Study of Photovoltaic Devices with Hybrid Active Layer

2019 ◽  
Vol 293 ◽  
pp. 51-64
Author(s):  
Pawel Jarka ◽  
Tomasz Tański ◽  
Bartlomiej Hrapkowicz ◽  
Barbara Hajduk ◽  
Kamil Bystroń ◽  
...  
Keyword(s):  
Optical Properties ◽  
Bulk Heterojunction ◽  
Photovoltaic Cells ◽  
Deposition Process ◽  
Thin Layers ◽  
Force Microscopy ◽  
Active Layers ◽  
Transmission Electron ◽  
Current Voltage ◽  
The Individual

The aim of this work is to present the influences of composition of the material and manufacturing technology conditions of the organic photovoltaics devices (OPv) with the organic and hybrid bulk heterojunction on the active layers properties and cells performance. The layers were produced by using small molecular compounds: the metal-phthalocyanine (MePc) and perylene derivatives (PTCDA) and the titanium dioxide (TiO2) nanoparticles. Two kinds of metal phthalocyanines (NiPc, TiOPc) were used as donor material and pperylenetetracarboxylic dianhydride (PTCDA) as an acceptor. The used manufacturing technique allowed to employ thin layers of materials in a fast deposition process. Bulk heterojunction was created by simultaneously applying the MePc:PTCDA materials during the evaporation of the components mixture.The research was based on the estimate of composition of bulk heterojunction, the examination of the surface morphology of the used layers and optical properties studies of the heterojunction and its implementation to photovoltaic architecture. The produced photovoltaic cells parameters were determined on the basis of current - voltage characteristics.The researches of structure of obtained layers were conducted by using scanning electron microscope (SEM) and transmission electron microscopy (TEM). The quantitative determination of surface topography by determining RMS and Ra coefficients were performed by atomic force microscopy (AFM). In order to determine the optical properties of the films the UV-Visible spectroscope have been utilized. Current - voltage characteristics were employed to determine the basic photovoltaic parameters using a dedicated device.The paper describes the influence of the individual components sharing the bulk heterojunction on its structure, optical properties and morphology of surface. In addition it allows for linking active layers properties with the parameters of the photovoltaic cells. The obtained results suggest the possibility of developing the utilized materials and technology in the further works on photovoltaic structures.

Preparation and investigations of electrical and optical properties of thin composite layers PAN/SiO2, TiO2 and Bi2O3

2018 ◽  
Vol 1 (91) ◽  
pp. 15-22
Author(s):  
W. Matysiak ◽  
P. Jarka ◽  
T. Tański
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Mass Concentration ◽  
Energy Gap ◽  
Absorption Function ◽  
Force Microscopy ◽  
Composite Layers ◽  
Coating Method ◽  
Potential Applications ◽  
The Individual

Purpose: The aim of this study was to present the influence of mass concentration of the reinforcement phase on the structure and optical properties of the obtained composite thin films with a polymer matrix reinforced by SiO2, TiO2 and Bi2O3 nanoparticles, produced by the spin-coating method. Design/methodology/approach: To produce composite materials, 10% wt. polymer solutions of polyacrylonitrile (PAN) and N, N - Dimethyloformamide (DMF) were used, containing nanoparticles with a mass concentration ratio of, sequentially: 0, 4, 8, 12%. The morphology, structure and chemical composition of the obtained thin films were determined on the basis of surface topography images, taken using atomic force microscopy (AFM) and a scanning electron microscope (SEM) with EDX and QBSD spectrometers. In order to analyse the optical properties, UV-Visible spectroscopy (UV-Vis) was used. The width of the band gap was determined on the basis of the absorption spectra of radiation (UV-Vis). Findings: The carried out morphology and surface structure research showed that with increasing mass increased porosity of the produced coating surface was observed. In addition, the greater the diameter of the applied ceramic nanoparticles, the more noticeable this effect was. The analysis of the optical properties of the obtained nanomaterials, carried out based on the registered spectra in absorption function of the wavelength, revealed a strong absorption of this type of layers under ultraviolet radiation. Research limitations/implications: The nanostructured materials as components provides nanocomposite optical properties, such as absorption and width of the energy gap. In addition, nanoparticle content causes changes of the surface morphology, which is an important parameter of thin films in potential applications. Originality/value: The properties of films depend not only on the individual components used, but also on the morphology and the interfacial characteristics.

