Search

This article presents an innovative and low-cost solution for optimizing the acquisition of performance data of small-laboratory-scale photovoltaic devices. A novel measuring setup is proposed, designed based on an Arduino microcontroller and low-cost components, coupled with open source hardware and software. The manuscript describes in detail the instrument design, components and assembly enabling the reproduction and customization of the instrument for any reader. The setup is combined with an optional web-platform, which enables fast analysis and comparison of the collected data. For the demonstration of the instrument in operation, comparison of measurements of solar cell with the developed setup and commercial products has been conducted. It is shown that the presented prototype provides values of accuracy and precision during I-V curve recording, comparable with the values measured using a commercial source-meter (Keithley 2400). The study also discusses the unique advantages of easy transport and data collection by the setup and the drawbacks in the hardware, which have been observed during a round robin study. © 2019 IOP Publishing Ltd.

Copyright 2015 Society of Photo Optical Instrumentation Engineers (SPIE). One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this publication for a fee or for commercial purposes, or modification of the contents of the publication are prohibited. Over the last three decades, progress in the organic photovoltaic field has resulted in some device features which make organic cells applicable in electricity generation configurations where the standard silicon-based technology is not suitable, for instance, when a semi-transparent photovoltaic panel is needed. When the thin film solar cell performance is evaluated in terms of the device's visible transparency and power conversion efficiency, organic solar cells offer the most promising solution. During the last three years, research in the field has consolidated several approaches for the fabrication of high performance semi-transparent organic solar cells. We have grouped these approaches under three categories: devices where the absorber layer includes near-infrared absorption polymers, devices incorporating one-dimensional photonic crystals, and devices with a metal cavity light trapping configuration. We herein review these approaches.

Aquest article pot ser utilitzat per a fins no comercials, d'acord amb els termes i condicions d’auto-arxiu de Wiley. https://authorservices.wiley.com/author-resources/Journal-Authors/licensing-open-access/open-access/self-archiving.html An optical metal cavity configuration is used to trap near infrared light in a semitransparent organic solar cell. The efficiency for such cell, which has a higher than 20% transparency in the visible region, is equal to 90% of the efficiency of the corresponding opaque cell.

International audience; Introducing plasmonic resonant scatterers in photovoltaic devices is a promising way to increase energy conversion efficiencies by trapping incoming light in ultra-thin solar cells. Colloidal nanogap antennas are obtained following a cost-effective self-assembly strategy and incorporated in organic-based cells produced using spin-coating techniques in ambient air conditions. We report an interesting increase of both external quantum efficiency (EQE) and short circuit current for solar cells loaded with plasmonic oligomers compared with reference organic cells with and without isolated gold nanoparticle. Theoretical calculations demonstrate that the wavelength dependent EQE enhancement is a resonant process due to the increased scattering efficiency in plasmonic antennas allowed by a chemically controlled 1 nm nanogap. This method opens the way towards roll-to-roll fabrication of efficient plasmonic ultra-thin photovoltaic devices.

Investigations of ultrafast processes occurring on the nanoscale require a combination of femtosecond pulses and nanometer spatial resolution. However, controlling femtosecond pulses with nanometer accuracy is very challenging, as the limitations imposed both by dispersive optics on the time duration of a pulse and by the spatial diffraction limit on the focusing of light must be overcome simultaneously. In this paper, we provide a universal method that allows full femtosecond pulse control in subdiffraction-limited areas. We achieve this aim by exploiting the intrinsic coherence of the second harmonic emission from a single nonlinear nanoparticle of deep subwavelength dimensions. The method is proven to be highly sensitive, easy to use, quick, robust and versatile. This approach allows measurements of minimal phase distortions and the delivery of tunable higher harmonic light in a nanometric volume. Moreover, the method is shown to be compatible with a wide range of particle sizes, shapes and materials, allowing easy optimization for any given sample. This method will facilitate the investigation of light–matter interactions on the femtosecond–nanometer level in various areas of scientific study. Scientists at ICFO, the Institute of Photonics Sciences in Barcelona, have demonstrated control of laser pulses with both femtosecond- and nanometre-scale precision. Nicolo Accanto and co-workers combined broad-band pulse shaping with second-harmonic detection from individual nanoparticles inside a microscope to gain control over ultra-short light pulses in a sub-diffraction area. The universal approach allows to compensate for the phase distortions experienced by a laser pulse in-situ, and to assess Fourier limited pulses at the nanoscale. The scheme's precision will aid the study of ultrafast dynamics for a variety of nanoscale objects, such as single molecules, quantum dots, plasmonic nanostructures and diamond colour centres. The technique could also prove useful for realizing nanometre-scale sources of tuneable coherent light.

