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1.
The use of lithium‐ion conductive solid electrolytes offers a promising approach to address the polysulfide shuttle and the lithium‐dendrite problems in lithium‐sulfur (Li‐S) batteries. One critical issue with the development of solid‐electrolyte Li‐S batteries is the electrode–electrolyte interfaces. Herein, a strategic approach is presented by employing a thin layer of a polymer with intrinsic nanoporosity (PIN) on a Li+‐ion conductive solid electrolyte, which significantly enhances the ionic interfaces between the electrodes and the solid electrolyte. Among the various types of Li+‐ion solid electrolytes, NASICON‐type Li1+xAlxTi2‐x(PO4)3 (LATP) offers advantages in terms of Li+‐ion conductivity, stability in ambient environment, and practical viability. However, LATP is susceptible to reaction with both the Li‐metal anode and polysulfides in Li‐S batteries due to the presence of easily reducible Ti4+ ions in it. The coating with a thin layer of PIN presented in this study overcomes the above issues. At the negative‐electrode side, the PIN layer prevents the direct contact of Li‐metal with the LATP solid electrolyte, circumventing the reduction of LATP by Li metal. At the positive electrode side, the PIN layer prevents the migration of polysulfides to the surface of LATP, preventing the reduction of LATP by polysulfides. 相似文献
2.
Organic–Inorganic Perovskite Light‐Emitting Electrochemical Cells with a Large Capacitance
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Huimin Zhang Hong Lin Chunjun Liang Hong Liu Jingjing Liang Yong Zhao Wenguan Zhang Mengjie Sun Weikang Xiao Han Li Stefano Polizzi Dan Li Fujun Zhang Zhiqun He Wallace C. H. Choy 《Advanced functional materials》2015,25(46):7226-7232
While perovskite light‐emitting diodes typically made with high work function anodes and low work function cathodes have recently gained intense interests. Perovskite light‐emitting devices with two high work function electrodes with interesting features are demonstrated here. Firstly, electroluminescence can be easily obtained from both forward and reverse biases. Secondly, the results of impedance spectroscopy indicate that the ionic conductivity in the iodide perovskite (CH3NH3PbI3) is large with a value of ≈10?8 S cm?1. Thirdly, the shift of the emission spectrum in the mixed halide perovskite (CH3NH3PbI3?xBrx) light‐emitting devices indicates that I? ions are mobile in the perovskites. Fourthly, this work shows that the accumulated ions at the interfaces result in a large capacitance (≈100 μF cm?2). The above results conclusively prove that the organic–inorganic halide perovskites are solid electrolytes with mixed ionic and electronic conductivity and the light‐emitting device is a light‐emitting electrochemical cell. The work also suggests that the organic–inorganic halide perovskites are potential energy‐storage materials, which may be applicable in the field of solid‐state supercapacitors and batteries. 相似文献
3.
Ryan Murphy Yucun Zhou Lei Zhang Luke Soule Weilin Zhang Yu Chen Meilin Liu 《Advanced functional materials》2020,30(35)
Reversible solid oxide cells based on ceramic proton conductors have potential to be the most efficient system for large‐scale energy storage. The performance and long‐term durability of these systems, however, are often limited by the ionic conductivity or stability of the proton‐conducting electrolyte. Here new family of solid oxide electrolytes, BaHfxCe0.8?xY0.1Yb0.1O3?δ (BHCYYb), which demonstrate a superior ionic conductivity to stability trade‐off than the state‐of‐the‐art proton conductors, BaZrxCe0.8?xY0.1Yb0.1O3?δ (BZCYYb), at similar Zr/Hf concentrations, as confirmed by thermogravimetric analysis, Raman, and X‐ray diffraction analysis of samples over 500 h of testing are reported. The increase in performance is revealed through thermodynamic arguments and first‐principle calculations. In addition, lab scale full cells are fabricated, demonstrating high peak power densities of 1.1, 1.4, and 1.6 W cm?2 at 600, 650, and 700 °C, respectively. Round‐trip efficiencies for steam electrolysis at 1 A cm?2 are 78%, 72%, and 62% at 700, 650, and 600 °C, respectively. Finally, CO2? H2O electrolysis is carried out for over 700 h with no degradation. 相似文献
4.
