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Controlling the size of the oligomer and introducing functional groups at the ends of the oligomer that allow it to react with separate electrodes are critical issues when preparing materials for molecular wires. We demonstrate a general synthetic approach to oligophenylenevinylene (OPV) derivative molecules with a molecular length up to 9-10 nm which allow for the introduction of aromatic thioacetate functionality in fully conjugated oligomer systems. Oligomers containing 3-15 phenyl units were synthesized by step wise Horner-Wadsworth-Emmons (HWE) reactions of a bifunctional OPV-monomer, which demonstrated good control of the size of the OPVs. Workup after each reaction step ensures a high purity of the final products. End group functionalization was introduced as a last step. [ABSTRACT FROM AUTHOR]

Four new monomers for directional stepwise synthesis of oligophenylenevinylenes (OPVs) (4-{2-[4-(5,5-dimethyl[1,3]dioxan-2-yl)-2,5-dipropoxyphenyl]vinyl}benzyl)phosphonic acid diethyl ester, (5-{2-[4-(5,5-dimethyl[1,3]dioxan-2-y])-2,5-dipropylphenyl]vinyl}thiophene-2-ylmethyl)phosphonic acid diethyl ester, (5-{2-[4-{5,5-dimethyl[1,3]dioxan-2-yl)-2,5-diprepoxyphenyl]vinyl}thiophene-2-ylmethyl)phosphonic add diethyl ester, and (7-{2-[4-(5,5-limethyl[1,3] dioxan-2-yl)z2,5-dipropylphenyl]-vinyl}benzo[1,2,5]thiadiazol-4-ylmethyl)phosphonic acid diethyl ester have been prepared. Trimeric OPVs were then synthesized and tested as active materials in photovoltaic cells. Conversion efficiencies in the range of 0.5–1% were obtained in blends with the soluble C60 derivative PCBM. A terpyridine end-functionalized trimer and a heterotrimer with a mixed composition of monomers were also prepared. [ABSTRACT FROM AUTHOR]

A new stepwise directional synthetic route to single-oligomer p-phenylenevinylenes (OPVs) has been developed. The first step in the reaction sequence is the condensation of a functionalized benzaldehyde with a novel monomer having a methyl phosphonate ester group in one end and an acetal-protected aldehyde at the other end of a stilbene core. Oligomerization then proceeds stepwise by alternating reaction of the previous aldehyde-terminated OPV fragment with the monomer and deprotection of the acetal. Thus, a series of OPVs with 3, 5, 7, 9, and 11 phenylene vinylene units has been prepared that has an electron-donating methoxy group at one end and an electron-accepting aldehyde group at the other end. Some examples where a dimethylamino group replaced the methoxy group were also prepared. The oligomer with seven phenylene vinylene units was then further derivatized at the aldehyde position to create a series of OPVs with a range of substituents from strongly electron-accepting nitrophenyl to electron-donating methoxyphenyl. Photovoltaic cells were assembled with the synthesized OPVs as the photoactive layer. Illumination under simulated sunlight (AM1.5) gave short circuit currents (Isc) in the range 0.015-0.5 mA cm-2 and typical open circuit voltages (Voc) of 0.4-0.8 V. The maximum efficiency obtained was ∼0.1%. [ABSTRACT FROM AUTHOR]

We report a new synthesis of a 10,20-diphenyl5,15-bis(4-cyanophenyl)porphyrin (1) and its reduction to give 10,20-diphenyl-5,15-bis(4-formylphenyl)porphyrin (2). When the conducting polymer poly(2',5'-diocty]-4,4'-terphenylenecyanovinylene) was prepared in the presence of 2, we obtained a three-domain structure, compound 3, consisting of two homopolymer blocks (J domains) with the porphyrin dye molecule (P domain) in the middle. The JPJ assembly was subjected to photophysical studies where we showed that the J domain could serve as a light-harvesting antenna for the P domain. [ABSTRACT FROM AUTHOR]

Investigates the effect of perfluorination on photophysical properties of isostructural donor-acceptor-donor dye molecules. Characterization of the molecules; Synthesis of fluorinated benzene compounds; Determination of the X-ray structure.

Examines the preparation of the potentially chiral 7,8-dioxa[6]helicenes through dehydrogenation. Structural properties of the two aromatic helicenes; Use of nuclear magnetic resonance and X-ray crystallization in the study; Structural characterization of the deuterium labeled compound.

