Efficient and stable air-processed ternary organic solar cells incorporating gallium-porphyrin as electron cascade material

Two gallium porphyrins, a tetraphenyl GaCl porphyrin, termed as (TPP)GaCl, and an octaethylporphyrin GaCl porphyrin, termed as (OEP)GaCl, were synthesized to use as an electron cascade in ternary organic bulk heterojunction films. A perfect matching of both gallium porphyrins’ energy levels with that of poly(3-hexylthiophene-2,5-diyl) (P3HT) or poly[N-9′-heptadecanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)] (PCDTBT) polymer donor and the 6,6-phenyl C71 butyric acid methyl ester (PCBM) fullerene acceptor, forming an efficient cascade system that could facilitate electron transfer between donor and acceptor, was demonstrated. Therefore, ternary organic solar cells (OSCs) using the two porphyrins in various concentrations were fabricated where a performance enhancement was obtained. In particular, (TPP)GaCl-based ternary OSCs of low concentration (1:0.05 vv%) exhibited a ~17% increase in the power conversion efficiency (PCE) compared with the binary device due to improved exciton dissociation, electron transport and reduced recombination. On the other hand, ternary OSCs with a high concentration of (TPP)GaCl (1:0.1 vv%) and (OEP)GaCl (1:0.05 and 1:0.1 vv%) showed the poorest efficiencies due to very rough nanomorphology and suppressed crystallinity of ternary films when the GaCl porphyrin was introduced to the blend, as revealed from X-ray diffraction (XRD) and atomic force microscopy (AFM). The best performing devices also exhibited improved photostability when exposed to sunlight illumination for a period of 8 h than the binary OSCs, attributed to the suppressed photodegradation of the ternary (TPP)GaCl 1:0.05-based photoactive film

Gefäßchirurgische Ausbildung in endovaskulärer Technik in Lausanne

Zusammenfassung: Zwischen 1995 und 2005 wuchs die Anzahl der jährlich von uns mit endovaskulären Techniken versorgten Aortenaneurysmen (EVAR) von 0 auf 50, und dies auf allen Stufen der Aorta. Zu unserer Organisation gehören ein breites Team von Chirurgen, ein Lager mit 3kompletten Familien von Endoprothesen (gerade Endoprothesen, konische Endoprothesen, und Bifurkationen), ein mobiler Wagen mit Zubehör (Einführungsbestecke, Führungsdrähte, Katheter, Ballone etc.) und ein Apparat auf Rädern für die intravaskuläre Ultraschalluntersuchung (IVUS). Letzterer erlaubt es zusammen mit einer mobilen Durchleuchtungsanlage (C-Bogen), in jedem Operationssaal unserer Institution endovaskulär Aneurysmen zu analysieren, und dies in der Regel ohne Angiographie bzw. Kontrastmittel. Deshalb sind wir nicht mehr auf eine ausgiebige bildgebende präoperative Abklärung potenzieller Kandidaten für eine endovaskuläre Sanierung von Aneurysmen angewiesen und können rupturierte Aneurysmen der Bauchaorta oder der thorakalen Aorta ohne Verzug behandeln. Bei der endovaskulären Sanierung von Aortenaneurysmen unterscheiden wir zwischen Prozessschritten (Indikationsstellung, Darstellung der Zugangsgefäße, Ausmessen mittels IVUS und Roadmapping mittels Durchleuchtung, Implantatwahl, Implantatinsertion, Positionierung, Implantatabwurf, Erfolgsbeurteilung, Rekonstruktion der Zugangsgefäße und Nachkontrolle) und Kompetenzstufen (Assistent, Oberarzt, Leitender Arzt). Unsere ultraschallgestützte Technik zur endovaskulären Sanierung von Aneurysmen wurde mittels IVUS-Transporter und Telementoring erfolgreich auch anderen Institutionen zur Verfügung gestell

Core-shell carbon-polymer quantum dot passivation for near infrared perovskite light emitting diodes