Water‐Induced Scandium Oxide Dielectric for Low‐Operating Voltage n‐ and p‐Type Metal‐Oxide Thin‐Film Transistors
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Ao Liu Guoxia Liu Huihui Zhu Huijun Song Byoungchul Shin Elvira Fortunato Rodrigo Martins Fukai Shan 《Advanced functional materials》2015,25(46):7180-7188
Solution‐processed metal‐oxide thin films based on high dielectric constant (k) materials have been extensively studied for use in low‐cost and high‐performance thin‐film transistors (TFTs). Here, scandium oxide (ScOx) is fabricated as a TFT dielectric with excellent electrical properties using a novel water‐inducement method. The thin films are annealed at various temperatures and characterized by using X‐ray diffraction, atomic‐force microscopy, X‐ray photoelectron spectroscopy, optical spectroscopy, and a series of electrical measurements. The optimized ScOx thin film exhibits a low‐leakage current density of 0.2 nA cm?2 at 2 MV cm?1, a large areal capacitance of 460 nF cm?2 at 20 Hz and a permittivity of 12.1. To verify the possible applications of ScOx thin films as the gate dielectric in complementary metal oxide semiconductor (CMOS) electronics, they were integrated in both n‐type InZnO (IZO) and p‐type CuO TFTs for testing. The water‐induced full oxide IZO/ScOx TFTs exhibit an excellent performance, including a high electron mobility of 27.7 cm2 V?1 s?1, a large current ratio (Ion/Ioff) of 2.7 × 107 and high stability. Moreover, as far as we know it is the first time that solution‐processed p‐type oxide TFTs based on a high‐k dielectric are achieved. The as‐fabricated p‐type CuO/ScOx TFTs exhibit a large Ion/Ioff of around 105 and a hole mobility of 0.8 cm2 V?1 at an operating voltage of 3 V. To the best of our knowledge, these electrical parameters are among the highest performances for solution‐processed p‐type TFTs, which represents a great step towards the achievement of low‐cost, all‐oxide, and low‐power consumption CMOS logics. 相似文献
5.
Wonho Lee Christopher K. Lyon Joo‐Hwan Seo Raymond Lopez‐Hallman Yongjun Leng Chao‐Yang Wang Michael A. Hickner Clive A. Randall Enrique D. Gomez 《Advanced functional materials》2019,29(20)
The development of solid electrolytes with the combination of high ionic conductivity, electrochemical stability, and resistance to Li dendrites continues to be a challenge. A promising approach is to create inorganic–organic composites, where multiple components provide the needed properties, but the high sintering temperature of materials such as ceramics precludes close integration or co‐sintering. Here, new ceramic–salt composite electrolytes that are cold sintered at 130 °C are demonstrated. As a model system, composites of Li1.5Al0.5Ge1.5(PO4)3 (LAGP) or Li1+x +y Alx Ti2?x Siy P3?y O12 (LATP) with bis(trifluoromethanesulfonyl)imide (LiTFSI) salts are cold sintered. The resulting LAGP–LiTFSI and LATP–LiTFSI composites exhibit high relative densities of about 90% and ionic conductivities in excess of 10?4 S cm?1 at 20 °C, which are comparable with the values obtained from LAGP and LATP sintered above 800 °C. It is also demonstrated that cold sintered LAGP–LiTFSI is electrochemically stable in Li symmetric cells over 1800 h at 0.2 mAh cm?2. Cold sintering provides a new approach for bridging the gap in processing temperatures of different materials, thereby enabling high‐performance composites for electrochemical systems. 相似文献
6.
