Read by QxMD icon Read


Le Duc Anh, Noboru Okamoto, Munetoshi Seki, Hitoshi Tabata, Masaaki Tanaka, Shinobu Ohya
Understanding and controlling the interfacial magnetic properties of ferromagnetic thin films are crucial for spintronic device applications. However, using conventional magnetometry, it is difficult to detect them separately from the bulk properties. Here, by utilizing tunneling anisotropic magnetoresistance in a single-barrier heterostructure composed of La0.6Sr0.4MnO3 (LSMO)/LaAlO3 (LAO)/Nb-doped SrTiO3 (001), we reveal the presence of a peculiar strong two-fold magnetic anisotropy (MA) along the [110]c direction at the LSMO/LAO interface, which is not observed in bulk LSMO...
August 18, 2017: Scientific Reports
Damien Canneson, Elena V Shornikova, Dmitri R Yakovlev, Tobias Rogge, Anatolie A Mitioglu, Mariana V Ballottin, Peter C M Christianen, Emmanuel Lhuillier, Manfred Bayer, Louis Biadala
The optical properties of colloidal cesium lead halide perovskite (CsPbBr3) nanocrystals are examined by time-resolved and polarization-resolved spectroscopy in high magnetic fields up to 30 T. We unambiguously show that at cryogenic temperatures the emission is dominated by recombination of negatively charged excitons with radiative decay time of 300 ps. The additional long-lived emission with a decay time of 10-30 ns, which decay time shortens and relative amplitude increases in high magnetic fields, evidence the presence of a dark exciton...
August 18, 2017: Nano Letters
Alexandra J Ramadan, Luke A Rochford, Sarah Fearn, Henry J Snaith
Cesium lead triiodide (CsPbI3) is an attractive material for photovoltaic applications due to its appropriate band gap, strong optical absorption and high thermal stability. However, the perovskite phase suffers from moisture induced structural instability. Previous studies have utilized a range of solvent systems to establish the role of solvent choice in structural instabilities. Despite this, effects of different solvents on the electronic structure of this material have not been compared. We report substantial chemical and compositional differences in thin films of CsPbI3 prepared from a range of solvent systems...
August 18, 2017: Journal of Physical Chemistry Letters
Jingrun Zhu, Xiaoling Yang, Yihua Zhu, Yuanwei Wang, Jin Cai, Jianhua Shen, Luyi Sun, Chunzhong Li
Here we report the room-temperature, atmospheric synthesis of Mn-doped cesium lead halide (CsPbX3) perovskite quantum dots (QDs). The synthesis is performed without any sort of protection, and the dual-color emission mechanism is revealed by density functional theory. The Mn concentration reaches a maximum atomic percentage of 37.73 at%, which is significantly higher in comparison to those achieved in earlier reports via high temperature hot injection method. The optical properties of as-prepared nanocrystals (NCs) remain consistent even after several months...
August 21, 2017: Journal of Physical Chemistry Letters
Mehedhi Hasan, Swaminathan Venkatesan, Dmitry A Lyashenko, Jason D Slinker, Alex Zakhidov
Organohalide lead (hybrid) perovskites have emerged as competitive semiconducting materials for photovoltaic devices due to their high performance and low cost. To further the understanding and optimization of these materials, solution based methods for interrogating and modifying perovskite thin films are needed. In this work, we report hydrofluoroether (HFE) solvent based electrolyte for electrochemical processing and characterization of organic-inorganic trihalide lead perovskite thin films. Organic perovskite films are soluble in most of the polar organic solvents and thus until now they were not considered suitable for electrochemical processing...
August 18, 2017: Analytical Chemistry
Kiyoshi Miyata, Daniele Meggiolaro, M Tuan Trinh, Prakriti P Joshi, Edoardo Mosconi, Skyler C Jones, Filippo De Angelis, X-Y Zhu
Lead halide perovskites show marked defect tolerance responsible for their excellent optoelectronic properties. These properties might be explained by the formation of large polarons, but how they are formed and whether organic cations are essential remain open questions. We provide a direct time domain view of large polaron formation in single-crystal lead bromide perovskites CH3NH3PbBr3 and CsPbBr3. We found that large polaron forms predominantly from the deformation of the PbBr3(-) frameworks, irrespective of the cation type...
August 2017: Science Advances
Sacha Fop, Eve J Wildman, Janet M S Skakle, Clemens Ritter, Abbie C Mclaughlin
The electrical and structural properties of the series Ba3Mo1-xNb1+xO8.5-x/2 (x = 0.0, 0.1, 0.2, 0.3) have been determined. Ba3Mo1-xNb1+xO8.5-x/2 crystallizes in a hybrid of the 9R hexagonal perovskite and palmierite structures, in which (Mo/Nb)O4 and (Mo/Nb)O6 units coexist within the structure. Nb substitutes preferentially at the octahedral site so that the ratio of (Mo/Nb)O4 tetrahedra to (Mo/Nb)O6 octahedra decreases with increasing x resulting in a reduction in the magnitude of the ionic conductivity from 1...
