Effect of Small-molecule Sensitizer on the Performance of Polymer Solar Cell

For improving optical absorption of organic solar cells, a small-molecule sensitizer, as a third material, is usually incorporated into binary solar cell system. In many cases, light harvesting can be improved but on the expense of charge carrier mobility of the solar cells. This obstacle can be addressed through the understanding solar cell physics. In the present work, we try to deeply understand the physics of the long-chain polymer solar cell composed of poly(3-hexylthiophene) (P3HT), as a donor polymer, and [6,6]-phenyl-C61 butyric acid methyl ester (PCBM), as an acceptor molecule. This understanding can be acquired through the effect of coumarin 6 dye (C6), as a small-molecule sensitizer, on optical absorption and photocurrent of the most common solar cell. From optical spectroscopy we found that, the C6 dye, as a small molecule, did not vary conjugation length of the long-chain polymer in the P3HT: PCBM: C6 solar cell. This was indicated from (1) unchanged vibronic structure of the P3HT after adding C6 dye and from (2) matching in the wavelength between absorption peaks of both pristine C6 and P3HT after adding C6 dye into blend. From photocurrent spectroscopy we found that, the incorporation of C6 dye, as a sensitizer, into P3HT: PCBM binary contributed to photocurrent and formed an additional charge carrier generation site through the C6: PCBM combination, which was individually found among with P3HT: PCBM combination in the same solar cell. In the same time, the C6 dye, as a shortchain molecule, restricted the transport of charge carriers generated by P3HT as a result of low hole mobility of the C6 short-chain molecules. Through the present study, the incorporation of a small-molecule sensitizer into polymer solar cell may acquire better understanding for the performance of the most common P3HT: PCBM solar cell.Keywords: Polymer Solar Cells; Device Physics; P3HT: PCBM Solar Cell

Effect of Small-molecule Sensitizer on the Performance of Polymer Solar Cell

For improving optical absorption of organic solar cells, a small-molecule sensitizer, as a third material, is usually incorporated into binary solar cell system. In many cases, light harvesting can be improved but on the expense of charge carrier mobility of the solar cells. This obstacle can be addressed through the understanding solar cell physics. In the present work, we try to deeply understand the physics of the long-chain polymer solar cell composed of poly(3-hexylthiophene) (P3HT), as a donor polymer, and [6,6]-phenyl-C61 butyric acid methyl ester (PCBM), as an acceptor molecule. This understanding can be acquired through the effect of coumarin 6 dye (C6), as a small-molecule sensitizer, on optical absorption and photocurrent of the most common solar cell. From optical spectroscopy we found that, the C6 dye, as a small molecule, did not vary conjugation length of the long-chain polymer in the P3HT: PCBM: C6 solar cell. This was indicated from (1) unchanged vibronic structure of the P3HT after adding C6 dye and from (2) matching in the wavelength between absorption peaks of both pristine C6 and P3HT after adding C6 dye into blend. From photocurrent spectroscopy we found that, the incorporation of C6 dye, as a sensitizer, into P3HT: PCBM binary contributed to photocurrent and formed an additional charge carrier generation site through the C6: PCBM combination, which was individually found among with P3HT: PCBM combination in the same solar cell. In the same time, the C6 dye, as a short chain molecule, restricted the transport of charge carriers generated by P3HT as a result of low hole mobility of the C6 short-chain molecules. Through the present study, the incorporation of a small-molecule sensitizer into polymer solar cell may acquire better understanding for the performance of the most common P3HT: PCBM solar cell

Recent activity on beam dynamics study during longitudinal bunch compression by using compact beam simulators for heavy ion inertial fusion

In heavy ion inertial fusion scenario, heavy ion beams with extreme high current are most important assignment [1]. Predictions of beam behavior are basic necessity to design the accelerator complex. Especially, a bunch compression manipulation in the final stage of accelerator complex is required to generate the beam with high current and suitable short pulse duration [2]..

