Quantum dot solar cells (QDSC) are an emerging field in solar cell research that uses quantum dots as the photovoltaic material, as opposed to better-known bulk semi-conductive materials such as silicon. Quantum dots have tunable bandgaps across a wide range of energy levels by changing the quantum dot size. This property makes quantum dots attractive for multi-junction solar cells, where a variety of different energy levels are used to extract more energy from the solar spectrum. A robust S2-/Sn2- electrolyte was specifically designed for compatibility with CdSe quantum dots in solar cells. The new pyrrolidinium ionic liquid reaches 1.86 % efficiency and short-circuit current close to 14 mA cm-2 under air-mass 1.5 global illumination, and improves the device lifetime with good photoanode stability over 240 hours. Photovoltaic characterization shows that the solar cell limitations relate to poor catalysis of regeneration at the counter electrode and high recombination. Further improvement of these factors in the robust electrolyte configuration may thus have a significant impact for advancing the state-of-art of QDSCs. Such an electrolyte may also be used in developing some other, for example chemical sensing, materials.
COBISS.SI-ID: 4863258
The recovery of phenols from olive mill wastewater (OMWW) was studied. Five sample preparation methods were compared: filtration, solid-phase (SPE), liquid-liquid (LLE) and ultrasonic (US)-assisted extraction of liquid and freeze-dried OMWW. US-assisted extraction of freeze-dried OMWW in 100% methanol (1.5 g/25 mL) offered the highest phenol yields without any US-induced alterations. This study also indicates that OMWW may be a valuable source of phenols, especially hydroxytyrosol and tyrosol.
COBISS.SI-ID: 2039803
A new sensitive hydrophilic interaction liquid chromatography/electrospray ionization mass spectrometry (HILIC/ESI-MS/MS) method was developed and validated for determination of 17 selected aliphatic, alicyclic and aromatic carboxylic acids in atmospheric aerosols. The influence of the chromatographic parameters on the acids retention under HILIC conditions was studied. The optimal conditions for both retention and sensitive tandem MS detection of acids were chosen after systematic method optimization. The final method allows determination in the ng/L (ppt) range for most of the acids and is generally more sensitive than previously published methods. The sample preparation (PM10 particles) was optimized both to maximize the analyte recovery and to minimize the operation time. The recoveries obtained were higher than 90% for most analytes. In comparison with the widely used GC-MS methods for acidic compounds in atmospheric aerosols, the new method lessens the analyte loss and tedious work associated with sample derivatization needed in GC-MS protocols. A big advantage of the new method is also its ability to detect and separate the isomeric compounds of the selected carboxylic acids. Our results demonstrate that the method is specific and sensitive for the determination of a wider range of polar carboxylic acids at low concentrations in complex samples of aerosol particles.
COBISS.SI-ID: 4657946