The current work proposes to incorporate gold nano-particle dimers and trimers inside the OPV device. The plasmon resonance of coupled particles shifts towards the red part of the spectrum where the losses of gold are much smaller. It can be theoretically show that the scattering over extinction cross-section of such oligomers is strongly reduced and leads to a significant increase of the light harvesting in the active material.

et al., The process of accurately gauging lifetime improvements in organic photovoltaics (OPVs) or other similar emerging technologies, such as perovskites solar cells is still a major challenge. The presented work is part of a larger effort of developing a worldwide database of lifetimes that can help establishing reference baselines of stability performance for OPVs and other emerging PV technologies, which can then be utilized for pass-fail testing standards and predicting tools. The study constitutes scanning of literature articles related to stability data of OPVs, reported until mid-2015 and collecting the reported data into a database. A generic lifetime marker is utilized for rating the stability of various reported devices. The collected data is combined with an earlier developed and reported database, which was based on articles reported until mid-2013. The extended database is utilized for establishing the baselines of lifetime for OPVs tested under different conditions. The work also provides the recent progress in stability of unencapsulated OPVs with different architectures, as well as presents the updated diagram of the reported record lifetimes of OPVs. The presented work is another step forward towards the development of pass-fail testing standards and lifetime prediction tools for emerging PV technologies., This work has been supported by the European Commission's StableNextSol COST Action MP1307. The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement n° 609788 (CHEETAH) and n° 290022 (ESTABLIS). ICN2 acknowledges the support of the Spanish MINECO through the Severo Ochoa Centers of Excellence Program under Grant Nos. SEV-2013-0295 and ENE2013-48816-C5-4-R. Thanks goes to Agencia de Gestio d'Ajuts Universitaris i de Recerca for the support through the Xarxa de Referencia en Materials Avançats per a l'Energia (XaRMAE) and consolidated research group No. 2014SGR-1212. This work has been carried out under the Materials Science Ph.D. Degree for A.M. of the Universitat Autònoma de Barcelona. R.R. and H.H. are grateful for financial support from BMBF (grant number 03EK3502) and ESF. F.P. received support from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement no. 659747. L.S. and M.R. received supported from the Portuguese Foundation for Science and Technology in the framework of the Strategic Program UID/FIS/04650/2013.

In this study, we demonstrate that nonlinear optical microscopy is a promising technique to characterize organic printed electronics. Using ultrashort laser pulses we stimulate two-photon absorption in a roll coated polymer semiconductor and map the resulting two-photon induced photoluminescence (TPPL) and second harmonic response. First, we show that the different nonlinear optical signals can be used to discriminate between the polymer semiconductor material and embedded metal nanoparticles which constitute the electrode in a real device. Next we demonstrate that the TPPL quenches when applying a current between source and drain; this decrease can be used to determine the electrical characteristic of the device [1]. Finally, we show that the TPPL increases with higher temperature in the 20 - 120 °C range, closely following the supported current characteristics of the semiconductor. With this technique, we can recognize different nanomaterials and we propose that the TPPL is a good indicator to map and monitor the charge carrier density and the molecular packing of the printed polymer material. Importantly, simple calculations based on the signal levels, suggest that this technique can be extended to the real time mapping of the polymer semiconductor film, even during the printing process, in which the high printing speed poses the need for equally high acquisition rates.

This study reports the results of a one-day point prevalence study of infections performed in 2001 (SPIR01) and 2002 (SPIR02) in a Regional network of ICUs in Piedmont, Italy. The study aims were to illustrate the overall proportion of infected patients and the rate of ICU-acquired infections. Mortality rate was evaluated three weeks after the study days. Resistance pattern of Staphylococcus aureus, coagulase negative Staphylococci and Pseudomonas aeruginosa were recorded. The primary end-point of the study was to document the prevalence and associated risk factors of the ICU-acquired infections, and the impact of infections on mortality. The prevalence of ICU-acquired infection was 30% in SPIR01, and 38.3% in SPIR02. The rate of methicillin-resistance was high among isolates of Staphylococcus aureus and coagulase-negative Staphylococci. The prevalence of ICU-acquired infections was lower than that reported in the EPIC study. In our experience, this Regional survey stimulated further research and collaboration to improve the prophylaxis, diagnosis and treatment of ICU-acquired infections.