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Influence of Focused Pulsed Laser Radiation on the Properties of Amorphous FeSi6B16 Metal Alloy
摘要： The effect of focused pulsed laser radiation (number of pulses and power density) on an amorphous FeSi6B16 metal film is studied. The states of the alloy before and after laser irradiation are analyzed using methods of atomic force microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and microhardness measurements. Focused laser radiation in any exposure mode is established to cause high-temperature heating of the surface of an amorphous alloy in the irradiation zone. The result of such heating is melting of the material surface and propagation of the heat wave front from the strongly heated surface to its inner layers, which induces the redistribution of elements in the Fe–Si–B system, a change in the structure, and an increase in the microhardness.
关键词： microhardness,nonequilibrium state,X-ray photoelectron spectroscopy,atomic-force microscopy,surface,laser radiation,amorphous alloys
更新于2025-09-23 15:21:01
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Modification of Hole Transport Layers for Fabricating High Performance Nona??fullerene Polymer Solar Cells
摘要： Interfacial engineering is expected to be a feasible strategy to improve the charge transport properties of the hole transport layer (HTL), which is of crucial importance to boosting the device performance of organic solar cells (OSCs). In this study, two types of alcohol soluble materials, 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ) and di-tetrabutylammoniumcis–bis(isothiocyanato)bis(2,2’-bipyridyl-4,4’-dicarboxylato) ruthenium (II) (N719) dye were selected as the dopant for HTL. The doping of F4-TCNQ and N719 dye in poly(ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) with and without integrating a graphene quantum-dots (G-QDs) layer has been explored in poly[[2,6′-4-8-di(5-ethylhexylthienyl)benzo[1,2-b:3,3-b]dithiophene][3-fluoro-2[(2-ethylhexyl)carbonyl]thieno[3,4-b]thio-phenediyl:(2,2′-((2Z,2′Z)-(((4,4,9,9-tetrakis(4-hexylphenyl)-4,9-dihydro-s-indaceno[1,2-b:5,6-b′]dithiophene-2,7-diyl)bis(4-((2-ethylhexyl)oxy)thiophene-5,2-diyl))bis(methanylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile (PTB7-Th:IEICO-4F) OSCs. The power conversion efficiency of the non-fullerene OSCs has been increased to 10.12% from 8.84%. The influence of HTL modification on the nano-morphological structures and photophysical properties is analyzed based on the comparative studies performed on the control and modified devices. The use of chemical doping and bilayer strategy optimizes the energy level alignment, nanomorphology, hole mobility, and work-function of HTL, leading to considerable reduction of the leakage current and recombination losses. Our work demonstrates that the doping of HTL and the incorporation of G-QDs layer to constitute a bilayer HTL is an promising strategy to fabricate high performance non-fullerene polymer solar cells.
关键词： UPS,PTB7-Th:IEICO-4F,atomic force microscopy,XPS,Organic solar cells
更新于2025-09-23 15:21:01
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Direct nanoscale mapping of open circuit voltages at local back surface fields for PERC solar cells
摘要： The open circuit voltage (VOC) is a critical and common indicator of solar cell performance as well as degradation, for panel down to lab-scale photovoltaics. Detecting VOC at the nanoscale is much more challenging, however, due to experimental limitations on spatial resolution, voltage resolution, and/or measurement times. Accordingly, an approach based on Conductive Atomic Force Microscopy is implemented to directly detect the local VOC, notably for monocrystalline Passivated Emitter Rear Contact (PERC) cells which are the most common industrial-scale solar panel technology in production worldwide. This is demonstrated with cross-sectioned monocrystalline PERC cells around the entire circumference of a poly-aluminum-silicide via through the rear emitter. The VOC maps reveal a local back surface ?eld extending * 2 lm into the underlying p-type Si absorber due to Al in-diffusion as designed. Such high spatial resolution methods for photovoltaic performance mapping are especially promising for directly visualizing the effects of processing parameters, as well as identifying signatures of degradation for silicon and other solar cell technologies.
关键词： solar cell,nanoscale,Conductive Atomic Force Microscopy,open circuit voltage,PERC cells
更新于2025-09-23 15:21:01
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Topographic characterization of zirconia-based ceramics by atomic force microscopy: A case study on different laser irradiations
摘要： The purpose of the present study is to evaluate the effects of different laser irradiations including Nd-YAG (neodymium-doped yttrium aluminum garnet laser; Nd:Y3Al5O12), Er-YAG (erbium-doped yttrium aluminum garnet laser, erbium YAG laser), and Carbon dioxide (CO2) infrared lasers on surface topography of zirconia-based ceramics samples which were prepared by copy milling technique. Three dimensional (3D) atomic force microscopy (AFM) images were applied to investigate surface properties by extracting information via MountainsMap? Premium software which divides the surface into peaks and pits and through watershed segmentation algorithm. This method made motif analysis possible by detecting surface dimensions, curvature, volume, perimeters, shape, structure, etc.
