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111.
We present here, a systematic investigation on orthorhombic perovskite type rare earth chromates; RCrO3 (R = La, Nd, Eu, Gd, Dy, and Y) powder samples via X-ray diffraction, Raman and UV–Visible spectroscopy. The Rietveld fitted X-ray diffraction patterns confirm the formation of single phase orthorhombic structure with Pnma space group for all the samples. A comprehensive analysis of Rietveld fitted data has been performed to further see the effect of change in the size of rare earth (R3+) ions on bond length and structural distortions. It has been noticed that bond length (RO) decreases with decrease in radius of R-site ions, consequently an increase in the distortion or the octahedral tilting. Raman spectroscopy results reveal the blue shift in these samples with decrease in the size of the rare-earth ion, owing to change in their bond lengths. Optical properties have been also noticed via UV–visible absorption spectroscopy technique. These results indicate that the RCrO3 materials are transparent in visible range with band gap varying from 2.19 to 3.20 eV. 相似文献
112.
J.A. Alonso M.J. Martínez-Lope A. Aguadero L. Daza 《Progress in Solid State Chemistry》2008,36(1-2):134-150
Neutron diffraction is a powerful tool for the characterization of materials and, particularly, oxides. Oxide materials find applications in solid oxide fuel cells (SOFCs) as solid electrolytes as well as anode and cathode materials. As a structural probe, neutrons are specially suitable for the crystallographic study of oxides, given the comparable scattering factors of O and other heavier elements, allowing its precise localization in the crystal structure. Many problems can be addressed by neutrons, related to the octahedral tilting in perovskites, phase transitions, order–disorder phenomena, presence of anionic vacancies, etc. Neutrons make possible an accurate determination of the thermal factors and provide a visualization of the diffusion paths in ionic conductors. Neutrons allow the localization of light atoms such as hydrogen, and make possible the distinction between neighbouring elements, typically Fe and Mn. In this work we will describe some recent applications of this technique in the field of solid electrolytes and electrode materials, including some examples from our group. 相似文献
113.
Dr. Pengwei Li Linfang Yan Qingli Cao Prof. Chao Liang He Zhu Sihui Peng Yongpeng Yang Yuncai Liang Rudai Zhao Prof. Shuangquan Zang Prof. Yiqiang Zhang Prof. Yanlin Song 《Angewandte Chemie (International ed. in English)》2023,62(13):e202217910
Low-dimensional Ruddlesden-Popper (LDRP) perovskites still suffer from inferior carrier transport properties. Here, we demonstrate that efficient exciton dissociation and charge transfer can be achieved in LDRP perovskite by introducing γ-aminobutyric acid (GABA) as a spacer. The hydrogen bonding links adjacent spacing sheets in (GABA)2MA3Pb4I13 (MA=CH3NH3+), leading to the charges localized in the van der Waals gap, thereby constructing “charged-bridge” for charge transfer through the spacing region. Additionally, the polarized GABA weakens dielectric confinement, decreasing the (GABA)2MA3Pb4I13 exciton binding energy as low as ≈73 meV. Benefiting from these merits, the resultant GABA-based solar cell yields a champion power conversion efficiency (PCE) of 18.73 % with enhanced carrier transport properties. Furthermore, the unencapsulated device maintains 92.8 % of its initial PCE under continuous illumination after 1000 h and only lost 3 % of its initial PCE under 65 °C for 500 h. 相似文献
114.
Hong Zhang Chenxu Zhao Jianxi Yao Wallace C. H. Choy 《Angewandte Chemie (International ed. in English)》2023,62(24):e202219307
Advancing inverted (p-i-n) perovskite solar cells (PSCs) is critical for commercial applications given their compatibility with different bottom cells for tandem photovoltaics, low-temperature processability (≤100 °C), and promising operational stability. Although inverted PSCs have achieved an efficiency of over 25 % using doped or expensive organic hole transport materials (HTMs), their synthesis cost and stability still cannot meet the requirements for their commercialization. Recently, dopant-free and low-cost non-stoichiometric nickel oxide nanocrystals (NiOx NCs) have been extensively studied as a low-cost and effective HTM in perovskite optoelectronics. In this minireview, we summarize the synthesis and surface-functionalization methods of NiOx NCs. Then, the applications of NiOx NCs in other perovskite optoelectronics beyond photovoltaics are discussed. Finally, we provide a perspective for the future development of NiOx NCs for the commercialization of perovskite optoelectronics. 相似文献
115.
