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The thin film (TF) solar market is challenged to produce solar modules with higher energy conversion efficiency while at the same time reducing the manufacturing cost. One way to improve the energy efficiency is to move to higher performance systems like Cadmiumtellurid (CdTe) or Cu(In,Ga)(S,Se)2 (CIGS) in comparison to TF Silicon (Si) based technologies. As today’s a-Si and CdTe structuring technology for module development is based on laser scribing, the technology for CIGS modules is mostly dominated by mechanical scribing. As inexpensive as the mechanical scribing technology seems, it has its drawbacks when it comes to high precision scribing of TF materials and, subsequently, the reliability in the manufacturing process. Bringing together a high speed, high accuracy motion system with ultra short pulse laser sources opens up new ways CIGS solar cell production can be perceived. We present with this work an in depth evaluation of the influences of the laser pulse width and wavelength to the CIGS scribing process on glass substrate. A variation of the pulse width in the range of 10 ps to 100 ps and 1 ns up to 30 ns is studied and monitored to determine the influences on the scribing quality. At the end, a functional mini-module is presented featuring a dead zone of less than 200 μm. Incorporating the results into a scribing tool an innovative industrial concept is developed for future integration. An outlook is given on the possible impact on cell efficiency, manufacturing costs, and cost of ownership implementing such a concept into production. 26th European Photovoltaic Solar Energy Conference and Exhibition; 2986-2991

Upconversion (UC) of sub-band-gap photons is a promising approach to increase solar cell efficiencies, because it makes these sub-band-gap photons useful as well. We investigate the application of -NaYF4:20% Er3+ to silicon solar cells. We determine the external quantum efficiency of an UC silicon solar cell, both under monochromatic excitation and under white light illumination. We demonstrate that an UC silicon solar cell responds under white light with an average UC efficiency of 1.07 ± 0.13% in the spectral range from 1460 to 1600 nm. Concepts are discussed how the narrow absorption range of the UC material can be overcome. 25th European Photovoltaic Solar Energy Conference and Exhibition / 5th World Conference on Photovoltaic Energy Conversion, 6-10 September 2010, Valencia, Spain; 229-233

CEOCOR 2021 Madrid

In thin-film solar cells optical scattering eects at rough layer interfaces are exploited to enhance the light absorption and make it possible to construct thin cells with inorganic materials such as a-Si or c-Si [5]. SETFOS [2] is an optical and electrical device simulator, that is widely used in the OLED and OPV community. To perform an optical simulation of an arbitrary combination of inorganic or organic layers of any thickness, it is necessary to be able to treat light propagation both as coherent or incoherent. We have therefore extended the optical model of SETFOS for the treatment of mixed systems of incoherent/coherent layers. We have broadened the scope of the simulator by including scattering eects at rough layer interfaces. 24th European Photovoltaic Solar Energy Conference, 21-25 September 2009, Hamburg, Germany; 2893-2894

It is widely accepted that adherence (which reports to what is measured when performing an adhesion test) of the encapsulant to the main substrates of the module plays a key role in the long term reliability of the PV module. Consequently, adherence is commonly measured and used to assess or compare encapsulant compatibility with a given substrate. The most common procedures used in the PV field to characterize adhesion between a polymer film and a substrate are the so called peeling test, lap shear and compressive shear tests. Here we use a compressive shear setup to characterize the adherence of Poly Vinyl Butyral (PVB) and Polyethylene-covinyl acetate (EVA) to glass before and after degradation in damp-heat (DH) conditions (85°C, 85%RH). The adherence metrics that can be derived from a Compressive Shear Test (CST) are presented and discussed. We show that a single metric is not sufficient to characterize adherence and that a set of at least two indicators including the peak shear stress and the viscous dissipation should be used. Using this set it is found that the interface PVB/Glass is more affected by the degradation than the EVA/Glass interface. 26th European Photovoltaic Solar Energy Conference and Exhibition; 2597-2599

Proceedings INTER International Network on Timber Engineering Research, 52

ISBN:978-3-907234-59-4

This paper presents two models for converting hourly global into hourly direct beam irradiance based on a new parameterization of insolation conditions (Perez et al. 1990a). This parameterization does not require any additional input data than those already contained in a global irradiance time series but attempts to better utilize available information. The models are capable of using surface dew-point temperature as an additional input when this is available. The models are derived statistically from a large multiclimatic experimental data base. The two models differ technically but should be functionally equivalent: The first is a correction to the physically based DISC model(Maxwell 1987); the second consists of a set of simple linear relationships. Validation results are presented in reference to three existing models (Maxwell 1987; Erbs et al. 1982; Randall and Whitson 1977). The validation benchmarks consist of root mean square and mean bias errors as well as the ability of the models to recreate the skewness and kurtosis of actual direct irradiance distributions.