关键词： Atomic force microscopy,Laser irradiation,Stereometric analysis,Fractal analysis
更新于2025-09-23 15:21:01
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Controlled growth of InGaN quantum dots on photoelectrochemically etched InGaN quantum dot templates
摘要： Controlled growth of InGaN quantum dots (QDs) using photoelectrochemically (PEC) etched InGaN QD templates is demonstrated. The InGaN QDs are grown by a self-assembly (SA) method using metal-organic chemical vapor deposition on templates consisting of planar GaN and PEC etched InGaN QDs for comparison. The InGaN QD templates are formed using quantum-size-controlled PEC etching of planar InGaN layers on GaN, which produces controlled QD radiuses with a statistical mean (μ) of 17.3 nm and standard deviation (σ) of 6.2 nm, and densities of 1.2 × 1010 cm?2. The PEC etched QDs are capped with an AlGaN interlayer and GaN barrier layer to recover a planar surface morphology for subsequent SA growth of QDs. The PEC QD templates behave as seeds via localize strain near the PEC QDs which provide improved control of the SA QD growth. The SA grown QDs on PEC QD templates are smaller and have controlled radiuses with μ = 21.7 nm and σ = 11.7 nm compared to the SA QDs on planar GaN templates with radiuses of μ = 37.8 nm and σ = 17.8 nm. Additionally, the dot densities of the SA QDs on PEC QD templates are ~3 times higher and more closely match the underlying densities of the template (8.1 × 109 cm?2). Multiple quantum dots (MQDs) are also grown on both templates that consist of 4 periods of SA QDs and AlGaN/GaN interlayer/barrier layers. The MQDs grown on PEC QD templates better retain their planarized smooth surfaces after barrier layer growth, and exhibit ~3 times stronger PL intensity at room temperature compared to MQDs grown on planar GaN.
关键词： Metalorganic chemical vapor deposition,Nitrides,Quantum dots,Light emitting diodes,Atomic force microscopy,Photoelectrochemical etching
更新于2025-09-23 15:21:01
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Tapping Mode AFM Imaging in Liquids with blueDrive Photothermal Excitation
摘要： Photothermal excitation represents a significant instrumentation advance for imaging with dynamic modes of the atomic force microscope (AFM). Using a power-modulated laser to directly drive the cantilever oscillation provides substantial benefits over conventional piezoelectric excitation. Here we discuss photothermal excitation and its implementation as blueDrive by Oxford Instruments Asylum Research. We explain its operating principles and discuss its use for a range of practical applications. The results show that blueDrive sets new standards for imaging in liquid, visualizing dynamic events, and mapping nanomechanical properties.
关键词： tapping mode,liquid imaging,photothermal excitation,atomic force microscopy,nanoscale surface characterization
更新于2025-09-23 15:21:01
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Direct Observation of Crystal Engineering in Perovskite Solar Cells in a Moisture-Free Environment using Conductive Atomic Force Microscopy and Friction Force Microscopy
摘要： The origin of the increased efficiency of perovskite solar cells by control of environmental humidity was investigated using conductive atomic force microscopy (C-AFM) and friction force microscopy (FFM). The perovskite thin films fabricated in a humidity-free environment exhibited better crystallinity and lower number of trap sites than the films fabricated in a high-humidity environment. Through in-depth analysis using C-AFM and FFM, we found that there was locally decrystallized area in the perovskite structure fabricated in a high-humidity environment. By suppressing local decrystallization in a humidity-free environment, the power conversion efficiency (PCE) was increased by about 122%. This was mainly attributed to increase of the current density that elimination of the locally decrystallized area increase the effective active area. From this perspective, mapping local current and friction force using C-AFM and FFM could be new techniques for visualizing the effect of crystal engineering of perovskite solar cells in a humidity-free environment.
