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Aims Limited data exist on the efficacy of catheter ablation (CA) for sport-related atrial fibrillation (AF). Impact of sports practice resumption post-CA remains unknown. We aimed to determine AF CA efficacy in athletes vs. non-athletes, and to assess the impact of sport practice resumption. Methods and results From 1153 first-time AF CA performed between 2009 and 2017, 73 athletes were matched with 73 sedentary patients based on age, sex, and closest CA procedure date. Athletes were defined as performing ≥6 h/week of vigorous sports to achieve ≥2000 h accumulated lifetime sports activity. They were mostly males (93.2%) with a mean age of 55 ± 9.8 years. Before CA, athletes practiced 10.2 ± 3.9 h/week of vigorous exercise vs. 4.6 ± 3.4 after CA. Within first year after CA, physical activity was stopped in 12 (16.4%) athletes, lowered in 45 (61.9%), and resumed at same intensity in 16 (21.9%). Athletes and non-athletes suffered from same AF recurrence rates during 5-year follow-up after CA: 38 (52.0%) vs. 35 (47.9%), respectively [adjusted hazard ratio (HR) on age, body mass index (BMI), obstructive sleep apnoea (OSA), and reduced left ventricular ejection fraction (LVEF), 1.17 (0.70–1.97, P = 0.54)]. No significant impact of physical activity resumption status was found regarding AF recurrence rates at 1-year and beyond (P = 0.60). Procedure effectiveness was significantly lower in athletes with non-paroxysmal AF [adjusted on age, BMI, reduced LVEF, and OSA HR 2.36 (confidence interval 1.19–4.70), P = 0.01]. Conclusion Sports practice before and after CA has no significant impact on AF recurrence rates in athletes within 5-year after AF CA.

The field of cardiac electrophysiology has greatly developed during the past decades. Consequently, the use of electrophysiological studies (EPSs) in clinical practice has also significantly augmented, with a progressively increasing number of certified electrophysiology centers and specialists. Since Zipes et al published the Guidelines for Clinical Intracardiac Electrophysiology and Catheter Ablation Procedures in 1995, no official document summarizing current EPS indications has been published.The current paper focuses on summarizing all relevant data of the role of EPS in patients with different types of cardiac pathologies and provides up-to-date recommendations on this topic.For this purpose, the PubMed database was screened for relevant articles in English up to December 2018 and ESC and ACC/AHA Clinical Practice Guidelines, and EHRA/HRS/APHRS position statements related to the current topic were analyzed.Current recommendations for the use of EPS in clinical practice are discussed and presented in 17 distinct cardiac pathologies. A short rationale, evidence, and indications are provided for each cardiac disease/group of diseases.In conclusion, because of its capability to establish a diagnosis in patients with a variety of cardiac pathologies, the EPS remains a useful tool in the evaluation of patients with cardiac arrhythmias and conduction disorders and is capable of establishing indications for cardiac device implantation and guide catheter ablation procedures. Keywords: Electrophysiological study, Indications, Arrhythmias

International audience; ObjectiveWe evaluated whether a combination of intraoperative contrast-enhanced cone beam computed tomography (ceCBCT) and postoperative contrast-enhanced ultrasound (CEUS) after infrarenal endovascular abdominal aortic aneurysm repair (EVAR) could reduce late stent graft–related complications and, consequently, reintervention.MethodsAll consecutive patients who had received infrarenal bifurcated stent grafts in our hybrid room (IGS 730; GE Healthcare, Île-de-France, France) during two discrete periods were included in the present study. From November 2012 to September 2013, two-dimensional completion angiography was performed after each EVAR, followed by computed tomography angiography (CTA) before discharge (group 1). From October 2013 to January 2015, intraoperative ceCBCT was performed, followed by CEUS within the first postoperative days (group 2). Comparative analyses of the outcomes were performed. The primary endpoint was late stent graft–related complications, a composite factor incorporating aneurysm-related death, type I or III endoleaks, kink or occlusion of the iliac limb, and aortic sac enlargement after the first 30 postoperative days. The secondary endpoint was all stent graft–related reinterventions. All-cause and aneurysm-related deaths were also recorded.ResultsOverall, 100 consecutive patients (50 each in groups 1 and 2) were enrolled, with a median follow-up of 60 months (interquartile range, 41-69 months). At 60 months after the index procedure, the freedom from late stent graft–related complications in each group was 61.6% (95% confidence interval [CI], 47.0%-80.6%) for group 1 and 81.7% (95% CI, 70.1%-95.2%) for group 2 (P = .033). The use of intraoperative ceCBCT was independently associated with a reduced rate of late stent graft–related complications on multivariate analysis (hazard ratio, 0.39; 95% CI, 0.16-0.95; P = .038) but did not appear to significantly protect against stent graft–related reinterventions (hazard ratio, 0.53; 95% CI, 0.20-1.39; P = .198) or all-cause death (P = .47).ConclusionsTo the best of our knowledge, the present study is the first to report the influence of routine ceCBCT on late outcomes after EVAR. The use of ceCBCT shows the potential for reducing late stent graft–related complications associated.

