Aged sol-gel solution-processed texture tin oxide for high-efficient perovskite solar cells.

Mesoporous n-i-p perovskite solar cells (PeSCs) demonstrate attractive potential for obtaining high power conversion efficiencies (PCEs), by employing inorganic electron transport layers (ETLs). However, these ETLs composed of dual layers (a condense layer and a mesoporous layer) suffer the composite process and high sintering temperature. Here, we demonstrate a simple and efficient process to improve the device performance of PeSCs by using a textured SnO2 film. Self-aged sol-gel SnO2 solution after spin coating results in a textured structure without sacrificing the surface coverage. Excellent light trapping ability is achieved by optimizing the aged time of sol-gel SnO2 solution, which mimics the evolution of the conventional mesoporous layer. Such a SnO2 textured structure provides a large contact area for rapid charge extraction, and alleviates interfacial recombination loss. Therefore, this PeSC yields an optimal PCE of 19%, which is prominent in state-of-the-art SnO2-based devices. These results indicate that one-step solution processed SnO2 with a textured structure offers a simple and efficient way to improve the device performance of PeSCs without a complex process.

Simultaneous determination and determination of sildenafil and its active metabolite in human plasma using LC-MS/MS method.

A sensitive and selective high-performance liquid chromatography-tandam mass spectrometry (LC-MS/MS) method was developed and validated for the simultaneous quantification of sildenafil and its metabolite N-desmethyl sildenafil in human plasma. Sildenafil-d8 was used as an internal standard. The analytes were extracted by precipitation extraction and chromatographed on a C18 column using mobile phase A of water (containing 0.1% formic acid) and mobile phase B of acetonitrile (containing 0.1% formic acid) with gradient elution. Quantification was done using multiple reaction monitoring mode to monitor the precursor-to-product ion transitions of m/z 475.4 → m/z 283.3 for sildenafil, m/z 461.4 → m/z 283.2 for N-desmethyl sildenafil and m/z 483.3 → m/z 108.1 for IS in positive ionization mode. The calibration curve was established over the range of 2.00-1,000 ng/ml and the correlation coefficient was >0.99. The intra-day and inter-day relative standard deviations were <6.5% for sildenafil and 6.3% for N-desmethyl sildenafil respectively. Accuracy determinaed at four concentrations was 86.50-105.67% for sildenafil and 96.83-114.40% for N-desmethyl sildenafil. This method was successfully applied to a pharmacokinetic description of sildenafil and the effect of food intake on the pharmacokinetics of sildenafil was also demonstrated in healthy Chinese volunteers.