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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(45):14375-14379
Herein we report the colloidal synthesis of Cs3Sb2I9 and Rb3Sb2I9 perovskite nanocrystals, and explore their potential for optoelectronic applications. Different morphologies, such as nanoplatelets and nanorods of Cs3Sb2I9, and spherical Rb3Sb2I9 nanocrystals were prepared. All these samples show band‐edge emissions in the yellow–red region. Exciton many‐body interactions studied by femtosecond transient absorption spectroscopy of Cs3Sb2I9 nanorods reveals characteristic second‐derivative‐type spectral features, suggesting red‐shifted excitons by as much as 79 meV. A high absorption cross‐section of ca. 10−15 cm2 was estimated. The results suggest that colloidal Cs3Sb2I9 and Rb3Sb2I9 nanocrystals are potential candidates for optical and optoelectronic applications in the visible region, though a better control of defect chemistry is required for efficient applications. 相似文献
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Zixin Huang Josie E. Auckett Peter E. R. Blanchard Brendan J. Kennedy Wojciech Miiller Qingdi Zhou Maxim Avdeev Mark R. Johnson Mohamed Zbiri Gaston Garbarino William G. Marshall Qinfen Gu Chris D. Ling 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(13):3482-3485
Pressure‐induced charge transfer from Bi to Ir/Ru is observed in the hexagonal perovskites Ba3+nBiM2+nO9+3n (n=0,1; M=Ir,Ru). These compounds show first‐order, circa 1 % volume contractions at room temperature above 5 GPa, which are due to the large reduction in the effective ionic radius of Bi when the 6s shell is emptied on oxidation, compared to the relatively negligible effect of reduction on the radii of Ir or Ru. They are the first such transitions involving 4d and 5d compounds, and they double the total number of cases known. Ab initio calculations suggest that magnetic interactions through very short (ca. 2.6 Å) M M bonds contribute to the finely balanced nature of their electronic states. 相似文献
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Jiajing Wu Dr. Jianyu Tong Dr. Yuan Gao Dr. Aifei Wang Prof. Tao Zhang Prof. Hairen Tan Prof. Shuming Nie Prof. Zhengtao Deng 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(20):7812-7816
A novel triphenylphosphine (TPP) treatment strategy was developed to prepare the near-infrared emission CsPbI3 nanocrystal (NC)-polymer composite thin-film luminescent solar concentrators (LSCs) featuring high absolute photoluminescence quantum yield (PLQY), low reabsorption, and high stability. The PL emission of the LSCs is centered at about 700 nm with 99.4±0.4 % PLQY and narrow full width at half maximum (FWHM) of 75 meV (30 nm). Compared with LSCs prepared with classic CsPbI3 NCs, the stability of the LSCs after TPP treatments has been greatly improved, even after long-term (30 days) immersion in water and strong mercury-lamp irradiation (50 mW cm−2). Owing to the presence of lone-pair electrons on the phosphorus atom, TPP is also used as a photoinitiator, with higher efficiency than other common photoinitiators. Large-area (ca. 75 cm2) infrared LSCs were achieved with a high optical conversion efficiency of 3.1 % at a geometric factor of 10. 相似文献
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Dr. Yitao Dai Dr. Corentin Poidevin Dr. Cristina Ochoa-Hernández Prof. Dr. Alexander A. Auer Priv.-Doz. Dr. Harun Tüysüz 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(14):5837-5845
Direct selective oxidation of hydrocarbons to oxygenates by O2 is challenging. Catalysts are limited by the low activity and narrow application scope, and the main focus is on active C−H bonds at benzylic positions. In this work, stable, lead-free, Cs3Bi2Br9 halide perovskites are integrated within the pore channels of mesoporous SBA-15 silica and demonstrate their photocatalytic potentials for C−H bond activation. The composite photocatalysts can effectively oxidize hydrocarbons (C5 to C16 including aromatic and aliphatic alkanes) with a conversion rate up to 32900 μmol gcat−1 h−1 and excellent selectivity (>99 %) towards aldehydes and ketones under visible-light irradiation. Isotopic labeling, in situ spectroscopic studies, and DFT calculations reveal that well-dispersed small perovskite nanoparticles (2–5 nm) possess enhanced electron–hole separation and a close contact with hydrocarbons that facilitates C(sp3)−H bond activation by photoinduced charges. 相似文献
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Chuantian Zuo Prof. Liming Ding 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(23):6628-6632
A family of perovskite light absorbers (NH4)3Sb2IxBr9−x (0≤x≤9) was prepared. These materials show good solubility in ethanol, a low-cost, hypotoxic, and environmentally friendly solvent. The light absorption of (NH4)3Sb2IxBr9−x films can be tuned by adjusting I and Br content. The absorption onset for (NH4)3Sb2IxBr9−x films changes from 558 nm to 453 nm as x changes from 9 to 0. (NH4)3Sb2I9 single crystals were prepared, exhibiting a hole mobility of 4.8 cm2 V−1 s−1 and an electron mobility of 12.3 cm2 V−1 s−1. (NH4)3Sb2I9 solar cells gave an open-circuit voltage of 1.03 V and a power conversion efficiency of 0.51 %. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(41):12645-12649
Lead‐based perovskite nanocrystals (NCs) have outstanding optical properties and cheap synthesis conferring them a tremendous potential in the field of optoelectronic devices. However, two critical problems are still unresolved and hindering their commercial applications: one is the fact of being lead‐based and the other is the poor stability. Lead‐free all‐inorganic perovskite Cs3Bi2X9 (X=Cl, Br, I) NCs are synthesized with emission wavelength ranging from 400 to 560 nm synthesized by a facile room temperature reaction. The ligand‐free Cs3Bi2Br9 NCs exhibit blue emission with photoluminescence quantum efficiency (PLQE) about 0.2 %. The PLQE can be increased to 4.5 % when extra surfactant (oleic acid) is added during the synthesis processes. This improvement stems from passivation of the fast trapping process (2–20 ps). Notably, the trap states can also be passivated under humid conditions, and the NCs exhibited high stability towards air exposure exceeding 30 days. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(28):8246-8250
We successfully prepared QDs incorporated into a silica/alumina monolith (QDs‐SAM) by a simple sol–gel reaction of an Al–Si single precursor with CsPbBr3 QDs blended in toluene solution, without adding water and catalyst. The resultant transparent monolith exhibits high photoluminescence quantum yields (PLQY) up to 90 %, and good photostability under strong illumination of blue light for 300 h. We show that the preliminary ligand exchange of didodecyl dimethyl ammonium bromide (DDAB) was very important to protect CsPbBr3 QDs from surface damages during the sol–gel reaction, which not only allowed us to maintain the original optical properties of CsPbBr3 QDs but also prevented the aggregation of QDs and made the monolith transparent. The CsPbBr3 QDs‐SAM in powder form was easily mixed into the resins and applied as color‐converting layer with curing on blue light‐emitting diodes (LED). The material showed a high luminous efficacy of 80 lm W−1 and a narrow emission with a full width at half maximum (FWHM) of 25 nm. 相似文献