Selective Passivation of Grain Boundaries via Incorporation of a Fluidic Small Molecule in Perovskite Solar Absorbers

CuInSe2, CuGaSe2, Cu(In,Ga)Se2and CuInS2thin-film solar absorbers in completed solar cells were studied in cross section by means of electron-backscatter diffraction. From the data acquired, grain-size distributions were extracted, and also the most frequent grain boundaries were determined. The grain-size distributions of all chalcopyrite-type thin films studied can be described well by lognormal distribution functions. The most frequent grain-boundary types in these thin films are 60°−〈221〉tetand 71°−〈110〉tet(near) Σ3 twin boundaries. These results can be related directly to the importance of {112}tetplanes during the topotactical growth of chalcopyrite-type thin films. Based on energetic considerations, it is assumed that the most frequent twin boundaries exhibit a 180°−〈221〉tetconstellation.

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Optimization of surface morphology to reduce the effect of grain boundaries and contact resistance in small molecule based thin film transistors

Applied Physics Letters ◽

10.1063/1.4766913 ◽

2012 ◽

Vol 101 (19) ◽

pp. 193307 ◽

Cited By ~ 20

Author(s):

Sarita Yadav ◽

Pramod Kumar ◽

Subhasis Ghosh

Keyword(s):

Thin Film ◽

Surface Morphology ◽

Contact Resistance ◽

Grain Boundaries ◽

Small Molecule ◽

Thin Film Transistors

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Morphology, Distribution and Identification of Micro-Constituents Along Grain Boundaries in Nickel-Base Alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100071326 ◽

1973 ◽

Vol 31 ◽

pp. 176-177

Author(s):

D. E. Fornwalt ◽

A. R. Geary ◽

B. H. Kear

Keyword(s):

Electron Microscope ◽

Grain Boundaries ◽

Volume Fraction ◽

Rupture Life ◽

Stress Rupture ◽

High Volume ◽

Precipitate Morphology ◽

Stress Rupture Life ◽

Nickel Base ◽

Scanning Electron

A systematic study has been made of the effects of various heat treatments on the microstructures of several experimental high volume fraction γ’ precipitation hardened nickel-base alloys, after doping with ∼2 w/o Hf so as to improve the stress rupture life and ductility. The most significant microstructural chan§e brought about by prolonged aging at temperatures in the range 1600°-1900°F was the decoration of grain boundaries with precipitate particles.Precipitation along the grain boundaries was first detected by optical microscopy, but it was necessary to use the scanning electron microscope to reveal the details of the precipitate morphology. Figure 1(a) shows the grain boundary precipitates in relief, after partial dissolution of the surrounding γ + γ’ matrix.

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Measurement of the Displacement Across a Coincidence Grain Boundary

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100078213 ◽

1977 ◽

Vol 35 ◽

pp. 124-125

Author(s):

J. W. Matthews ◽

W. M. Stobbs

Keyword(s):

Grain Boundary ◽

Grain Boundaries ◽

Stacking Fault ◽

The Other ◽

Measuring Technique ◽

High Angle ◽

Twin Boundaries ◽

Rigid Displacement ◽

Cubic Crystals ◽

Lattice Displacement

Many high-angle grain boundaries in cubic crystals are thought to be either coincidence boundaries (1) or coincidence boundaries to which grain boundary dislocations have been added (1,2). Calculations of the arrangement of atoms inside coincidence boundaries suggest that the coincidence lattice will usually not be continuous across a coincidence boundary (3). There will usually be a rigid displacement of the lattice on one side of the boundary relative to that on the other. This displacement gives rise to a stacking fault in the coincidence lattice.Recently, Pond (4) and Smith (5) have measured the lattice displacement at coincidence boundaries in aluminum. We have developed (6) an alternative to the measuring technique used by them, and have used it to find two of the three components of the displacement at {112} lateral twin boundaries in gold. This paper describes our method and presents a brief account of the results we have obtained.