Summary Background Reversion of an implantable cardioverter defibrillator (ICD) to back-up mode degrades the operating capabilities of the device, puts patients at risk and requires rapid intervention by a manufacturer's technician. Aim To illustrate the usefulness of remote monitoring of ICDs for the early detection of reversion to back-up mode. Methods In our centre, all patients implanted with an ICD, with or without resynchronisation, were offered remote monitoring as soon as the technology became available. Alerts triggered by the remote monitoring system were included prospectively in a register. During a mean follow-up of 5.7 ± 1.3 years, a total of 1594 patients with an ICD (441 with resynchronisation function) followed with remote monitoring were included in the register. Results Among 15,874 alerts, only 10 were related to a reversion to back-up mode. Among those, seven reversions were caused by radiotherapy, two were fake events and one was caused by magnetic resonance imaging. Except for the two fake events, the eight other patients had an emergency admission for the resetting and reprogramming of their ICD. None of the reversion to back-up mode alerts was followed by a clinical alert (i.e. a shock alert) before the ICD problem was resolved. Conclusions Reversion to back-up mode is a very rare event, accounting for 0.06% of total alerts; remote monitoring facilitates the early detection of this critical event to resolve the problem faster than the next scheduled follow-up. Remote monitoring can prevent serious damage to the patient and avoids systematic ambulatory control of the ICD after each radiotherapy session.

To evaluate whether the epicardial adipose tissue (EAT) phenotype is associated with the electrophysiological properties of adjacent atrial myocardium in patients with atrial fibrillation (AF). Between January and May 2017, 30 consecutive patients referred for a first AF catheter ablation were prospectively included. For each patient, a pre-procedural computed tomography scan was performed to assess total and left atrial (LA) EAT amount and radiodensity. A detailed point-by-point voltage mapping using an electroanatomic mapping system was realized to assess the presence of LA low-voltage zone (LVZ). Ten patients (33.3%) presented at least one LVZ. Older age (65 ± 7 vs. 58 ± 10 years, p = 0.05) was the only clinical parameter associated with LVZ. Despite no greater LA-EAT thickness by CT scan (3.0 [2.6–3.5] mm vs. 2.8 [2.2–3.1] mm, p = 0.354), patients with LA-LVZ presented significantly lower LA-EAT radiodensity than patients with no LA-LVZ (− 101.8 ± 12.5 HU vs. − 90.4 ± 6.3 HU, p = 0.004). No difference between total-EAT volume (131 ± 61 cm3 vs.107 ± 58 cm3, p = 0.361) and total-EAT radiodensity (− 106.8 ± 4.3 HU vs. − 102.4 ± 6.9 HU, p = 0.119) was found. Low LA-EAT radiodensity is associated with the presence of LVZ in patients with medical history of AF. • Cardiovascular risk factors are associated with low adipose tissue computed tomography attenuation. • Epicardial adipose tissue (EAT) has emerged as an important factor in the pathogenesis of metabolic-related cardiac diseases such as atrial fibrillation. • We showed that low left atrial EAT attenuation is associated with the presence of low-voltage zone, a surrogate for atrial fibrosis, within the adjacent myocardium.

Both genetic and environmental factors interact to control left ventricular (LV) remodeling in the context of aortic stenosis (AS). Epicardial adipose tissue (EAT) is a specific visceral adipose tissue with paracrine properties in close contact with the myocardium. We sought to assess determinants of EAT amount and its association with the magnitude and pattern of LV remodeling in patients suffering from severe AS. Between January 2014 and September 2017, we prospectively explored consecutive patients referred to our Heart Valve Center for SAVR presenting with severe AS and normal left ventricular ejection fraction (> 50%). Comprehensive transthoracic echocardiography (TTE) including assessment of LV remodeling and EAT amount were performed. 202 patients were included. EAT was significantly larger in elderly, diabetic and obese patients. EAT thickness was correlated positively with indexed LV mass in AS (r2 = 0.21; p

