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1.
Xuemin Shi Tingting Zhao Xinyue Zhang Cheng Sun Zhiwei Chen Siqi Lin Wen Li Hui Gu Yanzhong Pei 《Advanced materials (Deerfield Beach, Fla.)》2019,31(36)
Advancing thermoelectric n‐type Mg3Sb2 alloys requires both high carrier concentration offered by effective doping and high carrier mobility enabled by large grains. Existing research usually involves chalcogen doping on the anion sites, and the resultant carrier concentration reaches ≈3 × 1019 cm?3 or below. This is much lower than the optimum theoretically predicted, which suggets that further improvements will be possible once a highly efficient dopant is found. Yttrium, a trivalent dopant, is shown to enable carrier concentrations up to and above ≈1 × 1020 cm?3 when it is doped on the cation site. Such carrier concentration allows for in‐depth understand of the electronic transport properties over a broad range of carrier concentrations, based on a single parabolic band approximation. As well as reasonably high carrier mobility in coarse‐grain materials sintered by hot deforming and fusing of large pieces of ingots synthesized by melting, higher thermoelectric performance than earlier experimentally reported for n‐type Mg3Sb2 is found. In particular, the thermoelectric figure of merit, zT, is even higher than that of any known n‐type thermoelectric, including Bi2Te3 alloys, within 300–500 K. This might pave the way for Mg3Sb2 alloys to become a realistic material for n‐type thermoelectrics for sustainable applications. 相似文献
2.
Facile Synthesis of Highly Water‐Soluble Lanthanide‐Doped t‐LaVO4 NPs for Antifake Ink and Latent Fingermark Detection
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Cailing Chen Ying Yu Chunguang Li Dan Liu He Huang Chen Liang Yue Lou Yu Han Zhan Shi Shouhua Feng 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(48)
In the information age, it is important to protect the security and integrity of the information. As a result, the fluorescent ink as an antifake technology and the fingermark as an information carrier have aroused great interest. In this work, highly water‐soluble lanthanide (Ln3+)‐doped tetragonal phase (t‐) LaVO4 nanoparticles (NPs) are successfully obtained via a simple, fast, and green microwave‐assisted hydrothermal method. The average size of t‐LaVO4 NPs is about 43 nm. The aqueous solutions of Ln3+‐doped t‐LaVO4 exhibit excellent fluorescence properties under ultraviolet light (UV) excitation (t‐LaVO4:10%Eu is bright red and t‐LaVO4:0.5%Dy is close to white). Some superb antifake fluorescent patterns are printed using Ln3+‐doped t‐LaVO4 aqueous solution as ink, which indicates the as‐prepared Ln3+‐doped t‐LaVO4 NPs as fluorescent ink can meet the various antifake requirements. Notably, the designed convenient antifake fluorescent codes with improved security could be directly scanned and decoded by a smart phone. What's more, the as‐prepared NPs can be used for the development of latent fingermark on various substrates and the second‐level detail information can be clearly obtained from the magnification of a fingermark. These results indicate that the as‐prepared Ln3+‐doped t‐LaVO4 fluorescent NPs have great potential in security application. 相似文献
3.
Ultrasensitive and Fast All‐Inorganic Perovskite‐Based Photodetector via Fast Carrier Diffusion
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Bin Yang Fengying Zhang Junsheng Chen Songqiu Yang Xusheng Xia Tõnu Pullerits Weiqiao Deng Keli Han 《Advanced materials (Deerfield Beach, Fla.)》2017,29(40)
Low trap‐state density, high carrier mobility, and efficient charge carrier collection are key parameters for photodetectors with high sensitivity and fast response time. This study demonstrates a simple solution growth method to prepare CsPbBr3 microcrystals (MCs) with low trap‐state density. Time‐dependent photoluminescence study with one‐photon excitation (OPE) and two‐photon excitation (TPE) indicates that CsPbBr3 MCs exhibit fast carrier diffusion with carrier mobility over 100 cm2 V?1 S?1. Furthermore, CsPbBr3 MC‐based photodetectors with high charge carriers' collection efficiency are fabricated. Such photodetectors show ultrahigh responsivity (R ) up to 6 × 104 A W?1 with OPE and high R up to 6 A W?1 with TPE. The R for OPE is over one order of magnitude higher (the R for TPE is three orders of magnitude higher) than that of previously reported all‐inorganic perovskite‐based photodetectors. Moreover, the photodetectors exhibit fast response time of ≈1 ms, which corresponds to a gain ≈105 and a gain‐ bandwidth product of 108 Hz for OPE (a gain ≈103 and a gain‐bandwidth product of 106 Hz for TPE). 相似文献
4.