August 17, 2017: Inorganic Chemistry
E Tiguntseva, A Chebykin, A Ishteev, R Haroldson, B Balachandran, E Ushakova, F Komissarenko, H Wang, V Milichko, A Tsypkin, D Zuev, W Hu, S Makarov, A Zakhidov
Recently, hybrid halide perovskites have emerged as one of the most promising types of materials for thin-film photovoltaic and light-emitting devices because of their low-cost and potential for high efficiency. Further boosting their performance without detrimentally increasing the complexity of the architecture is critically important for commercialization. Despite a number of plasmonic nanoparticle based designs having been proposed for solar cell improvement, inherent optical losses of the nanoparticles reduce photoluminescence from perovskites...
August 17, 2017: Nanoscale
Ganghua Zhang, Haijie Chen, Zheming Gu, Peizhi Zhang, Tao Zeng, Fuqiang Huang
A new series of mixed valence perovskites, La0.75K0.25AMnTiO6 (A = Sr and Ba) nanocubes, have been synthesized by a mild hydrothermal route. From powder X-ray diffraction (XRD) analysis, the crystal structure of La0.75K0.25AMnTiO6 was solved as the orthorhombic symmetry (space group Pbnm) with a random A-site or B-site arrangement. The phase purity of the products was confirmed by ICP, SEM, and EDS analyses, and the oxidation states of the B-site metal atoms were determined to be +4 for Ti and +3/+4 for Mn from XPS results...
August 17, 2017: Inorganic Chemistry
Chintam Hanmandlu, Chih Wei Chu, Chien-Yu Chen, Karunakara Moorthy Boopathi, Hao-Wu Lin, Chao Sung Lai
Inorganic-organic hybrid perovskite solar cells (PSCs) are promising devices for providing future clean energy because of their low cost, ease of fabrication, and high efficiencies, similar to those of silicon solar cells. These materials have been investigated for their potential use in bifacial PSCs, which can absorb light from both sides of the electrodes. Here, we fabricated bifacial PSCs featuring transparent BCP/Ag/MoO3 rear electrodes, which we formed through low-temperature processing using thermal evaporation methods...
August 17, 2017: ACS Applied Materials & Interfaces
Wenke Zhou, Yicheng Zhao, Xu Zhou, Rui Fu, Qi Li, Yao Zhao, Kaihui Liu, Dapeng Yu, Qing Zhao
Due to light-induced effects in CH3NH3-based perovskites, such as ion migration, defects formation and halide segregation, the degradation of CH3NH3-based perovskite solar cells under maximum power point is generally concerned. Here we demonstrated that the effect of light-enhanced ion migration in CH3NH3PbI3 can be eliminated by inorganic Cs substitution, leading to an ultra-stable perovskite solar cell. Quantitatively, the ion migration barrier for CH3NH3PbI3 is 0.62 eV under dark, larger than CsPbI2Br (0...
August 17, 2017: Journal of Physical Chemistry Letters
Li Song, Xiaoyang Guo, Yongsheng Hu, Ying Lv, Jie Lin, Zheqin Liu, Yi Fan, Xingyuan Liu
Efficient inorganic perovskite light-emitting diodes (PeLEDs) with an ultrathin perovskite emission layer (~30 nm) were realized by doping Lewis base Polyethylene Glycol (PEG) into CsPbBr3 films. PEG in the perovskite films not only physically fills the crystal boundaries, but also interacts with the perovskite crystals to passivate the crystal grains, reduce nonradiative recombination and ensure the efficient luminance and high efficiency. As a result, promoted brightness, current efficiency (CE) and external quantum efficiency (EQE) were achieved...
August 17, 2017: Journal of Physical Chemistry Letters
Changyong Lan, Ruoting Dong, Ziyao Zhou, Lei Shu, Dapan Li, SenPo Yip, Johnny C Ho
Recently, due to the possibility of thinning down to the atomic thickness to achieve exotic properties, layered materials have attracted extensive research attention. In particular, PbI2 , a kind of layered material, and its perovskite derivatives, CH3 NH3 PbI3 (i.e., MAPbI3 ), have demonstrated impressive photoresponsivities for efficient photodetection. Herein, the synthesis of large-scale, high-density, and freestanding PbI2 nanosheets is demonstrated by manipulating the microenvironment during physical vapor deposition...
