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[Display omitted] Air filtration systems have difficulty avoiding problems of leakage and breakage of the filter medium, which aggravates the emission of dust particles. In this study, a numerical calculation model is established to study the dust-laden air filtration performance of a filter medium with pin holes. The calculation model is verified using experiments and by comparing the values of the filtration resistance and efficiency. The results demonstrated that, with the existence of leakage, the filtration efficiency decreased with time, decreased with an increase in the leakage ratio, and increased first and then decreased with an improvement in the filter medium accuracy. An extremely high filter medium accuracy was not conducive to improve the filtration efficiency, but it obviously increased the filtration resistance. The larger the leakage ratio, Lr , the smaller the optimal filter accuracy, e F , opt , and the maximum filtration efficiency, e T , max. The functional relationships between e F , opt , e T , max and Lr , as well as Q T , were obtained. With an increase in the leakage ratio, the filtration resistance and its rising rate decreased. The system quality factor decreased with the increase of the leakage ratio and increased with the increase of the filter quality factor. [ABSTRACT FROM AUTHOR]

Ionic radius of interfacial molecular can affect the interface property and key electron transfer processes occurring at interface in polymer solar cells. To study the effects of different ionic radius of electron transfer layer on device performances, we introduce various stearate salts (Na + , K + and Cs + ) as electron transfer layer to fabricate polymer solar cells. Interestingly, it is found that the key device parameters such as V oc , J sc , fill factor and PCE of polymer solar cells present regular change with the ionic radius increasing. We systematically study the effects of different ionic radius of electron transfer layer on the various parameters of polymer solar cells and believe this regularity paves a way for further understanding and improving the performances of polymer solar cells. [ABSTRACT FROM AUTHOR]

Zinc oxide is an attractive material applied for electron-transporting interlayers of polymer solar cells. Some factors limited the efficiency and performance of the ZnO-based PSCs, such as the poor conductivity and the traps existing on ZnO film. Here, we introduce a novel approach to optimize the property of ZnO electron-transporting interlayers for the further improvement of device performance by doping bis (trifluoromethane)-sulfonimide lithium salt (Li-TFSI) in ZnO film. It is found that this way not only increased electrical conductivity and charge extraction ability of the electron-transporting interlayers but also reduced charge recombination occurred at interface that was very important for fill factor improvement. Therefore, an optimized power conversion efficiency (PCE) of 9.94% was achieved, which was observed with 13.2% enhancement (9.94% vs 8.78%) compared to that of pure ZnO-based ones. This indicates that doping Li-TFSI in ZnO film is a promising strategy to optimize the ZnO film and enhance the performance of regular polymer solar cells. [ABSTRACT FROM AUTHOR]

The properties of electron transport layers play a crucial role in determining the performance of perovskite solar cells. Here we reported that graphdiyne doped in both PCBM and ZnO films of perovskite solar cells with an inverted structure based on MAPbI 3 for the first time. A high efficiency of 20.0% was achieved in MAPbI 3 perovskite solar cells. Moreover, the J - V hysteresis and stability were significantly improved as well. It was found that dual doping graphdiyne not only increased electrical conductivity, electron mobility, and charge extraction ability in the electron transport layers but also improved film morphology of the electron transport layers and reduced charge recombination which contribute to fill factor improvement. Therefore the results indicate that dual doping graphdiyne is a promising strategy to enhance perovskite solar cells performance. [ABSTRACT FROM AUTHOR]

Doping impure atoms into host semiconductor nanocrystals is used to tune the properties and functions of semiconductor nanocrystals (NCs). Here, we demonstrate a solution method for preparing O doped ZnS (ZnS(O)) colloidal NCs. The as-prepared NCs have been proved to be consistent with the crystal structure of ZnS and Zn 3d-O 2p hydrization existed in the as-prepared NCs as certified by O k-edge X-ray absorption spectra (XAS). The average size was measured to be about 8.5 nm by Transmission Electron Microscope (TEM). The role of pyridines was to control the size and tune the surface property. By doping oxygen into ZnS lattice, the energy levels of as-prepared NCs were moved down, giving a better band alignment for photovoltaic application. When it was applied to modify ZnO interlayer and form ZnO/ZnS(O) bilayer in the polymer solar cells (PSCs), the optimal power conversion efficiency (PCE) of the device based on ZnO/ZnS(O) reached 8.85% (8.59 ± 0.49%), which increased by 10% compared to ZnO-only control device with the optimal PCE of 8.00% (7.46 ± 0.54%). The novel approach has been proved to be facile and scalable, paving the way for synthetizing O doped semiconductor nanocrystal. [ABSTRACT FROM AUTHOR]

Hole-transporting materials play an important role in perovskite solar cells. In this study, we introduced a novel hole-transporting material without p-type dopant, a tetrathiafulvalene derivative anchored with eight carboxyl groups (TTA) into inverted structure perovskite solar cells. The devices with TTA as hole-transporting layer showed high power conversion efficiency of 16.7%, which was 44.5% improvement compared with the reference devices without hole-transporting layer. The performance improvement was ascribed to three factors: 1) the better match of energy level between ITO and perovskite layer; 2) enhanced hole extraction at anode interface; 3) improved perovskite morphology. [ABSTRACT FROM AUTHOR]