An efficient Li+-doping strategy to optimize the band alignment of a Cu2ZnSn(S,Se)4/CdS interface by a Se&LiF co-selenization process

2020 ◽  
Vol 8 (42) ◽  
pp. 22065-22074 ◽  
Author(s):  
Hongling Guo ◽  
Gang Wang ◽  
Rutao Meng ◽  
Yali Sun ◽  
Siyu Wang ◽  
...  
Keyword(s):  
Grain Growth ◽  
Band Alignment ◽  
Band Diagram ◽  
Li Doping ◽  
Selenization Process

A novel and efficient co-selenization approach was proposed to promote the grain growth and optimize the band diagram.

Band Alignment and Charge Transfer in CsPbBr3-CdSe Nanoplatelet Hybrids Coupled by Molecular Linkers

2019 ◽  
Author(s):  
Swayandipta Dey ◽  
Hagai Cohen ◽  
Iddo Pinkas ◽  
Hong Lin ◽  
Miri Kazes ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Band Alignment ◽  
Band Gaps ◽  
Band Diagram ◽  
Transfer Processes ◽  
Optical Band Gaps ◽  
Chemical Recognition ◽  
Interface Characteristics ◽  
Interface Potential ◽  
Induced Charge

<p>Controllable interface characteristics are demonstrated at the nanoscale, using two types of semiconducting nanoparticles with nearly identical optical band gaps, CsPbBr<sub>3</sub> nanocrystals and CdSe nanoplatelets, capped with molecular linkers. By exploiting chemical recognition of the capping molecules, the two types of nanoparticles are brought into mutual contact, thus initiating spontaneous charge transfer and the formation of a strong junction field. Depending on the choice of capping molecules, the magnitude of the latter field is shown to vary in a broad range, corresponding to an interface potential step as large as circa 1 eV. The band diagram of the system, as well as the emergence of photo-induced charge transfer processes across the interface are studied here by means of optical and photoelectron based spectroscopies. Our results propose an interesting template for generating and harnessing internal built-in fields in heterogeneous nanocrystal solids.</p>

Band Alignment and Charge Transfer in CsPbBr3-CdSe Nanoplatelet Hybrids Coupled by Molecular Linkers

2019 ◽  
Author(s):  
Swayandipta Dey ◽  
Hagai Cohen ◽  
Iddo Pinkas ◽  
Hong Lin ◽  
Miri Kazes ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Band Alignment ◽  
Band Gaps ◽  
Band Diagram ◽  
Transfer Processes ◽  
Optical Band Gaps ◽  
Chemical Recognition ◽  
Interface Characteristics ◽  
Interface Potential ◽  
Induced Charge

<p>Controllable interface characteristics are demonstrated at the nanoscale, using two types of semiconducting nanoparticles with nearly identical optical band gaps, CsPbBr<sub>3</sub> nanocrystals and CdSe nanoplatelets, capped with molecular linkers. By exploiting chemical recognition of the capping molecules, the two types of nanoparticles are brought into mutual contact, thus initiating spontaneous charge transfer and the formation of a strong junction field. Depending on the choice of capping molecules, the magnitude of the latter field is shown to vary in a broad range, corresponding to an interface potential step as large as circa 1 eV. The band diagram of the system, as well as the emergence of photo-induced charge transfer processes across the interface are studied here by means of optical and photoelectron based spectroscopies. Our results propose an interesting template for generating and harnessing internal built-in fields in heterogeneous nanocrystal solids.</p>

Grain Refinement in Titanium-Erbium Alloys

1974 ◽  
Vol 32 ◽  
pp. 522-523
Author(s):  
B. B. Rath ◽  
J. E. O'Neal ◽  
R. J. Lederich
Keyword(s):  
Electron Microscopy ◽  
Size Distribution ◽  
Grain Refinement ◽  
Grain Growth ◽  
Volume Fraction ◽  
Pure Titanium ◽  
Systematic Investigation ◽  
Second Phase ◽  
Titanium Matrix ◽  
Average Size

Addition of small amounts of erbium has a profound effect on recrystallization and grain growth in titanium. Erbium, because of its negligible solubility in titanium, precipitates in the titanium matrix as a finely dispersed second phase. The presence of this phase, depending on its average size, distribution, and volume fraction in titanium, strongly inhibits the migration of grain boundaries during recrystallization and grain growth, and thus produces ultimate grains of sub-micrometer dimensions. A systematic investigation has been conducted to study the isothermal grain growth in electrolytically pure titanium and titanium-erbium alloys (Er concentration ranging from 0-0.3 at.%) over the temperature range of 450 to 850°C by electron microscopy.

Microstructural characterization of a rapidly solidified Al-Fe-V-Si alloy for elevated temperature applications

1988 ◽  
Vol 46 ◽  
pp. 550-551
Author(s):  
R. E. Franck ◽  
J. A. Hawk ◽  
G. J. Shiflet
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Grain Growth ◽  
Volume Fraction ◽  
Microstructural Characterization ◽  
Second Phase ◽  
Microstructural Stability ◽  
Elevated Temperature Strength ◽  
Temperature Applications

Rapid solidification processing (RSP) is one method of producing high strength aluminum alloys for elevated temperature applications. Allied-Signal, Inc. has produced an Al-12.4 Fe-1.2 V-2.3 Si (composition in wt pct) alloy which possesses good microstructural stability up to 425°C. This alloy contains a high volume fraction (37 v/o) of fine nearly spherical, α-Al12(Fe, V)3Si dispersoids. The improved elevated temperature strength and stability of this alloy is due to the slower dispersoid coarsening rate of the silicide particles. Additionally, the high v/o of second phase particles should inhibit recrystallization and grain growth, and thus reduce any loss in strength due to long term, high temperature annealing.The focus of this research is to investigate microstructural changes induced by long term, high temperature static annealing heat-treatments. Annealing treatments for up to 1000 hours were carried out on this alloy at 500°C, 550°C and 600°C. Particle coarsening and/or recrystallization and grain growth would be accelerated in these temperature regimes.

