Formation and characterization of the CuIn(S,Se)2/buffer layer interface in electrodeposited solar cells

2005 ◽  
Vol 865 ◽  
Author(s):  
N. Naghavi ◽  
C. Hubert ◽  
O. Roussel ◽  
L. Sapin ◽  
M. Lamirand ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Fill Factor ◽  
Open Circuit ◽  
Solution Chemistry ◽  
Complexing Agents ◽  
Complexing Agent ◽  
Main Role ◽  
Near Surface

AbstractThis paper presents the influence of the solution chemistry of chemical bath deposition (pH and complexing agents) on the performance of CuIn(S,Se)2 cells after an initial CN treatment. It is shown that it is possible to modify the deposition conditions of the CdS by increasing the pH of the solution and by replacing the complexing agent (ammonia) by citrate ions. Both NH3 based and citrate based process give very homogenous and covering thin films. However, in the case of the citrate based process a decrease of open circuit voltage (Voc) and fill factor (FF) and thus of the cell efficiencies is observed. This points out that the main role of the buffer layer is not only related to the specific properties of the CdS itself but also to the near surface modifications of the CuIn(S,Se)2 caused by the presence of the complexing agent in the bath.

Microcrystalline (Si,Ge):H Solar Cells

2003 ◽  
Vol 762 ◽  
Author(s):  
Jianhua Zhu ◽  
Vikram L. Dalal
Keyword(s):  
Solar Cells ◽  
Buffer Layer ◽  
Quantum Efficiency ◽  
Fill Factor ◽  
Open Circuit Voltage ◽  
Defect Density ◽  
Cell Structure ◽  
Open Circuit ◽  
Base Layer ◽  
Ecr Plasma

AbstractWe report on the growth and properties of microcrystalline Si:H and (Si,Ge):H solar cells on stainless steel substrates. The solar cells were grown using a remote, low pressure ECR plasma system. In order to crystallize (Si,Ge), much higher hydrogen dilution (∼40:1) had to be used compared to the case for mc-Si:H, where a dilution of 10:1 was adequate for crystallization. The solar cell structure was of the p+nn+ type, with light entering the p+ layer. It was found that it was advantageous to use a thin a-Si:H buffer layer at the back of the cells in order to reduce shunt density and improve the performance of the cells. A graded gap buffer layer was used at the p+n interface so as to improve the open-circuit voltage and fill factor. The open circuit voltage and fill factor decreased as the Ge content increased. Quantum efficiency measurements indicated that the device was indeed microcrystalline and followed the absorption characteristics of crystalline ( Si,Ge). As the Ge content increased, quantum efficiency in the infrared increased. X-ray measurements of films indicated grain sizes of ∼ 10nm. EDAX measurements were used to measure the Ge content in the films and devices. Capacitance measurements at low frequencies ( ~100 Hz and 1 kHz) indicated that the base layer was indeed behaving as a crystalline material, with classical C(V) curves. The defect density varied between 1x1016 to 2x1017/cm3, with higher defects indicated as the Ge concentration increased.

Nanostructured Molybdenum Trioxide Layer on the Silver Anode of a Top-Incident Organic Photovoltaic Device

2021 ◽  
Vol 21 (3) ◽  
pp. 1659-1666
Author(s):  
Chia-Hsun Chen ◽  
Jiun Haw Lee ◽  
Chien-Liang Lin ◽  
Tien-Lung Chiu
Keyword(s):  
Buffer Layer ◽  
Deposition Rate ◽  
Fill Factor ◽  
Molybdenum Trioxide ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Short Circuit Current Density ◽  
Open Circuit ◽  
Organic Photovoltaic ◽  
20 Nm

A nanostructured molybdenum trioxide (MoO3) layer was successfully fabricated utilizing various deposition rates, employed as an anodic buffer layer to separate the active layer from a silver anode and modifying the anodic surface to facilitate hole transportation for top-incident organic photovoltaic (TIOPV) devices. The deposition rate and thickness of the MoO3 layer were crucial parameters for determining the surface morphology and work function, and the internal optical field distribution, respectively. These factors affected the performance of the devices in terms of their open-circuit voltage (VOC), short-circuit current density (JSC), and fill factor (FF). The baseline TIOPV device without a buffer layer had a power conversion efficiency (PCE) of only 0.47%. By contrast, with a smooth 20-nm MoO3 buffer layer fabricated using a deposition rate of 1 Å/s (which prevented problems caused by the Ag anode), another fabricated TIOPV device had substantially higher VOC, JSC and FF values, which improved the PCE by a factor of 6.2 to 2.92%. When an additional 5-nm nanostructured MoO3 layer was deposited at a deposition rate of 0.5 Å/s, the most efficient TIOPV device had an even greater PCE, a factor of 7.5 times higher at 3.53%.