H. Hildebrand 《Materialwissenschaft und Werkstofftechnik》2000,31(10):899-903
Semicoherent precipitates in a Fe‐Cr‐C alloy Precipitation processes in ferromagnetic materials can be recorded very well by measuring the sensitive coercive field strength. It should be tested, whether also semicoherent precipitates have a sufficient clear interaction with Bloch‐walls. For this purpose the mild‐magnetic alloy X1FeCr25 served. To carry out the evidence sensitively, a method based on differences between HCt (heat‐treated state at T = 600…︁700°C) – HC0 (quenched state from high temperature) = Δ HC was used. A quantitative record of the amount of precipitates (as particle size) is possible by a decomposition parameter Δ HC/Δ t. Plate‐like β′‐precipitates with planes {100}∥{100} in the α‐Fe solid solution have been proved by transmission electron microscopic investigations; this is the preparation state for the transition into the stable fcc phase M23C6. As a result, the quantitative electron microscopic proof of the β′‐phase can be supported by magnetic measurements, qualitatively and quantitatively. The estimated values of the activation energy for the process in the 1st maximum of precipitation in X1FeCr25 are higher than for the stable phases as the orthorhombic M3C or the cubic complex M6C in other steels and give a hint to the difficult processes related to nucleation as to the transition into M23C6. 相似文献
5.
Hassan Ali Yunyan Zhang Jing Tang Kai Peng Sibai Sun Yue Sun Feilong Song Attia Falak Shiyao Wu Chenjiang Qian Meng Wang Zhanchun Zuo Kui‐Juan Jin Ana M. Sanchez Huiyun Liu Xiulai Xu 《Small (Weinheim an der Bergstrasse, Germany)》2018,14(17)
Defects are detrimental for optoelectronics devices, such as stacking faults can form carrier‐transportation barriers, and foreign impurities (Au) with deep‐energy levels can form carrier traps and nonradiative recombination centers. Here, self‐catalyzed p‐type GaAs nanowires (NWs) with a pure zinc blende (ZB) structure are first developed, and then a photodetector made from these NWs is fabricated. Due to the absence of stacking faults and suppression of large amount of defects with deep energy levels, the photodetector exhibits room‐temperature high photoresponsivity of 1.45 × 105 A W?1 and excellent specific detectivity (D*) up to 1.48 × 1014 Jones for a low‐intensity light signal of wavelength 632.8 nm, which outperforms previously reported NW‐based photodetectors. These results demonstrate these self‐catalyzed pure‐ZB GaAs NWs to be promising candidates for optoelectronics applications. 相似文献
6.
Pankaj Yadav M. Ibrahim Dar Neha Arora Essa A. Alharbi Fabrizio Giordano Shaik Mohammed Zakeeruddin Michael Grätzel 《Advanced materials (Deerfield Beach, Fla.)》2017,29(40)
Perovskite solar cells (PSCs) based on cesium (Cs)‐ and rubidium (Rb)‐containing perovskite films show highly reproducible performance; however, a fundamental understanding of these systems is still emerging. Herein, this study has systematically investigated the role of Cs and Rb cations in complete devices by examining the transport and recombination processes using current–voltage characteristics and impedance spectroscopy in the dark. As the credibility of these measurements depends on the performance of devices, this study has chosen two different PSCs, (MAFACs)Pb(IBr)3 (MA = CH3NH3+, FA = CH(NH2)2+) and (MAFACsRb)Pb(IBr)3, yielding impressive performances of 19.5% and 21.1%, respectively. From detailed studies, this study surmises that the confluence of the low trap‐assisted charge‐carrier recombination, low resistance offered to holes at the perovskite/2,2′,7,7′‐tetrakis(N,N‐di‐p‐methoxyphenylamine)‐9,9‐spirobifluorene interface with a low series resistance (Rs), and low capacitance leads to the realization of higher performance when an extra Rb cation is incorporated into the absorber films. This study provides a thorough understanding of the impact of inorganic cations on the properties and performance of highly efficient devices, and also highlights new strategies to fabricate efficient multiple‐cation‐based PSCs. 相似文献
7.
