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The reported external quantum efficiencies (EQEs) of red-emitting PeLEDs based on CsPbBr x I 3−x perovskite are listed in Table S1 (Supporting Information). However, the soft basic nature of I − [1,[16][17][18][19] and the phase separation arising from halide ion migration cause low stability of CsPbBr x I 3−x PeQDs, making CsPbBr x I 3−x more difficult to apply to pure red PeLEDs. [11] Therefore, pure red PeLEDs based on CsPbBr x I 3−x perovskite with a high EQE and excellent stability remain a huge challenge. In previous research, the photoluminescence (PL) quantum yield (PLQY) and stability of PeQDs have been explored, including encapsulation by adding silicon oxide or aluminum oxide, [20,21] passivation of quantum dots (QDs) by PbSe, [22] and the use of additional ligands. [2,9,12,[23][24][25] However, the above-mentioned insulative oxide, PbSe, and ligands inevitably hinder the charge transfer of PeQDs, resulting in poor conductivity.Recently, a new strategy for metal ion doping has been proposed to improve the PLQY and stability of PeQDs, [10,[26][27][28][29][30][31][32][33][34] and solve the problem of lead toxicity. [31,35,36] For example, Yang et al. used K + ions to acquire high-color-stable red PeLEDs by the passivation effect, whereas the EQE of K + -PeLEDs was only 3.55%. [10] PeQDs modified by lanthanide (Ln 3+ ) ions were more stable than the corresponding pristine sample. [29] The PeQDdoped Sn 2+ soft ions contributed to the limited stability in applications, in which Sn 2+ ions were easily oxidized to Sn 4+ in air. [31] In addition to these metal ions, metal In 3+ ions have attracted attention in the field of solar cell applications. Liu et al. reported that an improvement in the power conversion efficiency of 13% for CsPbI 2 Br solar cells was obtained because the In 3+ ions located diagonally adjacent to Pb passivated the defects of the CsPbI 2 Br perovskite film. [36] However, to the best of our knowledge, In 3+ ions are rarely used in PeLEDs. Therefore, the synthesis of In 3+ -doped PeQDs and the passivation mechanisms of In 3+ ions are essential for studying the production of higher PLQY and more stable PeLEDs.In this study, a near-unity quantum yield (QY) and superior stable red-emitting CsPbBr x I 3−x PeQDs were obtained by adopting nontoxic and slightly smaller radii of In 3+ ions. It was found that the surface defect can be passivated by In 3+ doping, Although all-inorganic CsPbBr x I 3−x perovskite quantum dots (PeQDs) are increasingly being used as a competitive material for pure red perovskite light-emitting diodes (PeLEDs), they suffer from low luminescent ability and poor stability. In this study, an In 3+ -doped CsPbBr x I 3−x PeQD solution exhibits a near-unity photoluminescence quantum yield (PLQY) of ≈99.8% and superior stability for more than half a year in atmosphere. As far as known, this is the highest PLQY and stability achieved for mixed halide PeQDs. In 3+ ion doping not only reduces the surface vacancy defects because of the partial substitution of Pb 2+ by the smaller ...

The characteristics of paraffin confined in carbon nanotubes (CNTs) were investigated using experimental and molecular dynamics (MD) methods.

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A set of experimental system was built to study the concentration field change and influencing factors for the leakage and diffusion of indoor dense gas. CO2 was used in the experiment. CO2 gas tends to settle down after leakage. CO2 gas concentration values are disparate at different positions in the same height. It takes longer time to get the same CO2 gas concentration at higher positions than low positions. The concentration distribution is relatively approximate in the horizontal plane near the ground, while an uneven distribution is shown in the vertical plane. The concentration values increase with an increase in the leakage source strength at the positions which are lower than release source. Gas concentration is relatively stable at lower positions, while the fluctuation of gas concentration appears at higher positions. When the leakage source height is higher, the concentration near the ground reduces under the same condition. However, the whole space has a higher CO2 concentration which can generate greater risk. Incidence angle plays a great role in CO2 concentration. A theoretical calculation method was presented to predict CO2 concentration. The validation of the computation method was made by comparison of experimental data with calculation results. © 2018 American Institute of Chemical Engineers Environ Prog, 38: 424–434, 2019