejand Ihteaz M. Hossain Marius Jakoby Somayeh Moghadamzadeh Tobias Abzieher Saba Gharibzadeh Jonas A. Schwenzer Pariya Nazari Fabian Schackmar Dirk Hauschild Lothar Weinhardt Uli Lemmer Bryce S. Richards Ian A. Howard Ulrich W. Paetzold 《Liver Transplantation》2020,10(5)
All‐perovskite multijunction photovoltaics, combining a wide‐bandgap (WBG) perovskite top solar cell (EG ≈1.6–1.8 eV) with a low‐bandgap (LBG) perovskite bottom solar cell (EG < 1.3 eV), promise power conversion efficiencies (PCEs) >33%. While the research on WBG perovskite solar cells has advanced rapidly over the past decade, LBG perovskite solar cells lack PCE as well as stability. In this work, vacuum‐assisted growth control (VAGC) of solution‐processed LBG perovskite thin films based on mixed Sn–Pb perovskite compositions is reported. The reported perovskite thin films processed by VAGC exhibit large columnar crystals. Compared to the well‐established processing of LBG perovskites via antisolvent deposition, the VAGC approach results in a significantly enhanced charge‐carrier lifetime. The improved optoelectronic characteristics enable high‐performance LBG perovskite solar cells (1.27 eV) with PCEs up to 18.2% as well as very efficient four‐terminal all‐perovskite tandem solar cells with PCEs up to 23%. Moreover, VAGC leads to promising reproducibility and potential in the fabrication of larger active‐area solar cells up to 1 cm2. 相似文献
16.
Cheng Liu Yi Yang Xin Xia Yong Ding Zulqarnain Arain Shijie An Xuepeng Liu Roldn Carmona Cristina Songyuan Dai Mohammad Khaja Nazeeruddin 《Liver Transplantation》2020,10(9)
The unfavorable morphology and inefficient utilization of phase transition reversibility have limited the high‐temperature‐processed inorganic perovskite films in both efficiency and stability. Here, a simple soft template‐controlled growth (STCG) method is reported by introducing (adamantan‐1‐yl)methanammonium to control the nucleation and growth rate of CsPbI3 crystals, which gives rise to pinhole‐free CsPbI3 film with a grain size on a micrometer scale. The STCG‐based CsPbI3 perovskite solar cell exhibits a power conversion efficiency of 16.04% with significantly reduced defect densities and charge recombination. More importantly, an all‐inorganic solar cell with the architecture fluorine‐doped tin oxide (FTO)/NiOx/STCG‐CsPbI3/ZnO/indium‐doped tin oxide (ITO) is successfully fabricated to demonstrate its real advantage in thermal stability. By suppressing the inductive effect of defects during the phase transition and utilizing the unique reversibility of the phase transition for the high‐temperature‐processed CsPbI3 film, the all‐inorganic solar cell retains 90% of its initial efficiency after 3000 h of continuous light soaking and heating. 相似文献
17.
Cobalt Polypyridyl Complexes as Transparent Solution‐Processable Solid‐State Charge Transport Materials
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Muhammad K. Kashif Rebecca A. Milhuisen Michael Nippe Jack Hellerstedt David Z. Zee Noel W. Duffy Barry Halstead Filippo De Angelis Simona Fantacci Michael S. Fuhrer Christopher J. Chang Yi‐Bing Cheng Jeffrey R. Long Leone Spiccia Udo Bach 《Liver Transplantation》2016,6(24)
Charge transport materials (CTMs) are traditionally inorganic semiconductors or metals. However, over the past few decades, new classes of solution‐processable CTMs have evolved alongside new concepts for fabricating electronic devices at low cost and with exceptional properties. The vast majority of these novel materials are organic compounds and the use of transition metal complexes in electronic applications remains largely unexplored. Here, a solution‐processable solid‐state charge transport material composed of a blend of [Co(bpyPY4)](OTf)2 and Co(bpyPY4)](OTf)3 where bpyPY4 is the hexadentate ligand 6,6′‐bis(1,1‐di(pyridin‐2‐yl)ethyl)‐2,2′‐bipyridine and OTf? is the trifluoromethanesulfonate anion is reported. Surprisingly, these films exhibit a negative temperature coefficient of conductivity (dσ/dT) and non‐Arrhenius behavior, with respectable solid‐state conductivities of 3.0 S m?1 at room temperature and 7.4 S m?1 at 4.5 K. When employed as a CTM in a solid‐state dye‐sensitized solar cell, these largely amorphous, transparent films afford impressive solar energy conversion efficiencies of up to 5.7%. Organic–inorganic hybrid materials with negative temperature coefficients of conductivity generally feature extended flat π‐systems with strong π–π interactions or high crystallinity. The lack of these features promotes [Co(bpyPY4)](OTf)2+ x films as a new class of CTMs with a unique charge transport mechanism that remains to be explored. 相似文献
18.