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Lattice Imaging of Grain Boundaries in Ceramics

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100078171 ◽

1977 ◽

Vol 35 ◽

pp. 114-115

Author(s):

D. R. Clarke ◽

G. Thomas

Keyword(s):

Mechanical Properties ◽

High Temperature ◽

Silicon Nitride ◽

Grain Boundaries ◽

High Temperature Strength ◽

Current Interest ◽

Lattice Imaging ◽

Special Significance ◽

Structural Applications ◽

Refractory Ceramics

Grain boundaries have long held a special significance to ceramicists. In part, this has been because it has been impossible until now to actually observe the boundaries themselves. Just as important, however, is the fact that the grain boundaries and their environs have a determing influence on both the mechanisms by which powder compaction occurs during fabrication, and on the overall mechanical properties of the material. One area where the grain boundary plays a particularly important role is in the high temperature strength of hot-pressed ceramics. This is a subject of current interest as extensive efforts are being made to develop ceramics, such as silicon nitride alloys, for high temperature structural applications. In this presentation we describe how the techniques of lattice fringe imaging have made it possible to study the grain boundaries in a number of refractory ceramics, and illustrate some of the findings.

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The Effect of Specimen Thickness and Probe Size on Aem Analysis of Cr-Depletion Profiles in Sensitized Stainless Steel

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100055436 ◽

1982 ◽

Vol 40 ◽

pp. 518-519

Author(s):

E. L. Hall

Keyword(s):

Grain Boundaries ◽

Boundary Region ◽

Chromium Concentration ◽

Foil Thickness ◽

Specimen Thickness ◽

Probe Size ◽

Analytical Electron ◽

Analytical Electron Microscope ◽

Sensitization Process ◽

Compositional Gradients

Sensitization in stainless steels is caused by the formation of chromium-rich M23C6 carbides at grain boundaries, which depletes the adjacent matrix and boundary region of chromium, and hence leads to rapid intergranular attack. To fully understand the sensitization process, and to test the accuracy of theories proposed to model this process, it is necessary to obtain very accurate measurements of the chromium concentration at grain boundaries in sensitized specimens. Quantitative X-ray spectroscopy in the analytical electron microscope (AEM) enables the chromium concentration profile across these boundaries to be studied directly; however, it has been shown that a strong effect of foil thickness and electron probe size may be present in the analysis of rapidly-changing compositional gradients. The goal of this work is to examine these effects.

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Electrolytic Isolation of Twin-Type Shock Deformation Structures

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100061604 ◽

1967 ◽

Vol 25 ◽

pp. 318-319

Author(s):

F. I. Grace ◽

L. E. Murr

Keyword(s):

Grain Boundaries ◽

Thin Foil ◽

Electrolyte Composition ◽

Experimental Conditions ◽

Average Current Density ◽

Electron Transmission ◽

Deformation Structures ◽

The Matrix ◽

Average Current ◽

Specimen Edge

During the course of electron transmission investigations of the deformation structures associated with shock-loaded thin foil specimens of 70/30 brass, it was observed that in a number of instances preferential etching occurred along grain boundaries; and that the degree of etching appeared to depend upon the various experimental conditions prevailing during electropolishing. These included the electrolyte composition, the average current density, and the temperature in the vicinity of the specimen. In the specific case of 70/30 brass shock-loaded at pressures in the range 200-400 kilobars, the predominant mode of deformation was observed to be twin-type faults which in several cases exhibited preferential etching similar to that observed along grain boundaries. A novel feature of this particular phenomenon was that in certain cases, especially for twins located in the vicinity of the specimen edge, the etching or preferential electropolishing literally isolated these structures from the matrix.

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Elucidation of block boundaries as the dissolution channels in hydrated cement

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100109562 ◽

1978 ◽

Vol 36 (1) ◽

pp. 484-485

Author(s):

N.V. Belov ◽

U.I. Papiashwili ◽

B.E. Yudovich

Keyword(s):

Liquid Phase ◽

Grain Boundaries ◽

Benzoyl Peroxide ◽

Phase Contrast ◽

Active Role ◽

Point Of View ◽

Hardened Cement ◽

Hydrated Cement ◽

Hardened Cement Paste

It has been almost universally adopted that dissolution of solids proceeds with development of uniform, continuous frontiers of reaction.However this point of view is doubtful / 1 /. E.g. we have proved the active role of the block (grain) boundaries in the main phases of cement, these boundaries being the areas of hydrate phases' nucleation / 2 /. It has brought to the supposition that the dissolution frontier of cement particles in water is discrete. It seems also probable that the dissolution proceeds through the channels, which serve both for the liquid phase movement and for the drainage of the incongruant solution products. These channels can be appeared along the block boundaries.In order to demonsrate it, we have offered the method of phase-contrast impregnation of the hardened cement paste with the solution of methyl metacrylahe and benzoyl peroxide. The viscosity of this solution is equal to that of water.

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