Influence of PEDOT :PSS Layer on the Performances of Photovoltaic Cells Based on MEH-PPV:PCBM Blend

Date du colloque : 07/2011International audienc

The influence of LiF layer abd ZnO nanoparticels addings on the performances of flexible photovoltaic cells based on polymer blends

International audienceFlexible organic solar cells were successfully prepared using spin-coating technique on PET substrates covered with a thick layer of ITO. The goal of this study is to identify the effects of the LiF layer and ZnO nanoparticles mixing in PEDOT:PSS solution and to compare the photovoltaic properties of these „customized” cells PET/ITO/PEDOT:PSS + ZnO nanoparticles/P3HT:PCBM(1:1)/Al, PET/ITO/PEDOT:PSS + ZnO nanoparticles/P3HT:PCBM(1:1)/LiF/Al, with ones of the “conventional” structures, PET/ITO/PEDOT:PSS/P3HT:PCBM(1:1)/Al. The thickness of the LiF layer, deposited by thermal vacuum evaporation, was two nanometers. Composite samples were prepared by adding ZnO nanoparticles into PEDOT:PSS solution, followed by ultrasonication. I-V characteristics were measured in dark and under A.M.1.5 conditions for all samples immediately and after one month from the preparation date. The action spectra measurements revealed that the structures which have a nanometric LiF layer are more stable than those without. Photoelectrical measurements indicate that the ZnO nanoparticles have a positive influence on the conversion efficiency and also to reduce the serial resistance of the structure

Bistability of the BiOi complex and its implications on evaluating the acceptor removal

The dependencies of the B$_{i}$O$_{i}$ defect concentration on doping, irradiation fluence and particle type in p-type silicon diodes have been investigated. We evidenced that large data scattering occurs for fluences above $10^{12}$ 1 MeV neutrons/cm$^2$, becoming significant larger for higher fluences. We show that the B$_{i}$O$_{i}$ defect is metastable, with two configurations A and B, of which only A is detected by Deep Level Transient Spectroscopy and Thermally Stimulated Currents techniques. The defect's electrical activity is influenced by the inherent variations in ambient and procedural experimental conditions, resulting not only in a large scattering of the results coming from the same type of measurement but making any correlation between different types of experiments difficult. It is evidenced that the variations in [B$_{i}$O$_{i}^\mathrm{A}$] are triggered by subjecting the samples to an excess of carriers, by either heating or an inherent short exposure to ambient light when manipulating the samples prior to experiments. It causes $\approx$7h variations in both, the [B$_{i}$O$_{i}^\mathrm{A}$] and in the effective space charge. The analyses of structural damage in a diode irradiated with 10$^{19}$ 1 MeV neutrons/cm$^2$ revealed that the Si structure remains crystalline and vacancies and interstitials organize in parallel tracks normal to the Si-SiO$_{2}$ interface

InN Based Water Condensation Sensors on Glass and Flexible Plastic Substrates

In this paper, we report the realization and characterization of a condensation sensor based on indium nitride (InN) layers deposited by magnetron sputtering on glass and flexible plastic substrates, having fast response and using potentially low cost fabrication technology. The InN devices work as open gate thin film sensitive transistors. Condensed water droplets, formed on the open gate region of the sensors, deplete the electron accumulation layer on the surface of InN film, thus decreasing the current of the sensor. The current increases back to its initial value when water droplets evaporate from the exposed InN film surface. The response time is as low as 2 s

Influence of PEDOT:PSS layer on the performances of "bulk-heterojunction" photovoltaic cells based on MEH-PPV:PCBM(1:4) polymeric blends

cited By 9Photovoltaic cells having as active layer a mixture between poly[2-[2',5'-bis(2-ethyhexyloxy)phenyl]-1,4-phenylenevinylene]-co-[2-methoxy-5-(2'-ethylexyloxy)-1,4-phenylenevinylene] (MEH-PPV) regioregular polymer and [6,6]-phenyl C 61 butyric acid methyl ester (PCBM) fullerene derivative were prepared on ITO covered optical glass and plastic sheets, as substrates. The samples have the same architecture, the main difference between them being the presence or not of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS). For all the prepared structures, the morphological, optical and electrical characterization was carried out, comparatively. The current-voltage (I-V) characteristics in monochromatic light and the action spectra of the prepared structures were recorded, at room temperature. The parameters characterizing photovoltaic cells (short-circuit current, open circuit voltage and fill factor) were calculated and compared for prepared structures with or without PEDOT:PSS "buffer" layer