Hongwu Chen Yeye Wen Yingyi Qi Qian Zhao Liangti Qu Chun Li 《Advanced functional materials》2020,30(5)
2D titanium carbide (Ti3C2Tx MXene) has potential application in flexible/transparent conductors because of its metallic conductivity and solution processability. However, solution‐processed Ti3C2Tx films suffer from poor hydration stability and mechanical performance that stem from the presence of intercalants, which are unavoidably introduced during the preparation of Ti3C2Tx suspension. A proton acid colloidal processing approach is developed to remove the extrinsic intercalants in Ti3C2Tx film materials, producing pristine Ti3C2Tx films with significantly enhanced conductivity, mechanical strength, and environmental stability. Typically, pristine Ti3C2Tx films show more than twofold higher conductivity (10 400 S cm?1 vs 4620 S cm?1) and up to 11‐ and 32‐times higher strength and strain energy at failure (112 MPa, 1,480 kJ m?3, vs 10 MPa, 45 kJ m?3) than films prepared without proton acid processing. Simultaneously, the conductivity and mechanical integrity of pristine films are also largely retained during the long‐term storage in H2O/O2 environment. The improvement in mechanical performance and conductivity is originated from the intrinsic strong interaction between Ti3C2Tx layers, and the absence of extrinsic intercalants makes pristine Ti3C2Tx films stable in humidity by blocking the intercalation of H2O/O2. This method makes the material more competitive for real‐world applications such as electromagnetic interference shielding. 相似文献
7.
Hyun Woo Kim Jinhyup Han Young Jun Lim YunSeok Choi Eungje Lee Youngsik Kim 《Advanced functional materials》2021,31(2):2002008
Concerning the safety aspects of Li+ ion batteries, an epoxy-reinforced thin ceramic film (ERTCF) is prepared by firing and sintering a slurry-casted composite powder film. The ERTCF is composed of Li+ ion conduction channels and is made of high amounts of sintered ceramic Li1+xTi2-xAlx(PO4)3 (LATP) and epoxy polymer with enhanced mechanical properties for solid-state batteries. The 2D and 3D characterizations are conducted not only for showing continuous Li+ ion channels thorough LATP ceramic channels with over 10−4 S cm−1 of ionic conductivity but also to investigate small amounts of epoxy polymer with enhanced mechanical properties. Solid-state Li+ ion cells are fabricated using the ERTCF and they show initial charge–discharge capacities of 139/133 mAh g−1. Furthermore, the scope of the ERTCF is expanded to high-voltage (>8 V) solid-state Li+ ion batteries through a bipolar stacked cell design. Hence, it is expected that the present investigation will significantly contribute in the preparation of the next generation reinforced thin ceramic film electrolytes for high-voltage solid-state batteries. 相似文献
8.
Jian Lin Xingliang Dai Xiaoyong Liang Desui Chen Xuerong Zheng Yifei Li Yunzhou Deng Hui Du Yuxun Ye Dong Chen Chen Lin Luying Ma Qinye Bao Haibing Zhang Linjun Wang Xiaogang Peng Yizheng Jin 《Advanced functional materials》2020,30(5)
Solution‐processed oxide thin films are actively pursued as hole‐injection layers (HILs) in quantum‐dot light‐emitting diodes (QLEDs), aiming to improve operational stability. However, device performance is largely limited by inefficient hole injection at the interfaces of the oxide HILs and high‐ionization‐potential organic hole‐transporting layers. Solution‐processed NiOx films with a high and stable work function of ≈5.7 eV achieved by a simple and facile surface‐modification strategy are presented. QLEDs based on the surface‐modified NiOx HILs show driving voltages of 2.1 and 3.3 V to reach 1000 and 10 000 cd m?2, respectively, both of which are the lowest among all solution‐processed LEDs and vacuum‐deposited OLEDs. The device exhibits a T95 operational lifetime of ≈2500 h at an initial brightness of 1000 cd m?2, meeting the commercialization requirements for display applications. The results highlight the potential of solution‐processed oxide HILs for achieving efficient‐driven and long‐lifetime QLEDs. 相似文献
9.
