Search results

Filter

Filetype

Your search for "*" yielded 538647 hits

Apprenticeship training in Sweden

Apprenticeship training in Sweden and many other European countries goes back to the middle ages. Yet, this special model of vocational education still attracts significant interest due to the challenges young people face in preparing to enter the current labour market. This is obvious both in Sweden and in other comparable countries. The apprenticeship model is primarily promoted as achieving twoApprenticeship training in Sweden and many other European countries goes back to the middle ages. Yet, this special model of vocational education still attracts significant interest due to the challenges young people face in preparing to enter the current labour market. This is obvious both in Sweden and in other comparable countries. The apprenticeship model is primarily promoted as achieving two

One-pot synthesis of a stable and cost-effective silver particle-free ink for inkjet-printed flexible electronics

Silver particle-free inks display immense superiority and potential over silver nanoparticle-based inks in the aspect of synthesis, flexibility and low-temperature processing, which has attracted considerable research interest as an alternative for fabricating conductive structures in recent years. Although recent research on silver particle-free inks has led to beneficial results, there are still

Citizens on the driving seat of Photovoltaics

A more collaborative, interdisciplinary, open, transparent and reproducible science begins to be required by Public Funding Agencies along the world. This contribution explains how a real project funded by the European Commission and researching in six innovative photovoltaic solutions, has embraced concepts of Open Science to foster innovation in our sector. In this paper we mainly focus on the c

Enhancing the hole-conductivity of spiro-OMeTAD without oxygen or lithium salts by using spiro(TFSI)2 in perovskite and dye-sensitized solar cells

2,2′,7,7′-Tetrakis(N,N-di-p-methoxyphenylamine)-9, 9′-spirobifluorene (spiro-OMeTAD), the prevalent organic hole transport material used in solid-state dye-sensitized solar cells and perovskite-absorber solar cells, relies on an uncontrolled oxidative process to reach appreciable conductivity. This work presents the use of a dicationic salt of spiro-OMeTAD, named spiro(TFSI)2, as a facile means of

Melt-infiltration of spiro-OMeTAD and thermal instability of solid-state dye-sensitized solar cells

A method for achieving complete pore-filling in solid-state dye-sensitized solar cells termed melt-infiltration is presented: after the customary solution-processed deposition of spiro-OMeTAD, the device is heated above the glass transition temperature of spiro-OMeTAD to soften the material and allow capillary action to pull additional spiro-OMeTAD from the overlayer reservoir into the pores. The

Highly soluble energy relay dyes for dye-sensitized solar cells

High solubility is a requirement for energy relay dyes (ERDs) to absorb a large portion of incident light and significantly improve the efficiency of dye-sensitized solar cells (DSSCs). Two benzonitrile-soluble ERDs, BL302 and BL315, were synthesized, characterized, and resulted in a 65% increase in the efficiency of TT1-sensitized DSSCs. The high solubility (180 mM) of these ERDs allows for absor

Silicon-naphthalo/phthalocyanine-hybrid sensitizer for efficient red response in dye-sensitized solar cells

Introduction of a naphthalocyanine moiety to phthalocyanine allows for a gradual red shift of the absorption spectrum in the resulting chromophore. Using silicon as a core atom allows for the introduction of additional siloxane side chains which mitigate dye aggregation. A dye-sensitized solar cell with this hybrid sensitizer exhibits a broad and flat IPCE of 80% between 600 and 750 nm and high ph

Effect of the preparation procedure on the morphology of thin TiO2 films and their device performance in small-molecule bilayer hybrid solar cells

Flat titanium dioxide films, to be used as the acceptor layer in bilayer hybrid solar cell devices, were prepared by spray-pyrolysis and by spin-casting. Both preparation methods resulted in anatase titania films with similar optical and electronic properties but considerably different film morphologies. Spray pyrolysis resulted in dense TiO2 films grown onto and affected by the surface roughness

Excitation energy dependent charge separation at hole-transporting dye/TiO2 hetero interface

Interfacial charge separation in hybrid solar cells depends on both the energetic alignment and electronic coupling between the inorganic and organic semiconducting materials at the hetero interface. In the present work, bilayer solar cells comprising the small molecular semiconducting dye TDCV-TPA (tris-(thienylene-vinylene)-triphenylamine) and dense titanium dioxide (TiO2) films were investigate

