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Abstract: A new encapsulation method for organic solar cells has been tested on flexible solar modules and cells embedded in polyurethane, sandwiched between a tempered glass plate and a polycarbonate plate. Panels, each containing 10 organic solar modules/cells, were fabricated and installed for outdoor exposure in eight different countries for 4½ months. In order to minimize potential deviations in procedures and equipment, one person was responsible for the fabrication, installation and initial and final IV-measurements of the panels using the same equipment for all measurements and calibrations. The encapsulated modules/cells showed significantly reduced degradation compared with previous studies, with final average efficiencies around 40% of the original after 4½ months outdoor exposure. Photodegradation was furthermore found not to be the primary source of degradation. [Copyright &y& Elsevier]

Abstract: The presence of a transparent conductive electrode such as indium tin oxide (ITO) limits the reliability and cost price of organic photovoltaic devices as it is brittle and expensive. Moreover, the relative high sheet resistance of an ITO electrode on flexible substrates limits the maximum width of a single cell. We have developed an alternative ITO-free transparent anode, based on solution processed high conductive PEDOT:PSS in combination with a printed current collecting grid. The screen printed silver grid demonstrates a typical sheet resistance of 1Ω/□ with 6.4–8% surface coverage. The efficiency of a flexible device with an active area of 4cm2 with such a grid is much higher than a similar device based on ITO. Furthermore, as this composite anode is solution-processed, it is a step forward towards low-cost large area processing. [Copyright &y& Elsevier]

We report a cooperative study conducted between different laboratories to investigate organic solar cell degradation with respect to P3HT material properties and different solar cell architectures. Various batches of P3HT were collected from different suppliers reflecting commercial availability as well as properties variability. Among the materials properties explicitly considered were the molar mass, dispersity, regio-regularity, impurities by trace metals and intrinsic doping evaluated from radical concentrations. Each of the participating laboratories contributing test devices applied their own layer stack, i.e. their own device architecture and layout. This variation was appreciated as another parameter for evaluation. Even though a large amount of devices failed due to extrinsic degradation effects, indeed, some materials properties were found to be more important than others for obtaining long lifetimes and high stability of P3HT-based polymer solar cells. • P3HT:PCBM solar cells made from commercially available P3HTs were aged under three different ISOS protocols. • Solar cells were built by five different labs resulting in 5 different architectures. • The P3HT batches were studied for their properties like impurities, molar mass, dispersity, etc. • All P3HTs performed similar in regard to stability we concluded that commercially available P3HTs offer viable properties. • Layer stack and processor experience with P3HT used had a larger impact on stability than polymer properties. [ABSTRACT FROM AUTHOR]