Tailoring Optical Properties of Blue-Gap Poly(p-phenylene Vinylene)s for LEDs Applications

2010 ◽  
Vol 75 ◽  
pp. 118-123
Author(s):  
Elena Dilonardo ◽  
Maria M. Giangregorio ◽  
Maria Losurdo ◽  
Pio Capezzuto ◽  
Giovanni Bruno ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Indium Tin Oxide ◽  
Substrate Surface ◽  
Polymer Chains ◽  
Semiconducting Polymers ◽  
Force Microscopy ◽  
Glass Substrates ◽  
Self Assembling ◽  
Atomic Force

There has been growing interest in developing new semiconducting polymers for applications in optoelectronics (OLEDs) due to their exceptional processability and appealing characteristic of manipulating electronic and optical properties by tuning of molecular structure and self-assembling. This study is an investigation on the interplay among supermolecular organization and optical properties of thin films of the poly[2-(2-ethylhexyloxy)-5-methoxy]-1, 4-phenylenedifluorovinylene (MEH-PPDFV) conjugated polymer, which has fluorinated vinylene units. This interplay is elucidated exploiting atomic force microscopy, spectroscopy ellipsometry, photoluminescence and electroluminescence. Thin films of MEH-PPDFV have been deposited by drop casting on indium-tin-oxide (ITO), quartz and glass substrates. The dependence of polymer chains self-organization and morphology on substrate surface is presented. Furthermore, it is demonstrated that the presence of F-atoms in the vinylene units of the MEH-PPDFV yields a blue optical band gap with the maximum of the fundamental HOMO-LUMO transition at 331 nm and photoluminescence at 458 nm. The OLED built with the above polymer shows a very stable blue-greenish electroluminescence that is also achieved at 504 nm.

scholarly journals Investigating the Nanocomposite Thin Films of Hematite α-Fe2O3 and Nafion for Cholesterol Biosensing Applications

2020 ◽  
Vol 2 ◽  
Author(s):  
Indra Sulania ◽  
R. Blessy Pricilla ◽  
G. B. V. S. Lakshmi
Keyword(s):  
Thin Films ◽  
Indium Tin Oxide ◽  
Differential Pulse ◽  
Force Microscopy ◽  
Glass Substrates ◽  
Enzyme Substrate ◽  
Atomic Force ◽  
Nanocomposite Thin Films ◽  
Multi Phase ◽  
Cholesterol Biosensor

Nanocomposite materials are multi-phase materials, usually solids, which have two or more component materials having different chemical and physical properties. When blended together, a newer material is formed with distinctive properties which make them an eligible candidate for many important applications. In the present study, thin films of nafion (polymer) and hematite or α-Fe2O3 (nanoparticles) nanocomposite is fabricated on indium tin oxide (ITO) coated glass substrates, due to its enhanced ionic conductivity, for cholesterol biosensor applications. Scanning electron microscopy and Atomic force microscopy revealed the formation of nanorod structured α-Fe2O3 in the films. The cyclic voltammetry (CV) studies of nafion-α-Fe2O3/ITO revealed the redox properties of the nanocomposites. The sensing studies were performed on nafion-α-Fe2O3/CHOx/ITO bioelectrode using differential pulse voltammetry (DPV) at various concentrations of cholesterol. The enzyme immobilization leaded to the selective detection of cholesterol with a sensitivity of 64.93 × 10−2 μA (mg/dl)−1 cm−2. The enzyme substrate interaction (Michaelis–Menten) constant Km, was obtained to be 19 mg/dl.