Presents a conformational analysis of the calix[4]arenes based on the presentation of crystallographic data in a Ramachandran-type plot and the relation to the unconstrained diphenylmethane system. Comparison with other known [n]cyclophanes; Typical torsion angles for the different conformers of the calix[4]arene skeleton.

Focuses on a study which examined the synthesis of the 5,17-distyryltetrapropoxycalix[4]arenes, with reference to the calix[4]arenes. Definition of the calix[4]arenes; Details on the usage of X-ray diffraction; Establishment of the photophysical properties; Information on the Horner-Wadsworth-Emmons reaction; Methodology used to conduct the study; Results of the study.

Describes the preparation of 3,8-diaryldifurano[2,3-a:2',3'-f]naphthalenes. X-ray crystallography; Cyclization of the intermediates using methanesulfonic acid in methylene chloride.

Examines the characteristics of nonplanar polyaromatic molecule 14,15-dimethylbenzo[s]picene. Use of the Suzuki coupling reaction; Identification of atropisomers; Distortion from planarity and saddle shape of the molecule; Comparison between the molecular conformation of benzo[s]picene and beta-tribenzopyrene.

Abstract: In this paper we present an attempt to substitute liquid electrolyte (LC) dye-sensitized solar cells (DSSCs) by quasi-solid-state constructions (SC) for semi-transparency application adopting organic/inorganic gels in combination with standard (Pt based) and alternative (PEDOT:PSS based) counter electrodes. Gel polymer electrolytes are prepared by incorporating a liquid electrolyte into a polymer matrix such as polymethyl-methacrylate (PMMA) using propylene carbonate (PC) as gelling solvent. SC employing gel electrolytes with a high content in PC have been shown to exhibit increased lifetime up to 70h under A.M. 1.5 irradiation. Counter electrodes were prepared by an airbrushing and tape casting technique of Pt salt solutions or by spin coating of commercial PEDOT:PSS solution. PEDOT:PSS counter electrodes were found to show similar I3 −/I− catalytic activities to Pt based counter electrodes and the best SC obtained gave a short circuit current of 2mAcm−2 and a open circuit voltage of 625mV. [Copyright &y& Elsevier]

A multidomain compound with applications in the area of organic solar cells has been prepared. This all-in-one molecule compound integrates all the functionalities needed for solar cell action from light harvesting, carrier generation, and separation, to transport and contact to external electrodes. A convergent synthetic strategy with some 60 steps involving preparation of regioregular oligothiophenes, a zinc porphyrin, a bisterpyridine ruthenium(II) complex, a hetero oligo phenylenevinylene and functional end groups is described. Preliminary investigations of photovoltaic devices based on the target molecule gave values of 0.18 V, 0.0044 mA cm-2, 29% and 0.000081% for the open circuit voltage (Voc), short circuit current (Isc), fill factor (FF), and efficiency (η). These poor values are compared to those obtained with an oligo-3-hexylthiophene which gave values of 0.7 V, 0.046 mA cm-2, 24.6%, and 0.0081% for the open circuit voltage (Voc), short circuit current (Isc), fill factor (FF) and efficiency (η). This latter compound was also studied in a bulk heterojunction device with PCBM (1:1 blend) which gave values of 0.43 V, 0.45 mA cm-2, 33.5%, and 0.063%. [ABSTRACT FROM AUTHOR]

Abstract: Zinc-porphyrin dye molecules were incorporated into the backbone of a conjugated polymer material by a method, which allowed for the incorporation of only one zinc-porphyrin dye molecule into the backbone of each conjugated polymer molecule. The electronic properties of the homopolymer were established using ultraviolet photoelectron spectroscopy (UPS) for the determination of the electronic energy levels and the injection barrier for holes into the valence band. Pulse radiolysis time resolved microwave conductivity (PR-TRMC) was used to determine the sum of charge carrier mobilities. Electroluminescent devices of the homopolymer itself and of the zinc-porphyrin containing polymer were prepared and the nature of the electroluminescence was characterized. The homopolymer segments were found to optically pump the emission of the zinc-porphyrin dye moities. The homopolymer exhibits blue-green emission and the zinc-porphyrin linked homopolymers emit near-infrared/infrared light. This was demonstrated to be due to electroluminescence pumping of the zinc-porphyrin moieties that were covalently linked to homopolymer material. When only one zinc-porphyrin dye was incorporated into the backbone of each homopolymer molecule complete suppression of homopolymer electroluminescence was observed with exclusive near-infrared emission. [Copyright &y& Elsevier]

