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31.
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用基于第一性原理的密度泛函理论方法,对Cs3Bi2X9(X=Cl、Br、I)的光电特性进行理论计算,并系统阐述这3种晶体的表面效应对光电性能的影响。结果表明,3种材料的光学特性由铋原子和卤素原子最外层p轨道上的价电子主导。在可见光区中,材料的吸收峰会随卤素原子序数的增加呈现红移,其中一维结构的Cs3Bi2Cl9表面结构在光吸收能力上尤为特别且敏感;二维结构的Cs3Bi2Br9光吸收能力会受厚度影响;零维结构的Cs3Bi2I9非常稳定,且几乎不受表面特性和晶体厚度的影响。 相似文献
33.
空穴传输层(HTLs)厚度对反式钙钛矿太阳能电池(PSCs)性能具有重大影响,因其显著影响太阳光透过和HTLs的空穴传输性能。几个纳米至十几个纳米厚度的超薄HTLs在减少伴生吸收、电荷传输损失和材料消耗等方面具有明显优势。目前,有许多成熟的制备超薄无机HTLs的方法,并在反式和叠层PSCs中得到广泛研究与应用。最近,一些关于有机超薄HTLs的新型制备方法也展现出良好的性能并逐渐引起相关领域研究者关注。在此,本文主要总结反式PSCs中超薄HTLs的研究进展与应用,关注其未来发展的挑战和方向,为该领域进一步的研究提供参考。 相似文献
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铋基钙钛矿由于稳定性强及毒性低,被认为是未来极具发展潜力的环保型钙钛矿材料。(CH3NH3)3Bi2I9(MBI)因具有优异的光吸收性能而引起人们的普遍关注。本文介绍了MBI钙钛矿晶体的结构及性能,总结了其薄膜的制备方法,并重点叙述了不同方法制备的MBI钙钛矿薄膜在光伏电池中的应用情况。MBI钙钛矿与铅基钙钛矿的效率相比还有很大差距,如何提高其光电转换效率仍是今后研究的主要方向。 相似文献
36.
Dr. Jorge Pascual Dr. Diego Di Girolamo Marion A. Flatken Mahmoud H. Aldamasy Guixiang Li Dr. Meng Li Prof. Antonio Abate 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(12):e202103919
In 2020 dimethyl sulfoxide (DMSO), the ever-present solvent for tin halide perovskites, was identified as an oxidant for SnII. Nonetheless, alternatives are lacking and few efforts have been devoted to replacing it. To understand this trend it is indispensable to learn the importance of DMSO on the development of tin halide perovskites. Its unique properties have allowed processing compact thin-films to be integrated into tin perovskite solar cells. Creative approaches for controlling the perovskite crystallization or increasing its stability to oxidation have been developed relying on DMSO-based inks. However, increasingly sophisticated strategies appear to lead the field to a plateau of power conversion efficiency in the range of 10–15 %. And, while DMSO-based formulations have performed in encouraging means so far, we should also start considering their potential limitations. In this concept article, we discuss the benefits and limitations of DMSO-based tin perovskite processing. 相似文献
37.
Mn4+-activated double perovskite phosphors with composition diversity have presented excellent luminescent performances. However, the charge imbalance between Mn4+ and matrix cations would increase non-radiative recombination and reduce the structural stability. Here, novel high-efficiency stable Li+/Mn4+ co-incorporated Sr2YSbO6 red phosphors are successfully synthesized via a solid-state reaction method for warm w-LEDs, where the Li+ ions have the effect of charge balance for Sr2YSbO6:Mn4+ and reduce the non-radiative energy transfer among Mn4+ ions. It is demonstrated that the substitution of Li+–Mn4+ pairs for Sb5+ can enhance the bonding with low-shifted diffraction peaks and high emission intensity, and prolong the decay lifetime, compared with those of Mn4+ single-doped ones. Impressively, the thermal stability is enhanced to 89.72% from 84.61% at the original value of 303 K. Finally, a w-LED device based on the optimal phosphor Sr2YSbO6:0.01Mn4+/0.01Li+ red component exhibits a correlated color temperature of 4487 K and color rendering index of 80.2. Therefore, the incorporated Li+ ions serve as both charge compensator and co-activator in Mn4+-activated double perovskite phosphors with the aim of high luminescent performance and thermal stability. 相似文献
38.