Comparing spiro-OMeTAD and P3HT hole conductors in efficient solid state dye-sensitized solar cells

Two hole conductor materials, spiro-OMeTAD and P3HT, were compared in solid-state dye-sensitized solar cells. Two organic dyes containing one anchor unit (D35) or two anchor units (M3) were used in the comparison. Absorbed photon to current conversion efficiency close to unity was obtained for the devices with spiro-OMeTAD. Energy conversion efficiencies of 4.7% and 4.9% were measured for the devi

Contribution from a hole-conducting dye to the photocurrent in solid-state dye-sensitized solar cells

The hole transporting medium in solid-state dye-sensitized solar cells can be utilized to harvest sunlight. Herein we demonstrate that a triphenylamine-based dye, used as hole-transporting medium, contributes to the photocurrent in a squaraine-sensitized solid-state dye-sensitized solar cell. Steady-state photoluminescence measurements have been used to distinguish between electron transfer and en

Efficient infiltration of low molecular weight polymer in nanoporous TiO2

The polymer APFO3 was prepared with different molecular weights to study how the infiltration into nanoporous TiO2 films of different thickness depends on the size of the polymer. Also two different sizes of TiO2 nanoparticles were investigated to understand the effect of different pore size. It was observed that the lowest molecular weight polymer dissolved in chlorobenzene could infiltrate the n

Bilayer hybrid solar cells based on triphenylamine-thienylenevinylene dye and TiO2

Photoinduced energy conversion from multilayers of organic dye on dense TiO2 films was investigated in bilayer hybrid solar cells. Dye layers of varying thicknesses were prepared by spin-casting the star-shaped dye [tris(dicyano-vinyl-2-thienyl)phenyl]amine (1) from solutions onto dense TiO2 on conducting glass substrates. A spin-cast layer of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate

Transport of Caesium ions through thin poly-p-xylylene films

We describe an experimental setup for investigating the transport of alkali ions through poly(p-xylylene) membranes. It consists of an ion source where a continuous beam of alkali ions is generated from a surface emitter. Via ion-optics the ions are guided to the main chamber where the interaction with the free-standing membranes of variable thickness is investigated as a function of the impact en

Fastighetsnära källsortering ur de boendes perspektiv : blev det lätt och rätt?

Studien handlar om hur de som bor i stadsdelen Augustenborg i Malmö använde och upplevde den avfallshantering som introducerades 2008. Hur hållbara avfallssystem kan åstadkommas diskuteras med utgångspunkt i användning och upplevelse av den lokala avfallshanteringen. De primära frågeställningarna är:• Vilka begrepp och kategorier skapar och använder invånarna när det gäller avfall i vardagen? Hur

Från Hyphoff till LUX : Framtiden i retrospektiv

Den här texten ger en bild av de förutsättningar och överväganden som låg till grund för skapandet av den nya Institutionen för kulturvetenskaper vid Lunds universitet. Det är en historieskrivning för framtiden men också en berättelse om den framtid som kunde förutses före 2009 när institutionen bildades. Det är en backspegelsberättelse, ett retrospektiv mot vilket det som då var framtid och nu är

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients : the DecubICUs study

PURPOSE: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients.METHODS: International 1-day point-prevalence study; follow-up for outcome assessment unti

Sepsis at ICU admission does not decrease 30-day survival in very old patients : a post-hoc analysis of the VIP1 multinational cohort study

BACKGROUND: The number of intensive care patients aged ≥ 80 years (Very old Intensive Care Patients; VIPs) is growing. VIPs have high mortality and morbidity and the benefits of ICU admission are frequently questioned. Sepsis incidence has risen in recent years and identification of outcomes is of considerable public importance. We aimed to determine whether VIPs admitted for sepsis had different

The impact of frailty on ICU and 30-day mortality and the level of care in very elderly patients (≥ 80 years)

Purpose: Very old critical ill patients are a rapid expanding group in the ICU. Indications for admission, triage criteria and level of care are frequently discussed for such patients. However, most relevant outcome studies in this group frequently find an increased mortality and a reduced quality of life in survivors. The main objective was to study the impact of frailty compared with other varia