Dr. Keke Guo Weijun Li Yuhong He Xiaopeng Feng Jinmei Song Wanting Pan Wei Qu Prof. Bai Yang Prof. Haotong Wei 《Angewandte Chemie (International ed. in English)》2023,62(23):e202303445
The low-dimensional halide perovskites have attracted increasing attention due to their improved moisture stability, reduced defects, and suppressed ions migration in many optoelectronic devices such as solar cells, light-emitting diodes, X-ray detectors, and so on. However, they are still limited by their large band gap and short charge carriers’ diffusion length. Here, we demonstrate that the introduction of metal ions into organic interlayers of two-dimensional (2D) perovskite by cross-linking the copper paddle-wheel cluster-based lead bromide ([Cu(O2C−(CH2)3−NH3)2]PbBr4) perovskite single crystals with coordination bonds can not only significantly reduce the perovskite band gap to 0.96 eV to boost the X-ray induced charge carriers, but can also selectively improve the charge carriers’ transport along the out-of-plane direction and blocking the ions motion paths. The [Cu(O2C−(CH2)3−NH3)2]PbBr4 single-crystal device can reach a record charges/ions collection ratio of 1.69×1018±4.7 % μGyair−1 s, and exhibit a large sensitivity of 1.14×105±7% μC Gyair−1 cm−2 with the lowest detectable dose rate of 56 nGyair s−1 under 120 keV X-rays irradiation. In addition, [Cu(O2C−(CH2)3−NH3)2]PbBr4 single-crystal detector exposed to the air without any encapsulation shows excellent X-ray imaging capability with long-term operational stability without any attenuation of 120 days. 相似文献
116.
Dr. Greggory T. Kent Emily Morgan Kaitlin R. Albanese Dr. Anna Kallistova Dr. Alexandra Brumberg Linus Kautzsch Dr. Guang Wu Prof. Pratap Vishnoi Prof. Ram Seshadri Prof. Anthony K. Cheetham 《Angewandte Chemie (International ed. in English)》2023,62(32):e202306000
Halide double perovskites [A2MIMIIIX6] are an important class of materials that have garnered substantial interest as non-toxic alternatives to conventional lead iodide perovskites for optoelectronic applications. While numerous studies have examined chloride and bromide double perovskites, reports of iodide double perovskites are rare, and their definitive structural characterization has not been reported. Predictive models have aided us here in the synthesis and characterization of five iodide double perovskites of general formula Cs2NaLnI6 (Ln=Ce, Nd, Gd, Tb, Dy). The complete crystal structures, structural phase transitions, optical, photoluminescent, and magnetic properties of these compounds are reported. 相似文献
117.
Jiaqian Zhou Peiran Xie Chao Wang Tieyuan Bian Dr. Jian Chen Dr. Yang Liu Zhu Guo Congcong Chen Xin Pan Prof. Dr. Min Luo Prof. Dr. Jun Yin Prof. Dr. Lingling Mao 《Angewandte Chemie (International ed. in English)》2023,62(35):e202307646
Double perovskites (DP) have attracted extensive attention due to their rich structures and wide application prospects in the field of optoelectronics. Here, we report 15 new Bi-based double perovskite derived halides with the general formula of A2BBiX6 (A=organic cationic ligand, B=K or Rb, X=Br or I). These materials are synthesized using organic ligands to coordinate with metal ions with a sp3 oxygen, and diverse structure types have been obtained with distinct dimensionalities and connectivity modes. The optical band gaps of these phases can be tuned by changing the halide, the organic ligand and the alkali metal, varying from 2.0 to 2.9 eV. The bromide phases exhibit increasing photoluminescence (PL) intensity with decreasing temperature, while the PL intensity of iodide phases changes nonmonotonically with temperature. Because the majority of these phases are non-centrosymmetric, second harmonic generation (SHG) responses are also measured for selected non-centrosymmetric materials, showing different particle-size-dependent trends. Our findings give rise to a series of new structural types to the DP family, and provide a powerful synthetic handle for symmetry breaking. 相似文献
118.