H2-SCR is served as the promising technology for the controlling of NOx emission, and the Pd-based derivative catalyst exhibited high NOx reduction performance. Effectively regulating the electronic configuration of the active component is favorable to the rational optimization of noble Pd. In this work, a series of Pr1-xCexMn1-yPdyO3@Ni were successfully synthesized and exhibited superior NO conversion efficiency at low temperatures. 92.7 % conversion efficiency was achieved at 200 °C over Pr0.9Ce0.1Mn0.9Pd0.1O3@Ni in the presence of 4 % O2 with a GHSV of 32000 h−1. Meanwhile, the outstanding performance was obtained in the resistance to SO2 (200 ppm) and H2O (8 %). Deduced from the results of XRD, Raman, XPS, and H2-TPR, the modification of d orbit states in palladium was confirmed originating from the incorporation in the B site of Pr0.9Ce0.1Mn0.9Pd0.1O3. The existence of higher valence (Pd3+ and Pd4+) than the bivalence in Pr0.9Ce0.1Mn0.9Pd0.1O3 catalyst was evidenced by XPS analysis. Our research provides a new sight into the H2-SCR through the higher utilization of Pd. 相似文献
39.
Jinhua Hong Shunsuke Kobayashi Akihide Kuwabara Yumi H. Ikuhara Yasuyuki Fujiwara Yuichi Ikuhara 《Molecules (Basel, Switzerland)》2021,26(12)
Solid electrolytes, such as perovskite Li3xLa2/1−xTiO3, LixLa(1−x)/3NbO3 and garnet Li7La3Zr2O12 ceramic oxides, have attracted extensive attention in lithium-ion battery research due to their good chemical stability and the improvability of their ionic conductivity with great potential in solid electrolyte battery applications. These solid oxides eliminate safety issues and cycling instability, which are common challenges in the current commercial lithium-ion batteries based on organic liquid electrolytes. However, in practical applications, structural disorders such as point defects and grain boundaries play a dominating role in the ionic transport of these solid electrolytes, where defect engineering to tailor or improve the ionic conductive property is still seldom reported. Here, we demonstrate a defect engineering approach to alter the ionic conductive channels in LixLa(1−x)/3NbO3 (x = 0.1~0.13) electrolytes based on the rearrangements of La sites through a quenching process. The changes in the occupancy and interstitial defects of La ions lead to anisotropic modulation of ionic conductivity with the increase in quenching temperatures. Our trial in this work on the defect engineering of quenched electrolytes will offer opportunities to optimize ionic conductivity and benefit the solid electrolyte battery applications. 相似文献
40.
对于磁性氧化物的磁有序,传统的观点用超交换相互作用(SE)和双交换相互作用(DE)模型进行解释,其出发点都建立在全部氧离子是-2价的基础上.例如,对于LaMnO_3,认为其中的La和Mn都处于+3价,用SE模型解释相邻Mn~(3+)离子间的反铁磁序;当以二价的Sr离子替代一部分La离子后,认为等量的Mn~(3+)离子变为Mn~(4+)离子,用DE模型解释相邻Mn~(3+)和Mn~(4+)离子间的铁磁序.然而,事实上在氧化物中存在一部分负一价氧离子.Cohen[Nature 358 136]利用密度泛函理论计算了BaTiO_3的价电子态密度,结果得到只有Ba离子的化合价与传统观点相同,为+2价;而Ti和0分别为+2.89价和-1.63价,不是传统观点的+4价和-2价,但是与多年来关于氧化物电离度的研究[Rev.Mod.Phys.42 317]和X射线光电子谱(XPS)的研究结果相符合.本文经过不同热处理条件制备了名义成分为La_(0.95)Sr_(0.05)MnO_3的三个样品,通过对样品的XPS分析,发现样品中不存在Mn~(4+)离子,只存在Mn2+和Mn~(3+)离子,平均价态随热处理程序的增加而升高.尽管三个样品有相同的晶体结构,但磁矩明显不同.对于这样的性能,不能用SE和DE模型解释其磁结构.利用本课题组最近在研究尖晶石结构铁氧体磁有序过程中提出的O 2p巡游电子模型解释了这种现象,利用样品在10 K的磁矩估算出的Mn离子平均价态变化趋势与XPS分析结果一致.O 2p巡游电子模型的出发点建立在氧化物中存在一部分负一价氧离子的基础上,这是其与SE和DE模型的根本区别. 相似文献