To address sustainability challenges, photovoltaics (PV) are regarded as a promising renewable energy technology. Decreasing PV module costs and increasing residential electricity prices have made self-consumption of PV-generated electricity financially more attractive than exporting to the grid. Organic photovoltaics (OPV) are an emerging thin-film PV technology that shows promise of greatly improving the environmental and economic performances of PV technologies. Previous studies have estimated the current and future costs of OPV technologies, but the attractiveness of investing in OPV systems has not been evaluated under real market conditions, especially under PV self-consumption schemes. In this study, we investigate the self-consumption of electricity generation from conventional and organic PV systems installed at residential houses in two different countries, Denmark and Greece, under current PV regulatory frameworks. We then focus on modelling and assessing the cost-competitiveness of organic PV technologies based on cost estimations for existing pilot-scale (kW-range), and projected scale-up (100MW) and industrial-scale (100 GW) manufacturing capacity levels. Our generic results applying to all PV technologies show that PV systems installed at residential houses in Greece perform economically better than those in Denmark do in terms of self-sufficiency and gross electricity bill savings (i.e. excluding PV costs). Using the two country cases, which present very different settings, we characterise and discuss the influence of three key parameters of the economic performance of PV systems, namely the PV regulatory scheme, the solar irradiation level and the temporal match between the electricity consumption and solar irradiation profiles. Focusing on organic PV systems developed in an industrial-scale cost setting (1.53 €/Wp), we find that they deliver significant electricity bill savings for residential houses in Greece (38%) under current conditions, while they may not be sufficiently attractive for residential houses in Denmark (6.5%) due to mainly the different PV regulatory schemes. Based on these findings, we therefore recommend investors interested in renewable energy technologies to pursue scaling up the manufacturing capacity of OPV technologies, as well as assess a large number of countries to identify and prioritise financially attractive settings for PV self-consumption. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The fabrication of substrates and superstrates prepared by scalable roll‐to‐roll methods is reviewed. The substrates and superstrates that act as the flexible carrier for the processing of functional organic electronic devices are an essential component, and proposals are made about how the general availability of various forms of these materials is needed to accelerate the development of the field of organic electronics. The initial development of the replacement of indium‐tin‐oxide (ITO) for the flexible carrier materials is described and a description of how roll‐to‐roll processing development led to simplification from an initially complex make‐up to higher performing materials through a more simple process is also presented. This process intensification through process simplification is viewed as a central strategy for upscaling, increasing throughput, performance, and cost reduction. [ABSTRACT FROM AUTHOR]

The active layer crystallization during roll-to-roll coating of organic solar cells is studied in situ. We developed an X-ray setup where the coater unit is an integrated part of the small angle X-ray scattering instrument, making it possible to control the coating process while recording scattering measurements in situ, enabling us to follow the crystal formation during drying. By varying the distance between the coating head and the point where the X-ray beam hits the film, we obtained measurements of 4 different stages of drying. For each of those stages, the scattering from as long a foil as possible is summed together,with the distance from coating head to scattering point kept constant. The results are average crystallographic properties for the active layer coated on a 30 m long foil. With this insight into the dynamics of crystallization in a roll-coated polymer film, we find that the formation of textured and untextured crystallites seems uncorrelated, and happens at widely different rates. Untextured P3HT crystallites form later in the drying process than expected which may explain previous studies speculating that untextured crystallization depends on concentration. Textured crystallites, however, begin forming much earlier and steadily increases as the film dries, showing a development similar to other in situ studies of these materials. [ABSTRACT FROM AUTHOR]

Silicon nano-particles grafted with two different organic oligomers were prepared; the oligomers used were a phenylene-vinylene (PV) oligomer and a 3,3'''-didodecylquaterthiophene. The graftings were performed by the use of two different functional groups, the PV oligomer was grafted by a hydroxyl-group in the form of a phenol and a lithium derivative was used to graft the 3,3'''-didodecylquaterthiophene. The morphology and size of the grafted particles were analyzed by atomic force microscopy (AFM) and the extent of the grafting was analyzed by NMR. Organic photovoltaics with normal geometry (ITO/PEDOT:PSS/active layer/Al) were prepared using these materials as a donor and phenyl-C61-butyric acid methyl ester ([60]PCBM) as the acceptor and yielded a power conversion efficiency (PCE) of 0.27%, an open circuit voltage (VOC) of 0.93 V, a short circuit current density (JSC) of 0.89 mA/cm², and a fill factor (FF) of 32.5% for a lead device with an active area of 0.25 cm&#178. [ABSTRACT FROM AUTHOR]

