bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Surface Nanoporus Structure on the Corrosion Fatigue of Type 316L Stainless Steel in Sodium Chloride Solution
Authors: Yamada Natsuko , Tsuchiya Hiroaki , Fujimoto Shinji 
Published: February 2020

Corrosion fatigue is one of the severe corrosion problems that leads to materials failure. Therefore numerous works have been dedicated in order to improve fatigue life. For example, it was reported that the surface treatment such as shot-peening improved fatigue life of a low-alloy steel. This result indicates that the surface properties and morphology may affect the corrosion fatigue behavior.
Recently nanopore arrays have been reported to be fabricated on stainless steels in perchloric acid containing organic solvents. The dimension of nanopore is controlled by applied voltage.[1-3]
In the present work, we investigated the impact of surface morphology on corrosion fatigue behavior of type 316L stainless steel in a 0.9% NaCl solution.
3 types of samples with different morphologies were prepared; mirror-finished, electropolished and nanoporus samples. In the sodium chloride solution, the fatigue test was performed to evaluate the effect of the surface morphology on fatigue life. Furthermore, fractured samples were observed by a scanning electron microscopy(SEM).
Results indicate that the surface morphology clearly affects on the fatigue life, that is, the presence of nanopore arrays improved fatigue life in the sodium chloride solution.
Details on influence of the surface nanoporus structure on the corrosion fatigue behavior will be discussed in the presentation.
[1]V.Vignal, J.C.Roux, S.Flandrois, A.Fevrier, Corrosion Science.42(2000)1041
[2]F.Martin, D.Del Frari, J.Cousty, C.Bataillon, Electrochimica Acta 54(2009)3086
[3]H.Tsuchiya, T.Suzumura, Y.Terada, S.Fujimoto, Electrochimica Acta 82(2012)333
Charge Accumulation Mechanisms Under Dark in Perovskite Solar Cells
Authors: Ripolles Teresa S. , Baranwal Ajay K. , García-Belmonte Germà , Hayase Shuzi 
Published: February 2020

Nowadays, organic-inorganic hybrid perovskite solar cells have emerged rapidly in over few years due to their impressive improvements in the photoconvertion efficiencies exceeding 21%.1 This technology has become an alternative to the conventional photovoltaic devices, such as Silicon Solar Cells which consume a large portion of the market. In spite of their powerful features, for instance: high absorbance and long-range balanced charge transport lengths within hybrid perovskites,2 there are still some issues that are complete unknown. The electrical processes such as carrier transport into the perovskite film and charge extraction at the interfaces as well as electric field that occurs in the timescale of seconds are still under debate.3 Particularly, we found a new current peak at forward bias in the current-voltage curves under dark for the standard mesoscopic perovskite solar cells. This shape only appears at reverse scan (RS) direction and when the solar cells were kept for several seconds at short-circuit conditions before starting the RS measurement. If the device remains at forward conditions, the mentioned peak disappears. To that end, several hole transport materials (Spiro-OMeTAD and P3HT) and perovskite absorbers with different organic/inorganic cations (CH3NH3PbI3 and CsPbI3) were analyzed in a complete mesoporous-TiO2 photovoltaic devices. We considered that shallow and/or deep traps states located at interface either perovskite/p-type or perovskite/n-type transport materials should be filled.

References

1 J. H. Noh, S. H. Im, J. H. Heo, T. N. Mandal, and S. I. Seok, Nano Lett. 13 (4), 1764 (2013).

2 B. Wu, K. W. Fu, N. Yantara, G. C. Xing, S. Y. Sun, T. C. Sum, and N. Mathews, Adv. Energy Mater. 5 (19), 8 (2015).

3 H. S. Duan, H. P. Zhou, Q. Chen, P. Y. Sun, S. Luo, T. B. Song, B. Bob, and Y. Yang, Phys. Chem. Chem. Phys. 17 (1), 112 (2015); X. D. Li, X. Y. Wang, W. J. Zhang, Y. L. Wu, F. Gao, and J. F. Fang, Org. Electron. 18, 107 (2015).
Stabilizing Hybrid Perovskites Via Non-Hydrolytic Atomic Layer Deposited Overlayers
Authors: Kim In Soo , Martinson Alex B. F. 
Published: February 2020

