To reveal the role of oxygen vacancies in the solar water oxidation of α-Fe 2 O 3 photoanodes, the kinetic and thermodynamic properties that are closely related to the water oxidation reaction of the α-Fe 2 O 3 photoanode containing oxygen vacancies were investigated. Compared with the pristine α-Fe 2 O 3 photoanode, the presence of surface oxygen vacancies can improve the water oxidation activity and stability of the α-Fe 2 O 3 photoanode simultaneously, but the bulk oxygen vacancies have a negative effect on the water oxidation performance of the α-Fe 2 O 3 photoanode. In thermodynamics, our investigations revealed that the presence of surface oxygen vacancies narrows the space charge region width of the α-Fe 2 O 3 photoanode, which could boost the charge separation and transfer efficiency of the α-Fe 2 O 3 photoanode during water oxidation. Because the surface property and hydrophilicity of α-Fe 2 O 3 are modified owing to the presence of surface oxygen vacancies, the water oxidation kinetics of the α-Fe 2 O 3 photoanode with surface oxygen vacancies is obviously boosted. Our findings in the present work provide comprehensive understanding of the thermodynamic and kinetic differences for α-Fe 2 O 3 photoanodes with and without oxygen vacancies for solar water oxidation.

Summary The produced energy from varied sources in modern power systems is to be optimally planned for planning and operating of power system under the determined limit conditions. Recently, the rising overall people population of the world, the increasing of people requirements, improvements of technology, and ecosystem and global climate changes have caused with the increasing of electric energy demand. One of the most important solution methods to meet this energy demand is considered as utilization of renewable energy sources (RESs) in power systems. The structure of power systems has become with the usage of RESs more complex. The optimal power flow (OPF) from planning and operation problems has converted to difficult problem with RESs integrated into modern power systems. This paper presents the OPF problem of power systems with a high penetration of controllable renewable sources. These kinds of sources are able to inject a determined power since they have a back‐up unit (storage). Uncertain solar irradiance and wind speed are simulated via log‐normal and Rayleigh probability distributions, respectively. The proposed OPF problem with controllable renewable sources is solved by the differential evolutionary particle swarm optimization (DEEPSO) algorithm. Simulations conducted on various test systems illustrate the effectiveness and efficiency of DEEPSO as compared with other algorithms including moth swarm algorithm, backtracking search algorithm, and differential search algorithm. In addition, the Wilcoxon signed‐rank test is applied to show the supremacy, effectiveness, and robustness of DEEPSO algorithm.

The one-pot synthesis of polysubstituted benzene derivatives was achieved via vinylogous Michael addition of vinyl malononitriles and nitroolefins as the key step and a sequential tandem reaction. A series of complex aryl compounds such as biphenyls and terphenyls can be obtained with satisfactory yields.

Despite the substantial development of efficient hole transporting materials (HTMs) for high‐performance perovskite solar cells (PSCs), optimization of the HTMs to sensitive‐dopant‐free HTMs for high efficient PSCs with prominent stability have rarely been reported. Herein, a low‐cost fluorinated spiro[fluorene‐9,9′‐xanthene] based HTM termed 2mF‐X59 is designed and synthesized. In comparison with its reported nonfluorinated counterpart X59, 2mF‐X59 shows lowered highest occupied molecular orbital (HOMO) level, improved hole mobility, and hydrophobicity. Aided by 2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane (F4TCNQ) to further lower the HOMO level of 2mF‐X59 and improve its hole transfer, the optimized 2mF‐X59 based PSCs show a maximum power conversion efficiency (PCE) of 18.13% without the use of any sensitive‐dopants (e.g., lithium salt/4‐tert‐butylpyridine), which is comparable to the Spiro‐OMeTAD based PSCs (18.22%) with sensitive dopants. More importantly, the sensitive‐dopant‐free 2mF‐X59 based PSCs maintain 95% of their initial performance for more than 500 h under air exposure, showing much better long‐term stability than control PSCs based on Spiro‐OMeTAD with sensitive dopanst. This is the first case that a sensitive‐dopant‐free HTM is demonstrated in PSCs with a high PCE (>18%) and good stability by optimizing the literature HTM. This work could pave a new way to develop low‐cost sensitive‐dopant‐free HTMs for highly efficient and stable PSCs for practical applications.

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