Summary Background On-pump cardiac surgery provokes a predictable perioperative myocardial ischaemia–reperfusion injury which is associated with poor clinical outcomes. We determined the occurrence of time-of-the-day variation in perioperative myocardial injury in patients undergoing aortic valve replacement and its molecular mechanisms. Methods We studied the incidence of major adverse cardiac events in a prospective observational single-centre cohort study of patients with severe aortic stenosis and preserved left ventricular ejection fraction (>50%) who were referred to our cardiovascular surgery department at Lille University Hospital (Lille, France) for aortic valve replacement and underwent surgery in the morning or afternoon. Patients were matched into pairs by propensity score. We also did a randomised study, in which we evaluated perioperative myocardial injury and myocardial samples of patients randomly assigned (1:1) via permuted block randomisation (block size of eight) to undergo isolated aortic valve replacement surgery either in the morning or afternoon. We also evaluated human and rodent myocardium in ex-vivo hypoxia–reoxygenation models and did a transcriptomic analysis in myocardial samples from the randomised patients to identify the signalling pathway(s) involved. The primary objective of the study was to assess whether myocardial tolerance of ischaemia–reperfusion differed depending on the timing of aortic valve replacement surgery (morning vs afternoon), as measured by the occurrence of major adverse cardiovascular events (cardiovascular death, myocardial infarction, and admission to hospital for acute heart failure). The randomised study is registered with ClinicalTrials.gov, number NCT02812901. Findings In the cohort study (n=596 patients in matched pairs who underwent either morning surgery [n=298] or afternoon surgery [n=298]), during the 500 days following aortic valve replacement, the incidence of major adverse cardiac events was lower in the afternoon surgery group than in the morning group: hazard ratio 0·50 (95% CI 0·32–0·77; p=0·0021). In the randomised study, 88 patients were randomly assigned to undergo surgery in the morning (n=44) or afternoon (n=44); perioperative myocardial injury assessed with the geometric mean of perioperative cardiac troponin T release was significantly lower in the afternoon group than in the morning group (estimated ratio of geometric means for afternoon to morning of 0·79 [95% CI 0·68–0·93; p=0·0045]). Ex-vivo analysis of human myocardium revealed an intrinsic morning–afternoon variation in hypoxia–reoxygenation tolerance, concomitant with transcriptional alterations in circadian gene expression with the nuclear receptor Rev-Erbα being highest in the morning. In a mouse Langendorff model of hypoxia–reoxygenation myocardial injury, Rev-Erb α gene deletion or antagonist treatment reduced injury at the time of sleep-to-wake transition, through an increase in the expression of the ischaemia–reperfusion injury modulator CDKN1a/p21. Interpretation Perioperative myocardial injury is transcriptionally orchestrated by the circadian clock in patients undergoing aortic valve replacement, and Rev-Erbα antagonism seems to be a pharmacological strategy for cardioprotection. Afternoon surgery might provide perioperative myocardial protection and lead to improved patient outcomes compared with morning surgery. Funding Fondation de France, Federation Francaise de Cardiologie, EU-FP7-Eurhythdia, Agence Nationale pour la Recherche ANR-10-LABX-46, and CPER-Centre Transdisciplinaire de Recherche sur la Longevite.

Introduction Several clinical studies have demonstrated that remote monitoring (RM) offers potential benefits in transvenous implantable cardioverter defibrillator (ICD). The potential interest of RM in subcutaneous-ICD (S-ICD) recipients has never been evaluated. The aim of this study was to evaluate the alert burden and its clinical relevance in a prospective cohort of S-ICD recipients. Methods We prospectively and consecutively enrolled all patients undergoing S-ICD implantation at Lille University Hospital from September 2015 to January 2017 and gave them a LATITUDE™ NXT RM system. The relevance of transmissions was assessed by the following ratio: number of transmissions leading to reaction or intervention per patient/number of transmissions per patient. Results From September 2015 to January 2017, 69 patients were enrolled with a mean follow-up of 415 ± 96.3 days. The mean age was 44.6 ± 15.6 years old, and 25% (n = 17) had ischemic cardiomyopathy. At the end of follow-up, 12% of the patients had events recorded by RM. These events were related to nine ICD shocks and eight untreated events. A total of 1,423 transmissions were collected. Most of these transmissions were patient-initiated without any event (77%, n = 1,096) or scheduled without any event (19%, n = 272). Only 3.2% ± 1.1 of the transmissions per patient led to reactions or interventions. Conclusion On the basis of the current method of transmitting, S-ICD RM allowed detection of relevant events in 12% of patients but generated a high unactionable transmission burden. As a result of these findings, efforts should be made to optimize transmissions considering automatic transmissions and to focus on patient education.

The definition of prosthesis–patient mismatch (PPM) remains to be refined to enhance its prognosis insight after surgical aortic valve replacement (SAVR) for severe aortic stenosis, especially in obese patients [(1)][1]. We aimed at investigating the respective prevalence and prognostic value of

Little is known about atrial arrhythmias in arrhythmogenic right ventricular cardiomyopathy (ARVC). A 46-year-old man with definite ARVC presented with palpitations and exertional dyspnoea. Electrocardiogram showed a supraventricular tachycardia. Despite no prior cardiac surgery or atrial fibrillation ablation, electrophysiological study revealed a left atrial (LA) re-entrant circuit characterized by a slow fractionated potential bounded by two areas of double potentials giving a figure-of-eight pattern on activation map. Located on the LA roof within a zone of low bipolar voltages, this unusual substrate can be associated with a primitive atrial myopathy in ARVC.

Changes in parameters of longitudinal systolic function after cardiac surgery (i.e., tricuspid annular plane systolic excursion [TAPSE] and peak systolic velocity [PSV] of tricuspid annulus obtained by M-mode or Doppler tissue imaging) have been described for many years, with almost no data on their

Citrazinic acid is used as a convenient starting material for both tridentate 2,6-di(pyrazol-1-yl)-pyridine and tetradentate 6,6'-di(pyrazol-1-yl)-2,2'-bipyridine ligands containing carboxylic groups useful for further anchoring of sensitizer on TiO2 for dye-sensitized solar cells (DSCs). Using 2,6-dichloro-4-carboxypyridine, the synthesis of the terdentate ligands was improved compared to previously used 2,6-dibromo-4-carboxypyridine or 2,6-dichloro-4-ethylcarboxylate pyridine. Controlling the reaction conditions, it is possible to efficiently obtain the monosubstituted 2-chloro-6-pyrazol-1-yl-4-carboxypyridine, a key intermediate for the preparation of tetradentate 6,6'-di(pyrazol-1-yl)-4,4'-dicarboxy-2,2'-bipyridine ligand. (C) 2010 Elsevier Ltd. All rights reserved.