关键词： power conversion efficiency,crystallinity,perovskite solar cells,friction force microscopy,conductive atomic force microscopy,humidity
更新于2025-09-23 15:19:57
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Micromanipulation of Mechanically Compliant Organic Single-Crystal Optical Microwaveguides
摘要： Flexible organic single crystals are evolving as new materials for optical waveguides that can be used for transfer of information in organic optoelectronic microcircuits. Integration in microelectronics of such crystalline waveguides requires downsizing and precise spatial control over their shape and size at the microscale, however that currently is not possible due to difficulties with manipulation of these small, brittle objects that are prone to cracking and disintegration. Here we demonstrate that atomic force microscopy (AFM) can be used to reshape, resize and relocate single-crystal microwaveguides in order to attain spatial control over their light output. Using an AFM cantilever tip, mechanically compliant acicular microcrystals of three N-benzylideneanilines were bent to an arbitrary angle, sliced along their longest axis into thinner crystals, cut into shorter crystals of arbitrary length, and moved across a solid surface. When excited by using laser light, such bent microcrystals act as active optical microwaveguides that transduce their fluorescence, with the total intensity of transduced light being dependent on the optical path length. This micromanipulation of the crystal waveguides using AFM is non-invasive, and after bending their emissive spectral output remains unaltered. The approach reported here effectively overcomes the difficulties that are commonly encountered with reshaping and positioning of small delicate objects (the “thick fingers” problem), and can be applied to mechanically reconfigure organic optical waveguides in order to attain spatial control over their output in two and three dimensions in optical microcircuits.
关键词： organic single crystals,micromanipulation,N-benzylideneanilines,atomic force microscopy,optical waveguides
更新于2025-09-23 15:19:57
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Visualizing light trapping within textured silicon solar cells
摘要： Random pyramids are the most widely used texture in commercial monocrystalline silicon solar cells to trap weakly absorbed photons with near-bandgap energies. There has been steady improvement in efforts to model the light-trapping performance of random pyramids, including a shift from an assumed pyramid base angle of 54.7° (ideal-random pyramids) to smaller values that are consistent with measured average angles. However, simulations have not yet considered the effects of a distribution of base angles (real-random pyramids), which all real textured wafers have. In this contribution, we benchmark the light-trapping capability of real-random pyramids against ideal-random pyramids and Lambertian scatterers by performing ray tracing of an accurate three-dimensional topographical map of the surface of a textured silicon wafer measured using atomic force microscopy. The angular distribution function (ADF) of light rays within the wafer, calculated at each pass as rays bounce between the front and rear surfaces, reveals that real-random pyramids are superior to ideal-random pyramids in trapping light precisely because of the distribution in their base angle. In particular, the ADF inside a wafer with real-random pyramids evolves to be Lambertian within just two passes—by the time (non-absorbed) light re-arrives at the front surface. Furthermore, the total path-length enhancement of light reaches nearly 60—exceeding that of a wafer with Lambertian surfaces—for narrow angles of incidence, though it falls short of the Lambertian reference for oblique angles.
关键词： atomic force microscopy,random pyramids,silicon solar cells,light trapping,Lambertian scatterers,ray tracing
更新于2025-09-23 15:19:57
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Micromanipulation of Mechanically Compliant Organic Single-Crystal Optical Microwaveguides
摘要： Flexible organic single crystals are evolving as new materials for optical waveguides that can be used for transfer of information in organic optoelectronic microcircuits. Integration in microelectronics of such crystalline waveguides requires downsizing and precise spatial control over their shape and size at the microscale, however that currently is not possible due to difficulties with manipulation of these small, brittle objects that are prone to cracking and disintegration. Here we demonstrate that atomic force microscopy (AFM) can be used to reshape, resize and relocate single-crystal microwaveguides in order to attain spatial control over their light output. Using an AFM cantilever tip, mechanically compliant acicular microcrystals of three N-benzylideneanilines were bent to an arbitrary angle, sliced along their longest axis into thinner crystals, cut into shorter crystals of arbitrary length, and moved across a solid surface. When excited by using laser light, such bent microcrystals act as active optical microwaveguides that transduce their fluorescence, with the total intensity of transduced light being dependent on the optical path length. This micromanipulation of the crystal waveguides using AFM is non-invasive, and after bending their emissive spectral output remains unaltered. The approach reported here effectively overcomes the difficulties that are commonly encountered with reshaping and positioning of small delicate objects (the “thick fingers” problem), and can be applied to mechanically reconfigure organic optical waveguides in order to attain spatial control over their output in two and three dimensions in optical microcircuits.
关键词： organic single crystals,micromanipulation,N-benzylideneanilines,atomic force microscopy,optical waveguides
更新于2025-09-23 15:19:57