Recent activity on beam dynamics study during longitudinal bunch compression by using compact beam simulators for heavy ion inertial fusion

In heavy ion inertial fusion scenario, heavy ion beams with extreme high current are most important assignment [1]. Predictions of beam behavior are basic necessity to design the accelerator complex. Especially, a bunch compression manipulation in the final stage of accelerator complex is required to generate the beam with high current and suitable short pulse duration [2]..

Development of NIR Bioimaging Systems

Abstract. Fluorescence bioimaging is one of the most important technologies in the biomedical field. The most serious issue concerning current fluorescence bioimaging systems is the use of short wavelength light, UV or VIS, for the excitation of phosphors such as fluorescent proteins or quantum dots. The authors propose a fluorescence bioimaging system excited by near infrared light using rare-earth doped ceramic nanophosphors. The requirements for the nanophosphors are a designed emission scheme under the near infrared excitation, a controlled size between 10 and 200 nm and surface modification of the particles with a biofunctional polymer, which prevents particle agglomeration and non-specific interaction to nontargeting substances and gives them a specific interaction for the targeted objects. The preparation of the bioimaging probe and demonstrative imaging work are reported

Demographics, practice patterns and long-term outcomes of patients with non–ST-segment elevation acute coronary syndrome in the past two decades: the CREDO-Kyoto Cohort-2 and Cohort-3

OBJECTIVES: To evaluate patient characteristics and long-term outcomes in patients with non-ST-segment elevation acute coronary syndrome (NSTEACS) in the past two decades. DESIGN: Multicenter retrospective study. SETTING: The Coronary REvascularization Demonstrating Outcome Study in Kyoto (CREDO-Kyoto) percutaneous coronary intervention (PCI)/coronary artery bypass grafting (CABG) Registry Cohort-2 (2005-2007) and Cohort-3 (2011-2013). PARTICIPANTS: 3254 patients with NSTEACS who underwent first coronary revascularisation. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome was all-cause death. The secondary outcomes were cardiovascular death, cardiac death, sudden cardiac death, non-cardiovascular death, non-cardiac death, myocardial infarction, definite stent thrombosis, stroke, hospitalisation for heart failure, major bleeding, any coronary revascularisation and target vessel revascularisation. RESULTS: Patients in Cohort-3 were older and more often had heart failure at admission than those in Cohort-2. The prevalence of PCI, emergency procedure and guideline-directed medical therapy was higher in Cohort-3 than in Cohort-2. In patients who received PCI, the prevalence of transradial approach, drug-eluting stent use and intravascular ultrasound use was higher in Cohort-3 than in Cohort-2. There was no change in 3-year adjusted mortality risk from Cohort-2 to Cohort-3 (HR 1.00, 95% CI 0.83 to 1.22, p=0.97). Patients in Cohort-3 compared with those in Cohort-2 were associated with lower adjusted risks for stroke (HR 0.65, 95% CI 0.46 to 0.92, p=0.02) and any coronary revascularisation (HR 0.76, 95%CI 0.66 to 0.87, p<0.001), but with higher risk for major bleeding (HR 1.25, 95% CI 1.06 to 1.47, p=0.008). The unadjusted risk for definite stent thrombosis was lower in Cohort-3 than in Cohort 2 (HR 0.29, 95% CI 0.11 to 0.67, p=0.003). CONCLUSIONS: In the past two decades, we did not find improvement for mortality in patients with NSTEACS. We observed a reduction in the risks for definite stent thrombosis, stroke and any coronary revascularisation, but an increase in the risk for major bleeding

Usefulness of central venous oxygen saturation monitoring during bidirectional Glenn shunt