The amorphous Ta‐C‐N and Ta‐N thin films were deposited using magnetron sputtering on silicon wafer under the similar condition. The as‐prepared thin films were characterized using scanning electron microscope (SEM), optical profiling system, nano‐indentation and friction test instruments. The results show that, compared with the Ta‐N thin film, the Ta‐C‐N thin film has higher nano‐hardness (9.45 GPa) and elastic modulus (225.71 GPa). Furthermore, the lower friction coefficient and wear rate of the Ta‐C‐N thin film are 0.238 and 5.94×10–6 mm–3· N–1·m–1, respectively. The wear surface of Ta‐C‐N thin film is smoother than that of the Ta‐N thin film. Therefore, it shows better anti‐wear properties. 相似文献
8.
Peng Wang Benjamin Barnes Xiaojian Wu Haoran Qu Chiyu Zhang Yang Shi Robert J. Headrick Matteo Pasquali YuHuang Wang 《Advanced materials (Deerfield Beach, Fla.)》2019,31(33)
Single‐walled carbon nanotubes (SWCNTs) are a class of 1D nanomaterials that exhibit extraordinary electrical and optical properties. However, many of their fundamental studies and practical applications are stymied by sample polydispersity. SWCNTs are synthesized in bulk with broad structural (chirality) and geometrical (length and diameter) distributions; problematically, all known post‐synthetic sorting methods rely on ultrasonication, which cuts SWCNTs into short segments (typically <1 µm). It is demonstrated that ultralong (>10 µm) SWCNTs can be efficiently separated from shorter ones through a solution‐phase “self‐sorting”. It is shown that thin‐film transistors fabricated from long semiconducting SWCNTs exhibit a carrier mobility as high as ≈90 cm2 V?1 s?1, which is ≈10 times higher than those which use shorter counterparts and well exceeds other known materials such as organic semiconducting polymers (<1 cm2 V?1 s?1), amorphous silicon (≈1 cm2 V?1 s?1), and nanocrystalline silicon (≈50 cm2 V?1 s?1). Mechanistic studies suggest that this self‐sorting is driven by the length‐dependent solution phase behavior of rigid rods. This length sorting technique shows a path to attain long‐sought ultralong, electronically pure carbon nanotube materials through scalable solution processing. 相似文献
9.
Lei Cheng Hui Yin Chao Cai Jiajie Fan Quanjun Xiang 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(28)
It is greatly intriguing yet remains challenging to construct single‐atomic photocatalysts with stable surface free energy, favorable for well‐defined atomic coordination and photocatalytic carrier mobility during the photoredox process. Herein, an unsaturated edge confinement strategy is defined by coordinating single‐atomic‐site Ni on the bottom‐up synthesized porous few‐layer g‐C3N4 (namely, Ni5‐CN) via a self‐limiting method. This Ni5‐CN system with a few isolated Ni clusters distributed on the edge of g‐C3N4 is beneficial to immobilize the nonedged single‐atomic‐site Ni species, thus achieving a high single‐atomic active site density. Remarkably, the Ni5‐CN system exhibits comparably high photocatalytic activity for CO2 reduction, giving the CO generation rate of 8.6 µmol g?1 h?1 under visible‐light illumination, which is 7.8 times that of pure porous few‐layer g‐C3N4 (namely, CN, 1.1 µmol g?1 h?1). X‐ray absorption spectrometric analysis unveils that the cationic coordination environment of single‐atomic‐site Ni center, which is formed by Ni‐N doping‐intercalation the first coordination shell, motivates the superiority in synergistic N–Ni–N connection and interfacial carrier transfer. The photocatalytic mechanistic prediction confirms that the introduced unsaturated Ni‐N coordination favorably binds with CO2, and enhances the rate‐determining step of intermediates for CO generation. 相似文献
10.