High-performance perovskite light-emitting diodes (PeLEDs) require a high quality perovskite emitter and appropriate charge transport layers to facilitate charge injection and transport within the device. Solution-processed n-type metal oxides represent a judicious choice for the electron transport layer (ETL); however, they don't always present suitable surface properties and energetics in order to be compatible with the perovskite emitter. Moreover, the emitter itself exhibits poor nanomorphology and defect traps that compromise the device performance. Here we modulate the surface properties and interface energetics of the tin oxide (SnO2) ETL with the perovskite emitter by using an amino functionalized difluoro{2-[1-(3,5-dimethyl-2H-pyrrol-2-ylidene-N)ethyl]-3,5-dimethyl-1H-pyrrolato-N}boron (BDP) compound and passivate the defects present in the perovskite with carbon-polymer core-shell quantum dots (PCDs) inserted into the perovskite precursor. Both these approaches synergistically improve the perovskite layer nanomorphology and enhance the radiative recombination. These properties resulted in the fabrication of near infrared (NIR) PeLEDs based on formamidinium lead iodide (FAPbI3) with a high radiance of 92 W sr-1 m-2, an external quantum efficiency (EQE) of 14% and reduced efficiency roll-off

A Silanol-Functionalized Polyoxometalate with Excellent Electron Transfer Mediating Behavior to ZnO and TiO 2 Cathode Interlayers for Highly Efficient and Extremely Stable Polymer Solar Cells

Combining high efficiency and long lifetime under ambient conditions still poses a major challenge towards commercialization of polymer solar cells. Here we report a facile strategy that can simultaneously enhance the efficiency and temporal stability of inverted photovoltaic architectures. Inclusion of a silanol-functionalized organic–inorganic hybrid polyoxometalate derived from a PW9O34 lacunary phosphotungstate anion, namely (nBu4N)3[PW9O34(tBuSiOH)3], significantly increases the effectiveness of the electron collecting interface, which consists of a metal oxide such as titanium dioxide or zinc oxide, and leads to a high efficiency of 6.51% for single-junction structures based on poly(3-hexylthiophene):indene-C60 bisadduct (P3HT:IC60BA) blends. The above favourable outcome stems from a large decrease in the work function, an effective surface passivation and a decrease in the surface energy of metal oxides which synergistically result in the outstanding electron transfer mediating capability of the functionalized polyoxometalate. In addition, the insertion of a silanol-functionalized polyoxometalate layer significantly enhances the ambient stability of unencapsulated devices which retain nearly 90% of their original efficiencies (T90) after 1000 hours

Photochemically-induced ligand exchange reactions of ethoxy-oxo-molybdenum(V) tetraphenylporphyrin in chlorinated solvents

Photochemically-induced ligand exchange reactions of ethoxy-oxo-molybdenum (V) 5,10,15,20-tetraphenylporphyrin, Mo(V)O(TPP)-OEt, under irradiation at the Soret band region, were investigated. The reactions were performed in chlorinated solvents and followed with ultraviolet-visible spectroscopy, whereas the products were analyzed with FTIR spectroscopy, ESR spectroscopy and gas chromatography. The chloro-oxo(TPP)Mo(V) complex was obtained as the final product, where the chlorine came from the solvent. Nevertheless, these reactions were not photocatalytic, due to the photochemical inertness of the formed chloro-oxo complex, and an excess of ethanol could not initiate a new photocatalytic cycle unless water was added as well, resulting in the formation of the correspondign oxo-Mo(IV) complex. The studied photoassisted reactions of oxoMo(V) porphyrins appear attractive for possible applications in the detection of chlorinated pollutants in sensing devices, but also for the dechlorination of pollutants upon suitable optimization of processing conditions

Modeling of a grid connected photovoltaic system using a geometrial transformer model

A grid connected single-phase photovoltaic system is modeled and simulated using a geometrical core-type transformer model. The transformer model that is used takes into account the magnetic core geometry as well as the hysteresis loop of the core material. In particular, the hysteresis loop is introduced using the Jiles-Atherton theory of magnetic hysteresis. Moreover, proper models for the photovoltaic array and the inverter have been used to assemble a system model in the field of state equations. Comparison with published results has been made with a prototype installation of the same configuration. Very good agreement is accomplished between the predicted and measured values. Thus, the proposed methodology can be used for the modeling of single-phase or three-phase grid connected photovoltaic systems