A significant challenge to the practical application of hybrid perovskites remains for photovoltaic application. Specifically, the presence of hygroscopic ionic small molecules – alkylammonium cations – has been identified as a primary source of the absorber's sensitivity towards any moisture and any temperatures greater than 150 °C. CH3NH3PbI3 , for instance, rapidly degrades upon exposure to modest relative humidity even at room temperature via:

CH3NH3PbI3(s) → PbI2(s) + CH3NH3I(aq)

A related, but distinct, decomposition pathway is induced by heating above 150 °C even under an inert and dry environment, where methylamine and hydroiodic acid have measurable vapor pressure:

CH3NH3PbI3(s) → PbI2(s) + CH3NH2↑ + HI↑

Various attempts have been made to improve system stability including modification of chemistry, two dimensional (2D) hybrid perovskites, and macroscopic encapsulation. While these measures may slow degradation the effect is often modest, transient, and adds significant device complexity. Synthetically-compatible, pinhole-free functional overlayers, in contrast, would provide a simple route to surface chemical passivation as well as a physical barrier to diffusion in or out of the active layer. Atomic Layer Deposition (ALD) is a vapor-phase deposition technique with the capability to produce ultra-thin and pinhole-free films with well-defined surface chemical control and precise physical thickness, providing a good match to these challenges. However, the vast majority of oxide ALD processes invoke water (H2O), hydrogen peroxide (H2O2) or ozone (O3) as oxygen sources, often at temperatures greater than 150 °C. Unfortunately, these chemicals and temperatures are predicted to be in direct conflict with most hybrid perovskite halides and therefore may preclude an integrated overlayer approach. However, we report low temperature non-hydrolytic (i.e. waterless) ALD to establish stabilizing overlayers of Al2O3 or TiO2 directly on CH3NH3PbI3−xClx films. We demonstrate not only that oxide ALD conditions exist that are compatible with hybrid perovskite halides, but that the resulting systems exhibit dramatically improved stability against moisture (85% RH) and enhanced resistance to considerably higher temperatures (up to 250 °C) and even liquid water. We further demonstrate the capability of nh-TiO2 to serve a dual role – stabilizing the absorber underlayer and accepting electrons in future inverted photovoltaics.
The figure shows the effect of a liquid water drop after two minutes directly on a perovskite halide thin film, without and with an ultrathin hybrid ALD passivation layer.

Figure 1
Enhancement in Efficiency of Hybrid Polymer Solar Cells By CdSe Quantum Dot Doping
Authors: Kumari Kusum , Chand Suresh 
Published: February 2020

Polymer solar cells (PSC) is a current frontier international research and development area owing to inherent advantages in these devices[1-5]. It includes cost effectiveness, flexibility, easy processibility, large area applications etc. Power conversion efficiency of ~ 10 % have already been achieved in bulk-heterojunction solar cells in single cell geometry and more than 11% in tendom configuration[8.9]. One of the limitations in the commercialization of this photovoltaic technology is the stability issue. To address both the efficiency and stability in these devices, there is another promising approach wherein inorganic semiconductor quantum dots are doped in polymer donor-acceptor composite matrix[6.7]. The advantage of these hybrid devices is that the inorganic components viz. quantum dots provide stability and enhanced mobility of charge carrier in the nanomatrix which in turn results in increase in efficiency as well. In this work we demonstrate the effect of Cadmium Selenide (CdSe) quantum dots (size~5nm) doping in poly(3-hexylthiophene) (P3HT):[6,6]-phenyl C61 butyric acid methyl ester (PCBM), and 2-methoxy-5-(2-ethylhexyloxy)-polyphenylenevinylene (MEH-PPV): PCBM bulk heterojunction matrix where it results in considerable enhancement in efficiency in these devices. In fact the devices have been made in ambient air rather than in inert glove box conditions to illustrate conceptually the effect of CdSe quantum dots where it results in the enhancement of efficiency from 1.3 to 2% for P3HT:PCBM matrix, and 0.6 to 1.5 % for MEH-PPV:PCBM matrix. This enhancement of efficiency on CdSe quantum dot doping has been attributed to the pivotal role played by CdSe quantum dots viz. (i) it results in faster separation of excitons at donor-acceptor interface, (ii) it enables the faster transport of electrons after separation and their subsequent extraction/collection at the electrodes. This work owes promise for developing further cost effective, better efficient and stable hybrid polymer solar cells.

