Organic Photovoltaics: Technologies and Manufacturing

It is assumed, that the organic electronics industries and organic solar cells in particular, are in the transition stage towards commercialization. The companies and R&D institutes in this area are moving now from research and development stage to manufacturing. The biggest challenges are how to scale from laboratory to full production, how to select the right tools and processes, and how to use tests and measurements to improve yield and quality. The step from lab-scale to volume production requires adjusting and optimizing of many system aspects, such as: a) deposition techniques and drying conditions, b) substrates, c) ink and solvent systems, d) electrodes and e) dimension of individual cells and modules. Each parameter has its influence on the performance of the final product. In this chapter we discuss a knowledge base concerning the influence of different parameters and process conditions on the performance, cost and lifetime of polymer solar cells

Degradation mechanisms in organic photovoltaic devices

\u3cp\u3eIn the present review, the main degradation mechanisms occurring in the different layer stacking (i.e. photoactive layer, electrode, encapsulation film, interconnection) of polymeric organic solar cells and modules are discussed. Bulk and interfacial, as well as chemical and physical degradation mechanisms are reviewed, as well as their implications and external or internal triggers. Decay in I-V curves in function of time is usually due to the combined action of sequential and interrelated mechanisms taking place at different locations of the device, at specific kinetics. This often makes the identification of specific root causes of degradation challenging in non-model systems. Additionally, constant development and refinement in terms of type and combination of materials and processes render the ranking of degradation mechanisms as a function of their probability of occurrence and their detection challenging. However, it clearly appears that for the overall stability of organic photovoltaic devices, the actual photoactive layer, as well as the properties of the barrier and substrate (e.g. cut of moisture and oxygen ingress, mechanical integrity), remain critical. Interfacial stability is also crucial, as a modest degradation at the level of an interface can quickly and significantly influence the overall device properties.\u3c/p\u3

Comparative Indoor and Outdoor Degradation of Organic Photovoltaic Cells via Inter-laboratory Collaboration

We report on the degradation of organic photovoltaic (OPV) cells in both indoor and outdoor environments. Eight different research groups contributed state of the art OPV cells to be studied at Pomona College. Power conversion efficiency and fill factor were determined from IV curves collected at regular intervals over six to eight months. Similarly prepared devices were measured indoors, outdoors, and after dark storage. Device architectures are compared. Cells kept indoors performed better than outdoors due to the lack of temperature and humidity extremes. Encapsulated cells performed better due to the minimal oxidation. Some devices showed steady aging but many failed catastrophically due to corrosion of electrodes not active device layers. Degradation of cells kept in dark storage was minimal over periods up to one year

Opbouw van het 1(H)pyrazino-(1,2-a) chinolineskelet

KULeuven Campusbibliotheek Exacte Wetenschappen / UCL - Université Catholique de LouvainSIGLEBEBelgiu

Opbouw van het 1(H)pyrazino-(1,2-a) chinolineskelet

KULeuven Campusbibliotheek Exacte Wetenschappen / UCL - Université Catholique de LouvainSIGLEBEBelgiu

Rapid and low temperature processing of mesoporous TiO\u3csub\u3e2\u3c/sub\u3e for perovskite solar cells on flexible and rigid substrates

\u3cp\u3ePerovskite solar cells (PSCs) have recently attracted the attention of the scientific community because of the rapid advances in their development. Most of the state-of-the-art devices contain mesoporous titanium dioxide (TiO\u3csub\u3e2\u3c/sub\u3e) as an electron transport layer. The drawback of such TiO\u3csub\u3e2\u3c/sub\u3e layers is that it often needs high temperature sintering at 450–500 °C for 30 min, which slows down the fabrication process and is clearly not compatible with future roll-to-roll (R2R) manufacturing. The aim of this study was to develop low temperature and rapid curing techniques for mesoporous TiO\u3csub\u3e2\u3c/sub\u3e thin films, which are compatible with R2R processing and heat-sensitive plastic substrates for PSCs. Several alternative annealing techniques were tested on rigid and flexible substrates, such as UV-ozone (UV/O\u3csub\u3e3\u3c/sub\u3e) treatment, oxygen plasma treatment (O\u3csub\u3e2\u3c/sub\u3e plasma) and Intense Pulsed Light (IPL) sintering and compared to conventional thermal annealing. After each treatment, the mesoporous layers were characterized using Raman spectroscopy, UV–vis spectroscopy, thermogravimetric analysis and scanning electron microscopy. Low temperature sintering techniques were specifically optimized for the mesoporous TiO\u3csub\u3e2\u3c/sub\u3e layers and were adapted for the fabrication of PSCs. Sintering process and solar cells manufacturing were optimized for two different device architectures on glass as well as on polyethylene naphthalate (PEN) substrates. Moreover, the maximum temperature of the mesoporous TiO\u3csub\u3e2\u3c/sub\u3e layer during the IPL curing process was simulated to better understand the curing process. By employing IPL curing, the processing time for the mesoporous TiO\u3csub\u3e2\u3c/sub\u3e layer can be reduced from 30 min to a few seconds without significant loss in the device performance. In particular stabilized PCE of 16% and 12% were obtained using IPL on glass and PEN substrates respectively. This processing route paves the way for future low temperature R2R processing of mesoscopic PSC on plastic substrates.\u3c/p\u3

Steric and electronic effects relating to the Cu2+ Jahn-Teller Distortion in Zn1-xCuxAl2O4 spinels

Zn1-xCuxAl2O4 (0 < x < 1) compositions have been synthesized by solid-state route, and a color scale going from white (x = 0) to brownish-red (x = 1) with intermediate colors as pale green for x = 0.10 and pale brown for x = 0.30 can be observed..

Defects in divided zinc-copper aluminate spinels : structural features and optical absorption properties

Zn1-xCuxAl2O4 (0 < x < 0.30) compounds have been synthesized by polyesterification using metallic salts and annealing at low temperatures as well as by conventional solid state..