Heterocyclic Polymers Perspectives in Nanolayers of Donor Acceptor Heterojunction for Organic Photovoltaic Application

In this work new polymers for organic photovoltaic that are stable to aggressive external environment influence are discussed. Heterocyclic “ladder” structure polymers poly(perylenebenzimidazole- with oxygen bridge between monomer units) (PPBI-O) and poly(naphthoylene benzimidazole – with oxygen bridge between monomer units) (PNBI-O) were studied as potential alternative to poly-3-methyl hexyl thiophene (P3HT) and fullerene {6, 6} -phenyl-C (61) butyric acid (PCBM). This subject is of current interest for goal of reducing cost and time for organic solar cells, where one of the main problems is still high cost of donor and acceptor synthesis. Solar cells based on new polymers were produced. Even after first device investigations it is detected that he electrical resistivity level and device efficiency is also comparable with the target analogue for comparison P3HT. The possibility of molecular structural design provides a wide field for engineers to generate interest to heterocyclic structures based on die-perylene and naphthoyl, the possible combinations for the superposition of the absorption spectra. From this point of view, the creation of optically active polymers based on polybenzomidazofenantroline (PBF), 1, 4, 5, 8- naphthalene tetracarboxylic and 3, 4, 9, 10- perylenetetracarboxylic acids opens new opportunities in this important field of science and technology. The results are high absorption in visible spectrum and ability of morphology improvement. Advantages in the optical properties PPBI-O and PNBI-O above the target prototype P3HT, namely a peak absorption in the region of 555 nm to 700 nm red edge are detected

Metal-insulator transition in the In/Si(111) surface

The metal-insulator transition observed in the In/Si(111)-4x1 reconstruction is studied by means of ab initio calculations of a simplified model of the surface. Different surface bands are identified and classified according to their origin and their response to several structural distortions. We support the, recently proposed [New J. of Phys. 7 (2005) 100], combination of a shear and a Peierls distortions as the origin of the metal-insulator transition. Our results also seem to favor an electronic driving force for the transition.Comment: Presented in the 23 European Conference in Surface Science, Berlin, September 2005. Submitted to Surface Science (proceedings of the conference) in August 200

Film Growth Based on an Organic Basis for Photovoltaic p-Cells

The main measured parameters characterizing the solar cell are its photocurrent and fluorescence under the influence of electromagnetic radiation of the solar spectrum – derivatives of a number of elementary processes in the cell and determining the complex mechanism of its functioning. The main issue is to determine the allowable concentration of the polymer and the acceptor, allowing to obtain a film having a desired density and at the same time, the thickness, the optimum from the point of view of the diffusion length and the probability of dissociation of the intermediate particles with the formation of free charge carriers. From a comparison of the synthesized samples micrographs it can be concluded that the polymer concentration of 12.5 g/l gives a sufficiently dense and relatively uniform film without substantial amounts of undissolved polymer

CH3NH3PBI3 IV Output Parameters Degradation Investigation

Organic photovoltaics, based on hybrid inorganic organic optoelectronic perovskites, with structure alkali- metal- halide are the newest emerging technology in the third generation development. Despite tremendous efficiency records, more than 21 %, optoelectronic perovskites’ instability prevents their commercialization and mass production. Issues with degradation are caused by various types of environmental influences. The main issues with stability and power loss in devices are linked to moisture, oxygen, temperature, and light-induced structure defects. Initial measurements are taken after long term debugging with minimal aggressive exposure to environmental conditions. In this case, preliminary degradation studies begin from measurements of light-induced effects. In this work, we will present the main trends in degradation of external characteristics during common I-V measurements, in the order of parameters which were effected the least by environmental factors. This investigation was made on fixed CH3NH3PBI3 solar cells with standard 1.5 AM testing and initial efficiencies more than 8 %

Film Growth Based on an Organic Basis for Photovoltaic p-Cells

The main measured parameters characterizing the solar cell are its photocurrent and fluorescence under the influence of electromagnetic radiation of the solar spectrum – derivatives of a number of elementary processes in the cell and determining the complex mechanism of its functioning. The main issue is to determine the allowable concentration of the polymer and the acceptor, allowing to obtain a film having a desired density and at the same time, the thickness, the optimum from the point of view of the diffusion length and the probability of dissociation of the intermediate particles with the formation of free charge carriers. From a comparison of the synthesized samples micrographs it can be concluded that the polymer concentration of 12.5 g/l gives a sufficiently dense and relatively uniform film without substantial amounts of undissolved polymer

CH3NH3PBI3 IV Output Parameters Degradation Investigation

Organic photovoltaics, based on hybrid inorganic organic optoelectronic perovskites, with structure alkali- metal- halide are the newest emerging technology in the third generation development. Despite tremendous efficiency records, more than 21 %, optoelectronic perovskites’ instability prevents their commercialization and mass production. Issues with degradation are caused by various types of environmental influences. The main issues with stability and power loss in devices are linked to moisture, oxygen, temperature, and light-induced structure defects. Initial measurements are taken after long term debugging with minimal aggressive exposure to environmental conditions. In this case, preliminary degradation studies begin from measurements of light-induced effects. In this work, we will present the main trends in degradation of external characteristics during common I-V measurements, in the order of parameters which were effected the least by environmental factors. This investigation was made on fixed CH3NH3PBI3 solar cells with standard 1.5 AM testing and initial efficiencies more than 8 %

Imaging of Perovskite Photoactive Layer Cross-Section by Atomic Force Microscopy

The volume structure of photoactive layer has critical influence on perovskite solar cell performance and life time. In this study the perovskite photoactive layer cross-section was prepared by using Focused Ion Beam (FIB) and imaged by using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) methods (Fig. 16). Two different types of perovskite layers were investigated: FAPbBr3 and MAPbBr3

Study of the self-organization of atoms and molecules on the surface of silicon and germanium by means of scanning tunneling microscopy

Среди различных подходов последние годы все большее внимание исследователей привлекает создания наноструктур из отдельных атомов и молекул (так называемая технология «снизу вверх») с использованием механизмов самоорганизации. В докладе будут представлены возможности сканирующей туннельной микроскопии для исследования топографии поверхности, ее состава, атомной и локальной электронной структуры. При этом основное внимание будет уделено количественным аспектам методов и точности измерений.Among the various approaches in recent years, much attention of researchers has been attracted to the creation of nanostructures from individual atoms and molecules (the so-called bottom-up technology) using self-organization mechanisms. The report will present the possibilities of scanning tunneling microscopy for studying the topography of a surface, its composition, atomic and local electronic structure. The main attention will be paid to the quantitative aspects of the methods and accuracy of measurements