Juanhong Wang Chen Song Zhiwei He Chaohuang Mai Gancheng Xie Lan Mu Yangke Cun Jiali Li Jian Wang Junbiao Peng Yong Cao 《Advanced materials (Deerfield Beach, Fla.)》2018,30(39)
All‐solution‐processed pure formamidinium‐based perovskite light‐emitting diodes (PeLEDs) with record performance are successfully realized. It is found that the FAPbBr3 device is hole dominant. To achieve charge carrier balance, on the anode side, PEDOT:PSS 8000 is employed as the hole injection layer, replacing PEDOT:PSS 4083 to suppress the hole current. On the cathode side, the solution‐processed ZnO nanoparticle (NP) is used as the electron injection layer in regular PeLEDs to improve the electron current. With the smallest ZnO NPs (2.9 nm) as electron injection layer (EIL), the solution‐processed PeLED exhibits a highest forward viewing power efficiency of 22.3 lm W?1, a peak current efficiency of 21.3 cd A?1, and an external quantum efficiency of 4.66%. The maximum brightness reaches a record 1.09 × 105 cd m?2. A record lifetime T50 of 436 s is achieved at the initial brightness of 10 000 cd m?2. Not only do PEDOT:PSS 8000 HIL and ZnO NPs EIL modulate the injected charge carriers to reach charge balance, but also they prevent the exciton quenching at the interface between the charge injection layer and the light emission layer. The subbandgap turn‐on voltage is attributed to Auger‐assisted energy up‐conversion process. 相似文献
11.
《Current Opinion in Solid State & Materials Science》2002,6(1):47-54
The measurement of majority carrier concentration profiles in silicon carbide is critically discussed considering the most promising methods. Three different techniques are reviewed in detail: (1) capacitance–voltage measurements, (2) scanning capacitance microscopy and (3) spreading resistance profiling. The potentialities and the limitations of these methods are described and compared. The investigated samples include p- and n-type epitaxial layers with a doping concentration in the range 1016–1019 cm−3 and ion implanted samples at several doses. The applications of spreading resistance profiling and scanning capacitance microscopy in p- and n-type implanted samples are shown both for uniformly doped samples and single implantation profile. The carrier profiles measured by scanning capacitance microscopy can be quantified by calculations of a complete set of capacitance–voltage curves. Difficulties are presented when quantitative carrier concentration profiles should be calculated by the spreading resistance measurements. 相似文献
12.
Vapor‐Phase‐Gating‐Induced Ultrasensitive Ion Detection in Graphene and Single‐Walled Carbon Nanotube Networks
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Ji Hao Bo Li Hyun Young Jung Fangze Liu Sanghyun Hong Yung Joon Jung Swastik Kar 《Advanced materials (Deerfield Beach, Fla.)》2017,29(23)
Designing ultrasensitive detectors often requires complex architectures, high‐voltage operations, and sophisticated low‐noise measurements. In this work, it is shown that simple low‐bias two‐terminal DC‐conductance values of graphene and single‐walled carbon nanotubes are extremely sensitive to ionized gas molecules. Incident ions form an electrode‐free, dielectric‐ or electrolyte‐free, bias‐free vapor‐phase top‐gate that can efficiently modulate carrier densities up to ≈0.6 × 1013 cm?2. Surprisingly, the resulting current changes are several orders of magnitude larger than that expected from conventional electrostatic gating, suggesting the possible role of a current‐gain inducing mechanism similar to those seen in photodetectors. These miniature detectors demonstrate charge–current amplification factor values exceeding 108 A C?1 in vacuum with undiminished responses in open air, and clearly distinguish between positive and negative ions sources. At extremely low rates of ion incidence, detector currents show stepwise changes with time, and calculations suggest that these stepwise changes can result from arrival of individual ions. These sensitive ion detectors are used to demonstrate a proof‐of‐concept low‐cost, amplifier‐free, light‐emitting‐diode‐based low‐power ion‐indicator. 相似文献
13.