Background The definition of prosthesis-patient mismatch (PPM) remains to be refined to enhance its prognosis insight after SAVR, especially in obese patients. Purpose To test the prognostic impact of effective and predicted prosthetic orifice area (OA) according to body weight status after surgical aortic valve replacement (SAVR) for severe aortic stenosis (AS). Methods Between 2009 and 2016, we prospectively explored all consecutive patients referred to our Heart Valve Clinic for a first SAVR for severe AS. Indexed OA predicted from reference normal value (iPOA) and calculated by transthoracic echocardiography (iEOA) were assessed at discharge. Patients were followed for major events (ME), i.e. cardiovascular death, cardiac hospitalization for acute heart failure and stroke. Results 762 patients were included with a mean follow-up of 4 ± 2.5 years. Severe PPM was more frequently observed with iEOA than iPOA (20.5% vs. 7%, P Conclusion iEOA with the unique cut-off of 0.85 cm2/m2 showed the best accuracy to predict ME after SAVR in lean and overweight but not in obese patients. Further studies are needed to explore the lack of prognostic insight of PPM in obese patients.

Exploration of new ruthenium-based sensitizers for dye-sensitized solar cell (DSC) applications requires an easy access to multifunctionalized ligands for efficient screening of sensitizers' properties. Based on the Horner-Emmons-Wadsworth reaction, a convenient synthetic route for the extension of the it-system on 4,4'-disubstituted-2,2'-bipyridines was used to develop a novel series of functionalized 2,2'-bipyridine ligands with either electron-withdrawing or donating end-capping group. H-1 NMR spectroscopy revealed that all the new bipyridyl ligands were obtained exclusively in their fully E isomers. (C) 2010 Elsevier Ltd. All rights reserved.

An orange-red-emitting iridium complex (N958) was prepared, and its photophysical and device-based characteristics were investigated. Despite N958 displaying quite poor photophysical properties in solution (acetonitrile), organic light-emitting diode (OLED) devices based on the complex exhibit an efficiency close to 10%.

Reference LPI-ARTICLE-2007-033doi:10.1002/adma.200602172View record in Web of Science Record created on 2007-11-08, modified on 2017-05-12

Ru(4,4-dicarboxylic acid-2,2'-bipyridine) (4,4'-bis(2-(4-(1,4,7,10-tetraoxyundecyl)phenyl)ethenyl)-2,2'-bipyridine) (NCS)(2), a new high molar extinction coefficient ion-coordinating ruthenium sensitizer was synthesized and characterized using H-1 NMR, Fourier transform IR (FTIR), and UV/vis spectroscopies and cyclic voltammetry. Using this sensitizer in combination with a nonvolatile organic-solvent-based electrolyte, we obtain a photovoltaic efficiency of 8.4% under standard global AM 1.5 sunlight. These devices exhibit excellent stability when subjected to continuous thermal stress at 80 degrees C or light soaking at 60 degrees C for 1000 h. An electrochemical impedance spectroscopy study revealed that device stability is maintained by stabilizing the TiO2/dye/electrolyte and Pt/electrolyte interface during the aging process. The influence of Li+ present in the electrolyte on the device photovoltaic parameters was studied, and the FTIR spectral and photovoltage transient study showed that Li+ coordinates to the triethyleneoxide methylether side chains on the K60 sensitizer molecules.

Two novel heteroleptic sensitizers, Ru((4,4-dicarboxylic acid-2,2'-bipyridine)(4,4'-bis(p-hexyloxystyryl)-2,2-bipyridine)(NCS)2 and Ru((4,4-dicarboxylic acid-2,2'-bipyridine)(4,4'-bis(p-methoxystyryl)-2,2'-bipyridine) (NCS)2, coded as K-19 and K-73, respectively, have been synthesized and characterized by 1H NMR, FTIR, UV-vis absorption, and emission spectroscopy and excited-state lifetime and spectroelectrochemical measurements. The introduction of the alkoxystyryl group extends the conjugation of the bipyridine donor ligand increasing markedly their molar extinction coefficient and solar light harvesting capacity. The dynamics of photoinduced charge separation following electronic excitation of the K-19 dye was scrutinized by time-resolved laser spectroscopy. The electron transfer from K-19 to the conduction band of TiO2 is completed within 20 fs while charge recombination has a half-life time of 800 s. The high extinction coefficients of these sensitizers enable realization of a new generation of a thin film dye sensitized solar cell (DSC) yielding high conversion efficiency at full sunlight even with viscous electrolytes based on ionic liquids or nonvolatile solvents. An unprecedented yield of over 9% was obtained under standard reporting conditions (simulated global air mass 1.5 sunlight at 1000 W/m2 intensity) when the K-73 sensitizer was combined with a nonvolatile "robust" electrolyte. The K-19 dye gave a conversion yield of 7.1% when used in conjunction with the binary ionic liquid electrolyte. These devices exhibit excellent stability under light soaking at 60 degrees C. The effect of the mesoscopic TiO2 film thickness on photovoltaic performance has been analyzed by electrochemical impedance spectroscopy (EIS).