Microstructures and Highly Accelerated Lifetime Test of X5R Type BaTiO3-Based Ni-MLCC with Ultra-Thin Active Layers

2014 ◽  
Vol 602-603 ◽  
pp. 695-699
Author(s):  
Hui Ling Gong ◽  
Xiao Hui Wang ◽  
Shao Peng Zhang ◽  
Xin Ye Yang ◽  
Long Tu Li
Keyword(s):  
Dielectric Properties ◽  
Shell Structure ◽  
Casting Process ◽  
Thin Layers ◽  
Core Shell ◽  
Active Layers ◽  
Transmission Electron ◽  
Lifetime Test ◽  
Accelerated Lifetime ◽  
Core Shell Structure

Microstructure control in thin-layer multilayer ceramic capacitors (MLCCs) is one of the challenges for increasing capacitive volumetric efficiency and high voltage dielectric properties. In this paper, the X5R-MLCCs with ultra-thin dielectric layers (~1.2 μm) owning uniform grain size distribution were prepared by wet casting process. The microstructures and dielectric properties of the MLCCs were investigated. The existence of core-shell structure was proved by transmission electron microscopy observation and energy dispersive spectroscopy analysis. The existence of core-shell structure makes the temperature coefficient of capacitance (TCC) performance meet X5R standard. Moreover, a highly accelerated lifetime test (HALT) result shows that MLCCs with ultra-thin layers under high electric field are more easily to fail with increasing test temperatures. And the results reveal that the activation energy is similar to the value reported for mid-dielectric constant dielectrics.

EFFECT OF SUBSTRATE TEMPERATURE ON THE STRUCTURAL AND THE OPTICAL PROPERTIES OF CdTe (100) EPITAXIAL FILMS GROWN ON GaAs (100) SUBSTRATES

2007 ◽  
Vol 14 (04) ◽  
pp. 755-759 ◽  
Author(s):  
D. U. LEE ◽  
J. H. JUNG ◽  
T. W. KIM ◽  
H. S. LEE ◽  
H. L. PARK ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Substrate Temperature ◽  
Misfit Dislocations ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Cdte Thin Films ◽  
Xrd Patterns

CdTe thin films were grown on GaAs (100) substrates by using molecular beam epitaxy at various temperatures. The results of the X-ray diffraction (XRD) patterns showed that the orientation of the grown CdTe thin films was the (100) orientation. XRD patterns, atomic force microscopy images, high-resolution transmission electron microscopy (HRTEM) images, and photoluminescence spectra showed that the crystallinity of CdTe (100) epilayers grown on GaAs (100) substrates was improved by increasing the substrate temperature. HRTEM images showed that misfit dislocations existed at the CdTe / GaAs heterointerface. These results can help improve understanding of the substrate temperature effect on the structural and the optical properties of CdTe (100)/ GaAs (100) heterostructures.

scholarly journals The Nature and Origin of Lateral Composition Modulations in Short-Period Strained-Layer Superlattices

1999 ◽  
Vol 583 ◽  
Author(s):  
A. G. Norman ◽  
S. P. Ahrenkiel ◽  
H. R. Moutinho ◽  
C. Ballif ◽  
M. M. Al-Jassim ◽  
...  
Keyword(s):  
Mole Fraction ◽  
Great Promise ◽  
Strained Layer ◽  
Force Microscopy ◽  
Growth Plane ◽  
Transmission Electron ◽  
Inp Substrate ◽  
Short Period ◽  
The Individual ◽  
Strained Layer Superlattices

AbstractThe nature and origin of lateral composition modulations in (AlAs)m(InAs)n short-period strained-layer superlattices grown by molecular beam epitaxy on InP substrates have been investigated by x-ray diffraction, atomic force microscopy, and transmission electron microscopy. Strong modulations were observed for growth temperatures between ≈ 540 and 560° C. The maximum strength of modulations was found for SPS samples with InAs mole fraction x (= n/(n+m)) close to ≈ 0.50 and when n ≈ m ≈ 2. The modulations were suppressed at both high and low values of x. For x > 0.52 (global compression), the modulations were along the <100> directions in the (001) growth plane. For x < 0.52 (global tension), the modulations were along the two <310> directions rotated ≈ ±27° from [110] in the growth plane. The remarkably constant wavelength of the modulations, between ≈ 20–30 nm, and the different modulation directions observed, suggest that the origin of the modulations is due to surface roughening associated with the high misfit between the individual SPS layers and the InP substrate. Highly uniform unidirectional modulations have been grown by control of the InAs mole fraction and growth on suitably offcut substrates, which show great promise for application in device structures.