High‐Mobility Helical Tellurium Field‐Effect Transistors Enabled by Transfer‐Free,Low‐Temperature Direct Growth
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Guanyu Zhou Rafik Addou Qingxiao Wang Shahin Honari Christopher R. Cormier Lanxia Cheng Ruoyu Yue Christopher M. Smyth Akash Laturia Jiyoung Kim William G. Vandenberghe Moon J. Kim Robert M. Wallace Christopher L. Hinkle 《Advanced materials (Deerfield Beach, Fla.)》2018,30(36)
The transfer‐free direct growth of high‐performance materials and devices can enable transformative new technologies. Here, room‐temperature field‐effect hole mobilities as high as 707 cm2 V?1 s?1 are reported, achieved using transfer‐free, low‐temperature (≤120 °C) direct growth of helical tellurium (Te) nanostructure devices on SiO2/Si. The Te nanostructures exhibit significantly higher device performance than other low‐temperature grown semiconductors, and it is demonstrated that through careful control of the growth process, high‐performance Te can be grown on other technologically relevant substrates including flexible plastics like polyethylene terephthalate and graphene in addition to amorphous oxides like SiO2/Si and HfO2. The morphology of the Te films can be tailored by the growth temperature, and different carrier scattering mechanisms are identified for films with different morphologies. The transfer‐free direct growth of high‐mobility Te devices can enable major technological breakthroughs, as the low‐temperature growth and fabrication is compatible with the severe thermal budget constraints of emerging applications. For example, vertical integration of novel devices atop a silicon complementary metal oxide semiconductor platform (thermal budget <450 °C) has been theoretically shown to provide a 10× systems level performance improvement, while flexible and wearable electronics (thermal budget <200 °C) can revolutionize defense and medical applications. 相似文献
14.
25th Anniversary Article: Charge Transport and Recombination in Polymer Light‐Emitting Diodes
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Martijn Kuik Gert‐Jan A. H. Wetzelaer Herman T. Nicolai N. Irina Craciun Dago M. De Leeuw Paul W. M. Blom 《Advanced materials (Deerfield Beach, Fla.)》2014,26(4):512-531
This article reviews the basic physical processes of charge transport and recombination in organic semiconductors. As a workhorse, LEDs based on a single layer of poly(p‐phenylene vinylene) (PPV) derivatives are used. The hole transport in these PPV derivatives is governed by trap‐free space‐charge‐limited conduction, with the mobility depending on the electric field and charge‐carrier density. These dependencies are generally described in the framework of hopping transport in a Gaussian density of states distribution. The electron transport on the other hand is orders of magnitude lower than the hole transport. The reason is that electron transport is hindered by the presence of a universal electron trap, located at 3.6 eV below vacuum with a typical density of ca. 3 × 1017 cm?3. The trapped electrons recombine with free holes via a non‐radiative trap‐assisted recombination process, which is a competing loss process with respect to the emissive bimolecular Langevin recombination. The trap‐assisted recombination in disordered organic semiconductors is governed by the diffusion of the free carrier (hole) towards the trapped carrier (electron), similar to the Langevin recombination of free carriers where both carriers are mobile. As a result, with the charge‐carrier mobilities and amount of trapping centers known from charge‐transport measurements, the radiative recombination as well as loss processes in disordered organic semiconductors can be fully predicted. Evidently, future work should focus on the identification and removing of electron traps. This will not only eliminate the non‐radiative trap‐assisted recombination, but, in addition, will shift the recombination zone towards the center of the device, leading to an efficiency improvement of more than a factor of two in single‐layer polymer LEDs. 相似文献
15.
Nicholas R. Glavin Kelson D. Chabak Eric R. Heller Elizabeth A. Moore Timothy A. Prusnick Benji Maruyama Dennis E. Walker Jr. Donald L. Dorsey Qing Paduano Michael Snure 《Advanced materials (Deerfield Beach, Fla.)》2017,29(47)
Flexible gallium nitride (GaN) thin films can enable future strainable and conformal devices for transmission of radio‐frequency (RF) signals over large distances for more efficient wireless communication. For the first time, strainable high‐frequency RF GaN devices are demonstrated, whose exceptional performance is enabled by epitaxial growth on 2D boron nitride for chemical‐free transfer to a soft, flexible substrate. The AlGaN/GaN heterostructures transferred to flexible substrates are uniaxially strained up to 0.85% and reveal near state‐of‐the‐art values for electrical performance, with electron mobility exceeding 2000 cm2 V?1 s?1 and sheet carrier density above 1.07 × 1013 cm?2. The influence of strain on the RF performance of flexible GaN high‐electron‐mobility transistor (HEMT) devices is evaluated, demonstrating cutoff frequencies and maximum oscillation frequencies greater than 42 and 74 GHz, respectively, at up to 0.43% strain, representing a significant advancement toward conformal, highly integrated electronic materials for RF applications. 相似文献
16.