A new ruthenium(II) complex, tetrabutylammonium [ruthenium (4-carboxylic acid-4'-carboxylate-2,2'-bipyridine)(4,4'-di(2-(3,6-dimethoxyphenyl)ethenyl)-2,2'-bipyridine)(NCS)(2)] (N945H), was synthesized and characterized by analytical, spectroscopic, and electrochemical techniques. The absorption spectrum of the N945H sensitizer is dominated by metal-to-ligand charge-transfer (MLCT) transitions in the visible region, with the lowest allowed MLCT bands appearing at 25 380 and 18 180 cm(-1). The molar extinction coefficients of these bands are 34 500 and 18 900 M(-1) cm(-1), respectively, and are significantly higher when compared to than those of the standard sensitizer cis-dithiocyanatobis(4,4'-dicarboxylic acid-2,2'-bipyridine)ruthenium(II). An INDO/S and density functional theory study of the electronic and optical properties of N945H and of N945 adsorbed on TiO(2) was performed. The calculations point out that the top three frontier-filled orbitals have essentially ruthenium 4d (t(2g) in the octahedral group) character with sizable contribution coming from the NCS ligand orbitals. Most critically the calculations reveal that, in the TiO(2)-bound N945 sensitizer, excitation directs charge into the carboxylbipyridine ligand bound to the TiO(2) surface. The photovoltaic data of the N945 sensitizer using an electrolyte containing 0.60 M butylmethylimidazolium iodide, 0.03 M I(2), 0.10 M guanidinium thiocyanate, and 0.50 M tert-butylpyridine in a mixture of acetonitrile and valeronitrile (volume ratio = 85:15) exhibited a short-circuit photocurrent density of 16.50 +/- 0.2 mA cm(-2), an open-circuit voltage of 790 +/- 30 mV, and a fill factor of 0.72 +/- 0.03, corresponding to an overall conversion efficiency of 9.6% under standard AM (air mass) 1.5 sunlight, and demonstrated a stable performance under light and heat soaking at 80 degrees C.

Sun sensitivity: A charge-transfer sensitizer with an ion-complexing moiety formed by oxyethylene side groups (see picture) is used in a solid-state dye-sensitized solar cell. Lithium coordination to the dye backbone produces under realistic conditions photovoltages of nearly 900 mV and efficiencies of 3.8%. (Chemical Equation Presented) © 2005 Wiley-VCH Verlag GmbH and Co. KGaA.

Readily prepared N-functionalized benzotriazole-1-carboximidoyl chlorides are proposed as stable and novel isocyanide dichloride synthetic equivalents. Subsequent condensations of these new intermediates afford polysubstituted guanidines, S-aryl isothioureas, and 2-aminoquinazolin-4-thiones.

Readily prepared N-functionalized benzotriazole-1-carboximidoyl chlorides are proposed as stable and novel isocyanide dichloride synthetic equivalents. Subsequent condensations of these new intermediates afford polysubstituted guanidines, S-aryl isothioureas, and 2-aminoquinazolin-4-thiones.

A new ion-coordinating ruthenium polypyridyl sensitizer, NaRu(4-carboxylic acid-4′-carboxylate)(4,4′-bis[(triethyleneglycolmethylether) heptylether]-2,2′-bipyridine)(NCS)2 (coded as K68), has been synthesized and characterized by 1H NMR, FTIR, UV-Vis absorption and emission spectroscopy. A power conversion efficiency of 6.6% was obtained for dye-sensitized solar cells (DSCs) based on the K68 dye and a newly developed binary ionic liquid electrolyte containing 1-propyl-3-methyl-imidazolium iodide (PMII) and 1-ethyl-3-methyl-imidazolium tetracyanoborate (EMIB(CN)4). For a non-volatile organic solvent based electrolyte, a photovoltaic power conversion efficiency of 7.7% was obtained under simulated full sun light and exhibited a good thermal stability during the accelerated test under 80 °C in the dark. Solid-state DSCs incorporating K68 also perform remarkably well, out-performing our previously best ruthenium complexes employed in this type of DSC. © 2007 Elsevier B.V. All rights reserved.

Efficient and stable mesoscopic dye-sensitized solar cells (DSCs) introducing a low-viscosity binary ionic liquid (1-propyl-3-methyl-imidazolium iodide (PMII) and 1-ethyl-3-methyl-imidazolium tetracyanoborate (EMIB(CN)(4))) electrolyte in combination with a new high-molar-extinction-coefficient ruthenium complex, Ru(2,2'-bipyridine-4,4'-dicarboxylic acid)(4,4'-bis(2-(4-tert-butyloxy -phenyl)ethenyl) -2,2'-bipyridine) (NCS)(2), are demonstrated. The dependence of photovoltaic performance, charge transport and electron lifetime on the composition of the binary ionic-liquid electrolyte with different ratios of PMII/EMIB(CN)(4) were investigated by electrochemical impedance and photovoltage transient techniques. A photovoltaic conversion efficiency of 7.6 % was obtained under simulated full sunlight illumination, which is a record for solvent-free DSCs. These devices exhibit excellent stability at 80 degrees C in the dark or under visible-light soaking at 60 degrees C during 1000 h of accelerated tests.