REFERENCES

Scharber M. C., Mühlbacher D., Koppe M., Denk P., Waldauf C., Heeger A. J., Brabec C. J., Adv. Mater. 18 (2006) 789–794.

Ma W., Yang C. Gong X., Lee K., Heeger A. J., Adv. Funct. Mater. 15 (2005) 1617-1622.

Heinemann M. D., Maydell K. von, Zutz F., Kolny-Olesiak J., Borchert H., Riedel I., Parisi J., Adv. Funct. Mater. 19 (2009) 3788–3795.

Riedel I., Parisi J., Dyakonov V., Lutsen L. Vanderzande D., Hummelen J.C., Adv. Funct. Mater. 14 (2004) 38-44.

Yu G., Gao J., Hummelen J. C., Wudi F., Heeger A. J., Science 270 (1995)1789-1791.

Huynh W.U., Dittmer J. J., Alivisatos A. P., Science 295 (2002) 2425- 2427.

Greenham N. C., Peng X., Alivisatos A. P., Phys. Rev. B 54 (1996) 17628.

Sih-Hao Liao, Hong-Jyun Jhuo, Po-Nan Yeh, Yu-Shan Cheng, Yi-Lun Li, Yu-Hsuan Lee, Sunil Sharma & Show-An Chen, SCIENTIFIC REPORTS (2014) 4 : 6813.

By Yongye Liang, Zheng Xu, Jiangbin Xia, Szu-Ting Tsai, Yue Wu, Gang Li,*Claire Ray, and Luping Yu, Adv. Mater. 22 (2010) E135–E138.
Surface Passivation of Lead Sulfide Nanocrystalswith Low Electron Affinity Metals:Photoluminescence and Photovoltaicperformance
Authors: Tavakoli Mohammad Mahdi , Tavakoli Rouhollah , Fan Zhiyong , Simchi Abdolreza 
Published: February 2020

During the last decade, solution-processed colloidal quantum dots (CQDs) have attracted significant
attention for low-cost fabrication of optoelectronic devices. In this study, lead sulfide (PbS) CQDs were
synthesized via the hot injection method and the effect of doping elements with low electron affinity,
including cadmium, calcium and zinc, on the passivation of trap states was investigated. A red-shift
in the luminescence emission was observed by doping through passivation of lead dangling bonds.
Time-resolved photoluminescence measurements showed that the lifetime of charged carriers was
significantly enhanced by cadmium doping (B80%) which is quite noticeable compared with calciumand
zinc-doped nanocrystals. External quantum efficiency measurements on thin solid films (B300 nm)
prepared by spin coating supported improved lifetime of carriers through passivation of mid-gap trap
states. In order to show the potential application of the doping process, bulk heterojunction CQD solar
cells were fabricated. It was found that the power conversion efficiency (PCE) was improved up to
B40%; the highest improvement was observed with the Cd treatment. Finally, density functional theory
(DFT) and electrochemical impedance spectroscopy (EIS) were employed to study the effect of doping
on the density of states. The results showed that doping with low electron affinity metals effectively
reduced the deep trap states of PbS QDs.

Figure 1
Tantalum Oxide Resistive Memory Devices By Ion Assisted Deposition
Authors: Goeke Ronald S. , Hughart David R. , Jacobs-Gedrim Robin Bay , Smith Carl L. , James Conrad D. , Marinella Matthew J. 
Published: February 2020

Nano-ionic resistive memory devices are of significant interest as a high density storage-class memory, and well as in neuromorphic accelerator computing. For both of these applications, a key challenge is cycle to cycle (temporal) and device to device write variability. Highly uniform films with evenly distributed concentrations of oxygen vacancies are desired for this purpose. The switchable resistive properties of these resistive memory devices have been typically fabricated from sub-stoichiometric tantalum pentoxide using reactive sputtering of Tantalum metal with a mixture of Argon and Oxygen, which does not result in a highly uniform film. Alternatively, by using annealed stoichiometric atomic layer deposited films combined with a reducing metal layer a more uniform film is obtained, but the oxygen vacancy distribution cannot be precisely controlled. Using Ion Assisted Deposition (IAD), we have successfully made memristor devices with a significant improvement in yield and a significant reduction in device performance variability. The IAD deposition approach involves e-beam evaporation of tantalum metal with a reactive beam of argon and oxygen ions impinging upon the growing film. Using this technique, the oxide formation occurs at the substrate resulting in better control over film stoichiometry. IAD is a popular technique for the deposition of oxide thin films in the optical coating industry, but this is the first known usage of this technique for stoichiometry control of ReRAM thin films.
Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Figure 1
Silicon Oxide Reram Device
Authors: Mehonic Adnan , Buckwell Mark , Montesi Luca , Munde Manveer , Chater Richard John , McPhail David S , Bosman Michel , Kenyon Anthony Joseph 
Published: February 2020