August 17, 2017: Advanced Materials
Yohan Ko, Yeong Rim Kim, Haneol Jang, Chanyong Lee, Man Gu Kang, Yongseok Jun
We report the performance of perovskite solar cells (PSCs) with an electron transport layer (ETL) consisting of a SnO2 thin film obtained by electrochemical deposition. The surface morphology and thickness of the electrodeposited SnO2 films were closely related to electrochemical process conditions, i.e., the applied voltage, bath temperature, and deposition time. We investigated the performance of PSCs based on the SnO2 films. Remarkably, the experimental factors that are closely associated with the photovoltaic performance were strongly affected by the SnO2 ETLs...
August 16, 2017: Nanoscale Research Letters
Keqiang Chen, Jing Zhou, Wen Chen, Qiaohui Zhong, Tingqiang Yang, Xue Yang, Chunyu Deng, Yueli Liu
Multinary copper-based metal sulfide (Cu-M-S) nanocrystals (NCs) usually have high absorption coefficients and near-optimum direct band gaps, which have been considered as novel photo-absorption materials for quantum dot-sensitized solar cells (QDSCs) and hole-transport materials for perovskite solar cells (PSCs). However, the formation and phase transformation mechanisms of Cu-M-S NCs during the solution-based preparing approaches are complicated. Herein, Cu-M-S NCs, including Cu2ZnSnS4 (CZTS), Cu2SnS3 (CTS), CuInS2 (CIS), and CuSbS2 (CAS), have been synthesized through solution-based hot-injection methods...
August 17, 2017: Nanoscale
Hao Zhang, Mian Tao, Baizhi Gao, Wei Chen, Qi Li, Qingyu Xu, Shuai Dong
The fabrication of high-quality organic-inorganic hybrid halide perovskite layers is the key prerequisite for the realization of high efficient photon energy harvest and electric energy conversion in their related solar cells. In this article, we report a novel fabrication technique of CH3NH3PbI3 layers based on high temperature chemical vapor reaction. CH3NH3PbI3 layers have been prepared by the reaction of PbI2 films which were deposited by pulsed laser deposition, with CH3NH3I vapor at various temperatures from 160 °C to 210 °C...
August 16, 2017: Scientific Reports
Hidenori Hiramatsu, Hitoshi Yusa, Ryo Igarashi, Yasuo Ohishi, Toshio Kamiya, Hideo Hosono
The electronic structures of 35 A(2+)B(4+)O3 ternary cubic perovskite oxides, including their hypothetical chemical compositions, were calculated by a hybrid functional method with the expectation that peculiar electronic structures and unique carrier transport properties suitable for semiconductor applications would be hidden in high-symmetry cubic perovskite oxides. We found unique electronic structures of Si-based oxides (A = Mg, Ca, Sr, and Ba, and B = Si). In particular, the unreported cubic BaSiO3 has a very narrow band gap (4...
August 16, 2017: Inorganic Chemistry
Manuel Salado, Ramesh K Kokal, Laura Calio, Samrana Kazim, Melepurath Deepa, Shahzada Ahmad
Triple cation based perovskite solar cells offer enhanced moisture tolerance and stability compared to mixed perovskites. Slight substitution of methyl ammonium or formamidinium cation by cesium (Cs(+)), was also reported to eliminate halide segregation due to its smaller size. To elucidate the device kinetics and understand the role of the Cs, we undertook different modes of scanning probe microscopy and electrochemical impedance spectroscopy (EIS) experiments. Kelvin probe force microscopy revealed that the incorporation of the Cs cation increases the contact potential difference (CPD), this CPD further increases when Spiro-OMeTAD is used as a hole transport material...
August 16, 2017: Physical Chemistry Chemical Physics: PCCP
Quyet Van Le, Jong Beom Kim, Soo Young Kim, Byeongdu Lee, Dong Ryeol Lee
In this study, we have intensively investigated the effect of the reaction temperature of hot-injection method on the structural properties of CsPbX3 (X: Br, I, Cl) perovskite nanocrystals (NCs) using the small- and wide-angle X-ray scattering. Furthermore, light emitting diodes (LEDs) performance as well as photoluminescence characteristics for high-efficient LEDs is compared with reaction temperature. It is confirmed that the size of the NCs decreased as the reaction temperature decreased, resulting stronger quantum confinement...
August 16, 2017: Journal of Physical Chemistry Letters
Junwoo Lee, Mahdi Malekshahi Byranvand, Gyeongho Kang, Sung Y Son, Seulki Song, Guan-Woo Kim, Taiho Park
In addition to having proper energy levels and high hole mobility (μh) without the use of dopants, hole-transporting materials (HTMs) used in n-i-p-type perovskite solar cells (PSCs) should be processed using green solvents to enable environmentally friendly device fabrication. Although many HTMs have been assessed, owing to the limited solubility of HTMs in green solvents, no green-solvent-processable HTM has been reported to date. Here we report on a green-solvent-processable HTM, an asymmetric D-A polymer (asy-PBTBDT) that exhibits superior solubility even in the green solvent, 2-methylanisole, which is a known food additive...
August 16, 2017: Journal of the American Chemical Society
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"