Lin Zhang Fang Yuan Jun Xi Bo Jiao Hua Dong Jingrui Li Zhaoxin Wu 《Advanced functional materials》2020,30(40)
Stability issue is one of the major concerns that limit emergent perovskite light‐emitting diodes (PeLEDs) techniques. Generally, ion migration is considered as the most important origin of PeLEDs degradation. In this work, an all‐inorganic device architecture, LiF/perovskite/LiF/ZnS/ZnSe, is proposed to address this imperative problem. The inorganic (Cs1?xRbx)1?yKyPbBr3 perovskite is optimized with achieving a photoluminescence quantum yield of 67%. Depth profile analysis of X‐ray photoelectron spectroscopy indicates that the LiF/perovskite/LiF structure and the ZnS/ZnSe cascade electron transport layers significantly suppress the electric‐field‐induced ion migrations of the perovskite layers, and impede the diffusion of metallic atoms from cathode into perovskites. The as‐prepared PeLEDs display excellent shelf stability (maintaining 90% of the initial external quantum efficiency [EQE] after 264 h) and operational stability (half‐lifetime of about 255 h at an initial luminance of 120 cd m?2). The devices also exhibit a maximum brightness of 15 6155 cd m?2 and an EQE of 11.05%. 相似文献
10.
Glass‐Like Through‐Plane Thermal Conductivity Induced by Oxygen Vacancies in Nanoscale Epitaxial La0.5Sr0.5CoO3−δ
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Xuewang Wu Jeff Walter Tianli Feng Jie Zhu Hong Zheng John F. Mitchell Neven Biškup Maria Varela Xiulin Ruan Chris Leighton Xiaojia Wang 《Advanced functional materials》2017,27(47)
Ultrafast time‐domain thermoreflectance (TDTR) is utilized to extract the through‐plane thermal conductivity (Λ LSCO) of epitaxial La0.5Sr0.5CoO3?δ (LSCO) of varying thickness (<20 nm) on LaAlO3 and SrTiO3 substrates. These LSCO films possess ordered oxygen vacancies as the primary means of lattice mismatch accommodation with the substrate, which induces compressive/tensile strain and thus controls the orientation of the oxygen vacancy ordering (OVO). TDTR results demonstrate that the room‐temperature Λ LSCO of LSCO on both substrates (1.7 W m?1 K?1) are nearly a factor of four lower than that of bulk single‐crystal LSCO (6.2 W m?1 K?1). Remarkably, this approaches the lower limit of amorphous oxides (e.g., 1.3 W m?1 K?1 for glass), with no dependence on the OVO orientation. Through theoretical simulations, origins of the glass‐like thermal conductivity of LSCO are revealed as a combined effect resulting from oxygen vacancies (the dominant factor), Sr substitution, size effects, and the weak electron/phonon coupling within the LSCO film. The absence of OVO dependence in the measured Λ LSCO is rationalized by two main effects: (1) the nearly isotropic phononic thermal conductivity resulting from the imperfect OVO planes when δ is small; (2) the missing electronic contribution to Λ LSCO along the through‐plane direction for these ultrathin LSCO films on insulating substrates. 相似文献
11.