Preparation and Characterization of BaTiO3 Thin Films on MgO-buffered Si(100) Substrates by RF Sputtering

1997 ◽  
Vol 12 (4) ◽  
pp. 1152-1159 ◽  
Author(s):  
Sangsub Kim ◽  
Shunichi Hishita
Keyword(s):  
Thin Films ◽  
Buffer Layer ◽  
Large Scale ◽  
Rf Sputtering ◽  
Morphological Characteristics ◽  
Electrical Measurements ◽  
Metal Type ◽  
Metal Insulator Metal

We report the results of a study on the deposition and characterization of partially oriented BaTiO3 thin films on MgO-buffered Si(100) by radio-frequency magnetron sputtering. The structural and morphological characteristics of the MgO buffer layer were investigated as a function of substrate temperature. The x-ray θ-2θ, φ scans, and observation of surface morphology revealed that MgO grew with a tendency of (001) orientation. Partially (00l) or (h00) textured BaTiO3 thin films were obtained on Si(100) with the MgO buffer layer while randomly oriented BaTiO3 thin films with large-scale cracks on the surface were made without the MgO layer. Pt/BaTiO3/Pt multistructures were formed on Si(100), MgO/Si(100), and MgO(100) single crystal substrates to conduct preliminary electrical measurements for metal-insulator-metal type capacitor. Comparison of the crystallographic orientation, morphology, and electrical properties between the BaTiO3 films on Si(100) with and without the MgO buffer layer supported the favorable role of the MgO layer as a buffer for the growth of BaTiO3 films on Si(100).

Differences in Internet and LMS Usage A Case Study in Higher Education

2012 ◽  
pp. 247-270
Author(s):  
Rosalina Babo ◽  
Ana Cláudia Rodrigues ◽  
Carla Teixeira Lopes ◽  
Paulo Coelho de Oliveira ◽  
Ricardo Queirós ◽  
...  
Keyword(s):  
Higher Education ◽  
Learning Management Systems ◽  
Internet Usage ◽  
The Internet ◽  
Main Role ◽  
Usage Patterns ◽  
Scientific Fields

The Internet plays an important role in higher education institutions where Learning Management Systems (LMS) occupies a main role in the eLearning realm. In this chapter we aim to characterize the Internet and LMS usage patterns and their role in the largest Portuguese Polytechnic Institute. The usage patterns were analyzed in two components: characterization of Internet usage and the role of Internet and LMS in education. Using a quantitative approach, the data analysis describes the differences between gender, age and scientific fields. The carried qualitative analysis allows a better understanding of students’ both motivations, opinions and suggestions of improvement. The outcome of this work is the presentation of the Portuguese students’ profile regarding Internet and LMS usage patterns. We expect that these results can be used to select the most suitable digital pedagogical processes and tools to be adopted regarding the learning process and most adequate LMS’s policies.

The Role of Arginine as a Complexing Agent in Copper CMP

2006 ◽  
Vol 914 ◽  
Author(s):  
Surya Sekhar Moganty ◽  
Ramanathan Srinivasan
Keyword(s):  
Hydrogen Peroxide ◽  
Removal Rate ◽  
Surface Characteristics ◽  
Corrosion Current ◽  
Copper Surface ◽  
Open Circuit ◽  
Complexing Agent ◽  
Polishing Tool ◽  
Polish Rate

AbstractChemical mechanical polishing (CMP) of copper was investigated in hydrogen peroxide and arginine slurries. Arginine was found to be a complexing agent for the copper in peroxide based slurries, in the alkaline region. The copper polish rate was measured in a Struers LaboPol-5 and LaboForce-3 CMP polishing tool. Static etch rate experiments of copper discs (25.4 mm Dia × 10 mm) were carried in 200 ml beakers with different combinations of hydrogen peroxide and arginine concentrations. Peroxide concentration was varied from 0 to 10 vol%, while the arginine concentration was varied from 0 to 1 wt% for both static etch and polish rate experiments. Fumed silica used as the abrasive medium for polishing.The electrochemical processes involved in oxidative dissolution of copper were investigated by the Tafel corrosion plots and OCP measurements, using the Princeton Applied Research potentiostat. Three electrode corrosion flat cell was used for the electrochemical measurements. Corrosion current density and open circuit potentials (OCP) were used to elucidate the oxidative behavior of peroxide and the complexing role of arginine. Surface characteristics of the polished copper surface were analyzed with the Digital Instruments NanoScope AFM. Polishing with these chemicals resulted in smooth finish.These results indicated that the arginine curtails the formation of oxidative layer on the copper surface and the removal rate was increased by forming complex with the copper.