Structural and Optical Properties of PbI2 Thin Films to Fabricate Perovskite Solar Cells

2020 ◽  
Vol 398 ◽  
pp. 140-146
Author(s):  
Kawther A. Khalaph ◽  
Zainab J. Shanan ◽  
Aqel Mashot Jafar ◽  
Falah Mustafa Al-Attar
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Energy Gap ◽  
Perovskite Solar Cells ◽  
Lead Iodide ◽  
Structural And Optical Properties ◽  
Solar Cell Application ◽  
Force Microscopy ◽  
Glass Substrates ◽  
Atomic Force

Recently, lead iodide is the most materials employment in the perovskite solar cell application. This paper has studied the character of preparation, structural and optical properties of pbI2 materials. Structural properties are included investigation of the measurements X-Ray Diffraction (XRD), Scan Electron Microscopy (SEM), Fourier Transform InfraRed spectroscopy (FTIR) and Atomic Force Microscopy (AFM) tests to the PbI2 thin films samples. Optical properties are included the investigation UV-Vis test of the thin film samples deposited on glass substrates and investigated the Absorption, Transmittance and evaluated energy gap (Eg = 2.3 eV).

scholarly journals Study of the Influence of Annealing Temperature on the Structural and Optical Properties of ZnTe Prepared by Vacuum Thermal Evaporation Technique

2018 ◽  
Vol 31 (1) ◽  
pp. 50
Author(s):  
Sarmad M. Ali ◽  
Alia A.A. Shehab ◽  
Samir A. Maki
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Annealing Temperature ◽  
Energy Gap ◽  
Force Microscopy ◽  
Glass Substrates ◽  
Atomic Force ◽  
High Smoothness ◽  
Evaporation Technique ◽  
20 Nm

   The ZnTe alloy was prepared as  deposited thin films on the glass substrates at a thickness of 400±20 nm using vacuum evaporation technique at pressure (1 × 10-5) mbar and room temperature. Then the thin films under vacuum (2 × 10-3 mbar) were annealing at (RT,100 and 300) °C for one hour. The structural properties were studied by using X-ray diffraction and AFM, the results show that the thin films had approached the single crystalline in the direction (111) as preferred orientation of the structure zinc-blende for cubic type, with small peaks of tellurium (Te) element for all prepared thin films. The calculated crystallite size (Cs) decreased with the increase in the annealing temperature, from (25) nm before the annealing to (21) nm after the annealing. The images of atomic force microscopy of all thin films appeared a homogenous structure and high smoothness through roughness values ​​that increased slightly from (1.4) nm to (3.4) nm. The optical properties of the ZnTe at (RT,100 and 300) °C were studied transmittance and absorbance spectrum as a function of the wavelength. The energy gap was found about (2.4) eV for the thin films before the annealing and increased slightly to (2.5) eV after annealing at 300 °C  

Preparation and Characterization of BiFeO3 Film via Sol-Gel Spin-Coating Process

2011 ◽  
Vol 492 ◽  
pp. 202-205 ◽  
Author(s):  
Xi Wei Qi ◽  
Xiao Yan Zhang ◽  
Xuan Wang ◽  
Hai Bin Sun ◽  
Jian Quan Qi
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Indium Tin Oxide ◽  
Sol Gel ◽  
Secondary Phases ◽  
Force Microscopy ◽  
Glass Substrates ◽  
Atomic Force ◽  
Ito Glass

BiFeO3 thin films were spin-coated on conductive indium tin oxide (ITO)/glass substrates by a simple sol-gel possess annealed at 470-590°C. The crystal structure of as-prepared BiFeO3 thin films annealed at different temperature was determined to be rhombohedral of R3m space and free of secondary phases was also confirmed. Cross section scanning electron microscope (SEM) pictures revealed that the thickness of BiFeO3 thin film was about 320 nm. The double remanent polarization 2Pr of BiFeO3 thin film annealed at 500°C is 2.5 μC/cm2 without applied field at room temperature. Image of atomic force microscopy indicated that the root-mean-square surface roughness value of BiFeO3 thin film was 6.13 nm.

scholarly journals Ellipsometry Study of CdSe Thin Films Deposited by PLD on ITO Coated Glass Substrates

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3307
Author(s):  
Flavia P. N. Inbanathan ◽  
Pawan Kumar ◽  
Kiran Dasari ◽  
Ram S. Katiyar ◽  
Jixin Chen ◽  
...  
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Indium Tin Oxide ◽  
Nir Spectroscopy ◽  
Force Microscopy ◽  
Coated Glass ◽  
Glass Substrates ◽  
Tauc Plot ◽  
Atomic Force ◽  
Plot Analysis