We demonstrate a silicon oxide redox-based resistive RAM (ReRAM) device. The resistance switching in our devices is intrinsic to changes within the oxide layer and thus it is not an effect of diffusion of metallic ions from the metallic electrode as in the case of electrochemical metallization (ECM) cells.
In addition to standard two-level switching we demonstrate a multi-level switching as well as an analogue modulation of resistance. It is possible to switch devices in both bipolar and unipolar switching modes while dynamically adjusting the device electronic properties, in particular two desirable properties: non-linearity in I-V curves and self-rectification. We demonstrate room temperature quantisation of conductance in our devices, implying ballistic transport of electrons through a quantum constriction, associated with an individual conductive filament in the oxide bulk.
Scanning tunnelling microscopy (STM), atomic force microscopy (AFM), and conductive atomic force microscopy (C-AFM) measurements provide a more detailed insight into both the location and the dimensions of the conductive filaments responsible for the resistance change.
Further, we demonstrate the field-driven movement of oxygen ions that causes large-scale changes in oxide layer that are accompanied with the oxygen release. We report on the material changes leading to resistance switching using secondary ion mass spectroscopy (SIMS), x-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM).
Finally we demonstrate and discuss on the feasibility of using the ReRAM cell to model aspects of the electrical activity of the neuron that could provide a novel way of using ReRAM devices in neuromorphic systems.
(Invited) Plasma Deposition of Functional Nanocomposites
Authors: Faupel Franz , Strunskus Thomas , Polonskyi Oleksandr , Elbahri Mady , Bonitz Michael , Kersten Holger 
Published: February 2020

Nanocomposite films consisting of metal nanoparticles in a dielectric organic or ceramic matrix have unique functional properties with hosts of applications [1]. The present talk demonstrates how plasma and other vapor phase deposition techniques can be employed for tailoring the nanostructure and the resulting properties. Vapor phase deposition, inter alia, allows excellent control of the metallic filling factor and its depth profile as well as the incorporation of alloy nanoparticles with well-defined composition. The metallic nanoparticles typically form via self-organization during co-deposition of the metallic and matrix components due to the high cohesive energy of the metals and the low metal-matrix interaction energy. Various methods such as sputtering, plasma polymerization, and evaporation have been applied for the deposition of the matrix component, while the metallic component has mostly been sputter-deposited or evaporated. Moreover, gas aggregation cluster sources were utilized to obtain independent control of filling factor and size of the embedded nanoparticles [2,3]. Nanostructure formation was also studied by computer simulations [4]. In most applications, a high filling factor close to the percolation threshold is essential because the functional properties often require short range interaction between nanoparticles. Examples range from plasmonic composites [5,6] through high frequency magnetic cores [7] and sensors 8] to biocompatible antibacterial coatings with tailored release rate [9].