Lattice Structure and Electrical Properties of Epitaxial Aluminum on GaAs

1982 ◽  
Vol 18 ◽  
Author(s):  
Fernando ◽  
A. Ponce ◽  
Stephen J. Eglash
Keyword(s):  
Electron Microscopy ◽  
Lattice Structure ◽  
Epitaxial Relationship ◽  
Cross Sectional ◽  
Barrier Heights ◽  
Transmission Electron ◽  
Current Voltage ◽  
Abrupt Interface ◽  
Crystallographic Planes ◽  
The Individual

The crystal structure of aluminum layers grown by molecular beam epitaxy (MBE) on GaAs(100) was studied using high resolution transmission electron microscopy. We obtained cross-sectional images with nearly atomic resolution of the lattice structure at Al-GaAs interfaces. GaAs epitaxial layers were grown at 585 °C and cooled in the ultrahigh vacuum MBE growth chamber prior to aluminum deposition. After the desired substrate temperature had been achieved, aluminum was immediately deposited onto arsenic-rich surfaces at a rate of 1000 Å h−1.Aluminum layers deposited onto substrates at 80 °C exhibit an Al(110)/GaAs(100) epitaxial relationship along an abrupt interface. In some regions of the interface we observed isolated arsenic crystallites which were epitaxial with the GaAs substrate. The current-voltage (I-V) and capacitance-voltage (C–V) characteristics of this material are well behaved. Barrier heights of 0.79 eV and ideality factors of 1.04 were determined from room temperature I–V measurements.For aluminum deposited onto GaAs substrates at 400 °C, evidence of twodimensional nucleation and growth was observed. The resulting pyramid-shaped aluminum crystallites had facets along crystallographic planes. Two epitaxial relationships were observed: Al(100)/GaAs(100) and Al(110)/GaAs(100). We observed 12 Å steps along the Al(100)–GaAs(100) interface. C–V and scanning electron microscopy measurements indicate that the individual aluminum crystallites are electrically and physically separated.

Optical Properties and Defect Structure of MOVPE InGaN Films

1999 ◽  
Vol 588 ◽  
Author(s):  
A. Cremades ◽  
M. Albrecht ◽  
J. M. Ulloa ◽  
J. Piqueras ◽  
H. P. Strunk ◽  
...  
Keyword(s):  
Optical Properties ◽  
Strain Relaxation ◽  
Misfit Dislocations ◽  
Nonradiative Recombination ◽  
X Ray Diffraction ◽  
Band Bending ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Piezoelectric Fields

AbstractA series of 100 nm thick InGaN films with In content up to 14% has been grown by MOVPE on SiC substrates. Optical characterization was carried out by means of reflectance spectrometry, photoluminescence and cathodoluminescence. Optical properties of the samples have been correlated with the microstructural properties measured by atomic force microscopy, transmission electron microscopy and X-ray diffraction data. Results indicate a dependence of the optical properties on the In content in the sample, as well as on the residual stress in the films induced by Indium incorporation. Part of the strain is reduced elastically by formation of pinholes which reach the InGaN/GaN interface, where first misfit dislocations are observed to form. Our results show that luminescence is directly correlated with the strain distribution in the layers. Pinholes are observed to act as nonradiative recombination sites for carriers, while strain relaxation around pinholes may enhance luminescence emission. We discuss the influence of strain with respect to In incorporation, the appearance of piezoelectric fields and effects due to strain induced band bending.

scholarly journals Infrared photo-induced force microscopy unveils nanoscale features of Norway spruce fibre wall

Cellulose ◽  
2021 ◽  
Author(s):  
Kavindra Kumar Kesari ◽  
Padraic O’Reilly ◽  
Jani Seitsonen ◽  
Janne Ruokolainen ◽  
Tapani Vuorinen
Keyword(s):  
Cell Wall ◽  
Chemical Composition ◽  
Norway Spruce ◽  
Spatial Resolution ◽  
Lignin Content ◽  
Force Microscopy ◽  
Transmission Electron ◽  
High Resolution Images ◽  
The Individual ◽  
20 Nm