Scanning-tunneling spectroscopy on conjugated polymer films

2003 ◽  
Vol 771 ◽  
Author(s):  
M. Kemerink ◽  
S.F. Alvarado ◽  
P.M. Koenraad ◽  
R.A.J. Janssen ◽  
H.W.M. Salemink ◽  
...  
Keyword(s):  
Polymer Films ◽  
Conjugated Polymer ◽  
Three Dimensional ◽  
Field Enhancement ◽  
Direct Consequence ◽  
Scanning Tunneling Spectroscopy ◽  
Tunneling Spectroscopy ◽  
Band Alignment ◽  
Scanning Tunneling ◽  
Order Of Magnitude

AbstractScanning-tunneling spectroscopy experiments have been performed on conjugated polymer films and have been compared to a three-dimensional numerical model for charge injection and transport. It is found that field enhancement near the tip apex leads to significant changes in the injected current, which can amount to more than an order of magnitude, and can even change the polarity of the dominant charge carrier. As a direct consequence, the single-particle band gap and band alignment of the organic material can be directly obtained from tip height-voltage (z-V) curves, provided that the tip has a sufficiently sharp apex.

Impact of Rutile Fraction on TiO2 Visible-Light Absorption and Visible-Light-Induced Photocatalytic Activity

2018 ◽  
Author(s):  
David Maria Tobaldi ◽  
Luc Lajaunie ◽  
ana caetano ◽  
nejc rozman ◽  
Maria Paula Seabra ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Light Absorption ◽  
Solid Phase ◽  
Diffraction Method ◽  
Band Alignment ◽  
Quantitative Phase Analysis ◽  
Transmission Microscopy ◽  
Visible Light Absorption ◽  
X Ray

<div>Titanium dioxide is by far the most utilised semiconductor material for photocatalytic applications. Still, it is transparent to visible-light. Recently, it has been proved that a type-II band alignment for the rutile−anatase mixture would improve its visible-light absorption.</div><div>In this research paper we thoroughly characterised the real crystalline and amorphous phases of synthesised titanias – thermally treated at different temperatures to get distinct ratios of anatase-rutile-amorphous fraction – as well as that of three commercially available photocatalytic nano-TiO2. </div><div>The structural characterisation was done via advanced X-ray diffraction method, namely the Rietveld-RIR method, to attain a full quantitative phase analysis of the specimens. The microstructure was also investigated via an advanced X-ray method, the whole powder pattern modelling. These methods were validated combining advanced aberration-corrected scanning transmission microscopy and high-resolution electron energy-loss spectroscopy. The photocatalytic activity was assessed in the liquid- and gas-solid phase (employing rhodamine B and 4-chlorophenol, and isopropanol, respectively, as the organic substances to degrade) using a light source irradiating exclusively in the visible-range.</div><div>Optical spectroscopy showed that even a small fraction of rutile (2 wt%) is able to shift to lower energies the apparent optical band gap of an anatase-rutile mixed phase. But is this enough to attain a real photocatalytic activity promoted by merely visible-light?</div><div>We tried to give a reply to that question.</div><div>Photocatalytic activity results in the liquid-solid phase showed that a high surface hydroxylation led to specimen with superior visible light-induced catalytic activity (i.e. dye and ligand-to-metal charge transfer complexes sensitisation effects). That is: not photocatalysis <i>sensu-strictu</i>.</div><div>On the other hand, the gas-solid phase results showed that a higher amount of the rutile fraction (around 10 wt%), together with less recombination of the charge carriers, were more effective for an actual photocatalytic oxidation of isopropanol.</div>

Microstructural Considerations on the Reliability of 3D Packaging

2012 ◽  
Author(s):  
Zhiheng Huang ◽  
Zhiyong Wu ◽  
Hua Xiong ◽  
Yucheng Ma
Keyword(s):  
Mechanical Behavior ◽  
Grain Growth ◽  
Spinodal Decomposition ◽  
Elastic Energy ◽  
Modeling Approach ◽  
3D Packaging ◽  
Ultrafine Interconnects

Abstract Microstructure and its effect on mechanical behavior of ultrafine interconnects have been studied in this paper using a modeling approach. The microstructure from the processes of solidification, spinodal decomposition, and grain growth in ultrafine interconnects has highlighted its importance. The size, geometry and composition of interconnects as well as the elastic energy can influence microstructure and thus the mechanical behavior. Quantification of microstructure in ultrafine interconnects is a necessary step to establish the linkage between microstructure and reliability.

PREDICTION OF GRAIN GROWTH IN HYBRID WELDING HAZ OF TCS STAINLESS STEEL

2013 ◽  
Vol 48 (2) ◽  
pp. 199-204 ◽  
Author(s):  
Zhuanzhuan ZHANG ◽  
Chuansong WU ◽  
Jinqiang Gao
Keyword(s):  
Stainless Steel ◽  
Grain Growth ◽  
Hybrid Welding
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