James M. Perkins Sarah Fearn Stuart N. Cook Rajagopalan Srinivasan Chris M. Rouleau Hans M. Christen Geoff D. West Richard J. H. Morris Hamish L. Fraser Stephen J. Skinner John A. Kilner David W. McComb 《Advanced functional materials》2010,20(16):2664-2674
Significant recent interest has been directed towards the relationship between interfaces and reports of enhanced ionic conductivity. To gain a greater understanding of the effects of hetero‐interfaces on ionic conductivity, advanced analytical techniques including electron microscopy (TEM/STEM), electron energy loss spectroscopy (EELS), and secondary ion mass spectrometry (SIMS) are used to characterize CeO2/Ce0.85Sm0.15O2 multilayer thin films grown by pulsed laser deposition. High quality growth is observed, but ionic conductivity measured by impedance spectroscopy and 18O tracer experiments is consistent with bulk materials. EELS analysis reveals the unusual situation of layers containing only Ce(IV) adjacent to layers containing both Ce(III) and Ce(IV). Post oxygen annealing induced oxygen diffusion and mixed oxidation states in both layers, but only in the vicinity of low angle grain boundaries perpendicular to the layers. The implications of the anomalous behavior of the Ce oxidation states on the design of novel electrolytes for solid oxide fuel cells is discussed. 相似文献
12.
Nagore Ortiz‐Vitoriano Idoia Ruiz de Larramendi Stuart N. Cook Mónica Burriel Ainara Aguadero John A. Kilner Teófilo Rojo 《Advanced functional materials》2013,23(41):5131-5139
The La1–xCaxFe0.8Ni0.2O3–δ (0 ≤ x ≤ 0.9) system is investigated for potential application as a cathode material for intermediate temperature solid oxide fuel cells (IT‐SOFCs). A broad range of experimental techniques have been utilized in order to elucidate the characteristics of the entire compositional range. Low A‐site Ca content compositions (x ≤ 0.4) feature a single perovskite solid solution. Compositions with 40% Ca content (x = 0.4) exhibit the highest electrical and ionic conductivities of these single phase materials (250 and 1.9 × 10?3 S cm?1 at 800 °C, respectively), a level competitive with state‐of‐the‐art (La,Sr)(Fe,Co)O3. Between 40 and 50% Ca content (0.4 > x > 0.5) a solubility limit is reached and a secondary, brownmillerite‐type phase appears for all higher Ca content compositions (0.5 ≤ x ≤ 0.9). While typically seen as detrimental to electrochemical performance in cathode materials, this phase brings with it ionic conductivity at operational temperatures. This gives rise to the effective formation of pseudo‐composite materials which feature significantly enhanced performance characteristics, while also providing the closest match in thermal expansion behavior to typical electrolyte materials. This all comes with the advantage of being produced through a simple, single‐step, low‐cost production route without the issues associated with typical composite materials. The highest performing pseudo‐composite material (x = 0.5) exhibits electronic conductivity of 300–350 S cm?1 in the 600–800 °C temperature range while the best polarisation resistance (Rp) values of approximately 0.2 Ω cm2 are found in the 0.5 ≤ x ≤ 0.7 range. 相似文献
13.
Jeong Oh Kim Jae Seok Hur Daesik Kim Byeongmoon Lee Jae Min Jung Hyeon A. Kim Ui Jin Chung Seung Hee Nam Yongtaek Hong Kwon‐Shik Park Jae Kyeong Jeong 《Advanced functional materials》2020,30(9)
Stretchable electronic devices should be enabled by the smart design of materials and architectures because their commercialization is limited by the tradeoff between stretchability and electrical performance limits. In this study, thin‐film transistors are fabricated using strategies that combine the unit process of a novel hybrid gate insulator and low‐temperature indium gallium tin oxide (IGTO) channel layer and a stress‐relief substrate structure. Novel hybrid dielectric films are synthesized and their molecular structural configurations are analyzed. These films consist of a polymer [poly(4‐vinylphenol‐co‐methylmethacrylate)], cross‐linkers having different binding structures [1,6‐bis(trimethoxysilyl)hexane (BTMSH), dodecyltrimethoxysilane, and poly(melamine‐co‐formaldehyde)], and an inorganic zirconia component (ZrOx). The hybrid film with BTMSH cross‐linker and 0.2 M ZrOx exhibits excellent insulating properties as well as mechanical stretchability. IGTO transistors fabricated on polyimide‐coated glass substrates are transferred to the rubber substrate to offer stretchability of the transistor pixelated thin‐film transistors. IGTO transistors fabricated on stretchable substrates using these strategies show promising electrical performance and mechanical durability. After 200 stretchability test cycles under uniaxial elongation of approximately 300%, the IGTO transistor still retains a high carrier mobility of 21.7 cm2 V?1 s?1, a low sub‐threshold gate swing of 0.68 V decade?1 and a high ION/OFF ratio of 2.0 × 107. 相似文献
14.