300% Enhancement of Carrier Mobility in Uniaxial‐Oriented Perovskite Films Formed by Topotactic‐Oriented Attachment
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Dong Hoe Kim Jaehong Park Zhen Li Mengjin Yang Ji‐Sang Park Ik Jae Park Jin Young Kim Joseph J. Berry Garry Rumbles Kai Zhu 《Advanced materials (Deerfield Beach, Fla.)》2017,29(23)
Organic–inorganic perovskites with intriguing optical and electrical properties have attracted significant research interests due to their excellent performance in optoelectronic devices. Recent efforts on preparing uniform and large‐grain polycrystalline perovskite films have led to enhanced carrier lifetime up to several microseconds. However, the mobility and trap densities of polycrystalline perovskite films are still significantly behind their single‐crystal counterparts. Here, a facile topotactic‐oriented attachment (TOA) process to grow highly oriented perovskite films, featuring strong uniaxial‐crystallographic texture, micrometer‐grain morphology, high crystallinity, low trap density (≈4 × 1014 cm?3), and unprecedented 9 GHz charge‐carrier mobility (71 cm2 V?1 s?1), is demonstrated. TOA‐perovskite‐based n‐i‐p planar solar cells show minimal discrepancies between stabilized efficiency (19.0%) and reverse‐scan efficiency (19.7%). The TOA process is also applicable for growing other state‐of‐the‐art perovskite alloys, including triple‐cation and mixed‐halide perovskites. 相似文献
17.
Phong Nguyen Junwen Li T. S. Sreeprasad Kabeer Jasuja Nihar Mohanty Myles Ikenberry Keith Hohn Vivek B. Shenoy Vikas Berry 《Small (Weinheim an der Bergstrasse, Germany)》2013,9(22):3823-3828
The molecular dipole moment plays a significant role in governing important phenomena like molecular interactions, molecular configuration, and charge transfer, which are important in several electronic, electrochemical, and optoelectronic systems. Here, the effect of the change in the dipole moment of a tethered molecule on the carrier properties of (functionalized) trilayer graphene—a stack of three layers of sp2‐hybridized carbon atoms—is demonstrated. It is shown that, due to the high carrier confinement and large quantum capacitance, the trans‐to‐cis isomerisation of ‘covalently attached’ azobenzene molecules, with a change in dipole moment of 3D, leads to the generation of a high effective gating voltage. Consequently, 6 units of holes are produced per azobenzene molecule (hole density increases by 440 000 holes μm?2). Based on Raman and X‐ray photoelectron spectroscopy data, a model is outlined for outer‐layer, azobenzene‐functionalized trilayer graphene with current modulation in the inner sp2 matrix. Here, 0.097 V are applied by the isomerisation of the functionalized azobenzene. Further, the large measured quantum capacitance of 72.5 μF cm?2 justifies the large Dirac point in the heavily doped system. The mechanism defining the effect of dipole modulation of covalently tethered molecules on graphene will enable future sensors and molecular‐machine interfaces with graphene. 相似文献
18.