Alkali Activated Cementitious Materials: An Overview

1991 ◽  
Vol 245 ◽  
Author(s):  
D. M. Roy ◽  
M. R. Silsbee
Keyword(s):  
Amorphous Materials ◽  
Cementitious Materials ◽  
Solution Chemistry ◽  
Reaction Products ◽  
Alumino Silicate ◽  
Alkali Activated ◽  
Very High

ABSTRACTAlkali-activated cementitious materials have considerable potential, with properties ranging from very high early strength to very high long term strength and low porosity. The role of alkalis in activating industrial by-products such as ground granulated (glassy) blast-furnace slag, ultra-fine silica fume or other by-product silicas, glassy fly ashes, and other amorphous materials is discussed. These by-product materials are activated by alkali additions which break the strong silicon oxygen bonds in the silicate or alumino-silicate network, accompanied by the formation of new reaction products. The role of the different components in multi-component activated cements on the reactivity and the nature of the resultant products is discussed. Characterization of starting materials and reaction products by XRD, SEM (including environmental SEM), chemical, and particle characterization techniques has been made. Additional results include investigation of pore solution chemistry as a function of time. Some inferences for long term durability are discussed.

Impact of maximum copper content during the 3-stage process on CdS thickness tolerance in Cu(In,Ga)Se2-based solar cell

2013 ◽  
Vol 1538 ◽  
pp. 33-38
Author(s):  
Thomas Lepetit ◽  
Ludovic Arzel ◽  
Nicolas Barreau
Keyword(s):  
Buffer Layer ◽  
Layer Thickness ◽  
Fill Factor ◽  
Open Circuit Voltage ◽  
Photovoltaic Performance ◽  
Open Circuit ◽  
Cu Content ◽  
Thickness Tolerance ◽  
Stage Process ◽  
Buffer Layer Thickness

ABSTRACTThe tolerance of photovoltaic performances of Cu(In,Ga)Se2-based (CIGSe) solar cells prepared from 3-stage grown absorbers to cadmium sulfide (CdS) buffer layer thickness was investigated. We focus on the influence of the maximum Cu content y = [Cu]/([In]+[Ga]) reached during the co-evaporation process on this tolerance. By increasing the duration of the 2nd stage we varied ymax from 0.93±0.11 up to 1.06±0.12. Although final Cu content and CIGSe surface morphology seem to be similar for all absorbers, the photovoltaic performance of cells with higher maximum Cu content are better; moreover they tolerate much thinner CdS buffers (down to 10 nm-thick) without open circuit voltage or fill factor loss. Cells with lower ymax exhibit more erratic performance and J(V,T) measurements show a specific voltage distribution for thin CdS. From these results it appears possible to decrease the CdS buffer layer thickness if it is deposited on adapted absorbers.

scholarly journals Enhanced open-circuit voltages and efficiencies: the role of oxidation state of molybdenum oxide buffer layer in polymer solar cells

RSC Advances ◽  
2021 ◽  
Vol 11 (56) ◽  
pp. 35141-35146
Author(s):  
Pengfei Ma ◽  
Jiaying Xu ◽  
Chen Wang ◽  
Changhao Wang ◽  
Fanxu Meng ◽  
...  
Keyword(s):  
Solar Cells ◽  
Charge Transfer ◽  
Buffer Layer ◽  
Oxidation State ◽  
Polymer Solar Cells ◽  
Open Circuit ◽  
High Oxidation State ◽  
High Oxidation ◽  
Open Circuit Voltages

The high oxidation state MoOx buffer layer provides better level alignment and charge transfer efficiency, improving the open-circuit voltages and the efficiencies of polymer solar cells.

Characterization of PbS thin films obtained by chemical bath at low temperature using sodium citrate as complexing agent

MRS Advances ◽  
2016 ◽  
Vol 1 (37) ◽  
pp. 2623-2628 ◽  
Author(s):  
David Ramírez-Ceja ◽  
Luis A. González ◽  
José Escorcia-García ◽  
Arturo I. Martínez-Enríquez
Keyword(s):  
Thin Films ◽  
Sodium Citrate ◽  
Xrd Analysis ◽  
Open Circuit ◽  
Spherical Particles ◽  
Complexing Agent ◽  
Cds Thin Film ◽  
Short Current Density ◽  
Deposited Film

ABSTRACTThe deposition of PbS thin films by the chemical bath deposition method using sodium citrate as non-toxic complexing agent is presented. As-deposited PbS films and those annealed at 200 and 300 °C in argon atmosphere were formed by tightly compact spherical particles homogeneously distributed along the substrates. The XRD analysis shows that all the films had a galena type cubic crystalline structure. The crystallite size of the as-deposited film was 17 nm which decreased to 14 nm when the film was annealed to 300 °C. Thermal treatments to the films produced a shift of the optical band gap from 1.34 to 1.49 eV. Furthermore, the as-deposited PbS films were photosensitive showing a conductivity of 10-2 Ω-1 cm-1 under illumination. Such a conductivity increased to 10-1 Ω-1 cm-1 with the thermal treatment at 200 °C. The evaluation of the PbS film using a CdS thin film partner as window in the solar cell configuration showed an open circuit voltage of 88 mV and a short current density of 3.5 mA/cm2.

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