Reusable Cellulose‐Based Hydrogel Sticker Film Applied as Gate Dielectric in Paper Electrolyte‐Gated Transistors
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Inês Cunha Raquel Barras Paul Grey Diana Gaspar Elvira Fortunato Rodrigo Martins Luís Pereira 《Advanced functional materials》2017,27(16)
A new concept for reusable eco‐friendly hydrogel electrolytes based on cellulose is introduced. The reported electrolytes are designed and engineered through a simple, fast, low‐cost, and eco‐friendly dissolution method of microcrystalline cellulose at low temperature using an aqueous LiOH/urea solvent system. The cellulose solution is combined with carboxymethyl cellulose, followed by the regeneration and simultaneous ion incorporation. The produced free standing cellulose‐based electrolyte films exhibit interesting properties for application in flexible electrochemical devices, such as biosensors or electrolyte‐gated transistors (EGTs), because of their high specific capacitances (4–5 µF cm?2), transparency, and flexibility. Indium–gallium–zinc‐oxide EGTs on glass with laminated cellulose‐based hydrogel electrolytes (CHEs) as the gate dielectric are produced presenting a low working voltage (<2 V), showing an on–off current ratio (I on/off) of 106, a subthreshold swing lower than 0.2 V dec?1, and saturation mobility (μSat) reaching 26 cm2 V?1 s?1. The flexible CHE‐gated transistors on paper are also demonstrated, which operate at switching frequencies up to 100 Hz. Combining the flexibility of the EGTs on paper with the reusability of the developed CHEs is a breakthrough toward biodegradable advanced functional materials allied with disposable/recyclable and low‐cost electronic devices. 相似文献
15.
Xuyong Feng Po‐Hsiu Chien Zhuoying Zhu Iek‐Heng Chu Pengbo Wang Marcello Immediato‐Scuotto Hesam Arabzadeh Shyue Ping Ong Yan‐Yan Hu 《Advanced functional materials》2019,29(9)
All‐solid‐state rechargeable sodium (Na)‐ion batteries are promising for inexpensive and high‐energy‐density large‐scale energy storage. In this contribution, new Na solid electrolytes, Na3?yPS4?xClx, are synthesized with a strategic approach, which allows maximum substitution of Cl for S (x = 0.2) without significant compromise of structural integrity or Na deficiency. A maximum conductivity of 1.96 mS cm?1 at 25 °C is achieved for Na3.0PS3.8Cl0.2, which is two orders of magnitude higher compared with that of tetragonal Na3PS4 (t‐Na3PS4). The activation energy (Ea) is determined to be 0.19 eV. Ab initio molecular dynamics simulations shed light on the merit of maximizing Cl‐doping while maintaining low Na deficiency in enhanced Na‐ion conduction. Solid‐state nuclear magnetic resonance (NMR) characterizations confirm the successful substitution of Cl for S and the resulting change of P oxidation state from 5+ to 4+, which is also verified by spin moment analysis. Ion transport pathways are determined with a tracer‐exchange NMR method. The functional detects that promote Na ‐ion transport are maximized for further improvement in ionic conductivity. Full‐cell performance is demonstrated using Na/Na3.0PS3.8Cl0.2/Na3V2(PO4)3 with a reversible capacity of ≈100 mAh g‐1 at room temperature. 相似文献
16.