Jingying Liu Babar Shabbir Chujie Wang Tao Wan Qingdong Ou Pei Yu Anton Tadich Xuechen Jiao Dewei Chu Dongchen Qi Dabing Li Ruifeng Kan Yamin Huang Yemin Dong Jacek Jasieniak Yupeng Zhang Qiaoliang Bao 《Advanced materials (Deerfield Beach, Fla.)》2019,31(30)
Metal halide perovskites represent a family of the most promising materials for fascinating photovoltaic and photodetector applications due to their unique optoelectronic properties and much needed simple and low‐cost fabrication process. The high atomic number (Z) of their constituents and significantly higher carrier mobility also make perovskite semiconductors suitable for the detection of ionizing radiation. By taking advantage of that, the direct detection of soft‐X‐ray‐induced photocurrent is demonstrated in both rigid and flexible detectors based on all‐inorganic halide perovskite quantum dots (QDs) synthesized via a solution process. Utilizing a synchrotron soft‐X‐ray beamline, high sensitivities of up to 1450 µC Gyair?1 cm?2 are achieved under an X‐ray dose rate of 0.0172 mGyair s?1 with only 0.1 V bias voltage, which is about 70‐fold more sensitive than conventional α‐Se devices. Furthermore, the perovskite film is printed homogeneously on various substrates by the inexpensive inkjet printing method to demonstrate large‐scale fabrication of arrays of multichannel detectors. These results suggest that the perovskite QDs are ideal candidates for the detection of soft X‐rays and for large‐area flat or flexible panels with tremendous application potential in multidimensional and different architectures imaging technologies. 相似文献
19.
Effective Carrier‐Concentration Tuning of SnO2 Quantum Dot Electron‐Selective Layers for High‐Performance Planar Perovskite Solar Cells
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Guang Yang Cong Chen Fang Yao Zhiliang Chen Qi Zhang Xiaolu Zheng Junjie Ma Hongwei Lei Pingli Qin Liangbin Xiong Weijun Ke Gang Li Yanfa Yan Guojia Fang 《Advanced materials (Deerfield Beach, Fla.)》2018,30(14)
The carrier concentration of the electron‐selective layer (ESL) and hole‐selective layer can significantly affect the performance of organic–inorganic lead halide perovskite solar cells (PSCs). Herein, a facile yet effective two‐step method, i.e., room‐temperature colloidal synthesis and low‐temperature removal of additive (thiourea), to control the carrier concentration of SnO2 quantum dot (QD) ESLs to achieve high‐performance PSCs is developed. By optimizing the electron density of SnO2 QD ESLs, a champion stabilized power output of 20.32% for the planar PSCs using triple cation perovskite absorber and 19.73% for those using CH3NH3PbI3 absorber is achieved. The superior uniformity of low‐temperature processed SnO2 QD ESLs also enables the fabrication of ≈19% efficiency PSCs with an aperture area of 1.0 cm2 and 16.97% efficiency flexible device. The results demonstrate the promise of carrier‐concentration‐controlled SnO2 QD ESLs for fabricating stable, efficient, reproducible, large‐scale, and flexible planar PSCs. 相似文献
20.
Yong Zhang Masashi Konya Ayaka Kutsuma Seonghyeon Lim Toshihiko Mandai Hirokazu Munakata Kiyoshi Kanamura 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(36)
Magnesium batteries have the potential to be a next generation battery with large capability and high safety, owing to the high abundance, great volumetric energy density, and reversible dendrite‐free capability of Mg anodes. However, the lack of a stable high‐voltage electrolyte, and the sluggish Mg‐ion diffusion in lattices and through interfaces limit the practical uses of Mg batteries. Herein, a spinel MgIn2S4 microflower‐like material assembled by 2D‐ultrathin (≈5.0 nm) nanosheets is reported and first used as a cathode material for high‐temperature Mg batteries with an ionic liquid electrolyte. The nonflammable ionic liquid electrolyte ensure the safety under high temperatures. As prepared MgIn2S4 exhibits wide‐temperature‐range adaptability (50–150 °C), ultrahigh capacity (≈500 mAh g?1 under 1.2 V vs Mg/Mg2+), fast Mg2+ diffusibility (≈2.0 × 10?8 cm2 s?1), and excellent cyclability (without capacity decay after 450 cycles). These excellent electrochemical properties are due to the fast kinetics of magnesium by the 2D nanosheets spinel structure and safe high‐temperature operation environment. From ex situ X‐ray diffraction and transmission electron microscopy measurements, a conversion reaction of the Mg2+ storage mechanism is found. The excellent performance and superior security make it promising in high‐temperature batteries for practical applications. 相似文献