We compare a series of molecular sensitizers in dye-sensitized solar cells containing the organic hole transporter 2,2',7,7'-tetrakis(N,N-di-p-methoxypheny-amine)-9,9'-spirobifluorene (spiro-MeOTAD). Charge recombination is reduced by the presence of "ion-coordinating" moieties on the dye, with the longest electron lifetime and highest solar cell efficiency achieved using a novel sensitizer with diblock alkoxy-alkane pendent groups. By further increasing the optical path length in the active layer, we achieve a power conversion efficiency of over 5% under simulated sun light.

A novel iridium complex, [bis-(2-phenylpyridine)(2-carboxy-4-dimethylaminopyridine)iridium(III)] (N984), was synthesized and characterized using spectroscopic and electrochemical methods; a solution processable OLED device incorporating the N984 complex displays electroluminescence spectra with a narrow bandwidth of 70 nm at half of its intensity, with colour coordinates of x = 0.322; y = 0.529 that are very close to those suggested by the PAL standard for a green emitter. Bolink, Henk, Henk.Bolink@uv.es ; Coronado Miralles, Eugenio, Eugenio.Coronado@uv.es ; Garcia Santamaria, Sonsoles Amor, Sonsoles.Garcia@uv.es

We report a combined experimental and theoretical study on cationic Ir(III) complexes for OLED applications and describe a strategy to tune the phosphorescence wavelength and to enhance the emission quantum yields for this class of compounds. This is achieved by modulating the electronic structure and the excited states of the complexes by selective ligand functionalization. In particular, we report the synthesis, electrochemical characterization, and photophysical properties of a new cationic Ir(III) complex, [Ir(2,4-difluorophenylpyridine)2(4,4'-dimethylamino-2,2'-bipyridine)](PF(6)) (N969), and compare the results with those reported for the analogous [Ir(2-phenylpyridine)2(4,4'-dimethylamino-2,2'-bipyridine)](PF(6)) (N926) and for the prototype [Ir(2-phenylpyridine)2(4,4'-tert-butyl-2,2'-bipyridine)](PF(6)) complex, hereafter labeled N925. The three complexes allow us to explore the (C/\N) and (N/\N) ligand functionalization: considering N925 as a reference, we investigate in N926 the effect of electron-releasing substituents on the bipyridine ligand, while in N969, we investigate the combined effect of electron-releasing substituents on the bipyridine ligand and the effect of electron-withdrawing substituents on the phenylpyridine ligands. For N969 we obtain blue-green emission at 463 nm with unprecedented high quantum yield of 85% in acetonitrile solution at room temperature. To gain insight into the factors responsible for the emission color change and the different quantum yields, we perform DFT and TDDFT calculations on the ground and excited states of the three complexes, characterizing the excited-state geometries and including solvation effects on the calculation of the excited states. This computational procedure allows us to provide a detailed assignment of the excited states involved in the absorption and emission processes and to rationalize the factors determining the efficiency of radiative and nonradiative deactivation pathways in the investigated complexes. This work represents an example of electronic structure-driven tuning of the excited-state properties, thus opening the way to a combined theoretical and experimental strategy for the design of new iridium(III) phosphors with specific target characteristics.

A series of allyl-functionalized imidazolium salts are reported, including 1-allyl-3-ethylimidazolium iodide and 1-allyl-3-propylimidazolium iodide, which have melting points close to room temperature and show typical properties of supercooled fluids if heated above their melting points. Their viscosities in the liquid state are considerably lower than the benchmark ionic liquid used in solar cells, viz., 1-propyl-3-methylimidazolium iodide. Electrolytes containing these new liquids provide excellent efficiencies and good stability in dye-sensitized solar cells when subjected to an accelerated-light soaking test at 60 degrees C. The structures of three of the new salts have been established in the solid state by single-crystal X-ray analysis.

A Li+ coordinating sensitizer, NaRu(4-carboxylic acid-4'-carboxylate)(4,4'-bis[(triethylene glycol methyl ether) methyl ether]-2,2'-bipyridine)(NCS)2 (coded as K51), has been synthesized, and the effect of Li+ coordination on its performance in mesoscopic titanium dioxide dye-sensitized solar cells has been investigated. Fourier transform infrared spectra suggest that Li+ coordinates to the triethylene oxide methyl ether side chains on the dye molecules. With the addition of Li+ to a nonvolatile liquid electrolyte, we observe a significant increase in the photocurrent density, with only a small decrease in the open-circuit voltage, contrary to a non ion coordinating dye which displays a large drop in potential with the addition of Li+. For a solar cell incorporating an organic hole-transporter, we find the potential rises with increasing the Li+ concentration in the hole-transporter matrix. For the liquid electrolyte and solid-state cells, we obtain power conversion efficiencies of 7.8% and 3.8%, respectively, under simulated sunlight.