William J. Scheideler Rajan Kumar Andre R. Zeumault Vivek Subramanian 《Advanced functional materials》2017,27(14)
Additive patterning of transparent conducting metal oxides at low temperatures is a critical step in realizing low‐cost transparent electronics for display technology and photovoltaics. In this work, inkjet‐printed metal oxide transistors based on pure aqueous chemistries are presented. These inks readily convert to functional thin films at lower processing temperatures (T ≤ 250 °C) relative to organic solvent‐based oxide inks, facilitating the fabrication of high‐performance transistors with both inkjet‐printed transparent electrodes of aluminum‐doped cadmium oxide (ACO) and semiconductor (InOx ). The intrinsic fluid properties of these water‐based solutions enable the printing of fine features with coffee‐ring free line profiles and smoother line edges than those formed from organic solvent‐based inks. The influence of low‐temperature annealing on the optical, electrical, and crystallographic properties of the ACO electrodes is investigated, as well as the role of aluminum doping in improving these properties. Finally, the all‐aqueous‐printed thin film transistors (TFTs) with inkjet‐patterned semiconductor (InOx ) and source/drain (ACO) layers are characterized, which show ideal low contact resistance (R c < 160 Ω cm) and competitive transistor performance (µ lin up to 19 cm2 V?1 s?1, Subthreshold Slope (SS) ≤150 mV dec?1) with only low‐temperature processing (T ≤ 250 °C). 相似文献
17.
Virtually Bare Nanocrystal Surfaces: Significantly Enhanced Electrical Transport in CuInSe2 and CuIn1−xGaxSe2 Thin Films upon Ligand Exchange with Thermally Degradable 1‐Ethyl‐5‐Thiotetrazole
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Jannika Lauth Jakob Marbach Andreas Meyer Sedat Dogan Christian Klinke Andreas Kornowski Horst Weller 《Advanced functional materials》2014,24(8):1081-1088
A facile and safe ligand exchange method for readily synthesized CuInSe2 (CIS) and CuIn1‐xGaxSe2 (CIGS) nanocrystals (NCs) from oleylamine to 1‐ethyl‐5‐thiotetrazole, preserving the colloidal stability of the chalcopyrite structure, is presented. 1‐Ethyl‐5‐thiotetrazole as thermally degradable ligand is adapted for the first time for trigonal pyramidal CIS (18 nm), elongated CIS (9 nm) and CIGS NCs (6 nm). Exchanged NC solutions are processed onto gold electrodes yielding ordered thin films. These films are thermally annealed at 260 °C to completely remove 1‐ethyl‐5‐thiotetrazol leaving individual closely assembled NCs with virtually bare surfaces. The current–voltage characteristics of the NC solids are measured prior to ligand thermolysis in the dark and under illumination and after ligand thermolysis in the same manner. The conductivity of trigonal pyramidal CIS increases by four orders of magnitude (1.4 × 10?9 S cm?1 (dark) to 1.4 × 10?5 S cm?1 (illuminated)) for ligand‐free NC films. Elongated CIS NC films show a three orders of magnitude conductivity increase and CIGS NC films exhibit improved conductivity by two orders of magnitude. Conductivity enhancement thereby depends on the NC size accentuating the role of trap‐states and internal grain boundaries in ligand‐free NC solids for electrical transport. This approach for the first time offers the possibility to address chalcopyrite materials’ electrical properties in a virtually ligand‐free state. 相似文献
18.