Cadmium selenide (CdSe) thin films were deposited on indium tin oxide (ITO) coated glass substrates using pulsed laser deposition (PLD) technique under different growth temperatures. Samples were investigated for their structural, morphological, and optical properties through X-ray diffraction (XRD), atomic force microscopy (AFM), and UV-Vis-NIR spectroscopy. AFM analysis revealed that the surface roughness of the as-grown CdSe thin films increased with the increase in deposition temperature. The optical constants and film thickness were obtained from spectroscopic ellipsometry analysis and are discussed in detail. The optical band gap of the as-grown CdSe thin films, calculated from the Tauc plot analysis, matched with the ellipsometry measurements, with a band gap of ~1.71 eV for a growth temperature range of 150 °C to 400 °C. The CdSe thin films were found to have a refractive index of ~3.0 and extinction coefficient of ~1.0, making it a suitable candidate for photovoltaics.

scholarly journals Surface Morphology of Cus Thin Films Observed by Atomic Force Microscopy

2011 ◽  
Vol 16 ◽  
pp. 24 ◽  
Author(s):  
Anuar Kassim ◽  
Ho Soon Min ◽  
Lim Kian Siang ◽  
Saravanan Nagalingam
Keyword(s):  
Thin Films ◽  
Atomic Force Microscopy ◽  
Surface Morphology ◽  
Deposition Time ◽  
Substrate Surface ◽  
Complexing Agent ◽  
Force Microscopy ◽  
Glass Substrates ◽  
Atomic Force ◽  
Incomplete Coverage

CuS thin films were deposited onto microscope glass substrates using the chemical bath deposition method in the presence of tartaric acid as a complexing agent. The objective of this paper was to study the influence of the deposition time on the morphology of thin films. The surface morphology of the thin films was investigated using atomic force microscopy. The thin films deposited for the shortest time were found to be   uniform,  without  cracks and with a dense  surface  morphology covering the entire substrate surface area. However, the films prepared for 60 min and above indicated incomplete coverage of the material over the substrate surface. The surface roughness and film thickness values that were observed depended mainly on the deposition time.  

scholarly journals Improving Performance of CIGS Solar Cells by Annealing ITO Thin Films Electrodes

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Chuan Lung Chuang ◽  
Ming Wei Chang ◽  
Nien Po Chen ◽  
Chung Chiang Pan ◽  
Chung Ping Liu
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Solar Cells ◽  
Indium Tin Oxide ◽  
Copper Indium Gallium Diselenide ◽  
Glass Substrates ◽  
Ito Film ◽  
Ito Thin Films ◽  
Cigs Solar Cells ◽  
Ito Films

Indium tin oxide (ITO) thin films were grown on glass substrates by direct current (DC) reactive magnetron sputtering at room temperature. Annealing at the optimal temperature can considerably improve the composition, structure, optical properties, and electrical properties of the ITO film. An ITO sample with a favorable crystalline structure was obtained by annealing in fixed oxygen/argon ratio of 0.03 at 400°C for 30 min. The carrier concentration, mobility, resistivity, band gap, transmission in the visible-light region, and transmission in the near-IR regions of the ITO sample were-1.6E+20 cm−3,2.7E+01 cm2/Vs,1.4E-03 Ohm-cm, 3.2 eV, 89.1%, and 94.7%, respectively. Thus, annealing improved the average transmissions (400–1200 nm) of the ITO film by 16.36%. Moreover, annealing a copper-indium-gallium-diselenide (CIGS) solar cell at 400°C for 30 min in air improved its efficiency by 18.75%. The characteristics of annealing ITO films importantly affect the structural, morphological, electrical, and optical properties of ITO films that are used in solar cells.

scholarly journals Microwave Spectroscopic Detection of Human Hsp70 Protein on Annealed Gold Nanostructures on ITO Glass Strips