Aishuak Konarov Hee Jae Kim Jae‐Hyeon Jo Natalia Voronina Yongseok Lee Zhumabay Bakenov Jongsoon Kim Seung‐Taek Myung 《Liver Transplantation》2020,10(24)
Recently, anionic‐redox‐based materials have shown promising electrochemical performance as cathode materials for sodium‐ion batteries. However, one of the limiting factors in the development of oxygen‐redox‐based electrodes is their low operating voltage. In this study, the operating voltage of oxygen‐redox‐based electrodes is raised by incorporating nickel into P2‐type Na2/3[Zn0.3Mn0.7]O2 in such a way that the zinc is partially substituted by nickel. As designed, the resulting P2‐type Na2/3[(Ni0.5Zn0.5)0.3Mn0.7]O2 electrode exhibits an average operating voltage of 3.5 V and retains 95% of its initial capacity after 200 cycles in the voltage range of 2.3–4.6 V at 0.1C (26 mA g?1). Operando X‐ray diffraction analysis reveals the reversible phase transition: P2 to OP4 phase on charge and recovery to the P2 phase on discharge. Moreover, ex situ X‐ray absorption near edge structure and X‐ray photoelectron spectroscopy studies reveal that the capacity is generated by the combination of Ni2+/Ni4+ and O2?/O1? redox pairs, which is supported by first‐principles calculations. It is thought that this kind of high voltage redox species combined with oxygen redox could be an interesting approach to further increase energy density of cathode materials for not only sodium‐based rechargeable batteries, but other alkali‐ion battery systems. 相似文献
19.
Hui‐Chun Fu Vinoth Ramalingam Hyunho Kim Chun‐Ho Lin Xiaosheng Fang Husam N. Alshareef Jr‐Hau He 《Liver Transplantation》2019,9(22)
MXene, a new class of 2D materials, has gained significant attention owing to its attractive electrical conductivity, tunable work function, and metallic nature for wide range of applications. Herein, delaminated few layered Ti3C2Tx MXene contacted Si solar cells with a maximum power conversion efficiency (PCE) of ≈11.5% under AM1.5G illumination are demonstrated. The formation of an Ohmic junction of the metallic MXene to n+‐Si surface efficiently extracts the photogenerated electrons from n+np+‐Si, decreases the contact resistance, and suppresses the charge carrier recombination, giving rise to excellent open‐circuit voltage and short‐circuit current density. The rapid thermal annealing process further improves the electrical contact between Ti3C2Tx MXene and n+‐Si surface by reducing sheet resistance, increasing electrical conductivity, and decreasing cell series resistance, thus leading to a remarkable improvement in fill factor and overall PCE. The work demonstrated here can be extended to other MXene compositions as potential electrodes for developing highly performing solar cells. 相似文献
20.
To solve critical issues related to device stability and performance of perovskite solar cells (PSCs), FA0.026MA0.974PbI3?yCly‐Cu:NiO (formamidinium methylammonium (FAMA)‐perovskite‐Cu:NiO) and Al2O3/Cu:NiO composites are developed and utilized for fabrication of highly stable and efficient PSCs through fully‐ambient‐air processes. The FAMA‐perovskite‐Cu:NiO composite crystals prepared without using any antisolvents not only improve the perovskite film quality with large‐size crystals and less grain boundaries but also tailor optical and electronic properties and suppress charge recombination with reduction of trap density. A champion device based on the composites as light absorber and Al2O3/Cu:NiO interfacial layer between electron transport layer and active layer yields power conversion efficiency (PCE) of 20.67% with VOC of 1.047 V, JSC of 24.51 mA cm?2, and fill factor of 80.54%. More importantly, such composite‐based PSCs without encapsulation show significant enhancement in long‐term air‐stability, thermal‐ and photostability with retaining 97% of PCE over 240 d under ambient conditions (25–30 °C, 45–55% humidity). 相似文献