Correlation of charge extraction properties and short circuit current in various organic binary and ternary blend photovoltaic devices

Charge extraction properties of various binary and ternary blends of organic photovoltaic devices covering both polymers and small molecules are studied. Due to their bipolar nature, both slow and fast carrier mobilities are identified from the extraction current transient. The equilibrium carrier concentration is also estimated for each of the blend films. The product of the slow carrier mobility and equilibrium concentration spreading two orders of magnitude can be used to estimate the short circuit current density. A good agreement between the estimated and measured short circuit current density is obtained with the accuracy reliant on the estimation of the slowest carrier mobility. This simplistic approach will be very useful to predict the short circuit current density for devices based on new materials.     

Quantification of triacylglycerols in butterfat by gas chromatography-electron impact mass spectrometry using molar correction factors for [M-RCOO]+ ions

A quantitative electron impact GC-MS method using molar correction factors (MCFs) for [M-RCOO]+ ions has been developed for determination of molecular species of triacylglycerols (TAGs). MCFs were determined by linear calibration for 226 ions of 104 TAG species with good reproducibility: on the average, coefficient of determination was 0.975 +/- 0.043 and 0.963 +/- 0.115 for saturated and unsaturated TAGs, respectively. The MCFs of the sn-1(3) regioisomers of short-chain TAGs were lower than those of sn-2 isomers indicating ca. 2-3-fold higher cleavage of butyroyl and caproyl groups from the primary positions than from the secondary position. The method enabled quantification of 139 and 135 individual TAG species of butterfat (BF) and interesterified butterfat, respectively, including several regioisomers of short-chain TAGs. The most abundant molecular species of the even-numbered TAGs in BF were butyroylpalmitoyloleoylglycerol (5.05 mol%), butyroyldipalmitoylglycerol (4.75 mol%), and palmitoyldioleoylglycerol (3.32 mol%). The method provides an alternative for elucidation of nutritional and technological properties of relatively saturated TAG mixtures.     

Quantized current of a hybrid single-electron transistor with superconducting leads and a normal-metal island

We discuss the operation of the superconductor–insulator–normal-metal–insulator–superconductor (SINIS) turnstile. This voltage-biased hybrid single-electron transistor (SET) provides current quantization even with only one radio-frequency (rf) control parameter, namely the gate voltage of the single island. We give an overview of the main error mechanisms of the turnstile and consider its feasibility as a quantum current standard. We also present experimental results of pumping with the SINIS structure which show decreased leakage current compared to earlier measurements with the opposite NISIN structure.