Chieh-Ming Hung Chi-Lun Mai Chi-Chi Wu Bo-Han Chen Chih-Hsuan Lu Che-Chun Chu Meng-Chuan Wang Prof. Shang-Da Yang Prof. Hsieh-Chih Chen Prof. Chen-Yu Yeh Prof. Pi-Tai Chou 《Angewandte Chemie (International ed. in English)》2023,62(40):e202309831
Self-assembled monolayers (SAMs) offer the advantage of facile interfacial modification, leading to significant improvements in device performance. In this study, we report the design and synthesis of a new series of carboxylic acid-functionalized porphyrin derivatives, namely AC-1, AC-3, and AC-5, and present, for the first time, a strategy to exploit the large π-moiety of porphyrins as a backbone for interfacing the indium tin oxide (ITO) electrode and perovskite active layer in an inverted perovskite solar cell (PSC) configuration. The electron-rich nature of porphyrins facilitates hole transfer and the formation of SAMs, resulting in a dense surface that minimizes defects. Comprehensive spectroscopic and dynamic studies demonstrate that the double-anchored AC-3 and AC-5 enhance SAMs on ITO, passivate the perovskite layer, and function as conduits to facilitate hole transfer, thus significantly boosting the performance of PSCs. The champion inverted PSC employing AC-5 SAM achieves an impressive solar efficiency of 23.19 % with a high fill factor of 84.05 %. This work presents a novel molecular engineering strategy for functionalizing SAMs to tune the energy levels, molecular dipoles, packing orientations to achieve stable and efficient solar performance. Importantly, our comprehensive investigation has unraveled the associated mechanisms, offering valuable insights for future advancements in PSCs. 相似文献
119.
Jiakang Zhang Xueqing Niu Cheng Peng Haokun Jiang Le Yu Prof. Hong Zhou Prof. Zhongmin Zhou 《Angewandte Chemie (International ed. in English)》2023,62(50):e202314106
The migration of ions is known to be associated with various detrimental phenomena, including current density-voltage hysteresis, phase segregation, etc., which significantly limit the stability and performance of perovskite solar cells, impeding their progress toward commercial applications. To address these challenges, we propose incorporating a polymerizable organic small molecule monomer, N-carbamoyl-2-propan-2-ylpent-4-enamide (Apronal), into the perovskite film to form a crosslinked polymer (P-Apronal) through thermal crosslinking. The carbonyl and amino groups in Apronal effectively interact with shallow defects, such as uncoordinated Pb2+ and iodide vacancies, leading to the formation of high-quality films with enhanced crystallinity and reduced lattice strain. Furthermore, the introduction of P-Apronal improves energy level alignment, and facilitates charge carrier extraction and transport, resulting in a champion efficiency of 25.09 %. Importantly, P-Apronal can effectively suppress the migration of I− ions and improve the long-term stability of the devices. The present strategy sets forth a path to attain long-term stability and enhanced efficiency in perovskite solar cells. 相似文献
120.
NiO/LaMnO3催化剂用于乙醇水蒸气重整反应 总被引:3,自引:0,他引:3
采用柠檬酸络合-浸渍法制备了NiO/LaMnO3钙钛矿型复合氧化物催化剂并将其应用于乙醇水蒸汽重整制氢反应, 考察了NiO含量、焙烧温度对催化剂性能的影响, 采用XRD、TPR和热分析等手段对催化剂进行了表征. 结果表明, 该催化剂具有高活性、高选择性和良好的稳定性. 催化剂中的NiO含量和焙烧温度对催化性能有显著影响. 在原料气体积组成为20%(体积分数, φ) C2H5OH 和水以及80%(φ)N2, 其中水醇摩尔比为3:1, 空速为80000 mL·h-1·g-1 cat, 反应温度为400 ℃时, 15%(质量分数, w)的NiO/LaMnO3上, 乙醇转化率接近100%. 关联催化剂活性和TPR及XRD实验结果, 发现催化剂的高活性源于由催化剂前驱体中进入钙钛矿型复合氧化物晶格中的镍离子被还原所得的金属镍. 相似文献