[1] F. Faupel, V. Zaporojtchenko, T. Strunskus, M. Elbahri, Adv. Eng.
Mater.
12, 1177 (2010).
[2] O. Polonsky, T. Peter, V. Zaporojtchenko, H. Biedermann, F, Faupel, Appl. Phys. Lett.
103 (2013) 033118.
[3] T. Peter, M. Wegner, V. Zaporojtchenko, T. Strunskus, S. Bornholdt, H. Kersten, F. Faupel, Surface & Coatings Technology 205, 38 (2011).
[4] J. W. Abraham, N. Kongsuwan, T. Strunskus, F. Faupel, and M. Bonitz, J. Appl. Phys. 117 , 014305 (2015).
[5] M. Elbahri, M. K. Hedayati, V. S. K. Chakravadhanula, M. Jamali, T. Strunkus, V. Zaporochentko, F. Faupel, Adv. Mater.
23, 1993 (2011).
[6] M. K. Hedayati, M. Javaherirahim, B. Mozooni, R. Abdelaziz, A. Tavassolizadeh, V. S. K. Chakravadhanula, V. Zaporojtchenko, T. Strunkus, F. Faupel and M. Elbahri, Adv. Mater.
23, 5410 (2011)
[7] H. Greve, C. Pochstein, H. Takele, V. Zaporojtchenko, F. Faupel, A. Gerber, M. Frommberger, E. Quandt, Appl. Phys. Lett.
89, 242501 (2006).
[8] C. Hanisch, N. Ni, A. Kulkarni, V. Zaporojtchenko, T. Strunskus, F. Faupel, J. Mater. Sci.
46, 438 (2010).
[9] T. Hrkac, C. Röhl, R. Podschun, V. Zaporojtchenko, T. Strunskus, H. Papavlassopoulos, D. Garbe-Schönberg, F. Faupel, Mater. Sci. Eng. C
33, 2367 (2013).
Role of Low-Energy Ion Impact in Plasma Deposition of Cubic Boron Nitride Films
Authors: Murata Kazuma , Torigoe Masataka , Teii Kungen , Matsumoto Seiichiro 
Published: February 2020

Cubic boron nitride (cBN) is potentially expected as the semiconductor for high temperature condition due to the large band gap, high breakdown field, and high resistance to oxidation. cBN films have been synthesized from vapor phase using a variety of physical vapor deposition such as sputtering and ion beam deposition rather than plasma-enhanced chemical vapor deposition. However, high-energy (>50 eV) ion bombardment for cBN formation results in low-quality cBN films and thus obstructs their electrical applications. In our previous studies, high-quality cBN films were deposited under low-energy ion bombardment (<40 eV) by plasma-enhanced chemical vapor deposition using the chemistry of fluorine. The mean ion energy for cBN formation was reduced greatly, then the resulting films consisted of micron-sized grains with crystallographic morphology. In this study, the deposition mechanism of our cBN films is examined in terms of ion energy, ion flux, and ion to depositing boron flux ratio onto the substrate.
The ion energy and the ion to boron flux ratio are determined from the sheath potential and the ratio of incident ion flux to net deposited boron flux, respectively. For negative substrate biases where sp2-bonded BN phase only or no deposit is formed, both the ion energy and the ion to boron flux ratio are high. For positive substrate biases where cBN phase is formed, the ion energy and the ion to boron flux ratio are estimated in the range of a few eV to 35 eV and 100 to 130, respectively. The impact of negative ions is presumed to be negligible due to their low kinetic energy. The impact of positive ions with high ion to boron flux ratios is primarily responsible for reduction of the ion energy for cBN film deposition. [1] K. Teii and S. Matsumoto, Thin Solid Films 576, 50-54 (2015).
Plasma Synthesis of Platinum-Palladium Alloy Nanoparticles and Their Application to the Counter Electrode of Dye-Sensitized Solar Cells
Authors: Lee Woo-Yeol , Dao Van-Duong , Choi Ho-Suk 
Published: February 2020

Dry plasma reduction (DPR) is an excellent approach for easy synthesis of PtPd alloys with different sizes, shapes (nanoparticles, nanorods, microrods, etc.), and distributions on fluorine-doped tin oxide (FTO) substrates through simply controlling the volume ratio of the Pt and Pd precursor solution under atmospheric pressure near room temperature. These alloys are optimized for use in highly efficient counter electrodes (CEs) of dye-sensitized solar cells (DSCs). In order to combine both high conductivity and ultrahigh catalytic activity in the regeneration of iodide ions from triiodide ions, seven different CEs are prepared through the immobilization of Pt, Pd, and PtPd alloys from solutions with different volume ratios of Pt to Pd precursors (1:0, 0.9:0.1, 0.7:0.3, 0.5:0.5, 0.3:0.7, 0.1:0.9, and 0:1) on the surface of fluorine-doped tin oxide (FTO) substrates via DPR. Dye-sensitized solar cells (DSCs) utilizing a bimetallic Pt0.5Pd0.5 nanorod counter electrode exhibit better performance than those of DSCs fabricated with Pt and Pd electrodes. The obtained results establish a foundation for the use of PtPd alloy CEs as well as the economic utility of Pt in efficient and low-cost DSCs.