Qi Zhang Haomiao Yu Fenggui Zhao Liying Pei Jinpeng Li Kai Wang Bin Hu 《Advanced functional materials》2019,29(35)
Solution‐processing hybrid metal halide perovskites are promising materials for developing flexible thin‐film devices. This work reports the substrate effects on the spin–orbit coupling (SOC) in perovskite films through thermal expansion under thermal annealing. X‐ray diffraction (XRD) measurements show that using a flexible polyethylene naphthalate (PEN) substrate introduces a smaller mechanical strain in perovskite MAPbI3?xClx films, as compared to conventional glass substrates. Interestingly, the linear/circular photoexcitation‐modulated photocurrent studies find that decreasing mechanical strain gives rise to a weaker orbit–orbit interaction toward decreasing the SOC in the MAPbI3?xClx films prepared on flexible PEN substrates relative to rigid glass substrates. Simultaneously, decreasing the mechanical strain causes a reduction in the internal magnetic parameter inside the MAPbI3?xClx films, providing further evidence to show that introducing mechanical strain can affect the SOC in hybrid perovskite films upon using flexible substrates toward developing flexible perovskite thin‐film devices. Furthermore, thermal admittance spectroscopy indicates that the trap states are increased in the perovskite films prepared on flexible PEN substrates as compared to glass substrates. Consequently, PEN and rigid glass substrates lead to shorter and longer photoluminescence lifetimes, respectively. Clearly, these findings provide an insightful understanding on substrate effects on optoelectronic properties in flexible perovskite thin‐film devices. 相似文献
19.
Zhen Li Zhi‐Wei Liu Zeyu Li Tian‐Xiong Wang Fulai Zhao Xuesong Ding Wei Feng Bao‐Hang Han 《Advanced functional materials》2020,30(10)
Defects are deliberately introduced into covalent organic frameworks (COFs) via a three‐component condensation strategy. The defective COFs (dCOF‐NH2‐Xs, X = 20, 40, and 60) possess favorable crystallinity and porosity, as well as have active amine functional groups as anchoring sites for further postfunctionalization. By introducing imidazolium functional groups onto the pore walls of COFs via the Schiff‐base reaction, dCOF‐ImBr‐Xs‐ and dCOF‐ImTFSI‐Xs‐based materials are employed as all‐solid‐state electrolytes for lithium‐ion conduction with a wide range of working temperatures (from 303 to 423 K), and the ion conductivity of dCOF‐ImTFSI‐60‐based electrolyte reaches 7.05 × 10?3 S cm?1 at 423 K. As far as it is known, it is the highest value for all polymeric crystalline porous material based all‐solid‐state electrolytes. Furthermore, Li/dCOF‐ImTFSI‐60@Li/LiFePO4 all‐solid Li‐ion battery displays satisfactory battery performance under 353 K. This work not only provides a new methodology to construct COFs with precisely controlled defects for postfunctionalization, but also makes them promising candidate materials as all‐solid‐state electrolytes for lithium‐ion batteries operate at high temperatures. 相似文献
20.
Solid‐state lithium (Li) batteries using solid electrolytes and Li anodes are highly desirable because of their high energy densities and intrinsic safety. However, low ambient‐temperature conductivity and poor interface compatibility of solid electrolytes as well as Li dendrite formation cause large polarization and poor cycling stability. Herein, a high transference number intercalated composite solid electrolyte (CSE) is prepared by the combination of a solution‐casting and hot‐pressing method using layered lithium montmorillonite, poly(ethylene carbonate), lithium bis(fluorosulfonyl)imide, high‐voltage fluoroethylene carbonate additive, and poly(tetrafluoroethylene) binder. The electrolyte presents high ionic conductivity (3.5 × 10?4 S cm?1), a wide electrochemical window (4.6 V vs Li+/Li), and high ionic transference number (0.83) at 25 °C. In addition, a 3D Li anode is also fabricated via a facile thermal infusion strategy. The synergistic effect of high transference number intercalated electrolyte and 3D Li anode is more favorable to suppress Li dendrites in a working battery. The solid‐state batteries based on LiFePO4 (Al2O3 @ LiNi0.5Co0.2Mn0.3O2), CSE, and 3D Li deliver admirable cycling stability with discharge capacity 145.9 mAh g?1 (150.7 mAh g?1) and capacity retention 91.9% after 200 cycles at 0.5 C (92.0% after 100 cycles at 0.2 C) at 25 °C. This work affords a splendid strategy for high‐performance solid‐state battery. 相似文献