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The article presents an overview of polymeric materials for flexible substrates in photovoltaic (PV)

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Abstract. In this article the process of realization of ball-lensed optical fibers is described. The implementation of four different types of balllensed optical fibers developed in Optical Fibers Techniques Laboratory at Lodz University of Technology is presented. Focal lengths of the presented microlenses, which were obtained in simulations and measurements, are also shown in this paper.

The paper included fabrication and characterization of the bulk heterojunction organic solar cell (BHJ OSC) based on poly[(9,9-di-noctylfluorenyl-2,7-diyl)-alt-(benzo[2,1,3]thiadiazol-4,8-diyl)] (F8BT) and fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester (C60PCBM). It was studied the influence of annealing the temperature range: 120˚C-200˚C on absorption properties of F8BT, C60PCBM and F8BT:C60PCBM films. The annealing of films and the encapsulation of OSC's was carried out under nitrogen atmosphere in glove boxes. Fabricated devices were examined in terms of basic operational parameters such as: open circuit voltage, short circuit current, fill factor, power conversion efficiency. Annealing process at 120°C resulted in power conversion efficiency about 0.053% and fill factor ratio about 31%. Encapsulation after fabrication improved the work parameters of the OSCs and extended their lifetime in relation to non-encapsulation devices. Streszczenie. W ramach prac wytworzono i scharakteryzowano objętościowe heterozłączowe polimerowe, ogniwo fotowoltaiczne (OPV) oparte na poli [(9,9-din -oktylofluoren l2,7-diylu)-alt-(benzo [2,1,3] tiadiazolo-4,8-diylu)] (F8BT) oraz pochodną fulerenu [6,6]-fenylo-C61-estru metylowego kwasu masłowego (C60PCBM). Zbadano wpływ wygrzewania warstw F8BT, C60PCBM oraz blendy F8BT:C60PCBM w zakresie od 120˚C do 200˚C na właściwości absorpcyjne. Wygrzewanie badanych warstw oraz hermetyzację OSC wykonywano w atmosferze azotu w komorach rękawicowych. Dla skonstruowanych urządzeń wyznaczono charakterystyki prądowo-napięciowe oraz podstawowe parametry użytkowe: napięcie obwodu otwartego, prąd obwodu zamkniętego, współczynnik wypełnienia oraz sprawność. Dla fotoogniw wygrzewanych w 120˚C uzyskano najwyższą sprawność wynoszącą 0,053% przy współczynniku wypełnienia równym 0,31%. Hermetyzacja po procesie wytwarzania spowodowała poprawę parametrów roboczych urządzeń oraz przedłużyła ich czas życia w stosunku do urządzeń niehermetyzowanych. (Ocena właściwości organicznego ogniwa fotowoltaicznego opartego na polimerze F8BT i pochodnej fulerenu C60PCBM).

The paper presents research focused on the efficiency improvement of inorganic flexible thin-film solar cells, using energy converting layers. The light capture enhancement was achieved through the introduction of layers based on rare-earth elements, as top coatings on the amorphous silicon photovoltaic structures. Such luminescent layers are converting high-energy photons into low-energy ones, which are more efficient in photovoltaic conversion of the investigated solar cells. Towards this goal, powders consisting rare-earth elements were applied as active particles in polymer layer. For practical experiments, the screen-printing method, as a cheap, reliable and industrially-ready technology was used for layers deposition. For the experiments two compositions were selected: Sr4Al14O25: Eu,Dy (BGL-300M) and SrAl2O4: Eu,Dy (G-300M). These materials are characterized by excellent thermal and optical stability and interesting luminescent properties (they absorb ultraviolet and emit in the visible range). For the verification of investigated materials and methods, various compositions of powders and proportions were tested and analyzed.

One of the major performance limitations in chip designs is clock skew, the uncertainty in arrival times between a pair of clocks. Clock skew can limit overall circuit performance, or even cause functional errors. The main goal of this paper is to analyse and compare the most popular analytical models for estimating the clock skew for present and future VLSI systems. These models are compared for a generic global clock distribution network (an H-tree) with a JAVA program. Finally based on the presented models, a prevision for the clock skew value in upcoming technology nodes will be given.