AbstractInfrared photo-induced force microscopy (IR PiFM) was applied for imaging ultrathin sections of Norway spruce (Picea abies) at 800–1885 cm−1 with varying scanning steps from 0.6 to 30 nm. Cell wall sublayers were visualized in the low-resolution mode based on differences in their chemical composition. The spectra from the individual sublayers demonstrated differences in the orientation of cellulose elementary fibrils (EFs) and in the content and structure of lignin. The high-resolution images revealed 5–20 nm wide lignin-free areas in the S1 layer. Full spectra collected from a non-lignified spot and at a short distance apart from it verified an abrupt change in the lignin content and the presence of tangentially oriented EFs. Line scans across the lignin-free areas corresponded to a spatial resolution of ≤ 5 nm. The ability of IR PiFM to resolve structures based on their chemical composition differentiates it from transmission electron microscopy that can reach a similar spatial resolution in imaging ultrathin wood sections. In comparison with Raman imaging, IR PiFM can acquire chemical images with ≥ 50 times higher spatial resolution. IR PiFM is also a surface-sensitive technique that is important for reaching the high spatial resolution in anisotropic samples like the cell wall. All these features make IR PiFM a highly promising technique for analyzing the recalcitrant nature of lignocellulosic biomass for its conversion into various materials and chemicals. Graphic abstract

Alkanethiol Mediated Release of Surface Bound Nanoparticles Fabricated by Nanosphere Lithography

2005 ◽  
Vol 900 ◽  
Author(s):  
Jing Zhao ◽  
Amanda J Haes ◽  
Xiaoyu Zhang ◽  
Shengli Zou ◽  
Erin M Hicks ◽  
...  
Keyword(s):  
Optical Properties ◽  
Ag Nanoparticles ◽  
Theoretical Calculations ◽  
Nanosphere Lithography ◽  
Dipole Approximation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Dda Method

ABSTRACTThis work presents an innovative approach to produce monodisperse solution-phase triangular silver nanoparticles with well-controlled geometry. Ag nanotriangles are fabricated by nanosphere lithography (NSL), functionalized with alkanethiol molecules and then released from the substrate into solution. The resulting single isolated nanoparticles are subsequently asymmetrically functionalized with alkanedithiol molecules to form dimer pairs. The optical properties of the Ag nanoparticles have been measured using UV-Vis spectroscopy while their structural properties have been characterized using atomic force microscopy (AFM) and transmission electron microscopy (TEM). Theoretical calculations based on Mie theory and the Discrete Dipole Approximation (DDA) method have been done to interpret the optical properties of the released Ag nanoparticles.

Morphology, structure and optical properties of MOCVD grown pseudo-binary alloy nanowires of Zn1-xCdxSe on Si and GaAs substrates

2005 ◽  
Vol 876 ◽  
Author(s):  
C. M. Ng ◽  
C. X. Shan ◽  
Z. Liu ◽  
S. K. Hark
Keyword(s):  
Electron Microscopy ◽  
Optical Properties ◽  
Binary Alloy ◽  
Substrate Surface ◽  
Chemical Vapor ◽  
Growth Conditions ◽  
Stable Form ◽  
Force Microscopy ◽  
Transmission Electron ◽  
Alloy Nanowires

AbstractLong and fine Zn1-xCdxSe pseudo-binary alloy nanowires of various compositions x covering the entire range were grown by metalorganic chemical vapor deposition, using diethlyzinc, dimethylcadmium and diisopropylselenide as precursors, on Si (100) and GaAs (100) substrates; sputtered gold was used as a catalyst to promote nanowire formation. By controlling the ratio of the flows of the precursors, the temperature and the pressure during growth, we obtained nanowires of desired compositions. The morphology, structure and optical properties of the nanowires were studied by various techniques, including secondary electron microscopy, atomic force microscopy, transmission electron microscopy, X-ray diffraction, photoluminescence, and Raman scattering. Depending on the substrate, composition and conditions of growth, either the zincblende or wurtzite nanowires were obtained. At compositions where the stable form would have been normally wurtzite, the zincblende form could be obtained under certain growth conditions. From the orientations of the ordered nanowires on the substrate surface, their directions of growth were deduced and confirmed by high resolution lattice imaging. The relationship between the band gap and the composition of the nanowires were measured and found to deviate from that of bulk alloys and epilayers. The interplay between the growth conditions and compositions and morphology of the nanowires are discussed.

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