A highly luminescent novel cationic iridium complex [iridium bis(2-phenylpyridine)(4,4'-(dimethylamino)-2,2'-bipyridine)]PF6 was synthesized and characterized using NMR, UV-visible absorption, and emission spectroscopy and electrochemical methods. This complex displays intense photoluminescence maxima in the green-blue region of the visible spectrum and exhibits unprecedented phosphorescence quantum yields, 80 +/- 10% with an excited-state lifetime of 2.2 mus in a dichloromethane solution at 298 K. Single-layer light-emitting electrochemical cells with the charged complex as conducting and electroluminescent material sandwiched between indium-tin oxide and Ag electrodes were fabricated, which emit green-blue light with an onset voltage as low as 2.5 V. Density functional theory calculations were performed to provide insight into the electronic structure of the [iridium bis(2-phenylpyridine)(4,4'-(dimethylamino)-2,2'-bipyridine)]PF6 complex, comparing these results with those obtained for [iridium bis(2-phenylpyridine)(4,4'-tert-butyl-2,2'-bipyridine)]PF6.

An amphiphilic heteroleptic polypyridyl ruthenium complex with a high molar extinction coefficient was synthesized and demonstrated as an efficient, thermostable sensitizer in nanocrystalline dye-sensitized solar cells.

In this study, a novel phosphorescent Ir(III) complex [Ir(2-phenylpyridine)2(4,4'-bis(2-(4-N,N-methylhexylaminophenyl)ethyl)-2-2'-bipyridine)Cl] (for convenience, the complex was given the synonym N-948) has been designed and synthesized, to be used as an oxygen probe. It was characterized by spectroscopic and analytical methods when incorporated in a polystyrene and nanostructured metal oxide support. N-948 is the first Ir complex in the literature with a luminescence emission at a wavelength higher than 650 nm (665 nm), with a quantum yield higher than 0.50 (0.58 +/- 0.05) and an extremely long phosphorescence lifetime (102 micros) which has been used for developing oxygen-sensitive films. In addition, the new complex shows a Stern-Volmer constant which is 20 times higher than that of other Ir complexes known from the literature when they are immobilized in polystyrene. The sensing film shows long-term stability (up to 12 months), complete reversibility of the signal quenched by oxygen and a quick response time to various oxygen concentrations (2 s changing from 10 vol% pO2 to 90 vol% pO2). Thus, it is an interesting and promising complex for developing oxygen-selective sensors for gas analysis and the analysis of dissolved oxygen.

Ruthenium(II) complexes [Ru(L2)(NCS)2] (K8) and [Ru(L)(L9)(NCS)2] (K9) (where L = 4,4′-bis(carboxyvinyl)-2,2′-bipyridine and L9 = 4,4′-dinonyl-2,2′-bipyridine) were synthesized and characterized by spectroscopic and electrochemical techniques. The performance of K8 and K9 complexes as charge transfer photosensitizers in nanocrystalline TiO2-based solar cells was investigated. These complexes when anchored onto TiO2 films exhibit very efficient sensitization yielding 75 ± 5% incident photon-to-current efficiencies (IPCE) in the visible region using an electrolyte consisting of 0.6 M methyl-N-butyl imidazolium iodide, 0.05 M iodine, 0.1 M LiI and 0.5 M tert-butylpyridine in 50/50 (v/v) mixture of valeronitrile and acetonitrile. At one sun, the K8 complex gave a short circuit photocurrent density of 18 ± 0.5 mA/cm2, the open circuit voltage 640 ± 50 mV and fill factor of 0.75 ± 0.05, corresponding to an overall conversion efficiency of 8.64 ± 0.5%. Under similar conditions, the K9-sensitized solar cell gave a photocurrent density of 16.5 ± 0.5 mA/cm2, 666 ± 50 mV open circuit potential and 0.71 ± 0.05 fill factor yielding 7.81% ± 0.6% efficiency.

Reference LPI-ARTICLE-2007-002doi:10.1016/j.jphotochem.2006.06.028View record in Web of Science Record created on 2007-01-09, modified on 2016-08-08

A novel ligand 4,4'-bis(carboxyvinyl)-2,2'-bipyridine (L) and its ruthenium(II) complex [Ru(II)L(2)(NCS)(2)] (K8) were synthesized and characterized by analytical, spectroscopic, and electrochemical techniques. The performance of the K8 complex as a charge transfer photosensitizer in nanocrystalline TiO(2) based solar cells was studied. When the K8 complex anchored onto a nanocrystalline TiO(2) film, we achieved very efficient sensitization yielding 77 +/-5% incident photon-to-current efficiencies (IPCE) in the visible region using an electrolyte consisting of 0.6 M methyl-N-butyl imidiazolium iodide, 0.05 M iodine, 0.05 M LiI, and 0.5 M 4-tert-butylpyridine in a 50/50 (v/v) mixture of valeronitrile and acetonitrile. Under standard AM 1.5 sunlight, the complex K8 gave a short circuit photocurrent density of 18 +/- 0.5 mA/cm(2), and the open circuit voltage was 640 +/- 50 mV with fill factor of 0.75 +/- 0.05, corresponding to an overall conversion efficiency of 8.64 +/- 0.5%.