Biosensors ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 118
Author(s):  
Rodica Ionescu ◽  
Raphael Selon ◽  
Nicolas Pocholle ◽  
Lan Zhou ◽  
Anna Rumyantseva ◽  
...  
Keyword(s):  
Indium Tin Oxide ◽  
Stress Disorders ◽  
Force Microscopy ◽  
Glass Substrates ◽  
Conductive Glass ◽  
Hsp70 Protein ◽  
Atomic Force ◽  
Ito Glass ◽  
First Time ◽  
Human Heat Shock Protein

Conductive indium-tin oxide (ITO) and non-conductive glass substrates were successfully modified with embedded gold nanoparticles (AuNPs) formed by controlled thermal annealing at 550 °C for 8 h in a preselected oven. The authors characterized the formation of AuNPs using two microscopic techniques: scanning electron microscopy (SEM) and atomic force microscopy (AFM). The analytical performances of the nanostructured-glasses were compared regarding biosensing of Hsp70, an ATP-driven molecular chaperone. In this work, the human heat-shock protein (Hsp70), was chosen as a model biomarker of body stress disorders for microwave spectroscopic investigations. It was found that microwave screening at 4 GHz allowed for the first time the detection of 12 ng/µL/cm2 of Hsp70.

WO3:Mo and WO3:Ti Thin Films Deposited by Spray Pyrolysis: The Influence of Metallic Concentration on Physical Properties: An Electron Microscopy and Atomic Force Study

2019 ◽  
Vol 286 ◽  
pp. 49-63
Author(s):  
Dwight Acosta ◽  
Francisco Hernández ◽  
Alejandra López-Suárez ◽  
Carlos Magaña
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Ultra Violet ◽  
Surface Characteristics ◽  
Structural Defects ◽  
Force Microscopy ◽  
Glass Substrates ◽  
Atomic Force ◽  
Transmission Electron ◽  
Resolution Electron

WO3:Mo and WO3:Ti thin films have been deposited on FTO/Glass substrates by the pulsed chemical spray technique at a substrate temperature of Ts= 450°C. The influence of Mo and Ti doping on the structural, electrical, and optical behavior of WO3thin films, has been studied by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Atomic Force Microscopy (AFM), Ultra Violet and Visible Spectrometry (UV-VIS), and Surface Conductivity Methods (Four Points). Doped WO3films presents similar polycrystalline structures but with noticeable modifications in surface configurations at micrometric and nanometric levels, as the Mo and Ti concentration is systematically increased in the starting sprayed solution. From processed High-Resolution Electron Micrographs (HREM), a low density of structural defects was found on pure and doped WO3grains. This lead to conclude that variations in films surface characteristics are mainly related with metallic doping concentrations which in turn, have noticeable influence in electrical and optical behaviors reported in this work.

Synthesis and Characterization of Nb-Doped TiO2 Thin Films Prepared by RF Magnetron Sputtering

2015 ◽  
Vol 1117 ◽  
pp. 139-142 ◽  
Author(s):  
Marius Dobromir ◽  
Radu Paul Apetrei ◽  
A.V. Rogachev ◽  
Dmitry L. Kovalenko ◽  
Dumitru Luca
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Photoelectron Spectroscopy ◽  
Rf Magnetron Sputtering ◽  
X Ray ◽  
Force Microscopy ◽  
Glass Substrates ◽  
Atomic Force ◽  
Vis Spectroscopy ◽  
Diffraction Patterns

Amorphous Nb-doped TiO2 thin films were deposited on (100) Si and glass substrates at room temperature by RF magnetron sputtering and a mosaic-type Nb2O5-TiO2 sputtering target. To adjust the amount of the niobium dopant in the film samples, appropriate numbers of Nb2O5 pellets were placed on the circular area of the magnetron target with intensive sputtering. By adjusting the discharge conditions and the number of niobium oxide pellets, films with dopant content varying between 0 and 16.2 at.% were prepared, as demonstrated by X-ray photoelectron spectroscopy data. The X-ray diffraction patterns of the as-deposited samples showed the lack of crystalline ordering in the samples. Surfaces roughness and energy band gap values increase with dopant concentration, as showed by atomic force microscopy and UV-Vis spectroscopy measurements.

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