As the performance in terms of power conversion efficiency and operational stability for polymer and organic solar cells is rapidly approaching the key 10–10 targets (10 % efficiency and 10 years of stability) the quest for efficient, scalable, and rational processing methods has begun. The 10–10 targets are being approached through consistent laboratory research efforts, which coupled with early commercial efforts have resulted in a fast moving research field and the dawning of a new industry. We review the roll-to-roll processing techniques required to bring the magnificent 10–10 targets into reality, using quick methods with low environmental impact and low cost. We also highlight some new targets related to processing speed, materials, and environmental impact. [Copyright &y& Elsevier]

The use of hydrated vanadium(V)oxide as a replacement of the commonly employed hole transporting material PEDOT:PSS was explored in this work. Polymer solar cells were prepared by spin coating on glass. Polymer solar cells and modules comprising 16 serially connected cells were prepared using full roll-to-roll (R2R) processing of all layers. The devices were prepared on flexible polyethyleneterphthalate (PET) and had the structure PET/ITO/ZnO/P3HT:PCBM/V2O5∙(H2O)n/Ag. The ITO and silver electrodes were processed and patterned by use of screen printing. The zinc oxide, P3HT:PCBM and vanadium(V)oxide layers were processed by slot-die coating. The hydrated vanadium(V)oxide layer was slot-die coated using an isopropanol solution of vanadyl-triisopropoxide (VTIP). Coating experiments were carried out to establish the critical thickness of the hydrated vanadium(V)oxide layer by varying the concentration of the VTIP precursor over two orders of magnitude. Hydrated vanadium(V)oxide layers were characterized by profilometry, scanning electron microscopy, energy dispersive X-ray spectroscopy, and grazing incidence wide angle X-ray scattering. The power conversion efficiency (PCE) for completed modules was up to 0.18%, in contrast to single cells where efficiencies of 0.4% were achieved. Stability tests under indoor and outdoor conditions were accomplished over three weeks on a solar tracker. [ABSTRACT FROM AUTHOR]

• Potential of organic PV (OPV) in residential electricity self-consumption is studied. • We perform a combined assessment of profitability and environmental impacts of OPV. • We assess cost-effectiveness of OPV systems in/excl. batteries for Greece and Denmark. • Environmental gains are strongly dependent on battery storage and grid mix composition. • We provide recommendations for future development of OPV technology and energy policy. Recent economic developments have signalled that self-consumption of photovoltaics (PV)-generated electricity could be financially more attractive than exporting it to the grid in many countries. As an emerging PV technology, organic photovoltaics (OPV) have been recognized as potential bearer of economic and environmental gains. Yet, could OPV deliver a profitable investment and environmental impact reductions in the context of residential electricity self-consumption? Here, we conduct a study of unprecedented scoping that combines both economic analysis and life cycle assessment to gauge OPV self-consumption with or without battery storage for household settings. The upscaling of OPV technologies from pilot- to industrial scale was modelled, and we used the two contrasting cases of Denmark and Greece to identify potential patterns. Our economic results indicate that the addition of battery storage is not financially viable unless battery costs are reduced by more than 10% for Greece and 30% for Denmark. Furthermore, we identify OPV cost thresholds of 0.9 €/Wp for Denmark and 1.6 €/Wp for Greece, below which OPV-battery systems are more cost-effective than OPV systems without battery. Building on the economic analysis, we find that battery storage can improve the environmental performances of OPV systems under certain conditions on the battery costs, the capacity of the cost-optimal OPV-battery system, and the environmental impacts of the battery. Furthermore, the composition of the electricity grid mix in the country studied was found to be an important factor to determine where OPV self-consumption was environmentally beneficial. These findings can support energy policy-makers in their development of energy strategies as well as OPV technology developers, who should adopt a systemic approach and integrate battery storage and the balance of system within their development phases. [ABSTRACT FROM AUTHOR]