A new amphiphilic polypyridyl ruthenium complex, cis-Ru(dpbpy)(dnbpy)(NCS)2 (dpbpy = 4,4‘-diphosphonic acid-2,2‘-bipyridine; dnbpy = 4,4‘-dinonyl-2,2‘-bipyridine), was synthesized and demonstrated as an efficient sensitizer. The sensitizer was characterized by NMR, voltammetry, ATR-FTIR, resonance Raman, as well as electronic absorption and emission spectra. Nanocrystalline dye-sensitized solar cells (DSCs) with this new sensitizer generated ≥8.0% power conversion efficiencies under illumination with simulated air mass 1.5 sunlight. This is the first time such a high solar-to-electricity power conversion efficiency for DSCs has been reached by a sensitizer bearing non-carboxylic acid anchoring groups. Additionally, the devices exhibited excellent stability under light soaking at 55 to 60 °C. Time-resolved nanosecond laser experiments revealed that the dye regeneration rate of this new sensitizer seems to be quite similar but the charge recombination is significantly slower in comparison to the analogues c...

We demonstrate a ⩾8% efficient nanocrystalline dye-sensitized solar cell retaining over 98% of its initial performance after 1000 h of accelerated tests subjected to thermal stress at 80 °C in the dark. Device degradation was also negligible following 1000 h of visible light soaking at 60 °C. This high performance and stable device was realized by using a robust electrolyte of low volatility in conjunction with the amphiphilic ruthenium sensitizer [Ru(4,4′-dicarboxylic acid-2,2′-bipyridine)(4,4′-bis(p-hexyloxystyryl)-2,2′-bipyridine)(NCS)2], coded as K-19, which was grafted together with 1-decylphosphonic acid on the mesoporous titania film acting as photoanode.

We present two sensitizers, Ru(4,4'-dicarboxyvinyl)-2,2'-bipyridine)(4,4'-dinonyl-2,2'-bipyridine)(NCS)(2) (K9) and Ru(4,4'-dicarboxy(phenylethenyl)-2,2'-bipyridine)(4,4'-dinonyl-2,2'-bipyridine)(NCS)(2) (K23), which were synthesized and characterized by analytical, spectroscopic, and electrochemical impedance measurements. The two sensitizers that contain hydrophobic alkyl chains and an extended pi-conjugation bridge between carboxylic acid groups and the ruthenium chromophore center exhibit enhanced red response and higher molar extinction coefficients when compared to the Ru(4,4'-dicarboxy-2,2'-bipyridine)(4,4'-dinonyl-2,2'-bipyridine)(NCS)(2) (Z907) sensitizer. The performances of the K9, K23, and Z907 sensitizers in nanocrystalline TiO2-based thin film solar cells were studied using transparent 2.6-mu m-thick mesoporous layers, which show short-circuit photocurrent densities (J(sc)) of 7.80, 8.31, and 7.16 mA/cm(2), corresponding to overall conversion efficiencies of 4.14, 4.41, and 4.06%, respectively. The increase in the J(sc) of the cells with K9 and K23 with respect to that with Z907 is due to the enhanced molar extinction coefficient of the new sensitizers. The incident monochromatic photon-to-current conversion efficiency for die K23 is plotted as a function of excitation wavelength show in the plateau region 79% and even at 700 nm 69%.

Highly phosphorescent blue-light-emitting anionic iridium complexes (C4H9)(4)N[lr(2-phenylpyridine)(2)(CN)(2) (1), (C4H9)(4)N[Ir(2-phenyl-4-dimethylaminopyridine)(2)(CN)(2)] (2), (C4H9)(4)N[Ir(2-(2,4-difluorophenyl)-pyridine)2(CN)(2)] (3), (C4H9)(4)N[Ir(2-(2,4-difluorophenyl)-4-dimethylaminopyddine)2(CN)(2)] (4), and (C4H9)4N[lr(2-(3,5-difluorophenyl)-4-dimethylaminopyddine)2(CN)21 (5) were synthesized and characterized using NMR, UV-vis absorption, and emission spectroscopy and electrochemical methods. In these complexes color and quantum yield tuning aspects are demonstrated by modulating the ligands with substituting donor and acceptor groups on both the pyridine and phenyl moieties of 2-phenylpyridine. Complexes 1-5 display intense photoluminescence maxima in the blue region of the visible spectrum and exhibit very high phosphorescence quantum yields, in the range of 50-80%, with excited-state lifetimes of 1-4 mu s in acetonitrile solution at 298 K. DFT and time dependent-DFT calculations were performed on the ground and excited states of the investigated complexes to provide insight into the structural, electronic, and optical properties of these systems.

Recombination between injected electrons and iodine limits the photovoltage in dye-sensitized solar cells (DSSCs). We have recently suggested that many new dye molecules, intended to improve DSSCs, can accelerate this reaction, negating the expected improvement (J. Am. Chem. Soc. 2008, 130, 2907). Here we study two dyes with only a two-atom change in the structure, yet which give different V(oc)s. Using a range of measurements we show conclusively that the change in V(oc) is due solely to the increase in the recombination rate. From the structure of the dyes, and literature values for iodine binding of similar compounds, we find that it is very likely that the change in V(oc) is due solely to the difference in iodine binding at the site of the two-atom change. Using the large amount of literature on iodine complexation, we suggest structures for dyes that might show improved V(oc).