A PediaSat(TM) oximetry catheter (PediaSat : Edwards Lifesciences Co., Ltd., Irvine, CA, U.S.A.), which facilitates continuous measurement of central venous oxygen saturation (ScvO2), may be useful for surgery for pediatric congenital heart disease. We used PediaSat during a bidirectional Glenn shunt. The patient was a 13-month-old boy. Under a diagnosis of left single ventricle (pulmonary atresia, right ventricular hypoplasia, atrial septal defect) and residual left aortic arch/left superior vena cava, a modified right Blalock- Taussig shunt was performed. Cyanosis deteriorated, so a bidirectional Glenn shunt was scheduled. After anesthesia induction, a 4.5 Fr double-lumen (8 cm) PediaSat was inserted through the right internal jugular vein for continuous ScvO2 monitoring. Furthermore, the probe of a near-infrared, mixed blood oxygen saturation-measuring monitor was attached to the forehead for continuous monitoring of the regional brain tissue mixed blood oxygen saturation (rSO2) (INVOS(TM) 5100C, Covidien ; Boulder, CO, U.S.A.). Blockage of the right pulmonary artery and right superior vena cava decreased the oxygen saturation, ScvO2, and rSO2, but increased the central venous pressure. Although changes in ScvO2 were parallel to those in rSO2, the former showed more marked changes. A combination of ScvO2 and rSO2 for monitoring during Glenn shunt may be safer

Effect of Sulfur Concentration on the Morphology of Carbon Nanofibers Produced from a Botanical Hydrocarbon

Carbon nanofibers (CNF) with diameters of 20–130 nm with different morphologies were obtained from a botanical hydrocarbon: Turpentine oil, using ferrocene as catalyst source and sulfur as a promoter by simple spray pyrolysis method at 1,000 °C. The influence of sulfur concentration on the morphology of the carbon nanofibers was investigated. SEM, TEM, Raman, TGA/DTA, and BET surface area were employed to characterize the as-prepared samples. TEM analysis confirms that as-prepared CNFs have a very sharp tip, bamboo shape, open end, hemispherical cap, pipe like morphology, and metal particle trapped inside the wide hollow core. It is observed that sulfur plays an important role to promote or inhibit the CNF growth. Addition of sulfur to the solution of ferrocene and turpentine oil mixture was found to be very effective in promoting the growth of CNF. Without addition of sulfur, carbonaceous product was very less and mainly soot was formed. At high concentration of sulfur inhibit the growth of CNFs. Hence the yield of CNFs was optimized for a given sulfur concentration

EVI1 triggers metabolic reprogramming associated with leukemogenesis and increases sensitivity to L-asparaginase

Metabolic reprogramming of leukemia cells is important for survival, proliferation, and drug resistance under conditions of metabolic stress in the bone marrow. Deregulation of cellular metabolism, leading to development of leukemia, occurs through abnormally high expression of transcription factors such as MYC and Ecotropic Virus Integration site 1 protein homolog (EVI1). Overexpression of EVI1 in adults and children with mixed lineage leukemia-rearrangement acute myeloid leukemia (MLL-r AML) has a very poor prognosis. To identify a metabolic inhibitor for EVI1-induced metabolic reprogramming in MLL-r AML, we used an XFp extracellular flux analyzer to examine metabolic changes during leukemia development in mouse models of AML expressing MLL-AF9 and Evi1 (Evi1/MF9). Oxidative phosphorylation (OXPHOS) in Evi1/MF9 AML cells accelerated prior to activation of glycolysis, with a higher dependency on glutamine as an energy source. Furthermore, EVI1 played a role in glycolysis as well as driving production of metabolites in the tricarboxylic acid cycle. L-asparaginase (L-asp) exacerbated growth inhibition induced by glutamine starvation and suppressed OXPHOS and proliferation of Evi1/MF9 both in vitro and in vivo; high sensitivity to L-asp was caused by low expression of asparagine synthetase (ASNS) and L-asp-induced suppression of glutamine metabolism. In addition, samples from patients with EVI1+MF9 showed low ASNS expression, suggesting that it is a sensitive marker of L-asp treatment. Clarification of metabolic reprogramming in EVI1+ leukemia cells may aid development of treatments for EVI1+MF9 refractory leukemia